--- title: "Boeing E-3 Sentry: America's Eye in the Sky" description: "Say the words \"military aircraft\" and most people picture something fast and sleek: the F-16, the Eurofighter Typhoon, the F-22 Raptor. The Boeing E-3 Sentry is none of those things. A modified Boeing 707-320, it stretches 152 ft (46.33 m) long, spreads a wingspan of 145 ft 9 in (44.42 m), and tips the scales at 185,000 lbs (84,000 kg) empty. This thing truly is a beast.\n\nAnd yet, despite all that bulk, a fully crewed E-3 carries only between 17 and 25 personnel. The military has plenty of uses for enormous aircraft — troop transport, hauling equipment — but this leviathan of the skies isn't built for any of that. So what is it for? You could sum up its role in just six words: the ultimate eye in the sky.\n\nFor decades the E-3 has flown its missions largely out of public view. Here, we strip back some of the mystery around the Sentry — its radar technology, its surveillance reach, and the long list of operations it has quietly shaped.\n\n## A Concept Born in the Second World War\n\nThe E-3 Sentry officially took to the skies for the first time on the 25th of May 1976, but its origins reach back much further — all the way to the Second World War.\n\nWhen America finally entered the war, the Navy had a problem. Many of its ships carried radar systems to detect incoming enemy aircraft, but those systems worked far less well when other ships were close by. To get accurate readings, a radar-equipped ship had to travel a fair distance from any backup — which turned it into a prime target for bombing raids.\n\nThe answer was Project Cadillac. A huge, radar-equipped destroyer might be a sitting duck for an enemy pilot, but an aircraft carrying similar equipment was a different story. Project Cadillac fitted an APS-20 early-warning radar to a modified Grumman Avenger (the XTBM-3W), which could both more easily avoid destruction and provide much earlier warning of incoming aircraft.\n\nThe concept worked so well that, after the war, similar equipment was installed in a Lockheed L-1049 Super Constellation airliner. Designated the \"Warning Star,\" it served as an advanced radar detection system into the early 1960s.\n\n## Replacing the Warning Star\n\nBy the early 1960s, radar technology had advanced so far, so fast, that the Warning Star was no longer fit for purpose and needed replacing. The United States Air Force issued preliminary development contracts to Boeing, Douglas, and Lockheed. In July 1970, Boeing won the final contract to build the aircraft that would eventually become the E-3 Sentry.\n\nBoeing initially planned to design and build an entirely new aircraft from the ground up, but quickly dropped that idea in favor of modifying the already-proven 707 to meet the Air Force's needs.\n\nAnd what were those needs? The original design brief wasn't available, but the concerns Congress raised during the funding application paint a clear picture. The new aircraft would need to detect an incoming threat from any direction at considerable distance, operate in a hostile environment, and counteract sophisticated communications jamming of the kind it might face in any campaign against the Soviet Union.\n\nOne requirement we do know about: the Air Force initially wanted a 14-hour uninterrupted flight capability. To hit that target, Boeing planned to install eight General Electric TF34 engines. But with costs spiraling, the required flight time was cut — which let Boeing use the Pratt & Whitney JT3D engines already fitted to the 707 airliner. The shorter range was offset by adding air-refueling capability.\n\n## Choosing the Radar\n\nRadar was the whole point of the aircraft, so Boeing tested two separate systems on two separate aircraft.\n\nThe first, built by Hughes Aircraft Company, appears to have been fairly effective — but its computer system struggled to pick out the signature of a low-flying enemy aircraft from the clutter of objects on the ground.\n\nThe second system, built by the Westinghouse Electric Corporation, solved that problem using the pulse-Doppler principle. Without turning this into a physics lesson: pulse-Doppler radar differs from more standard systems because, instead of relying on a single pulse repetition time (PRT), it uses multiple PRTs. Short PRTs detect targets at close range, while longer PRTs reach distant targets, letting the radar adapt to different ranges effectively.\n\nBecause the entire project was about achieving as close to 360 degrees of radar coverage as possible — and because the Westinghouse system could detect objects beyond the horizon — that was the system the Air Force chose.