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Propofol

Propofol is the active component of an intravenous anesthetic formulation used for induction and maintenance of general anesthesia. It is chemically termed 2,6-diisopropylphenol. The formulation was approved under the brand name Diprivan. Numerous generic versions have since been released. Intravenous administration is used to induce unconsciousness after which anesthesia may be maintained using a combination of medications. It is manufactured as part of a sterile injectable emulsion formulation using soybean oil and lecithin, giving it a white milky coloration.

Recovery from propofol-induced anesthesia is generally rapid and associated with less frequent side effects (e.g. drowsiness, nausea, vomiting) compared to other anesthetic agents. Propofol may be used prior to diagnostic procedures requiring anesthesia, in the management of refractory status epilepticus, and for induction and/or maintenance of anesthesia prior to and during surgeries. It may be administered as a bolus or an infusion, or some combination of the two.

First synthesized in 1973, by John B. Glen, a British veterinary anesthesiologist working for Imperial Chemical Industries (ICI, later AstraZeneca), in 1986 propofol was introduced for therapeutic use as a lipid emulsion in the United Kingdom and New Zealand. Propofol (Diprivan) received FDA approval in October 1989. It is on the World Health Organization's List of Essential Medicines.

Anesthesia
To induce general anesthesia, propofol is the drug used almost exclusively, having largely replaced sodium thiopental.

It is often administered as part of an anesthesia maintenance technique called total intravenous anesthesia, using either manually programmed infusion pumps or computer-controlled infusion pumps in a process called target controlled infusion (TCI).

Propofol is also used to sedate individuals who are receiving mechanical ventilation but not undergoing surgery, such as patients in the intensive care unit. In critically ill patients, propofol is superior to lorazepam both in effectiveness and overall cost. Propofol is relatively inexpensive compared to medications of similar use due to shorter ICU stay length. One of the reasons propofol is thought to be more effective (although it has a longer half-life than lorazepam) is that studies have found that benzodiazepines like midazolam and lorazepam tend to accumulate in critically ill patients, prolonging sedation.

Propofol has also been suggested as a sleep aid in critically ill adults in an ICU setting; however, the effectiveness of this medicine in replicating the mental and physical aspects of sleep for people in the ICU is not clear.

Propofol can be administered via a peripheral IV or central line. Propofol is often paired with fentanyl (for pain relief) in intubated and sedated people. The two drugs are molecularly compatible in an IV mixture form.

Propofol is also used for deepening of anesthesia in order to relieve laryngospasm. It may be used alone or followed by succinylcholine. Its use can avoid the need for paralysis and in some instances the potential side-effects of succinylcholine.

Routine procedural sedation
Propofol is safe and effective for gastrointestinal endoscopy procedures (colonoscopies etc.). Its use in these settings results in a faster recovery compared to midazolam. It can also be combined with opioids or benzodiazepines. Because of its rapid induction and recovery time, propofol is also widely used for sedation of infants and children undergoing MRI procedures. It is also often used in combination with ketamine with minimal side effects.

COVID-19
In March 2021, the U.S. Food and Drug Administration (FDA) issued an emergency use authorization (EUA) for Propofol‐Lipuro 1% to maintain sedation via continuous infusion in people older than sixteen with suspected or confirmed COVID-19 who require mechanical ventilation in an intensive care unit ICU setting. During the public health emergency, it was considered unfeasible to limit Fresenius Propoven 2% Emulsion or Propofol-Lipuro 1% to patients with suspected or confirmed COVID-19, so it was made available to all ICU patients under mechanical ventilation. This EUA has since been revoked.

Status epilepticus
Status epilepticus may be defined as seizure activity lasting beyond five minutes needing anticonvulsant medication. Several guidelines recommend the use of propofol for the treatment of refractory status epilepticus.

Assisted death in Canada
A lethal dose of propofol is used for medical assistance in dying in Canada to quickly induce deep coma and death, but rocuronium is always given as a paralytic ensuring death, even when the patient has died as a result of initial propofol overdose.

Capital punishment
Use of propofol as part of an execution protocol has been considered, although no individual has been executed using this agent. This is largely due to European manufacturers and governments banning the exportation of this propofol for such use.

Recreational use
Recreational use of the drug via self-administration has been reported but is relatively rare due to its potency and the level of monitoring required for safe use. Critically, a steep dose-response curve makes recreational use of propofol very dangerous, and deaths from self-administration continue to be reported. The short-term effects sought via recreational use include mild euphoria, hallucinations, and disinhibition.

Recreational use of the drug has been described among medical staff, such as anesthetists who have access to the drug. It is reportedly more common among anesthetists on rotations with short rest periods, as usage generally produces a well-rested feeling. Long-term use has been reported to result in addiction.

Attention to the risks of off-label use of propofol increased in August 2009 due to the Los Angeles County coroner's conclusion that musician Michael Jackson died from a mixture of propofol and the benzodiazepine drugs lorazepam, midazolam, and diazepam on 25 June 2009. According to a 22 July 2009 search warrant affidavit unsealed by the district court of Harris County, Texas, Jackson's physician, Conrad Murray, administered 25 milligrams of propofol diluted with lidocaine shortly before Jackson's death.

Manufacturing
Propofol as a commercial sterile emulsified formulation is considered difficult to manufacture.

It was initially formulated in Cremophor for human use, but this original formulation was implicated in an unacceptable number of anaphylactic events. It was eventually manufactured as a 1% emulsion in soybean oil. Sterile emulsions represent complex formulation, the stability of which is dependent on the interplay of many factors such as micelle size and distribution.

Side effects
One of propofol's most common side effects is pain on injection, especially in smaller veins. This pain arises from activation of the pain receptor, TRPA1, found on sensory nerves and can be mitigated by pretreatment with lidocaine. Less pain is experienced when infused at a slower rate in a large vein (antecubital fossa). Patients show considerable variability in their response to propofol, at times showing profound sedation with small doses.

Additional side effects include low blood pressure related to vasodilation, transient apnea following induction doses, and cerebrovascular effects. Propofol has more pronounced hemodynamic effects relative to many intravenous anesthetic agents. Reports of blood pressure drops of 30% or more are thought to be at least partially due to inhibition of sympathetic nerve activity. This effect is related to the dose and rate of propofol administration. It may also be potentiated by opioid analgesics.

Propofol can also cause decreased systemic vascular resistance, myocardial blood flow, and oxygen consumption, possibly through direct vasodilation. There are also reports that it may cause green discoloration of the urine.

Although propofol is widely used in the adult ICU setting, the side effects associated with medication seem to be more concerning in children. In the 1990s, multiple reported deaths of children in ICUs associated with propofol sedation prompted the FDA to issue a warning.

As a respiratory depressant, propofol frequently produces apnea. The persistence of apnea can depend on factors such as premedication, dose administered, and rate of administration, and may sometimes persist for longer than 60 seconds. Possibly as the result of depression of the central inspiratory drive, propofol may produce significant decreases in respiratory rate, minute volume, tidal volume, mean inspiratory flow rate, and functional residual capacity.

Propofol administration also results in decreased cerebral blood flow, cerebral metabolic oxygen consumption, and intracranial pressure. In addition, propofol may decrease intraocular pressure by as much as 50% in patients with normal intraocular pressure.

A more serious but rare side effect is dystonia. Mild myoclonic movements are common, as with other intravenous hypnotic agents. Propofol appears to be safe for use in porphyria, and has not been known to trigger malignant hyperpyrexia.

Propofol is also reported to induce priapism in some individuals, and has been observed to suppress REM sleep stage and to worsen the poor sleep quality in some patients.

Rare side effects include: As with any other general anesthetic agent, propofol should be administered only where appropriately trained staff and facilities for monitoring are available, as well as proper airway management, a supply of supplemental oxygen, artificial ventilation, and cardiovascular resuscitation.
 * anxiety
 * changes in vision
 * cloudy urine
 * coughing up blood
 * delirium or hallucinations
 * difficult urination
 * difficulty swallowing
 * dry eyes, mouth, nose, or throat

Because of propofol's formulation (using lecithin and soybean oil) it is prone to bacterial contamination, despite the presence of the bacterial inhibitor benzyl alcohol; consequently, some hospital facilities require the IV tubing (of continuous propofol infusions) to be changed after 12 hours. This is a preventive measure against microbial growth and potential infection.

Propofol infusion syndrome
A rare, but serious, side effect is propofol infusion syndrome. This potentially lethal metabolic derangement has been reported in critically ill patients after a prolonged infusion of high-dose propofol, sometimes in combination with catecholamines and/or corticosteroids.

