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Sukhoi Superjet 100

The Sukhoi Superjet 100 (Сухой Суперджет 100) or SSJ100 is a regional jet designed by Russian aircraft company Sukhoi Civil Aircraft, a division of the United Aircraft Corporation (now: Regional Aircraft – Branch of the Irkut Corporation ). With development starting in 2000, it made its maiden flight on 19 May 2008 and its first commercial flight on 21 April 2011 with Armavia.

The 46 – MTOW plane typically seats 87 to 98 passengers and is powered by two 77 – PowerJet SaM146 turbofans developed by a joint venture between French Safran and Russian NPO Saturn. By May 2018, 127 were in service and by September the fleet had logged 300,000 revenue flights and 460,000 hours. By November 2021 the fleet had logged at least 2,000,000 hours. The type has recorded four hull loss accidents and 89 deaths.

In 2022, Sukhoi announced a Russified version of the body and electronics, without most of the Western components; the engines are replaced by the Aviadvigatel PD-8 model. Aeroflot has ordered 89 Irkut SSJ-Russified aircraft. In August 2023, parent company Irkut rebranded itself as Yakovlev, with the Superjet to be known as the SJ-100.

Background
JSC Sukhoi was incorporated in May 2000 to develop the first all-new commercial aircraft in post-Soviet Russia. Studies of the Russian Regional Jet (RRJ) began in 2001. After analysing the Russian market, Sukhoi identified a need for an aircraft with a range of between 3000 and 4500 km, greater than typical regional jets. Three variants were initially envisaged: the RRJ60, RRJ75 and RRJ95, with 60, 78 and 98 seats respectively; a five-abreast layout was chosen as being optimal for this size range. Sukhoi estimated the targeted market to be around 800 aircraft, including 250–300 from Russia and the Commonwealth of Independent States.

On 15 October 2001, the Russian government allocated $46.6 million to the development of a new 70–80 seat regional jet, targeting first flight in 2006 and entry into service in 2007. Sukhoi's RRJ was competing against Myasishchev's M-60-70 and Tupolev's Tu-414 projects. Boeing provided advice to Sukhoi and its partners on programme management, engineering, marketing, product development, certification, supplier management and customer support. The Sukhoi RRJ was selected by Rosaviakosmos, the government's aviation and space agency, in March 2003.

The RRJ programme allocated $63.5 million to the development of a 4-5 tf engine between 2003 and 2015. Four engines were initially envisaged: the Pratt & Whitney PW800, the Rolls-Royce BR710, the General Electric CF34-8, and the Snecma/NPO Saturn SaM146. The BR710 and the CF34-8 were eliminated by July 2002, and the PW800 was subsequently rejected due to a perceived technical risk associated with its geared fan. A formal memorandum of understanding was signed with Snecma on 29 April 2003, confirming the selection of the 14,000-17,000 lbf SaM146, to be developed in a joint venture with NPO Saturn, based on the Snecma SPW14 and combining a Snecma DEM21 gas generator with an Aviadvigatel "cold section".

Key suppliers were selected in October 2003, including Thales for avionics, Messier-Bugatti-Dowty for landing gear, Honeywell for the auxiliary power unit, Liebherr for flight controls, Intertechnique for fuel systems, Parker Hannifin for hydraulic systems, B/E Aerospace for interiors. At this time, Sukhoi anticipated a market for 600 aircraft by 2020 – representing 10% of global demand for regional jets – for a total sales volume of $11 billion. Discussions were held with Air France and the SkyTeam alliance to ensure that the aircraft would meet western requirements. An application for EASA certification was made in 2004 and was expected to be granted six months after the Russian approval.

The Komsomolsk-on-Amur plant was selected in February 2005 for final assembly, implementing jig-less assembly, automatic component alignment and automatic riveting. The RRJ60 and RRJ75 were deemed to be less cost-effective, and development was focused on the largest model, the 98-seat RRJ95. The 78-seater RRJ75 remained under consideration, and a future stretch was also envisaged. The RRJ95 was renamed the Sukhoi Superjet 100 at the Farnborough Air Show in July 2005. The first order, for 30 aircraft, was signed on 7 December with Aeroflot.

In June 2007, Boeing expanded its assistance to cover flight and maintenance crew training and manuals, and spare parts management and supply. On 22 August, Sukhoi and Alenia Aeronautica established the SuperJet International joint venture for customer support outside Russia and Asia. Alenia Aeronautica took a 25% stake in Sukhoi Civil Aircraft Corporation (SCAC) for $250 million, valuing it at $1 billion. Development costs were expected to total $1 billion, with another $1 billion needed to develop the powerplant and for customer support.

Flight testing

The first SSJ was transported in an Antonov 124 from Komsomolsk-on-Amur to Zhukovsky, Moscow Oblast on 28 January 2007, for ground tests conducted by the Central Aerohydrodynamic Institute (TsAGI). The SuperJet was officially unveiled on 26 September 2007 at Dzyomgi Airport in Komsomolsk-on-Amur. By October 2007, initial deliveries were scheduled for 2009; plans called for the 95–98-seat model to be followed by a 75–78-seat shrink and a 110-seat stretch.

The SaM146 engine was first run on 21 February 2008. Tests were conducted by the Gromov Flight Research Institute, using an Ilyushin Il-76LL as a flying test bed. The SuperJet 100 made its maiden flight on 19 May 2008, taking off from Komsomolsk-on-Amur. By July, certification was expected for the third quarter of 2009, pushing back deliveries to later the same quarter. On 24 December 2008, the second SSJ made its maiden flight.

By January 2009, the first two aircraft had completed over 80 flights, and the engines had accumulated 2,300 hours of tests. In April 2009, the two prototypes were flown 3000 km from Novosibirsk to Moscow, and EASA pilots conducted a number of familiarisation flights. A third prototype joined the test campaign in July 2009.

The SSJ made its international debut at the 2009 Paris Air Show; during the show, Malév Hungarian Airlines placed a $1 billion order for 30 aircraft. As of June 2009, 13 aircraft were under construction, with the first four scheduled to be handed over to clients from December. Armenian Armavia was to receive the first two, followed by Aeroflot, having ordered 30 with an option for 15 more. Other customers include Russian Avialeasing, Swiss AMA Asset Management Advisor, and Indonesian Kartika Airlines. Sukhoi expected production to reach a rate of 70 aircraft per year by 2012.

In December 2009, engine availability issues resulted in deliveries being delayed indefinitely. On 4 February 2010, the fourth prototype made its maiden flight using engines removed from the first prototype, as a result of continuing delays in engine production, including NPO Saturn quality problems. On 15 September 2010, static tests for certification of the aircraft were completed by TsAGI.

Certification
By June 2010, certification was 90% complete but was delayed due to SaM146 engine problems that were not encountered during testing. In September 2010, certification was expected for November. In October 2010, noise was tested for certification authorities, Russian IAC and European EASA. On 4 November 2010, the first production aircraft, intended for Armavia, was first flown. By November 2010, the SSJ test fleet had made 948 flights totalling 2,245 hours.

On 3 February 2011, IAC granted a Type Certificate. EASA's Type Certificate followed on 3 February 2012, allowing operations in European countries.

On 14 March 2022, EASA revoked the Superjet's airworthiness certificate as part of the EU's sanctions against Russia following the Russian invasion of Ukraine.

In-service developments
In summer 2017, the business jet variant's additional fuel tanks were certified to carry 3,100 kg (6,800 lb) more fuel, increasing range from 4420 km to 6,000 km.

London City Airport is a major destination for Irish airline CityJet, which was to receive 15 SSJ100s, but its steep 5.5° approach required new control laws, wing flap setting and modified brakes: test flights were to begin in December 2017, with certification planned for 2018, and the modified aircraft to be available in 2019. In any event, CityJet ceased all use of SSJ-100 aircraft by November of 2020.

A new "sabrelet" winglet, helping takeoff and landing performance and delivering 3% better fuel burn, will be standard and available for retrofit. Designed with CFD tools by Sukhoi and TsAGI, the "saberlets" debuted flight tests on 21 December 2017. They should improve hot and high airport performance and cut costs up to $70,000 per year. Parts of the wing are reinforced for the aerodynamic loads distribution change. They should reduce fuel costs by 4%, flight-testing was completed after over 140 flights by October 2019. The first aircraft with the composite winglets was delivered to Russian carrier Severstal Aircompany in December 2019.

By November 2018, the TsAGI carried out wind tunnel tests on two modified wing designs to save structural weight: one with less wing sweep and the other with more relative thickness, also enhancing aerodynamics and load capabilities, and improving fuel efficiency by nearly 10%.