\n\n## Convincing Congress\n\nEven after all that testing, one major hurdle remained: funding. Congress was reluctant to approve it, citing a lack of evidence that the system would perform as advertised and doubts about whether the aircraft could survive and operate in a hostile environment.\n\nThose concerns ran deep enough that the 1975 defense spending bill carried a caveat: a special electronic countermeasures committee was to be formed by the Secretary of Defense to review the E-3's ability to overcome enemy jamming. Congress also demanded a personal certification from the Secretary of Defense that the new plane was genuinely capable of operating in any hostile environment.\n\nWith the budget requirements finally satisfied, Boeing was at last cleared to begin building the first of these aircraft — and it didn't hang around. In October 1976, 23 months after the project got the green light, the first E-3 Sentry Airborne Warning and Control System (AWACS) arrived at its designated home.\n\nThat home was Tinker Air Force Base in Oklahoma. As with everything about this aircraft, the base was chosen to maximize the E-3's capabilities. Sitting almost exactly in the middle of the United States, Tinker let the Sentry reach all US borders in minimal time. It was also home to the Oklahoma Air Logistics Center, providing the round-the-clock maintenance needed to keep the fleet in optimum condition.\n\n## Into Service: A Relentless Operational Tempo\n\nOn the 31st of March 1977, the E-3 took off on its first operational flight and quickly began to prove its worth. In support of the North American Aerospace Defense Command (NORAD), it stood ready to provide near-immediate assistance wherever needed.\n\nIt would be years before any E-3 saw actual combat, but the government found other uses fast. 1978 was a busy year: the Sentry made its first successful interception of cannabis traffickers trying to enter Florida by air, deployed to Kadena Air Base in Japan (which would later become a slightly less well-equipped E-3 base), and impressed enough in real-world conditions that NATO ordered 18 aircraft to build its own airborne early-warning system.\n\nBefore the decade was out, the E-3 flew two more important missions — sent to Yemen to provide advanced tactical support amid rising civil-war tensions, then performing a similar role in South Korea following the assassination of its president.\n\nThe 1980s offered no rest. After a joint training exercise with the Egyptian military, a group of E-3s deployed to Saudi Arabia over fears that the Iran-Iraq war might spill into neighboring countries; several aircraft remained in the region providing round-the-clock radar surveillance for the entire war.\n\nThen, in 1981, the doubts Congress had raised about facing the Soviet Union were finally put to rest. One E-3 successfully detected and coordinated the interception of a Soviet Bison aircraft near Iceland — proof that both its radar and its encrypted communications and anti-jamming suite worked as promised. Having also returned to Egypt earlier that year following another presidential assassination, the fleet of 24 E-3s set a new record of 26,365 hours of logged flight time in a single year.\n\nThe rest of the decade stayed eventful. E-3s were sent to Sudan to provide aircraft coordination that helped repel rebel forces; several joined Operation Urgent Fury, limiting air and sea travel in and out of Cuba; and a third E-3 base was established at Elmendorf AFB, Alaska. During 1987, the entire fleet began a series of extensive upgrades to its onboard computer, electronic surveillance, and communications systems.\n\n## Two Tragedies\n\nThe E-3 and its crews really did seem to be the ultimate reconnaissance team, executing almost any mission flawlessly. That reputation was shaken on the 14th of April 1994.\n\nOn that day, two United States Air Force Black Hawk helicopters were shot down by American fighter jets over Iraq. As a newspaper reported at the time, the helicopters — both Army UH-60 Black Hawks — were ferrying a team of foreign officers and Kurds on a routine visit to remote Kurdish villages, and the pilots of the US jets, both Air Force F-15C Eagles, \"somehow mistook the helicopters for Iraqi aircraft despite good visibility.\"\n\nGiven that all four aircraft were under the control of an E-3 AWACS, such a mistake should have been impossible. An official investigation into the incident, which killed 24 people, was quickly launched. As the Washington Post summarized, the pilots' confusion — \"made in daylight and clear skies\" — might not have been fatal if controllers aboard the nearby AWACS plane had intervened and told the F-15 pilots to hold their fire, since \"information available on the radar plane's computer screens made plain the helicopters were friendly.