Interactions
The respiratory effects of propofol are increased if given with other respiratory depressants, including benzodiazepines.

Pharmacodynamics
Propofol has been proposed to have several mechanisms of action,  both through potentiation of GABAA receptor activity and therefore acting as a GABAA receptor positive allosteric modulator, thereby slowing the channel-closing time. At high doses, propofol may be able to activate GABAA receptors in the absence of GABA, behaving as a GABAA receptor agonist as well. Propofol analogs have been shown to also act as sodium channel blockers. Some research has also suggested that the endocannabinoid system may contribute significantly to propofol's anesthetic action and to its unique properties, as endocannabinoids also play an important role in the physiologic control of sleep, pain processing and emesis. An EEG study on patients undergoing general anesthesia with propofol found that it causes a prominent reduction in the brain's information integration capacity.

Propofol is an inhibitor of the enzyme fatty acid amide hydrolase, which metabolizes the endocannabinoid anandamide (AEA). Activation of the endocannabinoid system by propofol, possibly via inhibition of AEA catabolism, generates a significant increase in the whole-brain content of AEA, contributing to the sedative properties of propofol via CB1 receptor activation. This may explain the psychotomimetic and antiemetic properties of propofol. By contrast, there is a high incidence of postoperative nausea and vomiting after administration of volatile anesthetics, which contribute to a significant decrease in the whole-brain content of AEA that can last up to forty minutes after induction.

Pharmacokinetics
Propofol is highly protein-bound in vivo and is metabolized by conjugation in the liver. The half-life of elimination of propofol has been estimated to be between 2 and 24 hours. However, its duration of clinical effect is much shorter, because propofol is rapidly distributed into peripheral tissues. When used for IV sedation, a single dose of propofol typically wears off within minutes. Onset is rapid, in as little as 15–30 seconds. Propofol is versatile; the drug can be given for short or prolonged sedation, as well as for general anesthesia. Its use is not associated with nausea as is often seen with opioid medications. These characteristics of rapid onset and recovery along with its amnestic effects have led to its widespread use for sedation and anesthesia.

History
John B. Glen, a veterinarian and researcher at Imperial Chemical Industries (ICI), spent thirteen years developing propofol, an effort for which he was awarded the 2018 Lasker Award for clinical research.

Originally developed as ICI 35868, propofol was chosen after extensive evaluation and structure–activity relationship studies of the anesthetic potencies and pharmacokinetic profiles of a series of ortho-alkylated phenols.

First identified as a drug candidate in 1973, propofol entered clinical trials in 1977, using a form solubilized in cremophor EL. However, due to anaphylactic reactions to cremophor, this formulation was withdrawn from the market and subsequently reformulated as an emulsion of a soya oil and propofol mixture in water. The emulsified formulation was relaunched in 1986 by ICI (whose pharmaceutical division later became a constituent of AstraZeneca) under the brand name Diprivan. The preparation contains 1% propofol, 10% soybean oil, and 1.2% purified egg phospholipid as an emulsifier, with 2.25% glycerol as a tonicity-adjusting agent, and sodium hydroxide to adjust the pH. Diprivan contains EDTA, a common chelation agent, that also acts alone (bacteriostatically against some bacteria) and synergistically with some other antimicrobial agents. Newer generic formulations contain sodium metabisulfite as an antioxidant and benzyl alcohol as antimicrobial agent. Propofol emulsion is an opaque white fluid due to the scattering of light from the emulsified micelle formulation.

Developments
A water-soluble prodrug form, fospropofol, has been developed and tested with positive results. Fospropofol is rapidly broken down by the enzyme alkaline phosphatase to form propofol. Marketed as Lusedra, this formulation may not produce the pain at injection site that often occurs with the conventional form of the drug. The U.S. Food and Drug Administration (FDA) approved the product in 2008.

By incorporation of an azobenzene unit, a photoswitchable version of propofol (AP2) was developed in 2012 that allows for optical control of GABAA receptors with light. In 2013, a propofol binding site on mammalian GABAA receptors has been identified by photolabeling using a diazirine derivative. Additionally, it was shown that the hyaluronan polymer present in the synovia can be protected from free-radical depolymerization by propofol.

Ciprofol is another derivative of propofol that is 4–6 times more potent than propofol. it is undergoing Phase III trials. Ciprofol appears to have a lower incidence of injection site pain and respiratory depression than propofol.

Propofol has also been studied for treatment resistant depression.

title: Propofol


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Line pair

In philately, a line pair is a coil pair of postage stamps bearing an inked line between the two stamps. There are at least two kinds of these:
 * A guide line pair has a guide line between the stamps. Since the guide lines are deliberately incised into the plate, they will generally be sharp and clear.
 * A joint line pair has a joint line between the stamps, deriving from the seam in the cylindrical plate used to print the stamps. These lines are somewhat smeared in appearance.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Line pair


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Tomahawk (disambiguation)

A tomahawk is a type of axe made and used by Native Americans.

Tomahawk may also refer to:

Australia

 * Tomahawk, Tasmania, a town

Canada

 * Tomahawk, Alberta, a hamlet

New Zealand

 * Ocean Grove, New Zealand, formerly called Tomahawk from the Māori toma haka, now a suburb of the city of Dunedin
 * Tomahawk Beach, the beach below Ocean Grove
 * Tomahawk Lagoon, a coastal lake adjacent to Ocean Grove

United States

 * Tomahawk Township, Searcy County, Arkansas, a township
 * Tomahawk, Kentucky, a small community in eastern Kentucky
 * Tomahawk, West Virginia, an unincorporated community
 * Tomahawk, Wisconsin, a city
 * Tomahawk (town), Wisconsin, a town adjacent to the city of the same name
 * Tomahawk School District, a school district in Wisconsin
 * Lake Tomahawk, Wisconsin, a town
 * Lake Tomahawk (community), Wisconsin, an unincorporated community
 * Tomahawk River, a river in Wisconsin

People

 * Tom Hawkins (footballer, born 1988), an Australian rules footballer, nicknamed "Tomahawk"
 * Tomahawk T.T., Takuya Onodera, a Japanese professional wrestler

Fictional entities

 * Tomahawk (comics), a DC Comics character, published in his own series from the 1940s to 1970s
 * Tomahawk (G.I. Joe), a helicopter in the G.I. Joe universe
 * Tomahawk (Transformers), a Transformers character

Music

 * Tomahawk (band), an alternative/experimental band fronted by Mike Patton
 * Tomahawk (album), an album by Tomahawk
 * Tomahawk Technique, an album by Sean Paul
 * "Tomahawk", a single by BT and Adam K

Other arts, entertainment, and media

 * Tomahawk (film) (1951), directed by George Sherman
 * Tomahawk (satirical magazine), a weekly magazine (1867–1870)

Military

 * Tomahawk (missile family), a cruise missile built in the United States
 * Curtiss P-40 Warhawk, early variants were named Tomahawk in RAF service
 * Nike-Tomahawk, a U.S. sounding rocket
 * Operation Tomahawk, an airborne military operation
 * Taurus Tomahawk, a two-stage elevator sounding rocket
 * TE-416 Tomahawk, a U.S. sounding rocket
 * USS Tomahawk (AO-88), a World War II fuel supply ship

Transportation

 * Tomahawk (train), a train operated by the Chicago, Milwaukee, St. Paul and Pacific Railroad (the "Milwaukee Road")
 * Tomahawk, a children's bicycle similar to the Raleigh Chopper
 * Dodge Tomahawk, a concept motorcycle
 * ITV Tomahawk, a French paraglider design
 * Piper PA-38 Tomahawk, a light general aviation aircraft
 * SRT Tomahawk Gran Turismo, a concept car created by SRT for the Gran Turismo series
 * Tomahawk Railway, a U.S. railroad

Moves or plays

 * In basketball, a one-handed slam dunk, where the ball is brought over the head before being stuffed into the basket, in a chopping motion
 * In beach volleyball, an overhead method of contacting the ball
 * In field hockey, a type of hit where the hockey stick is turned so that the rounded side faces the ground and then swung in such a way that it hits the ball in a downward chopping motion
 * In football/soccer, a name given to Cristiano Ronaldo's direct free kicks
 * A turning maneuver used in roller skating
 * Tomahawk chop, a controversial celebratory gesture made by fans of multiple American sports teams