Russified SSJ

To resist the Airbus–Boeing duopoly pressure on regional jets through the Embraer E-Jet E2 (once set to become a Boeing product, after its later failed acquisition of Embraer) and the Airbus A220, Sukhoi would upgrade the SSJ100 to the SSJ100B and the "Russianised" SSJ100R. Western content accounts for 55–60% of the original SSJ100's cost but sanctions against Russia are tightening. As of December 2018, the US authorities did not send any feedback to Sukhoi over exports to Iran. The SSJ100B would feature more powerful SaM146-1S18 engines, improved avionics software, enhanced high-lift devices controls and retrofittable "sabrelet" blended wingtip devices. After 2021 the SSJ100R would replace western components by Russian ones for government customers and countries subject to international sanctions such as Iran Air Tours and Iran Aseman.

SSJ100R could include a smaller variant of the Aviadvigatel PD-14 engine (Aviadvigatel PD-8 ); KRET electronic units to replace the Thales avionics; a Russian inertial navigation system and APU to replace Honeywell's; and the landing gear to replace one produced by Safran. Fuel burn would be reduced by 5–8% with a new composite wing. Russian content should double to 30% as US restrictions limit its export potential. Sukhoi forecasts 345 sales from 2018 to 2030, mostly in post-Soviet states and some in south-east Asia and Latin America, including an improved range business jet version. The seating capacity is to be raised to 110, and hot and high operations to 4000 m and 50 °C. A freighter variant is also being studied. Russian government has earmarked ₽3.2 billion ($51 million) toward the variant of the SSJ with indigenous propulsion and avionics, introduced at the Eurasia Airshow 2018 in Antalya alongside the SSJ75.

In May 2021, Rostec announced the completion of the first experimental core 'hot section' of the PD-8 engine. The 'Russified' variant of the SSJ with the composite wing, indigenous avionics and the PD-8 engine later became known as the SSJ-New. In July 2021, UEC exhibited the new engine at the 2021 Moscow Air Show and aimed to secure type certification by 2023. In January 2022, a new control system, developed by UEC for the PD-8 engine, was being tested prior to integration with the engine. The full domestic fabrications plan will take place in 2023 to 2024, replacing Western components.

Under a plan announced in June 2022 to bring the proportion of domestically produced aircraft to 80% of the Russian fleet by the end of the decade following the international sanctions brought in after the 2022 Russian invasion of Ukraine, serial production of the SSJ-New was targeted for 2023. In July 2022, a prototype SSJ-New fuselage was transported to test facilities near Moscow to undergo life cycle testing. Further prototypes were assembled in 2023, with structural testing of the updated airframe and certification of the PD-8 engine both expected to be completed by the autumn. As of May 2023, serial production was expected to begin in 2024.

Yakovlev carried out the first flight of its new version of the Superjet 100 featuring all-Russian components – now known as the SJ-100 – in August 2023, albeit with SaM146 engines rather than the intended PD-8s. As of mid-2024, the engine manufacturer was implementing a strategy of using a computer model of the PD-8 for testing in order to reduce the number of required real engine tests, so as to accelerate PD-8 certification.

Irkut Corporation integration
At the end of November 2018, United Aircraft Corporation transferred SCAC from Sukhoi to the Irkut Corporation, to become UAC's airliner division, as Leonardo S.p.A. pulled out in early 2017 because of Superjet's poor financial performance. Irkut managed the Superjet 100, the MC-21 and the Russo-Chinese CR929 widebody, but the Il-114 passenger turboprop and modernized Ilyushin Il-96-400 widebody stayed with Ilyushin. The new commercial division also included the Yakovlev Design Bureau, avionics specialist UAC–Integration Center and composite manufacturer AeroComposit. The aircraft was to be known simply as the Superjet 100, dropping the Sukhoi name.

In July 2023, Irkut announced that the entire company would be rebranded under the Yakovlev name, to be effective by the end of August, though it did not specify whether the Superjet would undergo a further change of designation. The name change was confirmed in August; the Superjet is to drop the Sukhoi name and be known as the SJ-100.

Potential Sukhoi divestment of SuperJet
In March 2023, a deal was announced that would see UAC completely exit the Superjet 100 programme by selling its entire stake in SuperJet International (SJI) to an Emirati investment fund, Markab Capital Investments. A new factory would be built at Al Ain International Airport, Abu Dhabi, where aircraft would be assembled before completion at SJI's Venice site. The deal would be conditional on SJI's assets being unfrozen by the European Union. With a new supply chain to be established in Italy by Leonardo to service the Abu Dhabi production line, and the sale of intellectual property, it is unclear how Russian production of the SSJ-New, now solely limited to servicing Russia's domestic market, could continue under the deal.

Design
The five-abreast cross-section is more optimised beyond 70 seats than the four-abreast Bombardier CRJs and Embraer E-Jets but smaller than the six-abreast Airbus A320 and Boeing 737. The SSJ100 typically seats 87 to 98 passengers. In Russia, it replaces the aging Tupolev Tu-134 and Yakovlev Yak-42 aircraft. It competes with the Antonov An-148, Embraer E190 and the Bombardier CRJ1000. Sukhoi claims cash operational costs are lower than competitors by 8-10%, with reduced fuel burn per seat and longer maintenance intervals.

The design meets CIS AP-25, US FAR-25 and EU JAR-25 aviation rules, and conforms to ICAO Chapter 4 and FAR 36 Section 4 noise standards from 2006. The PowerJet SaM146 turbofans provide 13,500 to(-) of thrust for 70–120 seat aircraft.

The Russian Ministry of Industry and Trade supports it as a priority project. In 2010, development costs were $1.4 billion excluding the SaM146 engine, with 25% funded from the federal budget, rising to US$ 1.5 billion by 2013. Unit cost was US$31–35 million in 2012, rising to a US$50.1 million base price in 2018.

Over 30 foreign partnerships are involved. The SaM146 engines are developed, manufactured and marketed by PowerJet, a joint-venture between the French Snecma and Russia's NPO Saturn. A joint venture between Alenia (later part of Leonardo S.p.A.) and Sukhoi, SuperJet International, was responsible for marketing in Europe, the Americas, Africa, Japan and Oceania, though Leonardo pulled out in early 2017 because of Superjet's poor financial performance and Sukhoi regained a 100% share in SCAC. Assembly is performed at the Komsomolsk-on-Amur Aircraft Plant in the Russian Far East, while the Novosibirsk Aircraft Production Association produces components; both are upgrading their facilities and were expecting to produce 70 airframes by 2012.

Introduction

On 19 April 2011, the first production aircraft was handed over to Armavia at Zvartnots Airport in Yerevan, to be operated to Moscow and Sochi, as well as Ukrainian cities. The aircraft was named after Yuri Gagarin. On 21 April, the first commercial flight landed at Moscow Sheremetyevo, lasting 2 h 55 min; Armavia used the Airbus A319 on this route before switching to the Superjet 100. On 1 May, it made its first commercial flight to Venice Airport in around 4 hours, it had accumulated 50 hours in 24 flights by then.

By March 2012, the six aircraft operated by Aeroflot were flying 3.9 hours/day instead of the standard 8–9 hours due to failures and parts delivery delays, and the airline asked for compensation. In August 2012, Armavia announced that it had returned both of its SSJ100s to the manufacturer. Armavia then avoided further deliveries.

In February 2013, Sukhoi stated teething problems are usual in new airliners.

The SSJ entered service with Mexican Interjet on 18 September 2013; in their first four weeks, the first two aircraft operated were flown 580 times over 600 hours with a daily utilisation of 9.74 hours and a dispatch reliability of 99.03%.

By June 2014, Interjet had received seven SSJ100s and the dispatch reliability had increased to 99.7%. On 12 September 2014, Interjet started regular passenger flights to the US, on the Monterrey, Mexico, – San Antonio, Texas, route. However, Interjet confirmed by January of 2020 that it was planning to phase out its SSJ100 fleet; but was unable, while sold all other but one plane of all other models. By November of that year it kept 3 or 4 of its 22 SSJ100 potentially able to fly, using other planes for parts; and in December the company was closed because was unable to continue operation.

On 3 June 2016, the Irish carrier CityJet was the first western European airline to take delivery of an SSJ100. But CityJet had ceased all use of SSJ-100 aircraft by November of 2020.

Dependability
On 24 December 2016, the Russian Federal Air Transport Agency grounded seven jets after a tail component of an IrAero SSJ100 showed metal fatigue, leading Sukhoi to inspect the entire fleet. By 27 December, all aircraft had been inspected and it had been shown that the defect was not systemic as it featured multiple redundancies and a safety margin doubling the normal loads. Interjet grounded half of its fleet of SSJ100s during this period, but all of its aircraft were returned to service by the first week of January 2017 after Sukhoi sent 22 technicians to repair the grounded aircraft.

