Boeing EC-135
Boeing EC-135C Looking Glass with Pacer Link modification
Role Airborne Command Post, Airborne Launch Control Center, Tracking and Telemetry Platform, Airborne Radio Relay
Manufacturer Boeing
Introduction 1965
Retired 2000
Status Retired from service
Primary user United States Air Force
Developed from C-135 Stratolifter

The Boeing EC-135 is a retired family of command and control aircraft derived from the Boeing C-135 Stratolifter. During the Cold War, the EC-135 was best known for being modified to perform the Looking Glass mission where one EC-135 was always airborne 24 hours a day to serve as flying command post for the Strategic Air Command in the event of nuclear war. Various other EC-135 aircraft sat on airborne and ground alert throughout the Cold War, with the last EC-135C being retired in 1998. The EC-135N variant served as the tracking aircraft for the Apollo program.

The Boeing E-6B Mercury "TACAMO" replaced the EC-135C.


Looking Glass

Gen. Richard Ellis, CINCSAC, in battle staff compartment, 1979

Officially known as "Operation Looking Glass", at least 11 EC-135C command post aircraft were provided to the Commander in Chief, Strategic Air Command (CINCSAC), and were based at various locations throughout the United States and worldwide. Operations began in 1961 with the 34th Air Refueling Squadron at Offutt Air Force Base (Nebraska), initially using EC-135As (converted from KC-135As) until the dedicated EC-135Cs entered service in 1964. Originally built as KC-135Bs, they were re-designated as EC-135Cs from 1 January 1965. Other Offutt-based units included the 38th Strategic Reconnaissance Squadron (1966–1970), the 2d Airborne Command and Control Squadron (1970–1994), and the 7th Airborne Command and Control Squadron (1994–1998).[1] Other units operating the Looking Glass mission included the following:[2]

Strategic Air Command Boeing EC-135 Looking-Glass at Offutt Air Force Base, Nebraska.

Other EC-135 aircraft (including EC-135A, G, and L models) supporting the Looking Glass missions (communications relay and Minuteman airborne launch control centers) were flown by the 906th Air Refueling Squadron at Minot Air Force Base (North Dakota) (1963–1970)1, the 70th Air Refueling Squadron at Grissom AFB (1975–1993), and the 301st Air Refueling Squadron at Lockbourne Air Force Base (Ohio) (1963–1970). All aircraft have been retired or repurposed.[4]

Strategic Air Command Personnel on-board the EC-135 Looking Glass

The United States nuclear strategy depends on its ability to command, control, and communicate with its nuclear forces under all conditions. An essential element of that ability is Looking Glass; its crew and staff ensure there is always an aircraft ready to direct bombers and missiles from the air should ground-based command centers be destroyed or rendered inoperable.[5] Looking Glass is intended to guarantee that U.S. strategic forces will act only in the manner dictated by the President. It took the nickname "Looking Glass" because the mission mirrored ground-based command, control, and communications centers.

The Strategic Air Command (SAC) began the Looking Glass mission on February 3, 1961, and Looking Glass aircraft were continuously airborne 24 hours a day for over 29 years, accumulating more than 281,000 accident-free flying hours. On July 24, 1990, "The Glass" ceased continuous airborne alert, but remained on ground or airborne alert 24 hours a day.[6] The EC-135A flew the Command Post mission until EC-135C were delivered starting in 1963. The aircraft were delivered to Offutt AFB and as well as one aircraft to each of the Stateside Numbered Air Force Headquarters – Second Air Force at Barksdale AFB (Louisiana); Eighth Air Force at Westover AFB (Massachusetts); and Fifteenth Air Force at March AFB (California). EC-135s flew all the missions except one, on March 4, 1980, when an E-4B was tested on an operational mission, flying a double sortie as the replacement aircraft could not launch due to weather. About a week after the flight, Washington deleted the funds for additional E-4 aircraft.[7]