Teams

 * Johnstown Tomahawks, a Tier II Junior A ice hockey team from Johnstown, Pennsylvania
 * Mississauga Tomahawks Jr. A, a Junior "A" box lacrosse team from Mississauga, Ontario
 * Tomahawks, the nickname for the United States national rugby league team
 * Toronto Tomahawks, a former team in the National Lacrosse League
 * Williamsport Tomahawks, a former Class AA Eastern League baseball team in Williamsport, Pennsylvania

Other uses

 * Tomahawk (geometry), a mathematical tool that can be used to trisect angles
 * Tomahawk (software), a cross-platform music player for Windows, Mac and Linux, see List of Linux audio software
 * Tomahawk, a set of Java Server Faces components created by the MyFaces development team prior to its donation to Apache
 * A tomahawk steak is a rib steak with the bone attached
 * Tomahawk, a series of switching chips at Broadcom Corporation

title: Tomahawk (disambiguation)


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Lockheed P-2 Neptune

The Lockheed P-2 Neptune (designated P2V by the United States Navy prior to September 1962) is a maritime patrol and anti-submarine warfare (ASW) aircraft. It was developed for the US Navy by Lockheed to replace the Lockheed PV-1 Ventura and PV-2 Harpoon, and was replaced in turn by the Lockheed P-3 Orion. Designed as a land-based aircraft, the Neptune never made a carrier landing, but a small number were converted and deployed as carrier-launched (using JATO assist), stop-gap nuclear bombers that would have to land on shore or ditch. The type was successful in export, and saw service with several armed forces.

Design and development

Development of a new land-based patrol bomber began early in World War II, with design work starting at Lockheed's Vega subsidiary as a private venture on 6 December 1941. At first, the new design was considered a low priority compared to other aircraft in development at the time, with Vega also developing and producing the PV-2 Harpoon patrol bomber. On 19 February 1943, the U.S. Navy signed a letter of intent for two prototype XP2Vs, which was confirmed by a formal contract on 4 April 1944 with a further 15 aircraft being ordered 10 days later. It was not until 1944 that the program went into full swing. A major factor in the design was ease of manufacture and maintenance, and this may have been a major factor in the type's long life and worldwide success. The first aircraft flew in May 1945. Production began in 1946, and the aircraft was accepted into service in 1947. Potential use as a bomber led to successful launches from aircraft carriers.

Beginning with the P2V-5F model, the Neptune became one of the first operational aircraft fitted with both piston and jet engines. The Convair B-36, several Boeing C-97 Stratofreighter, Fairchild C-123 Provider, North American AJ Savage, and Avro Shackleton aircraft were also so equipped. To save weight and complexity of two separate fuel systems, the Westinghouse J34 jet engines on P2Vs burned the 115–145 Avgas fuel of the piston engines, instead of jet fuel. The jet pods were fitted with intake doors that remained closed when the J-34s were not running. This prevented windmilling, allowing for economical piston-engine-only long-endurance search and patrol operations. In normal US Navy operations, the jet engines were run at full power (97%) to assure takeoff, then shut down upon reaching a safe altitude. The jets were also started and kept running at flight idle during low-altitude (500 ft during the day and 1000 ft at night) anti-submarine and/or anti-shipping operations as a safety measure should one of the radials develop problems.

Normal crew access was via a ladder on the aft bulkhead of the nosewheel well to a hatch on the left side of the wheel well, then forward to the observer nose, or up through another hatch to the main deck. There was also a hatch in the floor of the aft fuselage, near the sonobuoy chutes.

Early Cold War

Prior to the introduction of the P-3 Orion in the mid-1960s, the Neptune was the primary U.S. land-based anti-submarine patrol aircraft, intended to be operated as the hunter of a '"Hunter-Killer" group, with destroyers employed as killers. Several features aided the P-2 in its hunter role:
 * Sonobuoys could be launched from a station in the aft portion of the fuselage and monitored by radio
 * Some models were equipped with "pointable" twin .5 in machine guns in the nose, but most had a forward observation bubble with an observer seat, a feature often seen in images.
 * The AN/ASQ-8 Magnetic Anomaly Detector was fitted in an extended tail, producing a paper chart. Unmarked charts were not classified, but those with annotations were classified as secret.
 * A belly-mounted AN/APS-20 surface-search radar enabled detection of surfaced and snorkeling submarines at considerable distances.

As the P-2 was replaced in the US Navy by the P-3A Orion in active Fleet squadrons in the early and mid-1960s, the P-2 continued to remain operational in the Naval Air Reserve through the mid-1970s, primarily in its SP-2H version. As active Fleet squadrons transitioned to the P-3B and P-3C in the mid- and late-1960s and early 1970s, the Naval Air Reserve P-2s were eventually replaced by P-3As and P-3Bs and the P-2 exited active U.S. naval service. VP-23 was the last active duty patrol squadron to operate the SP-2H, retiring its last Neptune on 20 February 1970, while the last Naval Reserve patrol squadron to operate the Neptune, VP-94, retired its last SP-2H in 1978.

Nuclear bomber

At the end of World War II, the US Navy felt the need to acquire a nuclear strike capability to maintain its political influence. In the short term, carrier-based aircraft were the best solution. The large Fat Man nuclear munitions at that time were bulky and required a very large aircraft to carry them. The US Navy Bureau of Ordnance built 25 outdated but more compact Little Boy nuclear bomb designs to be used in the smaller bomb bay of the P2V Neptune. There was enough fissionable material available by 1948 to build ten complete uranium projectiles and targets, although there were only enough initiators to complete six. The U.S. Navy improvised a carrier-based nuclear strike aircraft by modifying the P2V Neptune for carrier takeoff using jet assisted takeoff (JATO) rocket boosters, with initial takeoff tests in 1948. However, the Neptune could not land on a carrier, therefore the crew had to either make their way to a friendly land base after a strike, or ditch in the sea near a U.S. Navy vessel. It was replaced in this emergency role by the North American AJ Savage (transferred to the Pacific Fleet in October 1952) the first nuclear strike aircraft that was fully capable of carrier launch and recovery operations; it was also short-lived in that role as the US Navy was adopting fully jet powered nuclear strike aircraft.

Covert operations P2V-7U/RB-69A variants

In 1954 under Project Cherry, the US Central Intelligence Agency (CIA) obtained five newly built P2V-7 and converted these into P2V-7U/RB-69A variants by Lockheed's Skunk Works at Hangar B5 in Burbank, California, for the CIA's own private fleet of covert ELINT/ferret aircraft. Later, to make up for P2V-7U/RB-69A operational losses, the CIA obtained and converted two existing US Navy P2V-7s, one in September 1962, and one in December 1964 to P2V-7U/RB-69A Phase VI standard, and also acquired an older P2V-5 from the US Navy as a training aircraft in 1963. Test flights were made by lead aircraft at Edwards AFB from 1955 to 1956, all the aircraft painted with dark sea blue color but with USAF markings. In 1957 one P2V-7U was sent to Eglin AFB for testing aircraft performance at low level and under adverse conditions.

The initial two aircraft were sent to Europe, based at Wiesbaden, West Germany, but were later withdrawn in 1959 when the CIA reduced its covert aircraft assets in Europe. The CIA sent the other two P2V-7U/RB-69As to Hsinchu Air Base, Taiwan, where by December 1957, they were given to a "black op" unit, the 34th Squadron, better known as the Black Bat Squadron, of the Republic of China Air Force; these were painted in ROCAF markings. The ROCAF P2V-7U/RB-69A's mission was to conduct low-level penetration flights into mainland China to conduct ELINT/ferret missions including mapping out China's air defense networks, inserting agents via airdrop, and dropping leaflets and supplies. The agreement for plausible deniability between US and Republic of China (ROC) governments meant the RB-69A would be manned by ROCAF crew while conducting operational missions, but would be manned by CIA crew when ferrying RB-69A out of Taiwan or other operational area to US.

The P2V-7U/RB-69A flew with ROCAF Black Bat Squadron over China from 1957 to November 1966. All five original aircraft (two crashed in South Korea, three shot down over China) were lost with all hands on board. In January 1967, two remaining RB-69As flew back to NAS Alameda, California, and were converted back to regular US Navy P2V-7/SP-2H ASW aircraft configurations. Most of the 34th Squadron's black op missions remain classified by the CIA—though a CIA internal draft history, Low-Level Technical Reconnaissance over Mainland China (1955–66), reference CSHP-2.348, written in 1972 that covers CIA/ROCAF 34th Squadron's black op missions is known to exist. The CIA does not plan to declassify it until after 2022.