In June 2017, dispatch reliability increased to 97.85% from 96.94% a year earlier, while there were 89.6 malfunctions per 1,000 flight-hours, down by 40%. On 21 July 2017, following the discovery of horizontal stabiliser rear spar cracks, the EASA mandated compulsory inspections. Sukhoi recognises it needs to improve customer support with more responsiveness and availability for flight training, engineering and spare parts supply. In early November 2017, the Russian Federal Air Transport Agency and Italian Civil Aviation Authority (ENAC) amended their bilateral airworthiness agreement, hitting SSJ export sales. Interjet claimed its capital cost for 10 Superjets was equivalent to the pre-delivery payment for one Airbus A320. The pre-delivery payment amounts to 15-30% of an aircraft list price. An A320 list price was $88.3M in 2012.

In January 2018, Bloomberg reported that four of Interjet's 22 SSJ100s were being cannibalised for parts to keep others running after having been grounded for at least five months because of SaM146 maintenance delays. This was later refuted by Interjet. One grounded SSJ100 was due to be back in service on 19 January 2018 and the remaining three in March. In August 2018, Russian regional carrier Yakutia Airlines considered withdrawing their SSJs, after two were grounded because their engines were removed after 1,500-3,000 cycles, below the 7,000 specified, and no replacements were available. PowerJet was expanding its repair capacity and lease pool as engine maturity improved, noting that the SaM146 engine achieved 99.9% dependability since its 2011 introduction.

Productivity
In September 2018, Interjet was reported to be considering replacing its SSJ100s with Airbus A320neos, to make better use of its slots, with the SSJ technical problems possibly also a factor. On 12 September, Interjet denied the report. It was later reported that Interjet intends to phase out some of its Superjets and take 20 more A320neos, maybe alongside newer Superjet deliveries; it will have access to an enhanced SSJ spares inventory in Mexico City and is installing a flight simulator in Toluca. The updated SSJs would have winglets, a higher MTOW and improved systems and interior. Sukhoi has also proposed to increase the cabin density from 93 to 108 seats by reducing the pitch from 34 to 30 in. While the airline was attracted by its low introductory price, Sukhoi was forced to reimburse Interjet in 2018 after its fleet of 30 suffered persistent faults.

In October 2018, Sukhoi and engine contractor UEC agreed on a plan, backed by the Russian government, to focus on customer support rather than deliveries in order to improve dispatch reliability. At the end of November 2018, United Aircraft Corporation transferred SCAC from Sukhoi Holding to the Irkut Corporation, to become UAC's airliner division. By then, Brussels Airlines was seeking alternatives for its four SSJ100s wet-leased from CityJet, as teething problems affected their reliability.

By February 2019, CityJet's remaining five SSJ100s stood idle and were expected to be transferred to Slovenia's Adria Airways, which committed for 15 in late 2018, though Adria subsequently cancelled its order in April 2019. Neither CityJet nor Brussels Airlines have commented as to why they dropped the SSJ, though low reliability, difficult maintenance and spare parts availability are suspected to have contributed.

By the end of the first quarter of 2019, 15 of Interjet's 22 SSJs were out of service. Further talks with Sukhoi were deadlocked, with Interjet reportedly unwilling to pay for repairs to the PowerJet SaM146 engines. Interjet's reliability issues are compounded by the lack of service facilities in the Americas for the SSJ, a factor which also contributed to the poor reliability recorded by CityJet.

On 15 May 2019, Interjet announced that it is to sell its 20 SSJs, of which only five are operational, as it is no longer profitable to operate aircraft of this size in Mexico. Therefore,, Sukhoi has had trouble selling the Superjet and renewing leasing contracts outside of Russia because of reliability and service network issues, resulting in an average of 109 flight hours per month for Russian airlines, approximately half the Embraer EMB 170 productivity, and just a third of a Boeing or Airbus jet. Unease with the SSJ's low reliability also spread to Russian operators.

Slow sales
Sukhoi delivered only three SSJs in the first half of 2019; its financial results show a sevenfold drop in aircraft sales revenue and a fourfold drop in overall sales revenue, resulting in a 32% increase in its net loss. The company needs to achieve a production rate of 32 to 34 aircraft per year to make a profit, though demand for Russian models in the 60–120 seat category is forecast to be only 10 aircraft per year over a 20-year period. In the short-term, the company's main hope is that Aeroflot will firm up its 2018 preliminary agreement for 100 SSJs.

Yamal Airlines, the second-largest Russian SSJ operator, announced the cancellation of its order for 10 further SSJs, citing high servicing costs. Of 30–40 SSJs owned by Aeroflot, only 10 are reportedly usable at a time due to maintenance problems. Aeroflot cancelled approximately 50 Superjet flights in the week following the Flight 1492 accident. Kommersant cited industry sources as saying the Superjet 100 had lower dispatch reliability than Airbus and Boeing aircraft in the airline's fleet historically and attributed a rise in cancellations to "increased safety measures" at Aeroflot while the accident is investigated. On 4 June, the Russian Federal Air Transport Agency (Rosaviatsiya) ordered carriers to perform one-time inspections of the SSJ, including a general check of the aircraft's condition and verification of aircraft and engine logs, by 25 June.

A total of 12 jets were delivered in 2020 to the following operators: Rossiya Airlines, Azimuth Airlines, Red Wings Airlines. The sole remaining western operator, Interjet, down by the end of November 2020 to just four operational SSJ100s, quit flying in December 2020 and entered bankruptcy in April 2021. Part of Interjet’s plan was to try to return its 22 SSJ-100s to Sukhoi to cancel its debt, and resume flying with 10 Airbus A320 aircraft. In December 2020, Rossiya Airlines announced that it intends to operate 66 Superjets by the end of 2021, transferred from its parent company Aeroflot which currently has 54 SJs. In September 2023, North Korea’s supreme leader Kim Jong Un visited a fighter aircraft production in Russia’s Far East, he also inspected civil aviation project, included the domestic made Superjet 100.

Impact of sanctions against Russia
Russian operators of the Superjet 100 encountered difficulties in keeping their fleets airborne as result of sanctions imposed following the Russian invasion of Ukraine. In 2023, it emerged that there was a shortage of parts for the SaM146 engines, namely igniter plugs produced in the United States and French fuel filters for which no domestic replacement could be found. Rossiya Airlines expressed fears that only 40% of its Superjet 100 fleet would be active in the spring and summer of 2023 due to lack of parts. In September 2022, UEC Saturn, producer of the SaM146, resorted to cleaning old filters as a method to extend the lifetime of the engines, though this procedure was banned by the Russian regulator due to lack of formal certification.

Variants
Three variants were initially planned, seating 60, 78 and 98 passengers: the RRJ-60, RRJ-75 and RRJ-95, respectively. By 2007, the RRJ-60 had been dropped, to focus on the 98-seater, with the 78-seater to follow. The basic version was certified by the EASA on 3 February 2012, the RRJ-95LR100 with an MTOW increased from 45.88 to 49.45 t and the RRJ-95B100 with thrust increased from the SaM146-1S17 of 76.84 to 79 kN -1S18s were added on 7 March 2017. The RRJ-95LR100 range is increased to 4578 km. The RRJ-95B100 takeoff distance is reduced by 10%.

130–140 seat stretch
In 2011, the Russian Ministry of Industry and Trade mentioned the stretched Superjet 130NG, seating 130. It would have an aluminium fuselage and composite wings. The new materials were intended to reduce weight by 15-20%, increase service life by 20–30% and reduce operating costs by 10–12%.

In 2013, funding was planned to start in 2016 for production from 2019 to 2020. It would have used a derivative of the Irkut MC-21 composite wing and Pratt & Whitney PW1000G engines. The 130-seat stretch would have been known as the Sukhoi Superjet 130NG. It would have competed with the Airbus A220 and Embraer E-Jet E2 family.

115–120 seat stretch
In 2016, a shorter stretch seating up to 120, using larger wings but the same engines and tail, was planned for introduction in 2020. In 2017, with a business plan for 150 aircraft, a go-ahead for the NG 130-seat stretch depended on the availability of engines with sufficient thrust and was due by the end of the year. The aircraft could carry up to 120 passengers with the existing engines, and up to 125 passengers with airframe continuous improvements; PowerJet could certify a thrust increase of 2% within three years. Sukhoi was to decide by the first quarter of 2018 whether to launch first a shortened 75-seat or a stretched variant needing higher thrust SaM146s or an alternative engine.