\" But the AWACS controllers, \"operating in what Defense Department officials described as a fog of complacency and lax procedures,\" did not alert the F-15 pilots. The incident drove changes in training and procedure, but it seriously damaged the E-3's public image.\n\nA different kind of tragedy struck on the 22nd of September 1995. A US Air Force E-3 Sentry operating under the callsign Yukla 27 went down shortly after takeoff from its base in Alaska. According to reports, several geese were sucked into the portside engines, causing them to shut down. All 24 personnel on board were killed in the crash. Remarkably, across nearly 50 years in service there have been only two other instances resulting in loss of life — and only one of those was attributed to pilot error.\n\n## Still the Eye in the Sky\n\nWith those tragedies behind it, the E-3 finished the decade with business very much as usual. The aircraft received a further upgrade replacing its old navigation systems with GPS and was dispatched to assist NATO efforts in the Balkans.\n\nAfter the September 11 attacks, the Sentry took on another vital role. Its unique surveillance and communications abilities made it essential to preventing further terrorist attacks, and AWACS was deployed to provide 24-hour surveillance of the skies over America. In 2004, with the skies over Iraq somewhat more peaceful, the E-3 again found itself helping law enforcement battle drug smugglers bringing product into the United States from Latin America.\n\nIt hasn't all been wars against terrorism or drugs, either. In 2005, after the devastation of hurricanes in Louisiana, Mississippi, and Alabama, the E-3 coordinated search-and-rescue and aid deployment from the skies.\n\nAll in all, the E-3 Sentry — a design now nearly half a century old — has not only fulfilled its original brief but exceeded it by a considerable margin. The fact that it's still flown by the United States, the UK, France, Japan, and Saudi Arabia shows it truly is an awesome bit of kit. And when the time finally comes for it to retire, whatever comes next will have some incredibly huge wings to fill.\n\n## Key Takeaways\n\n- The E-3 Sentry is a modified Boeing 707-320 built for one job: airborne early warning and control. Despite its enormous size, it carries only 17 to 25 crew.\n- The airborne-radar concept traces back to WWII's Project Cadillac and the later Lockheed \"Warning Star,\" both forerunners the E-3 was designed to succeed.\n- Boeing won the contract in July 1970 and chose Westinghouse's pulse-Doppler radar for its ability to detect low-flying targets against ground clutter and see beyond the horizon.\n- The aircraft first flew on 25 May 1976 and entered operational service in 1977, based at Tinker AFB in Oklahoma for its central US location and round-the-clock maintenance.\n- A 1994 friendly-fire shoot-down of two Black Hawks under AWACS control, and the 1995 Yukla 27 crash that killed all 24 aboard, are the darkest moments in the type's history.\n- Nearly 50 years on, the E-3 still serves the US, UK, France, Japan, and Saudi Arabia.\n\n## Frequently Asked Questions\n\n### What is the Boeing E-3 Sentry?\n\nThe E-3 Sentry is a modified Boeing 707-320 that serves as an Airborne Warning and Control System (AWACS) aircraft. Its job is airborne surveillance — detecting threats from any direction at long range and coordinating the response — which the script sums up as being \"the ultimate eye in the sky.\" Despite its size, a fully crewed aircraft carries only 17 to 25 personnel.\n\n### When did the E-3 Sentry first fly and enter service?\n\nThe E-3 officially took to the skies for the first time on the 25th of May 1976. The first AWACS aircraft arrived at its designated base in October 1976, and the type flew its first operational flight on the 31st of March 1977 in support of NORAD.\n\n### Why was the E-3 based at Tinker Air Force Base?\n\nTinker AFB in Oklahoma was chosen to maximize the aircraft's capabilities. Sitting almost exactly in the middle of the United States, it let the E-3 reach all US borders in minimal time. Tinker was also home to the Oklahoma Air Logistics Center, which provided the round-the-clock maintenance needed to keep the fleet in top condition.\n\n### What radar does the E-3 use, and why was it chosen?