Vietnam War
During the Vietnam War, the Neptune was used by the US Navy as a gunship, as an overland reconnaissance and sensor deployment aircraft, and in its traditional role as a maritime patrol aircraft. The Neptune was also utilized by the US Army's 1st Radio Research Company (Aviation), call sign "Crazy Cat", based at Cam Ranh Air Base in South Vietnam, as an electronic "ferret" aircraft intercepting low-powered tactical voice and morse code radio signals. The US Army operated the P-2 from 1967 until 1972, flying 42,500 hours with no accidents. Observation Squadron 67 (VO-67), call sign "Lindy", was the only P-2 Neptune aircraft squadron to ever receive the Presidential Unit Citation, flying Igloo White missions sowing seismic and acoustic sensors over the Ho Chi Minh trail. VO-67 lost three OP-2E aircraft and 20 aircrew to ground fire during its secret missions into Laos and Vietnam in 1967–68. The Republic of China Air Force (ROCAF) secret 34th Black Bat Squadron's RB-69A/P2V-7U ELINT/SIGINT aircraft flew a low level electronic reconnaissance from Da Nang Air Base, flying over Thanh Hóa Province on 20 August 1963 to investigate an air resupply drop zone that turned out to be a trap for a ROCAF C-123B airdrop mission 10 days earlier due to the air-inserted agents having been captured and turned. Next year, an air defense radar mapping mission was also flown by 34th Squadron's RB-69A/P2V-7U aircraft into North Vietnam and Laos on the night of 16 March 1964. The RB-69A took off from Da Nang, flew up the Gulf of Tonkin before coasting in near Haiphong, then flew down North Vietnam and the Laos border. The mission was requested by SOG for helping plan the insert or resupply of agents. Seven AAA sites, 14 early warning radar sites and two GCI radar signals were detected.

Falklands War

The Argentine Naval Aviation had received at least 16 Neptunes of different variants since 1958 including eight former RAF examples for use in the Escuadrilla Aeronaval de Exploración (Naval Exploration Squadron). They were intensively used in 1978 during the Operation Soberania against Chile including over the Pacific Ocean.

During the Falklands War in 1982, the last two airframes in service (2-P-111 and 2-P-112) carried out reconnaissance missions over the South Atlantic and on 4 May, after detecting a group of British warships, helped to direct an attack by two Dassault Super Étendards that resulted in the sinking of the British destroyer HMS Sheffield (D80). The lack of spare parts, caused by the US having enacted an arms embargo in 1977 due to the Dirty War, led to the type being retired before the end of the war; Argentine Air Force Lockheed C-130 Hercules took over the task of searching for targets for strike aircraft.

Other military operators
The Royal Canadian Air Force's Air Command replaced their aging Avro Lancaster maritime aircraft beginning in 1955 with P2V-7 Neptunes in the anti-submarine, anti-shipping, and maritime reconnaissance roles, as a stopgap pending deliveries of the Canadair CP-107 Argus, which began in 1960. Canadian Neptunes were delivered without the underwing Westinghouse J34 jet engine pods, which were retrofitted in 1959. Armament included two torpedoes, mines, depth charges, bombs carried internally plus unguided rockets mounted under the wings. Twenty five Neptunes served with 404, 405 and 407 squadrons until 1960. Upon unification of the Canadian Forces in 1968, the Neptune was re-designated the CP122 and was officially retired two years later.

With the founding of NATO in 1949 and the resulting additional maritime commitments it entailed for Britain, The Royal Air Force Coastal Command operated 52 P2V-5s, designated Neptune MR.1, as a stop-gap modern maritime patrol aircraft until sufficient numbers of the Avro Shackleton could enter service. The Neptunes were used from between 1952 and March 1957, being used for airborne early warning experiments as well as for maritime patrol.

In Australia, the Netherlands, and the US Navy, its tasks were taken over by the larger and more capable P-3 Orion, and by the 1970s, it was in use only by patrol squadrons in the US Naval Reserve and the Dutch Navy. The 320 Squadron of the Royal Dutch Navy retired its last seven Neptunes in March 1982 as they were being replaced by the Lockheed Orion. The US Naval Reserve retired its last Neptunes in 1978, those aircraft also having been replaced by the P-3 Orion. By the 1980s, the Neptune had fallen out of military use in most purchasing nations, replaced by newer aircraft.

The Netherlands received its first Neptunes in 1953–54, when it acquired 12 P2V-5s. These remained in service until 1960, when they were transferred to Portugal. The P2V-5s were initially not replaced, with the anti-submarine aircraft requirement being met by carrier-borne Grumman S-2 Trackers. A new, urgent, requirement for maritime patrol aircraft soon developed, for service over Dutch New Guinea, and 15 new P2V-7s were purchased, entering service from September 1961. While initially employed on reconnaissance and patrol duties, as Indonesian infiltration attempts against New Guinea increased, the Neptunes added bombing and strafing operations to their patrol duties. On 17 May 1962, a Netherlands Navy Neptune shot down an Indonesian C-47 transport. A truce ended the conflict in September 1962, with Dutch New Guinea passing to UN control before becoming part of Indonesia, and the P2V-7s returned to Europe. The aircraft were upgraded to SP-2H standard soon after returning to the Netherlands, and remained in service until March 1982, when they were replaced by Lockheed Orions.

In Japan, the Neptune was license-built from 1966 by Kawasaki as the P-2J, with the piston engines replaced by IHI-built T64 turboprops. Kawasaki continued their manufacture much later than Lockheed did; the P-2J remained in service until 1984.

Civilian firefighting
P-2/P2Vs have been employed in aerial firefighting roles by operators such as Minden Air Corp and Neptune Aviation Services. The fire fighters can carry 2080 usgal of retardant and have a service life of 15,000 hours. Neptune Aviation Services proposes to replace them with British Aerospace 146 aircraft, which have an estimated service life of 80,000 hours and carry upwards of 3000 usgal of retardant.

"The Truculent Turtle"
The third production P2V-1 was chosen for a record-setting mission, ostensibly to test crew endurance and long-range navigation but also for publicity purposes: to display the capabilities of the US Navy's latest patrol bomber, and to surpass the standing record set by a Japanese Tachikawa Ki-77. Its nickname was The Turtle, which was painted on the aircraft's nose (along with a cartoon of a turtle smoking a pipe pedaling a device attached to a propeller). However, in press releases immediately before the flight, the US Navy referred to it as "The Truculent Turtle".

Loaded with fuel in extra tanks fitted in practically every spare space in the aircraft, "The Turtle" set out from Perth, Australia to the United States. With a crew of four (and a nine-month-old gray kangaroo, a gift from Australia for the National Zoo in Washington, D.C.) the aircraft set off on 9 September 1946, with a RATO (rocket-assisted takeoff). $2 1/2$ days (55h, 18m) later, "The Turtle" touched down in Columbus, Ohio after 11236.6 mi. It was the longest un-refueled flight yet beating the unofficial 10212 mi record set by the Japanese Tachikawa Ki-77. This would stand as the absolute unrefueled distance record until 1962 when it was beaten by a USAF Boeing B-52 Stratofortress, and would remain as a piston-engined record until 1986 when the Rutan Voyager broke it circumnavigating the globe. "The Turtle" is preserved at the National Museum of Naval Aviation at NAS Pensacola.

Variants

Lockheed produced seven main variants of the P2V. In addition, Kawasaki built the turboprop-powered P-2J in Japan.

 * XP2V-1
 * Prototype, two built. Powered by two 2300 hp Wright R-3350-8 engines with four-bladed propellers, with armament of two .50 in machine guns in nose, tail and dorsal turrets, and 8000 lb of stores in an internal bomb bay.

 * P2V-1
 * First production model with R-3350-8A engine. Provision for 16 5 in HVAR or 4 11+3/4 in Tiny Tim rockets underwing; 14 built.

 * XP2V-2
 * Fifth production P2V-1 modified as a prototype for P2V-2. Powered by water injected R-3350-24W engines.

 * P2V-2
 * Second production model, powered by two 2800 hp R-3350-24W engines driving three-bladed propellers. Nose turret replaced by "attack" nose fitted with six fixed 20 mm cannon. First eight aircraft retained Bell tail turret fitted with twin .50 (12.7 mm) machine guns, with remaining aircraft using Emerson tail turret with twin 20 mm cannon. 80 built.