75 seat shrink
At the February 2018 Singapore Air Show, Sukhoi announced a possible 75-seat shrink, to enter service in 2022. With a smaller, optimised aluminium or composite wing, it would be powered by 17,000 lbf Pratt & Whitney PW1200Gs, detuned SaM146s or Aviadvigatel PD-14 derived PD-7s. The 3-3.5 m shorter fuselage would be 3 t lighter and it would fall within US scope clauses, but would require Western service and support experience.

Demand for such jets is 200–300 in Russia and up to 3,000 overseas; introduction could slip to early 2023. As Sukhoi and Irkut may be consolidated into United Aircraft, some structures and avionics could be closer to the Irkut MC-21 for commonality. A unified platform with identical controls would ease pilot conversions; S7 Airlines committed to 75 aircraft. In July 2018, a composite wing was preferred and a 3-metre test section will be manufactured and tested. The variant would retain the SaM146 and empty weight should be reduced by 12–15%.

In 2018, serial production was planned for 2025, four years after design approval. By 2019, the priority had shifted to the replacement of Western parts on the SSJ100 so that the aircraft can be sold to US-sanctioned countries such as Iran. S7 Airlines, which had committed to 75 of the shortened aircraft, may seek alternatives from Bombardier or Embraer. In September 2019, the owner of S7, Vladislav Filev, confirmed his understanding that the SSJ75 project had been abandoned. He explained that S7 had insisted on the participation of its own experts in the test programme, and had demanded the replacement of the composite floor that showed insufficient fire resistance in the Sheremetyevo crash, together with a redesign of the wheel wells.

Orders and deliveries
By August 2016, 133 SSJ100s were in operation with eight airlines and five governmental and business aviation organizations. In October 2017, there were 105 SSJ100s in service worldwide: some used by government bodies such as the Royal Thai Air Force and Kazakh government agencies. The fleet had logged 230,000 flights in 340,000 hours since its commercial operations debuted in 2011. At least 30 SSJ100s were to be delivered in 2017, with 38 planned for 2018 and 37 for 2019. In May 2018, ten years after its first flight, the fleet of 127 have logged over 275,000 commercial flights and 420,000 hours. In September 2018, it had logged over 300,000 revenue flights lasting 460,000 hours. As of April 2023, there were approx. 160 Superjet aircraft in service.

Accidents and incidents
As of July 2024, there have been four hull loss accidents, three of which resulted in a total of 89 fatalities.
 * On 9 May 2012, a demonstration flight directly struck Mount Salak in Indonesia, killing all 45 on board (Sukhoi personnel and representatives of various local airlines). The TAWS was ignored by the pilot, distracted by a conversation with a potential customer.
 * On 21 July 2013, during autoland evaluation of an RRJ-95B (Russian experimental registry) with a single engine in a crosswind at Keflavík Airport in Iceland, the fuselage hit and slid down the runway with the gear up. During an intended go-around, the fatigued pilot throttled down the wrong engine, causing the aircraft to lose thrust sufficient for controlled flight. The plane continued to lose altitude and hit the runway even as the pilot realized his mistake and throttled up the engine. One of the five crew was injured during evacuation. The Icelandic Aircraft Accident Investigation Board investigated the event and issued nine recommendations.  The aircraft was subsequently repaired and returned to service as part of the test fleet.
 * On 10 October 2018, a Yakutia Airlines SSJ100 slid off the runway at Yakutsk Airport as the main landing gear collapsed. All 87 passengers and five crew were safely evacuated and none were seriously injured. The excursion may have been caused by ice on the runway or the airstrip's poor state of repair. The airliner was damaged beyond repair and was expected to be written off.
 * On 5 May 2019, as Aeroflot Flight 1492 was climbing after takeoff from Moscow Sheremetyevo, at 6900 ft lightning discharged close to the aircraft from a nearby cumulonimbus cloud with a 6000 feet base. The radio and other equipment failed, and the flight crew chose to make an emergency landing at Sheremetyevo. The aircraft bounced several times after an initial touchdown, and after the fourth hard touchdown a fire erupted and engulfed the rear of the aircraft. An emergency evacuation was then carried out but 41 out of 78 occupants died.
 * On 12 July 2024, a Gazpromavia SSJ100 crashed near Kolomna during a test flight after repairs, killing the crew of three.

title: Sukhoi Superjet 100


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Social skills

A social skill is any competence facilitating interaction and communication with others where social rules and relations are created, communicated, and changed in verbal and nonverbal ways. The process of learning these skills is called socialization. Lack of such skills can cause social awkwardness.

Interpersonal skills are actions used to effectively interact with others. Interpersonal skills relate to categories of dominance vs. submission, love vs. hate, affiliation vs. aggression, and control vs. autonomy (Leary, 1957). Positive interpersonal skills include persuasion, active listening, delegation, and stewardship, among others. Social psychology, an academic discipline focused on research relating to social functioning, studies how interpersonal skills are learned through societal-based changes in attitude, thinking, and behavior.

Enumeration and categorization
Social skills are the tools that enable people to communicate, learn, ask for help, get needs met in appropriate ways, get along with others, make friends, develop healthy relationships, protect themselves, and in general, be able to interact with the society harmoniously. Social skills build essential character traits like trustworthiness, respectfulness, responsibility, fairness, caring, and citizenship. These traits help build an internal moral compass, allowing individuals to make good choices in thinking and behavior, resulting in social competence.

The important social skills identified by the Employment and Training Administration are:
 * Coordination – Adjusting actions in relation to others' actions.
 * Mentoring – Teaching and helping others learn how to do something (e.g. being a study partner).
 * Negotiation – Discussion aimed at reaching an agreement.
 * Persuasion – The action or fact of persuading someone or of being persuaded to do or believe something.
 * Service orientation – Actively looking for ways to evolve compassionately and grow psycho-socially with people.
 * Social perceptiveness – Being aware of others' reactions and able to respond in an understanding manner.

Social skills are goal oriented with both main goals and sub-goals. For example, a workplace interaction initiated by a new employee with a senior employee will first contain a main goal. This will be to gather information, and then the sub-goal will be to establish a rapport in order to obtain the main goal. Takeo Doi in his study of consciousness distinguished this as tatemae, meaning conventions and verbal expressions and honne, meaning true motive behind the conventions.

Causes of deficits
Deficits in social skills were categorized by Gresham in 1998, as failure to recognize and reflect social skills, a failure to model appropriate models, and failure to perform acceptable behavior in particular situations in relation to developmental and transitional stages. Social skill deficits are also a discouragement for children with behavioral challenges when it comes to adult adjustment.

Alcohol misuse
Social skills are often significantly impaired in people suffering from alcoholism. This is due to the neurotoxic long-term effects of alcohol misuse on the brain, especially the prefrontal cortex area of the brain. The social skills that are typically impaired by alcohol abuse, include impairments in perceiving facial emotions, prosody perception problems, and theory of mind deficits. The ability to understand humor is also often impaired in alcohol abusers. Impairments in social skills can also occur in individuals who have fetal alcohol spectrum disorders. These deficits persist throughout the affected people's lives, and may worsen over time due to the effects of aging on the brain.

ADHD and hyperkinetic disorder
People with ADHD and hyperkinetic disorder often have difficulties with social skills, such as social interaction. Approximately half of children and adolescents with ADHD will experience peer rejection, compared to 10–15 percent of non-ADHD youth. Adolescents with ADHD are less likely to develop close friendships and romantic relationships; they are usually regarded by their peers as immature or as social outcasts, with an exception for peers that have ADHD or related conditions themselves, or a high level of tolerance for such symptoms. As they begin to mature, however, it becomes easier to make such relationships. Training in social skills, behavioral modification, and medication have some beneficial effects. It is important for youth with ADHD to form friendships with people who are not involved in deviant or delinquent activities, people who do not have significant mental illnesses or developmental disabilities, in order to reduce emergence of later psychopathology. Poor peer relationships can contribute to major depression, criminality, school failure, and substance use disorders.

Autistic spectrum disorders
Individuals with autistic spectrum disorders including autism and Asperger syndrome are often characterized by their deficiency in social functioning. The concept of social skills has been questioned in terms of the autistic spectrum. In response to the needs of autistic children, Romanczyk has suggested adapting a comprehensive model of social acquisitions with behavioral modification rather than specific responses tailored for social contexts.

Anxiety and depression
Individuals with few opportunities to socialize with others often struggle with social skills. This can often create a downward spiral effect for people with mental illnesses like anxiety or depression. Due to anxiety experienced from concerns with interpersonal evaluation and fear of negative reaction by others, surfeit expectations of failure or social rejection in socialization leads to avoiding or shutting down from social interactions. Individuals who experience significant levels of social anxiety often struggle when communicating with others, and may have impaired abilities to demonstrate social cues and behaviors appropriately.