\n\nBoeing tested two radars: a Hughes system that struggled to distinguish low-flying aircraft from ground clutter, and a Westinghouse system using the pulse-Doppler principle. Pulse-Doppler uses multiple pulse repetition times — short PRTs for close targets, longer PRTs for distant ones. Because it could see low-flying targets and detect objects beyond the horizon, supporting near-360-degree coverage, the Air Force chose the Westinghouse system.\n\n### What happened in the 1994 Black Hawk incident?\n\nOn the 14th of April 1994, two US Air Force F-15C Eagles shot down two Army UH-60 Black Hawk helicopters over Iraq, killing 24 people. All four aircraft were under the control of an E-3 AWACS, and investigators found the radar screens made plain the helicopters were friendly. Controllers, described as operating in \"a fog of complacency and lax procedures,\" failed to intervene, and the incident seriously damaged the E-3's public image.\n\n### Is the E-3 Sentry still in service today?\n\nYes. The script notes that the E-3 — a design now nearly half a century old — remains in use not only by the United States but also by the UK, France, Japan, and Saudi Arabia. Its long record of fulfilling and exceeding its original brief is cited as proof of its enduring value.\n\n## Sources\n\n- [Original MegaProjects video: Boeing E-3 Sentry: Declassifying America's Ultimate Spyplane](https://www.youtube.com/watch?v=3VbyBbJYAgo)\n- [E-3 Sentry (AWACS) — U.S. Air Force official fact sheet](https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104504/e-3-sentry-awacs/)\n- [E-3 Sentry (AWACS) — Tinker Air Force Base fact sheet](https://www.tinker.af.mil/About-Tinker/Fact-Sheets/Display/Article/384781/e-3-sentry-awacs/)\n\n- [Hero image source](https://commons.wikimedia.org/wiki/File:E-3_Sentry_flies_during_Operation_Epic_Fury_(9593780).jpg) by U.S. Air Force / Wikimedia Commons, public domain.\n\n## Related Coverage\n\n- [RAT 55: Why the US Military Built the Weirdest Boeing Ever Made](/article/rat-55-nt-43a-secretive-boeing-737-stealth-testbed)\n\n- [AGM-183A ARRW: Why the Air Force Revived a Troubled Hypersonic Missile](/article/agm-183a-arrw-air-force-hypersonic-missile-revival)\n\n- [The Convair B-36 Peacemaker: The Absolute Unit That Carried America Into the Cold War](/article/convair-b-36-peacemaker-cold-war-bomber)" url: https://megaprojects.pub/article/boeing-e-3-sentry-awacs-eye-in-the-sky.md canonical: https://megaprojects.pub/article/boeing-e-3-sentry-awacs-eye-in-the-sky datePublished: 2026-06-09 dateModified: 2026-06-09 author: - name: Simon Whistler url: https://megaprojects.pub/author/simon-whistler publisher: MegaProjects image: https://media.megaprojects.pub/articles/3VbyBbJYAgo/hero.jpg type: Article contentHash: f72c299d5984edd67b572451ab0a3072b8259846d5297c1379cbc67f09b9b650 tokens: 3990 summaryUrl: https://megaprojects.pub/article/boeing-e-3-sentry-awacs-eye-in-the-sky.md.summary.md --- Say the words "military aircraft" and most people picture something fast and sleek: the F-16, the Eurofighter Typhoon, the F-22 Raptor. The Boeing E-3 Sentry is none of those things. A modified Boeing 707-320, it stretches 152 ft (46.33 m) long, spreads a wingspan of 145 ft 9 in (44.42 m), and tips the scales at 185,000 lbs (84,000 kg) empty. This thing truly is a beast. And yet, despite all that bulk, a fully crewed E-3 carries only between 17 and 25 personnel. The military has plenty of uses for enormous aircraft — troop transport, hauling equipment — but this leviathan of the skies isn't built for any of that. So what is it for? You could sum up its role in just six words: the ultimate eye in the sky. For decades the E-3 has flown its missions largely out of public view. Here, we strip back some of the mystery around the Sentry — its radar technology, its surveillance reach, and the long list of operations it has quietly shaped. ## A Concept Born in the Second World War The E-3 Sentry officially took to the skies for the first time on the 25th of May 1976, but its origins reach back much further — all the way to the Second World War. When America finally entered the war, the Navy had a problem. Many of its ships carried radar systems to detect incoming enemy aircraft, but those systems worked far less well when other ships were close by. To get accurate readings, a radar-equipped ship had to travel a fair distance from any backup — which turned it into a prime target for bombing raids. The answer was Project Cadillac. A huge, radar-equipped destroyer might be a sitting duck for an enemy pilot, but an aircraft carrying similar equipment was a different story. Project Cadillac fitted an APS-20 early-warning radar to a modified Grumman Avenger (the XTBM-3W), which could both more easily avoid destruction and provide much earlier warning of incoming aircraft. The