 * P2V-2N "Polar Bear"
 * Two P2V-2 modified for polar exploration under Project Ski Jump. Armament removed, with ski landing gear and provision for JATO rockets. Fitted with early MAD gear for magnetic survey purposes. Used for Operation Deep Freeze Antarctic exploration. The specially modified P2Vs had 16 ft long aluminum skis that were attached to the main landing gear units that when retracted, tucked into fairing just below the engines. This way the modified P2Vs could still land on a regular runway surface.

 * P2V-2S
 * One P2V-2 modified as a prototype anti-submarine variant with an AN/APS-20 search radar and additional fuel.

 * P2V-3
 * Improved patrol bomber with 3200 hp R-3350-26W engines with jet stack engine exhausts. 53 built.

 * P2V-3B
 * Conversions from other P2V-3 models, including P2V-3C and −3W, fitted with the ASB-1 Low Level Radar Bombing System; 16 converted. Redesignated as P-2C in 1962.

 * P2V-3C
 * Stop-gap carrier based one-way nuclear-armed bomber, not intended to return for a landing on a carrier. Fitted with JATO rocket to aid take-off from carrier and more fuel. Nose guns and dorsal turret removed to save weight. 11 P2V-3s and one P2V-2 modified.

 * P2V-3W
 * Airborne Early Warning variant, AN/APS-20 search radar; 30 built.

 * P2V-3Z
 * VIP combat transport with armored cabin in rear fuselage with seats for six passengers. Retained tail turret. Two converted from P2V-3s.

 * P2V-4
 * Improved anti-submarine aircraft. Fitted with AN/APS-20 search radar and provision for dropping sonobuoys with additional dedicated sonobuoy operator. Underwing tip-tanks added, with searchlight in nose of starboard tip tank. Gun Turrets in tail and dorsal position. First 25 aircraft powered by 3200 hp R-3350-26WA engines, with remaining 27 powered by 3250 hp Wright R-3350-30W turbo-compound engines. 52 built in total. Surviving aircraft redesignated P-2D in 1962.

 * P2V-5
 * Fitted with Emerson nose turret with two 20 mm cannon replacing solid nose of earlier versions, while retaining dorsal and tail turrets. New, larger, jettisonable tip tanks, with traversable searchlight slaved to nose turret in front of starboard tip-tank and AN/APS-8 radar in nose of port tip-tank. AN/APS-20 search radar under fuselage. Later aircraft featured glazed observation nose and MAD gear in place of nose and tail turrets, and revised crew accommodation, with many earlier aircraft refitted. Dorsal turret often removed. 424 built.

 * P2V-5F
 * Modification with two 3250 lbf J34 jet engines to increase power on take-off, and 3500 hp R-3350-32W piston engines. The J34 engines and R-3350 had a common fuel system burning AvGas rather than having dedicated jet fuel (as did all Neptunes with jets except the Kawasaki P-2J). Four underwing rocket pylons removed but increased 10000 lb weapon load. Redesignated P-2E in 1962.

 * P2V-5FD
 * P2V-5F converted for drone launch missions. All weaponry deleted. Redesignated DP-2E in 1962.

 * P2V-5FE
 * P2V-5F with additional electronic equipment. Redesignated EP-2E in 1962.

 * P2V-5FS
 * P2V-5F with Julie/Jezebel ASW gear, featuring AQA-3 long range acoustic search equipment and Julie explosive echo sounding gear. Redesignated SP-2E in 1962.

 * P2V-5JF
 * P2V-5F modified for weather reconnaissance, to include tropical storm/hurricane/typhoon penetrations, with Airborne Early Warning Squadron THREE (VW-3) and Weather Reconnaissance Squadron FOUR (VW-4)

 * AP-2E
 * Designation applied to P2V-5F with special SIGINT/ELINT equipment used by the US Army's 1st Radio Research Company at Cam Ranh Bay Air Base. Carrying a crew of up to fifteen, the AP-2E was the heaviest P-2, with a take-off weight of up to 80000 lb. Five converted (also designated RP-2E).

 * NP-2E
 * Single P-2E converted as permanent test aircraft.

 * OP-2E
 * Modified for use as part of Operation Igloo White for sensor deployment over South-East Asia with Observation Squadron 67 (VO-67). Fitted with terrain avoidance radar in nose, chaff dispensers, wing mounted gun pods and waist guns. 12 converted.

 * P2V-6
 * Multi-role version with lengthened weapons bay and provision for aerial minelaying and photo-reconnaissance. Smaller AN/APS-70 radar instead of AN/APS-20. Initially fitted with gun turrets as P2V-5, though retaining the ability to be refitted with glazed nose. A total of 67 were built for the US Navy and France. Redesignated P-2F in 1962.

 * P2V-6B
 * Anti-shipping version with provision to carry two AUM-N-2 Petrel anti-ship missiles. 16 built. Later redesignated P2V-6M then MP-2F in 1962.

 * P2V-6F
 * P2V-6 refitted with J34 jet engines. Redesignated P-2G in 1962.

 * P2V-6T
 * Crew trainer conversion with armament deleted, wingtip tanks often deleted. Redesignated TP-2F in 1962.

 * P2V-7
 * Last Neptune variant produced by Lockheed, powered by R-3350-32W and J-34 engines. Fitted with lower drag wingtip tanks, AN/APS-20 search radar in a revised radome and a bulged cockpit canopy. Early aircraft were fitted with defensive gun turrets but these were removed as for the P2V-5. 287 were built, including 48 assembled by Kawasaki in Japan. Redesignated P-2H in 1962.

 * P2V-7B
 * 15 aircraft with non-glazed nose fitted with four fixed 20 mm cannon for Royal Netherlands Naval Air Service. Subsequently fitted with glazed nose and modified to SP-2H standard. Supplemented by four SP-2H from France.

 * P2V-7LP
 * Four aircraft built with wheel/ski landing gear and JATO gear for Antarctic operations. Redesignated LP-2J in 1962. (No relation to Kawasaki P-2J)

 * P2V-7S
 * Additional ASW/ECM equipment including Julie/Jezebel gear. Redesignated SP-2H in 1962.

 * P2V-7U
 * Naval designation of the RB-69A variant.

 * AP-2H
 * Specialized night and all-weather ground attack variant fitted with FLIR and Low Light TV systems, tail turret, fuselage mounted grenade launchers and downwards firing miniguns. Bombs and napalm carried on underwing pylons. Four converted in 1968 for Heavy Attack Squadron 21 (VAH-21) for operation over South Vietnam.

 * DP-2H
 * P-2H converted for drone launch and control.

 * EP-2H
 * Single P-2H modified with UHF telemetry equipment instead of ASW systems.

 * NP-2H
 * Testbed conversion of P2V-H.

 * RB-69A
 * Five new built and two converted from P2V-7s for CIA covert operations, obtained with USAF help and operated by ROCAF 34th Squadron. Aerial reconnaissance/ELINT platform, modular sensor packages fitted depended on the mission needs. Originally fitted with Westinghouse APQ-56 Side Looking Airborne Radar (SLAR), the APQ-24 search radar, the Fairchild Mark IIIA cameras, the APR-9/13 radar intercept receiver, the QRC-15 DF system, the APA-69A DF display, the APA-74 pulse analyser, the Ampex tape recorder, the System 3 receiver to intercept enemy communications, the APS-54 RWR, a noise jammer, the RADAN system doppler radar navigation, and others. In May 1959, an upgrade program known as Phase VI was approved, and added the ATIR air-to-air radar jammer, replacing APR-9/13 with ALQ-28 ferret system, the QRC-15, 3 14-channel recorders and 1 7-channel high speed recorder to record ELINT systems, the K-band receiver, the ASN-7 navigation computer replacing RADAN, and Fulton Skyhook system.

 * Neptune MR.1
 * British designation of P2V-5; 52 delivered.

 * CP-122 Neptune
 * RCAF designation of P2V-7.(jet pod not initially fitted to 25 P2V-7 aircraft delivered to RCAF, but subsequently retrofitted)

 * Kawasaki P-2J (P2V-Kai)
 * Japanese variant produced by Kawasaki for JMSDF with T64 turboprop engines, various other improvements; 82 built.