The use of social media can also cause anxiety and depression. The Internet is causing many problems, according to a study with a sample size of 3,560 students. Problematic internet use may be present in about 4% of high school students in the United States, it may be associated with depression. About one fourth of respondents (28.51%) reported spending fifteen or more hours per week on the internet. Although other studies show positive effects from internet use.

Depression can also cause people to avoid opportunities to socialize, which impairs their social skills, and makes socialization unattractive.

Anti-social behaviors
The authors of the book Snakes in Suits: When Psychopaths Go to Work explore psychopathy in workplace. The FBI consultants describe a five phase model of how a typical psychopath climbs to and maintains power. Many traits exhibited by these individuals include: superficial charm, insincerity, egocentricity, manipulativeness, grandiosity, lack of empathy, low agreeableness, exploitativeness, independence, rigidity, stubbornness and dictatorial tendencies. Babiak and Hare say for corporate psychopaths, success is defined as the best revenge and their problem behaviors are repeated "ad infinitum" due to little insight and their proto-emotions such as "anger, frustration, and rage" are refracted as irresistible charm. The authors note that lack of emotional literacy and moral conscience is often confused with toughness, the ability to make hard decisions, and effective crisis management. Babiak and Hare also emphasizes a reality they identified with psychopaths from studies that psychopaths are not able to be influenced by any sort of therapy.

At the University at Buffalo in New York, Emily Grijalva has investigated narcissism in business; she found there are two forms of narcissism: "vulnerable" and "grandiose". It is her finding that "moderate" level of grandiose narcissism is linked to becoming an effective manager. Grandiose narcissists are characterized as confident; they possess unshakable belief that they are superior, even when it is unwarranted. They can be charming, pompous show-offs, and can also be selfish, exploitative and entitled. Jens Lange and Jan Crusius at the University of Cologne, Germany associates "malicious-benign" envy within narcissistic social climbers in workplace. It is their finding that grandiose narcissists are less prone to low self-esteem and neuroticism and are less susceptible to the anxiety and depression that can affect vulnerable narcissists when coupled with envy. They characterize vulnerable narcissists as those who "believe they are special, and want to be seen that way–but are just not that competent, or charming." As a result, their self-esteem fluctuates a lot. They tend to be self-conscious and passive, but also prone to outbursts of potentially violent aggression if their inflated self-image is threatened." Richard Boyatzis says this is an unproductive form of expression of emotions that the person cannot share constructively, which reflects lack of appropriate skills. Eddie Brummelman, a social and behavioral scientist at the University of Amsterdam in the Netherlands and Brad Bushman at Ohio State University in Columbus says studies show that in western culture narcissism is on the rise from shifting focus on the self rather than on relationships and concludes all narcissism to be socially undesirable ("unhealthy feelings of superiority"). David Kealy at the University of British Columbia in Canada states that narcissism might aid temporarily but in the long run it is better to be true to oneself, have personal integrity, and be kind to others.

Behavioral therapy
Behaviorism interprets social skills as learned behaviors that function to facilitate social reinforcement. According to Schneider & Byrne (1985), operant conditioning procedures for training social skills had the largest effect size, followed by modeling, coaching, and social cognitive techniques. Behavior analysts prefer to use the term behavioral skills to social skills. Behavioral skills training to build social and other skills is used with a variety of populations including in packages to treat addictions as in the community reinforcement approach and family training (CRAFT).

Behavioral skills training is also used for people with borderline personality disorder, depression, and developmental disabilities. Typically, behaviorists try to develop what are considered cusp skills, which are critical skills to open access to a variety of environments. The rationale for this type of approach to treatment is that people meet a variety of social problems and can reduce the stress and punishment from the encounter in a safe environment. It also addresses how they can increase reinforcement by having the correct skills.

title: Social skills


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Cup holder

A cup holder is a device, such as a zarf, to hold a cup or other drinking vessel. It may be free standing to hold cups securely on a desk or other flat surface, or in a tree style to store sets of cups in kitchens. They may be built into automobiles or chairs, or fixed to the walls of airplanes, boats, buses and trains.

Automobile cup holder

The development of the drive-in restaurant was a step in the cup holder's development. Servers would attach a tray that hooked over the car's side window, which needed to be left up a little for it to attach to. This gave a temporary table to hold drinks and food while eating in the car. The drive-in restaurant and cinema encouraged the development of built-in tray tables; often, the inside of the glove compartment lid, when folded down, had indentations to hold cups, cans as well as pistachio shells and were found in cars as early as the 1957 Chevrolet Bel Air. These were sufficient to hold beverages when the car was stopped, but not while in motion.

The later development of the drive-through restaurant encouraged the development of better holders for drinks, and a more fast-paced life and longer commute times made many drivers desire to drink their morning coffee in the car on the way to work. The 1960s saw coffee cups with wide, flat, rubberised bases being sold, which would keep them steady on the dash or console. A little later, aftermarket cup holders began to be sold. These often clipped onto the door windows, although other designs wedge in between the front seats and the center console.

Built-in cup holders began to be available in the 1920s. Minivans were pioneers in their availability, and they still offer the greatest number of them. Over time, automotive cup holders have become larger and more sophisticated, so that they can hold a variety of different cup sizes securely. Many offer spring-loaded holders that clasp the cup securely, no matter how large or small. The development of ever-larger cups by fast-food chains and convenience stores in the US and Canada has proven a challenge to automotive designers; many fast-food chains now offer 44 fl.oz. (1.3 L) drinks. The automobile cup-holder has also driven the development of "car cups" designed to fit within most cars' cup holders; these have a narrower base but flare outward after a short cylindrical distance.

The installation of cup holders in automobiles increased significantly after Stella Liebeck v. McDonald's Corporation, in which a 79-year-old woman in Albuquerque, New Mexico ordered hot coffee from a McDonald's restaurant and, when it spilled, was scalded so severely she required skin grafts. In her suit against McDonald's the jury awarded her US$2.7 million in damages (later reduced by the judge to US$640,000). Before the inevitable appeal could be heard, the case was settled privately for an undisclosed sum.

Desktop cup holder
Earlier wood versions of cup holders for tops of desks have been around decades such as one featured in a U.S. Airline catalog in the late 1980s. Cup holders for edges of desks and tables really picked up steam in the U.S. around 2006 regarding the GW Bush administration. Specifically, the CDC Department. Cup holders for such a use weren't for sale on the internet in the U.S. during most or all of 2005 and possibly not prior. The 1st appearance 2005 to 2006 was by Antro Technology with a cup holder for the edge of a construction table. The 2nd was a South Korean export with a clip for an indoor table. People sometimes drink beverages at their tables and work desks. It is very easy to knock over a cup or mug full of hot tea or coffee and this can then damage expensive laptops or keyboards. Also the hot liquid may cause injury to people or damage to books or carpets.

On a table or work desk, coffee cups can be knocked over by the person sitting and working at the desk by their arms or hands. This can happen very easily if they are disturbed e.g. by a telephone call or by a sudden impulse move. Coffee cups on desks can also be knocked over by pets such as dogs or cats who may jump up on to the desk. Coffee or tea can also spill out of a cup if the table is knocked by a person walking by.

Several devices were patented to hold coffee cups. The main problem in the endeavor is to provide a mechanism to hold the handle of the cup which usually protrudes a few centimeters from the side of the mug. Another problem facing the inventors is the varying sizes of coffee cups. Some devices which were patented are as follows.

In Japan several patents were applied for, but they were not finalized. They have since been commercialized by other manufacturers. These are:
 * US patent number 5984136 1999. This cup holder has slots to hold the handle and relies on an extended base to hold the cup upright.
 * US patent number 6039206 2000. This cup holder features legs which extend when the cup is placed into the holder.
 * US patent number D645,308 2011. This cup holder for a surface solves a lot of previous problems. It was shown shortly before being granted on U.S. television however it has not been sold.

 * Number 2006314739.
 * Number 2995040642. This cup holder has slots to accommodate the cups handle and has a suction cup to attach the holder to a smooth flat surface, so that it is held securely.

New Zealand patent number 565067. This is a completely free-standing desktop coffee cup holder that can sit on any flat surface this was invented by Digby Green, George Green and Aly Matthews. It can be manufactured in several materials, e.g. wood, metal or plastic. It has been manufactured in plastic by Adovationz Ltd in New Zealand under the brand name of Adkaf.