concept worked so well that, after the war, similar equipment was installed in a Lockheed L-1049 Super Constellation airliner. Designated the "Warning Star," it served as an advanced radar detection system into the early 1960s. ## Replacing the Warning Star By the early 1960s, radar technology had advanced so far, so fast, that the Warning Star was no longer fit for purpose and needed replacing. The United States Air Force issued preliminary development contracts to Boeing, Douglas, and Lockheed. In July 1970, Boeing won the final contract to build the aircraft that would eventually become the E-3 Sentry. Boeing initially planned to design and build an entirely new aircraft from the ground up, but quickly dropped that idea in favor of modifying the already-proven 707 to meet the Air Force's needs. And what were those needs? The original design brief wasn't available, but the concerns Congress raised during the funding application paint a clear picture. The new aircraft would need to detect an incoming threat from any direction at considerable distance, operate in a hostile environment, and counteract sophisticated communications jamming of the kind it might face in any campaign against the Soviet Union. One requirement we do know about: the Air Force initially wanted a 14-hour uninterrupted flight capability. To hit that target, Boeing planned to install eight General Electric TF34 engines. But with costs spiraling, the required flight time was cut — which let Boeing use the Pratt & Whitney JT3D engines already fitted to the 707 airliner. The shorter range was offset by adding air-refueling capability. ## Choosing the Radar Radar was the whole point of the aircraft, so Boeing tested two separate systems on two separate aircraft. The first, built by Hughes Aircraft Company, appears to have been fairly effective — but its computer system struggled to pick out the signature of a low-flying enemy aircraft from the clutter of objects on the ground. The second system, built by the Westinghouse Electric Corporation, solved that problem using the pulse-Doppler principle. Without turning this into a physics lesson: pulse-Doppler radar differs from more standard systems because, instead of relying on a single pulse repetition time (PRT), it uses multiple PRTs. Short PRTs detect targets at close range, while longer PRTs reach distant targets, letting the radar adapt to different ranges effectively. Because the entire project was about achieving as close to 360 degrees of radar coverage as possible — and because the Westinghouse system could detect objects beyond the horizon — that was the system the Air Force chose. ## Convincing Congress Even after all that testing, one major hurdle remained: funding. Congress was reluctant to approve it, citing a lack of evidence that the system would perform as advertised and doubts about whether the aircraft could survive and operate in a hostile environment. Those concerns ran deep enough that the 1975 defense spending bill carried a caveat: a special electronic countermeasures committee was to be formed by the Secretary of Defense to review the E-3's ability to overcome enemy jamming. Congress also demanded a personal certification from the Secretary of Defense that the new plane was genuinely capable of operating in any hostile environment. With the budget requirements finally satisfied, Boeing was at last cleared to begin building the first of these aircraft — and it didn't hang around. In October 1976, 23 months after the project got the green light, the first E-3 Sentry Airborne Warning and Control System (AWACS) arrived at its designated home. That home was Tinker Air Force Base in Oklahoma. As with everything about this aircraft, the base was chosen to maximize the E-3's capabilities. Sitting almost exactly in the middle of the United States, Tinker let the Sentry reach all US borders in minimal time. It was also home to the Oklahoma Air Logistics Center, providing the round-the-clock maintenance needed to keep the fleet in optimum condition. ## Into Service: A Relentless Operational Tempo On the 31st of March 1977, the E-3 took off on its first operational flight and quickly began to prove its worth. In support of the North American Aerospace Defense Command (NORAD), it stood ready to provide near-immediate assistance wherever needed. It would be years before any E-3 saw actual combat, but the government found other uses fast. 1978 was a busy year: the Sentry made its first successful interception of cannabis traffickers trying to enter Florida by air, deployed to Kadena Air Base in Japan (which would later become a slightly less well-equipped