Military operators

 * Argentine Navy – Argentine Naval Aviation (16 units)
 * Escuadrilla Aeronaval de Exploracion
 * Royal Australian Air Force
 * No. 10 Squadron RAAF
 * No. 11 Squadron RAAF
 * Brazilian Air Force (14 units)
 * 1°/7° Grupo de Aviação
 * 🇨🇦 Canada
 * Royal Canadian Air Force
 * No. 404 Squadron RCAF
 * No. 405 Squadron RCAF
 * No. 407 Squadron RCAF
 * French Naval Aviation
 * 21F Flottilla (P2V-6) BAN Nîmes-Garons
 * 22F Flottilla (P2V-6) BAN Nîmes-Garons
 * 23F Flottilla (P2V-6) (P2V-7) BAN Lann-Bihoué
 * 24F Flottilla (P2V-7) BAN Lann-Bihoué
 * 25F Flottilla (P2V-7) BAN Lann-Bihoué
 * 8S Escadrille (P2V-6) Base aérienne 185 Hao
 * 9S Escadrille (P2V-7) BAN Tontouta
 * 12S Escadrille (P2V-7) Base aérienne 185 Hao
 * Japan Maritime Self-Defense Force
 * Air Patrol Squadron 3 (JMSDF)
 * Air Patrol Squadron 2 (JMSDF)
 * Air Development Squadron 51 (JMSDF)
 * Dutch Naval Aviation Service
 * Portuguese Air Force (12 units)
 * Esquadra 61, Montijo Air Base
 * Detachment 61, Bissalanca Air Base (Portuguese Guinea) and Sal Air Base (Cape Verde)
 * Detachment 62, Luanda Air Base (Angola)
 * Detachment 63, Beira Air Base (Mozambique)
 * Republic of China Air Force
 * 34th Black Bat Squadron
 * Royal Air Force
 * No. 36 Squadron RAF
 * No. 203 Squadron RAF
 * No. 210 Squadron RAF
 * No. 217 Squadron RAF
 * No. 236 Operational Conversion Unit RAF
 * United States Army
 * United States Marine Corps
 * United States Navy
 * Central Intelligence Agency operated seven RB-69A in USAF colors.
 * No. 36 Squadron RAF
 * No. 203 Squadron RAF
 * No. 210 Squadron RAF
 * No. 217 Squadron RAF
 * No. 236 Operational Conversion Unit RAF
 * United States Army
 * United States Marine Corps
 * United States Navy
 * Central Intelligence Agency operated seven RB-69A in USAF colors.
 * Central Intelligence Agency operated seven RB-69A in USAF colors.

Civilian operators

 * Aero Union

Accidents and incidents

 * On 27 November 1950 a P2V-2 crashed while conducting a test run with rockets near Kaena Point in Hawaii. The starboard wing separated from the aircraft. The crew of five died on impact.
 * On 6 November 1951, a P2V of VP-6 carrying out a weather reconnaissance mission over international waters off Vladivostok was attacked and shot down by a number of MiG-15s. All ten crew were killed.
 * On 5 January 1952, a Lockheed P2V-2 Neptune (122443) operated by the United States Navy undershot the runway at RAF Burtonwood and collided with a USAF Douglas C-47 (42-100912). One crew member on the Neptune and six others on the C-47 were killed. Fifteen others were injured, eleven on the Neptune and four on the C-47.
 * On 18 January 1953, a P2V of VP-22 was shot down off Swatow in the Formosa Straits by Chinese anti-aircraft fire. Eleven of thirteen crewmen were rescued by a US Coast Guard PBM-5 under fire from shore batteries on Nan Ao Tao island. Attempting to takeoff in 8 to 12-foot swell, the PBM crashed. Ten survivors out of nineteen total (including five from the P2V) were rescued by USS Halsey Powell (DD-686). During the search effort, a PBM-5 from VP-40 received fire from a small-caliber machine gun, and USS Gregory (DD-802) received fire from shore batteries.
 * On December 17, 1953, P2V-5 Neptune S/N (BUN 12388) of VP-3 with a nine men crew, disappeared on a patrol flight from Keflavík Airport, an airfield near Iceland capital of Reykjavík. The Neptune took off from Keflavík at 2 pm. Thursday for routine patrol over North Atlantic waters. It was circling back through a storm toward that base when it radioed its last position. The wreck was sighted on Mýrdalsjökull glacier and at least three of the nine men crew were initially reported alive. A United States air rescue plane spotted the wreckage, which was described as "badly broken up“. Helicopter lift recovered one body, but bodies of 8 men remain in the frozen wreck until spring (1954). On October 14, 1982, the remains of American crewmen was found 28 years after the crash into the glacier. The wreck was discovered by farmers rounding up sheep, apparently the glacier movement uncovered the wreck. The crew was LT Henry Cason, LT Ishmuel M. Blum, ENS Sven Shieff, AD2 Eddie L. Cater, AN Everett Humbert, AT3 Amos W. Jones, AL2 Robert B. Whale, AO3 Marvin L Baker, ATAN William A. Ward.
 * On 4 September 1954, a P2V-5 of VP-19 operating from NAS Atsugi ditched in the Sea of Japan, 40 mi off the coast of Siberia after an attack by two Soviet Air Forces MiG-15s. One crewmen was killed, and the other nine were rescued by a USAF SA-16 Grumman Albatross amphibian.
 * On 22 June 1955, a P2V-5 of VP-9, flying a patrol mission from NAS Kodiak, Alaska, was attacked over the Bering Straits by two Soviet Air Forces MiG-15s. The P2V crash-landed on St. Lawrence Island after an engine was set afire. Of the eleven crew members, four sustained injuries due to gunfire and six were injured during the landing. The US government demanded $724,947 in compensation; the USSR finally paid half this amount.
 * On 26 September 1955, a P2V-3W (131442), callsign Snowcloud Five, was lost south of Jamaica while attempting to penetrate the center of Hurricane Janet with nine crew and two journalists aboard; despite an extensive search and rescue effort over the next five days involving 3,000 personnel, 60 aircraft, and seven ships, no trace of the aircraft or its occupants was ever found. This remains the only loss of a reconnaissance aircraft during penetration of an Atlantic hurricane.  The cause of the crash is unknown, although theories include an incorrect altimeter reading due the low barometric pressure in the hurricane and increased workload due to one of the usual crew members having been replaced by a reporter causing the crew to lose track of their height above the sea.
 * On 10 October 1956, a P2V-5 of No. 36 Squadron RAF (WX545) crashed into the side of Beinn na Lice, Mull of Kintyre, southwest Scotland, killing all nine crew members. WX545 was returning from an anti-submarine exercise off Derry, Northern Ireland to its base at RAF Topcliffe in North Yorkshire, England. Beinn na Lice was hidden by fog, and a member of 36 Squadron alleges that the aircraft in the exercise had been ordered not to use radar in inshore waters.
 * On 12 April 1957, a P2V-5F of VP-26 crashed on takeoff during a short takeoff practice exercise at NAS Brunswick, Maine. The apparent cause was a runaway varicam elevator control, which caused a hammerhead stall at very low altitude. The aircraft did an overhead loop, reversing its direction, but crashed into the woods near the departure end of the runway next to the base golf course. There were no survivors.
 * On 21 July 1957, a US Navy Neptune searching for a sister P2V Neptune crashed near Mount Pra, Italy, near the French border, killing nine airmen. The other P2V for had disappeared two days earlier, 19 July, with 11 on board on a flight from Casablanca to Treviso.
 * On 1 February 1958, USAF C-118A 53-3277 collided in mid-air with a US Navy Lockheed P2V Neptune 127723 over Norwalk, California, killing 47 of 49 on board both aircraft and 1 person on the ground.
 * On 4 February 1959, RAAF A89-308 crashed at RAAF Richmond, NSW, Australia. All eight crew died. The port engine began to disintegrate, causing a fuel leak in the wheel well. The resulting fire severed the magnesium wing spar, and the aircraft fell from the sky before the crew could bail out.
 * On 25 March 1960, an ROCAF RB-69A/P2V-7U (7101/140442/54-4040) crashed into a hill near Kunsan Air Base, South Korea, during a low-level ferry flight from Hsinchu, Taiwan to a staging area in Kunsan, South Korea. All 14 aircrew on board were killed.
 * On 6 November 1961, an ROCAF RB-69A/P2V-7U (7099/140440/54-4039) conducting a low-level penetration flight over mainland China was shot down by ground fire over Liaodong peninsula. All 14 aircrew on board were killed in action.
 * On 9 November 1961, an P2V-7LP of VX-6 crashed on takeoff from Wilkes Station, Antarctica, where it had refuelled en route to McMurdo Station. Four aircrew and one passenger were killed, with four aircrew surviving.
 * On 8 January 1962, a ROCAF RB-69A/P2V-7U(7097/140438/54-4038) crashed into the Korea Bay while conducting ELINT and leaflet dropping missions. All 14 aircrew on board were killed in action.
 * On 12 January 1962, a P2V-5 (designation LA-9) of VP-5 flew off course during a patrol over the Denmark Strait and crashed on the Kronborg Glacier in eastern Greenland. All 12 crew were killed. The wreckage was discovered by a party of British geologists in 1966.
 * On 19 June 1963, an ROCAF RB-69A/P2V-7U (7105/141233/54-4041) was conducting an ELINT mission over mainland China, and was shot down by PLAAF MiG-17PF over Linchuan, Jiangxi, after being intercepted repeatedly by multiple MiG-17PFs and Tu-4Ps. All 14 aircrew on board were killed in action.
 * On 11 June 1964, a RB-69A/P2V-7U (7047/135612/54-4037) was conducting an ELINT mission over mainland China and was shot down by a PLAN-AF MiG-15 over Shandong peninsula after being intercepted by MiG-15s and Il-28s. All 13 aircrew on board were killed in action.
 * On 22 January 1965, an RCAF P2V-7 #24115 crashed short of the runway at CFB Summerside, Prince Edward Island, when it ran out of battery power to run the fuel pumps to the J-34 jet engines. The aircraft had lost one reciprocating engine, and the generator failed on the other. Also, because Canadian Neptunes had no other generators, these failures led to the loss of all thrust and the subsequent crash.
 * On 22 January 1965, just before midnight, an MLD SP-2H (212) was taken from Vliegkamp Valkenburg, near The Hague, by two young aircraft mechanics lacking any flying experience. They managed to get the plane airborne, but stalled shortly after takeoff. It crashed into the North Sea, a few hundred metres offshore of the fishing town of Katwijk. The investigation report concluded that it was a drunken prank.
 * On 3 December 1967, a Lockheed P-2E aircraft departed Naval Air Station Brunswick for a routine patrol flight. At some point, the aircraft developed mechanical problems and received clearance to land at Otis Air Force Base. As the aircraft was making its final approach, it crashed a half mile short of the runway. All twelve men aboard escaped; four of them suffered minor injuries.
 * On 4 February 1970 at 4:39 a.m, French Navy Lockheed P2V7 Neptune No. 147571 of Flotilla 25F crashed after takeoff, killing all 12 crew members.
 * On 15 January 1971, French Navy Lockheed P2V7 Neptune No. 147564 of Flottilla 25F crashed at the start of runway 26 on the Lann-Bihoué naval aeronautics base, in the final phase of a landing in foggy weather, killing 6 of the 10 crew.
 * On 15 September 1976, an Argentine Navy Lockheed Neptune aircraft flew on a reconnaissance mission from Rio Gallegos to survey the sea ice conditions in Drake Passage at the beginning of the summer navigation season. The plane crashed in poor weather on the then-uninhabited Livingston Island, Antarctica, killing all 10 aircrew and a civilian television cameraman.
 * On 5 September 2008, a Neptune Aviation Services Lockheed Neptune, registered N4235T, crashed soon after takeoff from Reno/Stead Airport, Reno, Nevada. The left engine and then left wing were seen to catch fire before the aircraft crashed. All three crew members on board were killed.
 * On 3 June 2012, while engaged in firefighting operations in Utah, a Neptune Aviation Services Lockheed Neptune, registered N14447, crashed. Two crew members were killed.