On June 1, 1992, SAC was inactivated and replaced by the United States Strategic Command, which now controls the Looking Glass.[8][9] On October 1, 1998, the Navy's E-6 Mercury TACAMO replaced the USAF's EC-135C in the Looking Glass mission. The last active, former, Looking Glass was converted to a WC-135C Constant Phoenix,[10] where it was retired in November 2020.[11]


Airborne Launch Control Center

Airborne Launch Control Centers (ALCC—pronounced "Al-see") provided a survivable launch capability for the United States Air Force's LGM-30 Minuteman Intercontinental Ballistic Missile (ICBM) force by utilizing the Airborne Launch Control System (ALCS) on board that is operated by an airborne missileer crew. Historically, from 1967 to 1998, the ALCC mission was performed by United States Air Force Boeing EC-135 command post aircraft. This included EC-135A, EC-135C, EC-135G, and EC-135L aircraft.[12][13]

In the late 1960s and early 1970s, ALCS crews belonged to the 44th Strategic Missile Wing (SMW) at Ellsworth AFB and the 91st SMW at Minot AFB. ALCS equipment was installed on various Boeing EC-135 variants to include the EC-135A, EC-135C, EC-135G, and for a short while on the EC-135L.[14]

Starting in 1970, there were only two SAC squadrons that operated ALCS capable aircraft. This included the 2nd Airborne Command and Control Squadron (ACCS) operating EC-135C aircraft out of Offutt AFB and the 4th ACCS operating EC-135A, EC-135C, and EC-135G aircraft out of Ellsworth AFB . All three variants of these EC-135A/C/G aircraft had ALCS equipment installed on board.[12][15]

EC-135G at Ellsworth AFB in South Dakota

The 4th ACCS was the workhorse of ALCS operations. Three dedicated Airborne Launch Control Centers (ALCC) were on ground alert around-the-clock providing ALCS coverage for five of the six Minuteman ICBM Wings. These dedicated ALCCs were mostly EC-135A aircraft but could also have been EC-135C or EC-135G aircraft depending on availability. ALCC No. 1 was on ground alert at Ellsworth AFB and during a wartime scenario would have taken off and orbited between the Minuteman Wings at Ellsworth AFB and F.E. Warren AFB (Wyoming) providing ALCS assistance if needed. ALCCs No. 2 and No. 3 were routinely on forward deployed ground alert at Minot AFB. During a wartime scenario, ALCC No. 3 would have orbited between the Minuteman ICBM Wings at Minot AFB and Grand Forks AFB, both in North Dakota, providing ALCS assistance if needed. ALCC No. 2 was dedicated to orbiting near the Minuteman ICBM Wing at Malmstrom AFB (Montana) providing ALCS assistance if needed. The 4th ACCS also maintained an EC-135C or EC-135G on ground alert at Ellsworth AFB as the West Auxiliary Airborne Command Post (WESTAUXCP) as a backup to SAC's "Looking Glass" Airborne Command Post (ABNCP) as well as a radio relay link between the Looking Glass and ALCCs when airborne. Although equipped with ALCS, the WESTAUXCP did not have a dedicated Minuteman ICBM wing to provide ALCS assistance to.[12][14]

The 2nd ACCS was another major player in ALCS operations. The primary mission of the 2nd ACCS was to fly the SAC ABNCP "Looking Glass" aircraft in continuous airborne operations. However, due to its proximity in orbiting over the central United States, the airborne Looking Glass provided ALCS coverage for the Minuteman ICBM Wing located at Whiteman AFB (Missouri). Not only did Whiteman AFB have Minuteman II ICBMs, but it also had ERCS configured Minuteman missiles on alert. The 2nd ACCS also had an additional EC-135C on ground alert at Offutt AFB as the EASTAUXCP, providing backup to the airborne Looking Glass, radio relay capability, and a means for the Commander in Chief of SAC to escape an enemy nuclear attack. Although the EASTAUXCP was ALCS capable, it did not have a dedicated ALCS mission.[12][16]

Silk Purse

Further information: Operation Silk Purse

Operation Silk Purse program provided four EC-135H command post aircraft to the Commander, U.S. European Command (USEUCOM), which were based at RAF Mildenhall in the United Kingdom.[17] Flown by the 10th Airborne Command and Control Squadron 1970–91.[18] Onboard secure/non-secure communications and avionics equipment was maintained by the 513th Avionics Maintenance Squadron and the 2147th Communications Squadron. Aircraft S/Ns 61–0282, 285, 286 and 291.