E-3 base), and impressed enough in real-world conditions that NATO ordered 18 aircraft to build its own airborne early-warning system. Before the decade was out, the E-3 flew two more important missions — sent to Yemen to provide advanced tactical support amid rising civil-war tensions, then performing a similar role in South Korea following the assassination of its president. The 1980s offered no rest. After a joint training exercise with the Egyptian military, a group of E-3s deployed to Saudi Arabia over fears that the Iran-Iraq war might spill into neighboring countries; several aircraft remained in the region providing round-the-clock radar surveillance for the entire war. Then, in 1981, the doubts Congress had raised about facing the Soviet Union were finally put to rest. One E-3 successfully detected and coordinated the interception of a Soviet Bison aircraft near Iceland — proof that both its radar and its encrypted communications and anti-jamming suite worked as promised. Having also returned to Egypt earlier that year following another presidential assassination, the fleet of 24 E-3s set a new record of 26,365 hours of logged flight time in a single year. The rest of the decade stayed eventful. E-3s were sent to Sudan to provide aircraft coordination that helped repel rebel forces; several joined Operation Urgent Fury, limiting air and sea travel in and out of Cuba; and a third E-3 base was established at Elmendorf AFB, Alaska. During 1987, the entire fleet began a series of extensive upgrades to its onboard computer, electronic surveillance, and communications systems. ## Two Tragedies The E-3 and its crews really did seem to be the ultimate reconnaissance team, executing almost any mission flawlessly. That reputation was shaken on the 14th of April 1994. On that day, two United States Air Force Black Hawk helicopters were shot down by American fighter jets over Iraq. As a newspaper reported at the time, the helicopters — both Army UH-60 Black Hawks — were ferrying a team of foreign officers and Kurds on a routine visit to remote Kurdish villages, and the pilots of the US jets, both Air Force F-15C Eagles, "somehow mistook the helicopters for Iraqi aircraft despite good visibility." Given that all four aircraft were under the control of an E-3 AWACS, such a mistake should have been impossible. An official investigation into the incident, which killed 24 people, was quickly launched. As the Washington Post summarized, the pilots' confusion — "made in daylight and clear skies" — might not have been fatal if controllers aboard the nearby AWACS plane had intervened and told the F-15 pilots to hold their fire, since "information available on the radar plane's computer screens made plain the helicopters were friendly." But the AWACS controllers, "operating in what Defense Department officials described as a fog of complacency and lax procedures," did not alert the F-15 pilots. The incident drove changes in training and procedure, but it seriously damaged the E-3's public image. A different kind of tragedy struck on the 22nd of September 1995. A US Air Force E-3 Sentry operating under the callsign Yukla 27 went down shortly after takeoff from its base in Alaska. According to reports, several geese were sucked into the portside engines, causing them to shut down. All 24 personnel on board were killed in the crash. Remarkably, across nearly 50 years in service there have been only two other instances resulting in loss of life — and only one of those was attributed to pilot error. ## Still the Eye in the Sky With those tragedies behind it, the E-3 finished the decade with business very much as usual. The aircraft received a further upgrade replacing its old navigation systems with GPS and was dispatched to assist NATO efforts in the Balkans. After the September 11 attacks, the Sentry took on another vital role. Its unique surveillance and communications abilities made it essential to preventing further terrorist attacks, and AWACS was deployed to provide 24-hour surveillance of the skies over America. In 2004, with the skies over Iraq somewhat more peaceful, the E-3 again found itself helping law enforcement battle drug smugglers bringing product into the United States from Latin America. It hasn't all been wars against terrorism or drugs, either. In 2005, after the devastation of hurricanes in Louisiana, Mississippi, and Alabama, the E-3 coordinated search-and-rescue and aid deployment from the skies. All in all, the E-3 Sentry — a design now nearly half a century old — has not only fulfilled its original brief but exceeded it by a considerable margin. The fact that it's still flown