Surviving aircraft
There are a few Neptunes that have been restored and are on display in museums and parks.

Argentina

 * On display
 * SP-2H
 * 2-P-112 – Museo Aeronaval (MUAN) of Argentine Naval Aviation. This is the Neptune that tracked HMS Sheffield.

Australia

 * Airworthy
 * SP-2H
 * 149073 – Historical Aircraft Restoration Society, Illawarra Regional Airport, New South Wales, Australia. Ex A89-273 of No. 10 Squadron RAAF, now civil registered VH-IOY.
 * 147566 – Historical Aircraft Restoration Society, Illawarra Regional Airport, New South Wales, Australia. Delivered to French Aeronavale, assigned to Escadrille 12 last based in Tahiti. Currently displaying French Aeronavale colours, now civil registered VH-LRR.
 * On Display
 * SP-2H
 * 149075 – RAAF Museum, Point Cook, Victoria. Ex A89-275 of No. 10 Squadron RAAF
 * 149077 – Queensland Air Museum, Caloundra. Ex A89-277 of No. 10 Squadron RAAF
 * 149080 – RAAF Base Townsville entrance, owned by RAAF Museum. Ex A89-280 of No. 10 Squadron RAAF.
 * 149081 – Historical Aircraft Restoration Society, Illawarra Regional Airport, New South Wales. Ex A89-281 of No. 10 Squadron RAAF.
 * In Storage
 * SP-2H
 * 133640 – RAAF Museum, Point Cook, Victoria. Ex A89-302 of No. 11 Squadron RAAF, in storage for RAAF Museum.
 * 145921 – Registered to Valerio, located in Cunderdin, Western Australia, ex-USN, imported into Australia November 1988, converted to firefighting tanker, civil registered VH-NEP.
 * Under Restoration
 * SP-2E
 * 133640 – Historic Aircraft Restoration Society, Parkes Airport, New South Wales, Australia. Ex A89-302 of No. 11 Squadron RAAF. The oldest Neptune in Australia, it was gifted by the RAAF Museum in 2018, for static restoration.
 * SP-2H
 * 149072 – Historic Aircraft Restoration Society, Parkes Airport, New South Wales, Australia. Ex A89-272 of No. 10 Squadron RAAF. Donated to HARS by RAAF in February 2016 for restoration and display at the HARS Parkes satellite facility.

Canada

 * On display
 * EP-2H
 * 147969 – Greenwood Military Aviation Museum in Nova Scotia, Canada.

Chile

 * Under restoration
 * SP-2H
 * 147967 – To be displayed is the Neptune /Firestar registered CC-CHU of Heliworks Ltda. Currently dismantled in Concepción/Carriel Sur airport, N703AU/Tanker 03's incorporation into Chile's Museo Nacional Aeronáutico y del Espacio collection at the former Los Cerrillos airport in Santiago, was announced during the ceremony of the 69th Anniversary of Museum on 4 July 2013.

France

 * On Display
 * P2V-7
 * 334 - Musée de l'air et de l'espace in Paris-Le Bourget Airport
 * In Storage
 * P2V-7
 * 335 - in the Musée de l'air et de l'espace reserve in Dugny
 * 563 - To be retrieved by the Musée de l'air et de l'espace in Paris-Le Bourget Airport. Currently stored on an old airbase in Brienne-le-Château, Aube department

Netherlands

 * On display
 * SP-2H
 * 201 – on display outside at the Nationaal Militair Museum, Soesterberg.
 * 210 - on display outside at Aviodrome Lelystad AirPort. This aircraft was donated to KLM engineering & maintenance for training purposes and was painted in KLM colors. Afterwards transported by barge to Aviodrome and now in partial Dark Sea grey color.
 * 216 – gate guardian at the former naval airbase Valkenburg, after closing it was moved to naval airbase De Kooy near Den Helder, The Netherlands.

Portugal

 * On display
 * P2V
 * 4711 – Museu do Ar, Sintra.

United Kingdom

 * On display
 * P-2H
 * 204 – Royal Air Force Museum Cosford. former Royal Netherlands Navy, last airworthy airframe donated to the UK in 1982 after arrival of the first P-3c in the Royal Netherlands Navy.