Dorian Gibbs of Los Angeles, California had the earliest workable cup holder that attaches to a flat edge in the U.S. with US 5,842,671 granted Dec. 1, 1998. US 6,929,229 was granted on Aug. 16, 2005 to Chris D. Palmby of Bellingham, Washington. Perry Segretto of Elmhurst, Illinois had a similar cup holder pending like Palmby's in the U.S. around the same time. Segretto and Michael Koczor sold a cup holder called Drink Hold'em featured on HGTV's "I want that." Antro Technology sold one similar briefly. A South Korean company exported a clip type cup holder to the U.S. No lawsuits were involved to slow the product though mail was received. An agenda regarding jobs with a patent trolls interest occurred during the time of the Obama administration.

A wide variety of cup holders that attach to cylinders were produced in the late 2000s and early 2010s.

The bus/train/boat cup holder

Before the automobile cup holders, many buses and trains were built with wall-mounted cup holders. These cup holders are usually constructed by thin stainless steel plates. Some of them are covered by rubber. There are now many cup holders available which can be screwed to the walls of boats and buses and recreational vehicles.

Another popular cup holder for boats is the "drop in" cup holder. This is a round plastic item, that has a lip at the top. It requires that a hole is drilled into the boat's table or console and then the unit is inserted and the lip holds it in place. These do not accommodate cups with handles.

Cinema cup holder
AMC Theatres patented cup holder armrests in 1981.

The cup holder tree
These are devices which hold several mugs usually in a kitchen or dining room. People often buy sets of mugs for use in a family or guest situation and they need a place to store them ready for use. These cup holder trees are available in two types. The first type has a base with a vertical mast from which there are hooks to hold each cup or of an "accordion" arm where pegs are placed at each junction of a pivot point. The second type is screwed or mounted underneath shelves or in kitchen cupboards etc..

title: Cup holder


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RAF Barkston Heath

Royal Air Force Barkston Heath or RAF Barkston Heath is a Royal Air Force Relief Landing Ground under the command of RAF Cranwell near Grantham, Lincolnshire, England.

RAF Barkston Heath has the Naval Element of No. 3 Flying Training School RAF (3 FTS) which, for a period between approximately 1995 and 2010, operated the Slingsby T67M260 Firefly, followed by the Grob Tutor T.1 operated between 2010 and 2018.

No. 3 FTS currently provide elementary flying training for Royal Navy students on the Grob Prefect T.1. A secondary role of RAF Barkston Heath is as a Relief Landing Ground for the flying training activities at RAF Cranwell.

History
Barkston Heath was constructed in 1936 and was initially used as a satellite station for RAF Cranwell.

United States Army Air Forces use
In late 1943, Barkston Heath was made available to the United States Army Air Force's Ninth Air Force. It was earmarked for basing troop carrier units scheduled to be transferred from Sicily to participate in the forthcoming cross-Channel invasion, Operation Overlord. During its time as a USAAF airfield, Barkston Heath was designated as USAAF station 483.

61st Troop Carrier Group
The first US personnel arrived on 13 February from Sciacca, Sicily, and most of their Douglas C-47 Skytrains on the 17th and 18th, although not all aircraft were in place until a month later. These new occupants were the 61st Troop Carrier Group.

The 61st TCG was part of the 52nd Troop Carrier Wing, IX Troop Carrier Command. The headquarters of the 61st Troop Carrier Group moved to an Advanced Landing Ground (ALG) at Abbeville (ALG B-92), France, on 13 March 1945, but its squadrons went to RAF Chipping Ongar from where they participated in Operation Varsity on 24 March carrying British paratroops who dropped near Wesel.

349th Troop Carrier Group
An increased demand for theatre air transport brought the 349th TCG from Baer Field, Indiana in late March 1945, with its Curtiss C-46 Commando transports. Group headquarters was established at Barkston on 30 March, but the group only remained three weeks before moving to Rove/Amy, France, on 18 April.

Royal Air Force use
The USAAF returned control of the airfield to the Air Ministry in June 1945 when the war in Europe ended. From 1983 to 1989 Barkston was home to 'A' Flight 25 Squadron (with Bristol Bloodhound surface-to-air missiles) when they returned from RAF Bruggen in Germany.

Elementary Flying Training
On 1 April 1995, the Joint Elementary Flying Training School (JEFTS), which provided training to RAF and Fleet Air Arm (FAA) pilots, relocated to Barkston Heath from RAF Topcliffe in North Yorkshire. The school was equipped with eighteen civilian registered Slingsby T67M Firefly trainer aircraft.

In 1996 the Army Air Corps (AAC) joined JEFTS and the school operated as a tri-service organisation until 2003 when the RAF decided to instead provide elementary flying training through its network of University Air Squadrons. JEFTS as a result was renamed the Defence Elementary Flying Training School in July 2003, with the FAA element re-establishing itself as 703 Naval Air Squadron (703 NAS) and the AAC element as No. 674 Squadron.

In November 2009 the Fireflies were retired and replaced with the Grob Tutor T.1.

In April 2021, No. 674 Squadron was stood-down as ACC pilots will no longer be trained on the Prefect prior to rotary wing training at RAF Shawbury.

Other units
The following units were also here at some point:

 * No. 1 Elementary Flying Training School RAF
 * No. 2 Central Flying School RAF
 * No. 2 Flying Instructors School RAF
 * No. 3 (Coastal) Operational Training Unit RAF
 * No. 7 Equipment Disposal Depot RAF
 * No. 85 Squadron RAF
 * RAF College
 * RAF College Flying Training School RAF
 * RAF College Service Flying Training School RAF

Infrastructure and facilities
The RAF Barkston Heath site extends to 224 ha. It has three runways, 06/24 which is 1868 m long, 10/28 which is 1319 m long and 18/36 which is 1280 m long, all constructed from asphalt.

The airfield has limited facilities and relies on its parent station RAF Cranwell for support. The main building at Barkston Heath is the Operational Support Building which was re-opened in January 2018 after refurbishment as part of the UK Military Flying Training System (UKMFTS) programme. It was renamed the Esmonde Building in memory of Lieutenant Commander Eugene Esmonde, a distinguished Fleet Air Arm pilot who was a posthumous recipient of the Victoria Cross.

Out of six T2 type hangar and one B1 type constructed during the Second World War, only two T2 type remain on the site.

The airfield contains the decaying remains of an English Electric Canberra at the northern edge of the airfield site.

Defence Elementary Flying Training School
RAF Barkston Heath is home to the Defence Elementary Flying Training School, comprising 57 Squadron RAF, operating the Grob Prefect T1 in the elementary flying training role. Aircraft and support are provided by a civilian contractor, Ascent Flight Training, as part of the UK Military Flying Training System contract. Ascent also provides a significant proportion of the instructional staff, the Air Traffic Control service is provided by NATS Solutions Ltd, Affinity provide engineering personnel and other Station support personnel are provided by NBC and the MoD.

Although the school trains Fleet Air Arm crews, it is under the command of the RAF's No. 3 Flying Training School, based at nearby RAF Cranwell.

703 Naval Air Squadron
703 NAS trains Fleet Air Arm pilots destined to fly both rotary (AgustaWestland Merlin and AgustaWestland Wildcat) and fixed wing aircraft (Lockheed Martin F-35B II Lightning and BAE Hawk). Helicopter students graduate to No. 1 Flying Training School (1 FTS) at RAF Shawbury in Shropshire, whereas fast jet students move onto No. 4 Flying Training School at RAF Valley in Anglesey.

Relief Landing Ground
Barkston Heath acts as a Relief Landing Ground for the flying training activities at RAF Cranwell, which is four minutes flying time away.

Based units
The following flying units are based at RAF Barkston Heath. The station is also regularly used as relief landing ground by aircraft based at nearby RAF Cranwell.

Royal Air Force
No. 22 Group (Training) RAF

 * No. 3 Flying Training School / Defence Elementary Flying Training School
 * No. 57 Squadron – Grob Prefect T.1

title: RAF Barkston Heath


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Wikipedia:Requests for comment/24.168.92.117

In order to remain listed at Requests for comment, at least two people need to show that they tried to resolve a dispute with this user and have failed. This must involve the same dispute, not different disputes. The persons complaining must provide evidence of their efforts, and each of them must certify it by signing this page with ~. If this does not happen within 48 hours of the creation of this dispute page (which was: {insert UTC timestamp with }), the page will be deleted. The current date and time is:, 29 July 2024 (UTC).

 * (24.168.92.117 | talk | contributions)
 * Also uses (24.168.95.76 | talk | contributions)
 * Also uses (24.168.91.84 | talk | contributions)
 * Also uses (24.168.66.27 | talk | contributions)
 * Also uses (63.169.104.2 | talk | contributions)
 * I believe this is the same person as (Keith Wigdor | talk | contributions)

Statement of the dispute
This is a summary written by users who dispute this user's conduct.