by the United States, the UK, France, Japan, and Saudi Arabia shows it truly is an awesome bit of kit. And when the time finally comes for it to retire, whatever comes next will have some incredibly huge wings to fill. ## Key Takeaways - The E-3 Sentry is a modified Boeing 707-320 built for one job: airborne early warning and control. Despite its enormous size, it carries only 17 to 25 crew. - The airborne-radar concept traces back to WWII's Project Cadillac and the later Lockheed "Warning Star," both forerunners the E-3 was designed to succeed. - Boeing won the contract in July 1970 and chose Westinghouse's pulse-Doppler radar for its ability to detect low-flying targets against ground clutter and see beyond the horizon. - The aircraft first flew on 25 May 1976 and entered operational service in 1977, based at Tinker AFB in Oklahoma for its central US location and round-the-clock maintenance. - A 1994 friendly-fire shoot-down of two Black Hawks under AWACS control, and the 1995 Yukla 27 crash that killed all 24 aboard, are the darkest moments in the type's history. - Nearly 50 years on, the E-3 still serves the US, UK, France, Japan, and Saudi Arabia. ## Frequently Asked Questions ### What is the Boeing E-3 Sentry? The E-3 Sentry is a modified Boeing 707-320 that serves as an Airborne Warning and Control System (AWACS) aircraft. Its job is airborne surveillance — detecting threats from any direction at long range and coordinating the response — which the script sums up as being "the ultimate eye in the sky." Despite its size, a fully crewed aircraft carries only 17 to 25 personnel. ### When did the E-3 Sentry first fly and enter service? The E-3 officially took to the skies for the first time on the 25th of May 1976. The first AWACS aircraft arrived at its designated base in October 1976, and the type flew its first operational flight on the 31st of March 1977 in support of NORAD. ### Why was the E-3 based at Tinker Air Force Base? Tinker AFB in Oklahoma was chosen to maximize the aircraft's capabilities. Sitting almost exactly in the middle of the United States, it let the E-3 reach all US borders in minimal time. Tinker was also home to the Oklahoma Air Logistics Center, which provided the round-the-clock maintenance needed to keep the fleet in top condition. ### What radar does the E-3 use, and why was it chosen? Boeing tested two radars: a Hughes system that struggled to distinguish low-flying aircraft from ground clutter, and a Westinghouse system using the pulse-Doppler principle. Pulse-Doppler uses multiple pulse repetition times — short PRTs for close targets, longer PRTs for distant ones. Because it could see low-flying targets and detect objects beyond the horizon, supporting near-360-degree coverage, the Air Force chose the Westinghouse system. ### What happened in the 1994 Black Hawk incident? On the 14th of April 1994, two US Air Force F-15C Eagles shot down two Army UH-60 Black Hawk helicopters over Iraq, killing 24 people. All four aircraft were under the control of an E-3 AWACS, and investigators found the radar screens made plain the helicopters were friendly. Controllers, described as operating in "a fog of complacency and lax procedures," failed to intervene, and the incident seriously damaged the E-3's public image. ### Is the E-3 Sentry still in service today? Yes. The script notes that the E-3 — a design now nearly half a century old — remains in use not only by the United States but also by the UK, France, Japan, and Saudi Arabia. Its long record of fulfilling and exceeding its original brief is cited as proof of its enduring value. ## Sources - [Original MegaProjects video: Boeing E-3 Sentry: Declassifying America's Ultimate Spyplane](https://www.youtube.com/watch?v=3VbyBbJYAgo) - [E-3 Sentry (AWACS) — U.S. Air Force official fact sheet](https://www.af.mil/About-Us/Fact-Sheets/Display/Article/104504/e-3-sentry-awacs/) - [E-3 Sentry (AWACS) — Tinker Air Force Base fact sheet](https://www.tinker.af.mil/About-Tinker/Fact-Sheets/Display/Article/384781/e-3-sentry-awacs/) - [Hero image source](https://commons.wikimedia.org/wiki/File:E-3_Sentry_flies_during_Operation_Epic_Fury_(9593780).jpg) by U.S. Air Force / Wikimedia Commons, public domain. ## Related Coverage - [RAT 55: Why the US Military Built the Weirdest Boeing Ever Made](/article/rat-55-nt-43a-secretive-boeing-737-stealth-testbed) - [AGM-183A ARRW: Why the Air Force Revived a Troubled Hypersonic Missile](/article/agm-183a-arrw-air-force-hypersonic-missile-revival) - [The Convair B-36 Peacemaker: The Absolute Unit That Carried America Into the Cold War](/article/convair-b-36-peacemaker-cold-war-bomber)