United States

 * Airworthy
 * P2V-7/P-2H
 * 148360 – Erickson Aircraft Collection in Madras, Oregon
 * P2V-7S/SP-2H
 * 145915 – Mid-Atlantic Air Museum in Reading, Pennsylvania.
 * On display
 * P2V-1
 * 89082 Truculent Turtle – National Museum of Naval Aviation, NAS Pensacola, Florida.
 * P2V-5F/P-2E
 * 128392 - NAS Brunswick main gate, former NAS Brunswick, Maine.
 * 131410 – NAS Jacksonville Memorial Park, NAS Jacksonville, Florida.
 * P2V-5FS/AP-2E
 * 131485 – United States Army Aviation Museum at Fort Novosel, Alabama
 * P2V-5FS/SP-2E
 * 128402 – Pueblo Weisbrod Aircraft Museum in Pueblo, Colorado.
 * P2V-5/SP2-E
 * 128402 – On static display at Moffett Historical Museum, Moffett Federal Airfield (former NAS Moffett Field), California.
 * P2V-7/P-2H
 * 140443 – Yankee Air Museum in Belleville, Michigan
 * 147957 – Pima Air and Space Museum, adjacent to Davis-Monthan AFB in Tucson, Arizona.
 * 147966 – South Georgia Technical College in Americus, Georgia.
 * 147968 - Chico Air Museum in Chico, California.
 * P2V-7S/AP-2H
 * 135620 – Pima Air and Space Museum adjacent to Davis-Monthan AFB in Tucson, Arizona.
 * P2V-7S/SP-2H
 * 147954 – Museum of Aviation at Robins AFB, Georgia. The P-2 Neptune is painted to represent a USAF/CIA/Taiwan RB-69A.
 * 141234 – National Museum of Naval Aviation in NAS Pensacola, Florida.
 * 150279 – Gate guard at the Marine Corps Base Hawaii (former MCAS Kaneohe Bay), Hawaii. Relocated from former NAS Barbers Point, Hawaii in 1998 following that base's closure due to BRAC action.
 * Under restoration or in storage
 * P2V-5
 * 128422 – in storage by Neptune Aviation Services in Missoula, Montana.
 * P2V-5F/P-2E
 * 131502 – in storage by Premier Jets in Hillsboro, Oregon.
 * 131482 – in storage by Neptune Aviation Services in Missoula, Montana.
 * P2V-5FS/SP-2E
 * 131542 – for static display by the Historic Aircraft Restoration Project at former NAS New York / Floyd Bennett Field in Brooklyn, New York.
 * P2V-7/P-2H
 * 140154 – in storage by the Museum of Flight and Aerial Firefighting in Greybull, Wyoming.
 * 140972 – in storage by Neptune Aviation Services in Missoula, Montana.
 * 147949 – in storage by Neptune Aviation Services in Missoula, Montana.
 * 148341 – in storage by Neptune Aviation Services in Missoula, Montana.
 * 148346 – in storage by Neptune Aviation Services in Missoula, Montana.
 * 148356 – in storage by Neptune Aviation Services in Missoula, Montana.
 * 148359 – in storage by Neptune Aviation Services in Missoula, Montana.
 * 148362 – in storage by Neptune Aviation Services in Missoula, Montana.
 * P2V-7S/SP-2H
 * 147965 – in storage by Neptune Aviation Services in Missoula, Montana.
 * 148339 – in storage by Neptune Aviation Services in Missoula, Montana.
 * 148339 – in storage by Neptune Aviation Services in Missoula, Montana.

title: Lockheed P-2 Neptune


text:
Law of the iterated logarithm

In probability theory, the law of the iterated logarithm describes the magnitude of the fluctuations of a random walk. The original statement of the law of the iterated logarithm is due to A. Ya. Khinchin (1924). Another statement was given by A. N. Kolmogorov in 1929.

Statement
Let {Yn} be independent, identically distributed random variables with means zero and unit variances. Let Sn = Y1 + ... + Yn. Then

\limsup_{n \to \infty} \frac{|S_n|}{\sqrt{2n \log\log n}} = 1 \quad \text{a.s.}, $$ where "log" is the natural logarithm, "lim sup" denotes the limit superior, and "a.s." stands for "almost surely".

Discussion
The law of iterated logarithms operates "in between" the law of large numbers and the central limit theorem. There are two versions of the law of large numbers — the weak and the strong — and they both state that the sums Sn, scaled by n−1, converge to zero, respectively in probability and almost surely:

\frac{S_n}{n} \ \xrightarrow{p}\ 0, \qquad \frac{S_n}{n} \ \xrightarrow{a.s.} 0, \qquad \text{as}\ \ n\to\infty. $$

On the other hand, the central limit theorem states that the sums Sn scaled by the factor n−1/2 converge in distribution to a standard normal distribution. By Kolmogorov's zero–one law, for any fixed M, the probability that the event $$ \limsup_n \frac{S_n}{\sqrt{n}} \geq M $$ occurs is 0 or 1. Then

 * $$ \Pr\left( \limsup_n \frac{S_n}{\sqrt{n}} \geq M \right) \geqslant \limsup_n \Pr\left( \frac{S_n}{\sqrt{n}} \geq M \right) = \Pr\left( \mathcal{N}(0, 1) \geq M \right) > 0$$

so

 * $$\limsup_n \frac{S_n}{\sqrt{n}}=\infty \qquad \text{with probability 1.}$$

An identical argument shows that

 * $$ \liminf_n \frac{S_n}{\sqrt{n}}=-\infty \qquad \text{with probability 1.}$$

This implies that these quantities cannot converge almost surely. In fact, they cannot even converge in probability, which follows from the equality

 * $$\frac{S_{2n}}{\sqrt{2n}}-\frac{S_n}{\sqrt{n}} = \frac1{\sqrt2}\frac{S_{2n}-S_n}{\sqrt{n}} - \left (1-\frac1\sqrt2 \right )\frac{S_n}{\sqrt{n}}$$

and the fact that the random variables

 * $$\frac{S_n}{\sqrt{n}}\quad \text{and} \quad \frac{S_{2n}-S_n}{\sqrt{n}}$$

are independent and both converge in distribution to $$\mathcal{N}(0, 1).$$

The law of the iterated logarithm provides the scaling factor where the two limits become different:

\frac{S_n}{\sqrt{2n\log\log n}} \ \xrightarrow{p}\ 0, \qquad \frac{S_n}{\sqrt{2n\log\log n}} \ \stackrel{a.s.}{\nrightarrow}\ 0, \qquad \text{as}\ \ n\to\infty. $$

Thus, although the absolute value of the quantity $$S_n/\sqrt{2n\log\log n}$$ is less than any predefined ε > 0 with probability approaching one, it will nevertheless almost surely be greater than ε infinitely often; in fact, the quantity will be visiting the neighborhoods of any point in the interval (-1,1) almost surely.

Generalizations and variants
The law of the iterated logarithm (LIL) for a sum of independent and identically distributed (i.i.d.) random variables with zero mean and bounded increment dates back to Khinchin and Kolmogorov in the 1920s.

Since then, there has been a tremendous amount of work on the LIL for various kinds of dependent structures and for stochastic processes. The following is a small sample of notable developments.

Hartman–Wintner (1940) generalized LIL to random walks with increments with zero mean and finite variance. De Acosta (1983) gave a simple proof of the Hartman–Wintner version of the LIL.

Chung (1948) proved another version of the law of the iterated logarithm for the absolute value of a brownian motion.

Strassen (1964) studied the LIL from the point of view of invariance principles.

Stout (1970) generalized the LIL to stationary ergodic martingales.

Wittmann (1985) generalized Hartman–Wintner version of LIL to random walks satisfying milder conditions.

Vovk (1987) derived a version of LIL valid for a single chaotic sequence (Kolmogorov random sequence). This is notable, as it is outside the realm of classical probability theory.

Yongge Wang (1996) showed that the law of the iterated logarithm holds for polynomial time pseudorandom sequences also. The Java-based software testing tool tests whether a pseudorandom generator outputs sequences that satisfy the LIL.

Balsubramani (2014) proved a non-asymptotic LIL that holds over finite-time martingale sample paths. This subsumes the martingale LIL as it provides matching finite-sample concentration and anti-concentration bounds, and enables sequential testing and other applications.

title: Law of the iterated logarithm


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Star 94

"Star 94" is the moniker of at least two radio stations in the U.S.:

 * WSTR-FM 94.1 FM in Atlanta (Smyrna, Georgia)
 * WMSR-FM 94.9 in Muscle Shoals (Florence, Alabama / Collinwood, Tennessee)

Both stations use the same name, but are not simulcast.

title: Star 94


text:
User talk:Bsoft

Feel free to leave me a message. 07:36, 22 June 2006 (UTC)

Proposed deletion of GeForce PCX
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If no one objects to the deletion within five days by removing the "prod" notice, the article may be deleted without further discussion. If you remove the prod notice, the deletion process will stop, but if an editor is still not satisfied that the article meets Wikipedia guidelines, it may be sent to Articles for deletion for consensus. NickelShoe (Talk) 19:10, 22 May 2007 (UTC)

title: User talk:Bsoft


text:
96 Rock

96 Rock can refer to an American radio station:

 * WDIZ_AM - HD2 - Streaming 96rock.iHeart.com in Panama City, Florida
 * WBBB in Raleigh, North Carolina
 * WFTK in Cincinnati, Ohio
 * WKZP in Salisbury/Ocean City, Maryland
 * WWPW Former longtime 96 Rock station in Atlanta, Georgia. Now, branded as Power 96.1

title: 96 Rock