24.168.92.117 seems to spend all his time on Wikipedia engaging in edit wars. From June 29 to July 29, for example, three quarters of this user's contributions were reverts in revert wars, almost exclusively to remove information he felt unimportant, or to restore his POV that one of a dozen users removed. All the rest of his contributions were comments, occasionally inflamatory (e.g. "You are violating my rights!"), and sometimes on the article pages themselves.
 * Description:

 * Evidence of disputed behavior (provide diffs and links):
 * On Surrealism, repeated self-promotion (e.g. "Surrealism is KEITH WIGDOR."), repeated removal of links to other artists, repeated insertion of blatantly POV material (e.g. "which was a huge mistake by the surrealist movement to have ignored his great contributions!"), and repeated removal of info about other groups: ad nauseam.
 * Gratuitous reversion of info on Zazie. At first it was a reasonable disagreement, but due to a lack of justification on Talk:Zazie, this quickly became purely puerile. ad nauseam.
 * Repeated removal of info he felt was unimportant (though apparently not inaccurate) from Collage, without discussion except for a single unrelated accusation: ad nauseam.
 * Repeated removal of info he felt was unimportant from Chicago Surrealist Group:
 * Repeated removal of info he felt was unimportant from Automatism and the computer without discussion:
 * Repeated removal of info he felt was unimportant from Decalcomania without discussion:
 * Repeated removal of info he felt was unimportant from Penelope Rosemont without discussion:
 * Repeated removal of info he felt was unimportant from Parallel collage without discussion:
 * Similar removal of info on Dale Houstman with no discussion:
 * . . .and Franklin Rosemont: (nearly identical, listed in history at )
 * . . .and List of surrealist poets:
 * . . .and Surrealist Movement in the United States:

 * Applicable policies:
 * Neutral_point_of_view
 * How_to_revert_a_page_to_an_earlier_version
 * No_personal_attacks
 * Log in before making drastic changes
 * Don't create articles about yourself

 * Evidence of trying and failing to resolve the dispute (provide diffs and links):
 * The following users politely informed the user on his talk pages that he was violating various policies: UninvitedCompany, Tagishsimon, Daniel C. Boyer, Wyllium, No One Jones, Guanaco, Texture, and RickK. Apparently this has not worked, as the revert wars continue.

 * Users certifying the basis for this dispute (sign with ~ ):
 * Quadell (talk) 17:21, Jul 29, 2004 (UTC)
 * Daniel C. Boyer 17:47, 29 Jul 2004 (UTC)
 * Guanaco 23:48, Jul 29, 2004 (UTC)
 * Tagishsimon 20:19, 30 Jul 2004 (UTC)

 * Other users who endorse this summary (sign with ~ ):
 * Neutrality 17:55, 29 Jul 2004 (UTC)
 * Valmi 05:06, 11 Aug 2004 (UTC)

Response
This is my response to the good gentlemen, Daniel C.Boyer concerning the edits that were made in good faith. I am providing this response for the benefit of the entire Wikipedia Community and the public, so they have Factual Information on Surrealism; Dear Daniel, I have read the Requests for Comments concerning the edits. You do not provide any response to my questions regarding the factual information that I am requesting. The reason for my edits is for the benefit of the entire Wikipedia Community, so that they have the best and most accurate information on Surrealism. Daniel, you have been on Wikipedia for quite some time know, and with all due respect to you sir, I can see that your efforts to maintain a vested self-interest for exposure for your friends, is very obvious. Daniel, this is not an allegation, nor is this inflammatory at all. Consider the simple question that I ask you over and over again, yet you still do not answer. Did Franklin and his wife Penelope Rosemont really meet Andre Breton, and is there any pictures to prove that? Daniel, these people are your friends and you are a contributor to Ron's book, that all of your friends are in together. Whether or not, your contribution to, "Surrealist Subversions" is minimal or not, does not make a difference. These people are your friends, you collaborate with all of them and you have a vested self-interest in getting exposure that is needed. Remember, Daniel, all of your friends do sell their art, or am I wrong? Anyway, I respectfully disagree with the allegations against the edits. They are in good faith. Regarding Zazie, she is a Cyberartist and she is part of the WEBISM Movement. Pygoya's Webism Manifesto is absolutely inconsistent and hostile to anything that has to do with Surrealism. You read it, so did I. Zazie is a Webist, not a surrealist, that I respectfully say is a fact. In regards to your friends, The Rosemonts, I say, they never met Andre Breton, that is not true and very misleading to the public. Also, the removal of THE WEST COAST SURREALIST GROUP from the SURREALISM article is not fair. They were Very Involved with Surrealism and their work has been documented by Jose Pierre, Andre Breton's personal assistant. I know that you really want me off Wikipedia, I can see that. However, my edits are in good faith. I will not stand by and allow the Wikipedia Community and the public believe innaccurate misinformation on Surrealism. I asked you for a simple Picture of Franklin and Penelope with Breton. If you show me that, I can work out any compromises with you, as I have done with the Surrealism page, before it was unprotected. Also, if you were to show me any public statement by Zazie denouncing Webism, then I would stand by All of your information on here 100%. Daniel, this is Surrealism, you know it. Daniel, I would also like to see any article on Andre Thirion, that would be nice.

 * You yourself could write an article on Thirion. I would be all in favour of this.  --Daniel C. Boyer 16:39, 16 Aug 2004 (UTC)

Users who endorse this summary (sign with ~ ):

Outside view
This is a summary written by users not directly involved with the dispute but who would like to add an outside view of the dispute.

I believe that, while User:24.168.92.117 can and should take a lesson from Wikiquitte, many of the edits he has made are factually sound. The surrealism-related articles do at present suffer, on the whole, a POV that is neither mainstream nor neutral. Therefore, I suggest that this dispute be reframed as chiefly a matter of Wikiquitte rather than a problem with the substance of the edits themselves.

Users who endorse this summary (sign with ~ ):
 * 1) UninvitedCompany 18:15, 29 Jul 2004 (UTC).  More in my response at User talk:Quadell.

Discussion
All signed comments and talk not related to a vote or endorsement, should be directed to this page's discussion page.

 * I cannot contribute to discussion of the actions of this user as I do not participate in the topics in question nor do I fully understand all of them. However, my only interaction was to support Wikiquitte suggested to the user by Guanaco.  The user's reply was detailed with facts and viewpoints that I am unqualified to discuss but the tone of the reply was respectful. -  Tεx  τ  urε  18:25, 29 Jul 2004 (UTC)


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Internal set theory

Internal set theory (IST) is a mathematical theory of sets developed by Edward Nelson that provides an axiomatic basis for a portion of the nonstandard analysis introduced by Abraham Robinson. Instead of adding new elements to the real numbers, Nelson's approach modifies the axiomatic foundations through syntactic enrichment. Thus, the axioms introduce a new term, "standard", which can be used to make discriminations not possible under the conventional ZFC axioms for sets. Thus, IST is an enrichment of ZFC: all axioms of ZFC are satisfied for all classical predicates, while the new unary predicate "standard" satisfies three additional axioms I, S, and T. In particular, suitable nonstandard elements within the set of real numbers can be shown to have properties that correspond to the properties of infinitesimal and unlimited elements.

Nelson's formulation is made more accessible for the lay-mathematician by leaving out many of the complexities of meta-mathematical logic that were initially required to justify rigorously the consistency of number systems containing infinitesimal elements.

Intuitive justification
Whilst IST has a perfectly formal axiomatic scheme, described below, an intuitive justification of the meaning of the term standard is desirable. This is not part of the formal theory, but is a pedagogical device that might help the student interpret the formalism. The essential distinction, similar to the concept of definable numbers, contrasts the finiteness of the domain of concepts that we can specify and discuss, with the unbounded infinity of the set of numbers; compare finitism.
 * The number of symbols one writes with is finite.
 * The number of mathematical symbols on any given page is finite.
 * The number of pages of mathematics a single mathematician can produce in a lifetime is finite.
 * Any workable mathematical definition is necessarily finite.
 * There are only a finite number of distinct objects a mathematician can define in a lifetime.
 * There will only be a finite number of mathematicians in the course of our (presumably finite) civilization.
 * Hence there is only a finite set of whole numbers our civilization can discuss in its allotted lifespan.
 * What that limit actually is, is unknowable to us, being contingent on many accidental cultural factors.
 * This limitation is not in itself susceptible to mathematical scrutiny, but that there is such a limit, whilst the set of whole numbers continues forever without bound, is a mathematical truth.

The term standard is therefore intuitively taken to correspond to some necessarily finite portion of "accessible" whole numbers. The argument can be applied to any infinite set of objects whatsoever – there are only so many elements that one can specify in finite time using a finite set of symbols and there are always those that lie beyond the limits of our patience and endurance, no matter how we persevere. We must admit to a profusion of nonstandard elements—too large or too anonymous to grasp—within any infinite set.

Principles of the standard predicate
The following principles follow from the above intuitive motivation and so should be deducible from the formal axioms. For the moment we take the domain of discussion as being the familiar set of whole numbers.
 * Any mathematical expression that does not use the new predicate standard explicitly or implicitly is an internal formula.
 * Any definition that does so is an external formula.
 * Any number uniquely specified by an internal formula is standard (by definition).
 * Nonstandard numbers are precisely those that cannot be uniquely specified (due to limitations of time and space) by an internal formula.
 * Nonstandard numbers are elusive: each one is too enormous to be manageable in decimal notation or any other representation, explicit or implicit, no matter how ingenious your notation. Whatever you succeed in producing is by definition merely another standard number.
 * Nevertheless, there are (many) nonstandard whole numbers in any infinite subset of N.
 * Nonstandard numbers are completely ordinary numbers, having decimal representations, prime factorizations, etc. Every classical theorem that applies to the natural numbers applies to the nonstandard natural numbers. We have created, not new numbers, but a new method of discriminating between existing numbers.
 * Moreover, any classical theorem that is true for all standard numbers is necessarily true for all natural numbers. Otherwise the formulation "the smallest number that fails to satisfy the theorem" would be an internal formula that uniquely defined a nonstandard number.
 * The predicate "nonstandard" is a logically consistent method for distinguishing large numbers—the usual term will be illimited. Reciprocals of these illimited numbers will necessarily be extremely small real numbers—infinitesimals. To avoid confusion with other interpretations of these words, in newer articles on IST those words are replaced with the constructs "i-large" and "i-small".
 * There are necessarily only finitely many standard numbers—but caution is required: we cannot gather them together and hold that the result is a well-defined mathematical set. This will not be supported by the formalism (the intuitive justification being that the precise bounds of this set vary with time and history). In particular we will not be able to talk about the largest standard number, or the smallest nonstandard number. It will be valid to talk about some finite set that contains all standard numbers—but this non-classical formulation could only apply to a nonstandard set.

Formal axioms for IST
IST is an axiomatic theory in the first-order logic with equality in a language containing a binary predicate symbol ∈ and a unary predicate symbol st(x). Formulas not involving st (i.e., formulas of the usual language of set theory) are called internal, other formulas are called external. We use the abbreviations
 * $$\begin{align}\exists^\mathrm{st}x\,\phi(x)&=\exists x\,(\operatorname{st}(x)\land\phi(x)),\\

\forall^\mathrm{st}x\,\phi(x)&=\forall x\,(\operatorname{st}(x)\to\phi(x)).\end{align}$$ IST includes all axioms of the Zermelo–Fraenkel set theory with the axiom of choice (ZFC). Note that the ZFC schemata of separation and replacement are not extended to the new language, they can only be used with internal formulas. Moreover, IST includes three new axiom schemata – conveniently one for each initial in its name: Idealisation, Standardisation, and Transfer.

I: Idealisation

 * For any internal formula $$\phi$$ without a free occurrence of z, the universal closure of the following formula is an axiom:
 * $$\forall^\mathrm{st}z\,(z\text{ is finite}\to\exists y\,\forall x\in z\,\phi(x,y,u_1,\dots,u_n))\leftrightarrow\exists y\,\forall^\mathrm{st}x\,\phi(x,y,u_1,\dots,u_n).$$
 * In words: For every internal relation R, and for arbitrary values for all other free variables, we have that if for each standard, finite set F, there exists a g such that R(g, f) holds for all f in F, then there is a particular G such that for any standard f we have R(G, f), and conversely, if there exists G such that for any standard f, we have R(G, f), then for each finite set F, there exists a g such that R(g, f) holds for all f in F.

The statement of this axiom comprises two implications. The right-to-left implication can be reformulated by the simple statement that elements of standard finite sets are standard. The more important left-to-right implication expresses that the collection of all standard sets is contained in a finite (nonstandard) set, and moreover, this finite set can be taken to satisfy any given internal property shared by all standard finite sets.

This very general axiom scheme upholds the existence of "ideal" elements in appropriate circumstances. Three particular applications demonstrate important consequences.

Applied to the relation ≠
If S is standard and finite, we take for the relation R(g, f): g and f are not equal and g is in S. Since "For every standard finite set F there is an element g in S such that g ≠ f for all f in F" is false (no such g exists when ), we may use Idealisation to tell us that "There is a G in S such that G ≠ f for all standard f" is also false, i.e. all the elements of S are standard.

If S is infinite, then we take for the relation R(g, f): g and f are not equal and g is in S. Since "For every standard finite set F there is an element g in S such that g ≠ f for all f in F" (the infinite set S is not a subset of the finite set F), we may use Idealisation to derive "There is a G in S such that G ≠ f for all standard f." In other words, every infinite set contains a nonstandard element (many, in fact).

The power set of a standard finite set is standard (by Transfer) and finite, so all the subsets of a standard finite set are standard.

If S is nonstandard, we take for the relation R(g, f): g and f are not equal and g is in S. Since "For every standard finite set F there is an element g in S such that g ≠ f for all f in F" (the nonstandard set S is not a subset of the standard and finite set F), we may use Idealisation to derive "There is a G in S such that G ≠ f for all standard f." In other words, every nonstandard set contains a nonstandard element.

As a consequence of all these results, all the elements of a set S are standard if and only if S is standard and finite.

Applied to the relation <
Since "For every standard, finite set of natural numbers F there is a natural number g such that g > f for all f in F" – say, – we may use Idealisation to derive "There is a natural number G such that G > f for all standard natural numbers f." In other words, there exists a natural number greater than each standard natural number.

Applied to the relation ∈
More precisely we take for R(g, f): g is a finite set containing element f. Since "For every standard, finite set F, there is a finite set g such that f ∈ g for all f in F" – say by choosing itself – we may use Idealisation to derive "There is a finite set G such that f ∈ G for all standard f." For any set S, the intersection of S with the set G is a finite subset of S that contains every standard element of S. G is necessarily nonstandard.

S: Standardisation

 * If $$\phi$$ is any formula (it may be external) without a free occurrence of y, the universal closure of
 * $$\forall^\mathrm{st}x\,\exists^\mathrm{st}y\,\forall^\mathrm{st}t\,(t\in y\leftrightarrow(t\in x\land\phi(t,u_1,\dots,u_n)))$$
 * is an axiom.

 * In words: If A is a standard set and P any property, internal or otherwise, then there is a unique, standard subset B of A whose standard elements are precisely the standard elements of A satisfying P (but the behaviour of B ' s nonstandard elements is not prescribed).

T: Transfer

 * If $$\phi(x,u_1,\dots,u_n)$$ is an internal formula with no other free variables than those indicated, then
 * $$\forall^\mathrm{st}u_1\dots\forall^\mathrm{st}u_n\,(\forall^\mathrm{st}x\,\phi(x,u_1,\dots,u_n)\to\forall x\,\phi(x,u_1,\dots,u_n))$$
 * is an axiom.

 * In words: If all the parameters A, B, C, ..., W of an internal formula F have standard values then F(x, A, B,..., W) holds for all xs as soon as it holds for all standard xs—from which it follows that all uniquely defined concepts or objects within classical mathematics are standard.

Formal justification for the axioms
Aside from the intuitive motivations suggested above, it is necessary to justify that additional IST axioms do not lead to errors or inconsistencies in reasoning. Mistakes and philosophical weaknesses in reasoning about infinitesimal numbers in the work of Gottfried Leibniz, Johann Bernoulli, Leonhard Euler, Augustin-Louis Cauchy, and others were the reason that they were originally abandoned for the more cumbersome real number-based arguments developed by Georg Cantor, Richard Dedekind, and Karl Weierstrass, which were perceived as being more rigorous by Weierstrass's followers.

The approach for internal set theory is the same as that for any new axiomatic system—we construct a model for the new axioms using the elements of a simpler, more trusted, axiom scheme. This is quite similar to justifying the consistency of the axioms of elliptic non-Euclidean geometry by noting they can be modeled by an appropriate interpretation of great circles on a sphere in ordinary 3-space.

In fact via a suitable model a proof can be given of the relative consistency of IST as compared with ZFC: if ZFC is consistent, then IST is consistent. In fact, a stronger statement can be made: IST is a conservative extension of ZFC: any internal formula that can be proven within internal set theory can be proven in the Zermelo–Fraenkel axioms with the axiom of choice alone.

Related theories
Related theories were developed by Karel Hrbacek and others.

title: Internal set theory


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title: User talk:Cooljinsoo