Scope Light

Operation Scope Light provided five EC-135C/HJ/P command post aircraft to the Commander in Chief, U.S. Atlantic Command (CINCLANT), which were based at Langley AFB (Virginia). Operated by the 6th Airborne Command and Control Squadron 1972–92.[18]

Blue Eagle

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Operation Blue Eagle provided five EC-135J/P command post aircraft to the Commander in Chief, U.S. Pacific Command (USCINCPAC), which were based at Hickam AFB (Hawaii). Operated by the 9th Airborne Command and Control Squadron 1969–92.[18] Communications, secure/unsecure voice and teletype, handled by the 1957th Communications Group, Hickam AFB (1969–1992)

"Upkeep" was the call sign for the EC135 flying in southeast Asia during 1969 to 1971, based out of Hickam AFB. It was under the direction of PACAF of which 5th AF in Fuchu AS, Tokyo Japan handled their voice communications both unsecure and secure. <1956 Comm Gp USAF 1969 to 1971>

Blue Eagle Ground Stations were located at Hickam AFB, Yakoto AB (Japan) Kadena AB (Okinawa), and Clark AB (Philippines).  There may have been an additional Ground Station on Guam.

At Kadena AB, the 1962nd Communications Group hosted the Blue Eagle Ground Station.  The call sign for the Kadena Blue Eagle Operation was “Settler”.

All Blue Eagle Ground Stations were contracted to Philco Corporation and consisted of two trailer vans that could be pulled by a single tractor.  One van was configured with a 15KW diesel powered generator and diesel fuel tank and the other was outfitted with a 15-ton heavy duty air conditioning unit, three motor generators, three UHF/VHF FM transmitters and receivers, two multiplexers each providing up to 24 telephone lines and a dedicated, individual telephone line provided to the aircraft.

The ground stations were self sufficient in that they were configured in trailers so they could be relocated to safer positions in the event of a national emergency.  The equipment installed in the vans was identical to the electronics on board the aircraft.  This necessitated the requirement for motor-generators to provide conversion from 60 Hz to 400 Hz power.

Each equipment van had an omni-directional antenna mounted on the roof of the van and 3 additional portable antennas that were deployed on telephone poles.  The antennas could be switched electro-mechanically from each transmitter/receiver pair.  The vans at Kadena AB were never moved from their initial installation location.

Blue Eagle was formed in 1965 and started 24/7 operation in October 1965 and continued until disbanded in 1992.


Operation Nightwatch provided three EC-135J[17] command post aircraft to the President of the United States which were based at Andrews AFB (Maryland). All three aircraft were transferred to other ABNCP missions.

Nightwatch was initiated in the mid-1960s utilizing the three EC-135J aircraft, modified from KC-135Bs, as command post aircraft. The three Nightwatch aircraft were ready to fly the President and the National Command Authority (NCA) out of Washington in the event of a nuclear attack. The E-4 aircraft (a modified Boeing 747-200) came on line with the Nightwatch program in 1974 replacing the EC-135s on this mission.[19]


The 310th Airlift Squadron, part of the 6th Air Mobility Wing at MacDill AFB (Florida), operated two NKC-135s that were reconfigured as EC-135Y aircraft from 1989 to 2003 as executive transport and command & control platforms to support the Commander, United States Central Command. These aircraft have since been replaced with three C-37A Gulfstream V aircraft.

Advanced Range Instrumentation Aircraft

EC-135E "Droop Snoot" on display at USAF Museum

The Advanced Range Instrumentation Aircraft are EC-135Bs, modified C-135B cargo aircraft and EC-18B (former American Airlines 707-320) passenger aircraft that provided tracking and telemetry information to support the US space program in the late 1960s and early 1970s.

During the early 1960s, NASA and the Department of Defense (DoD) needed a very mobile tracking and telemetry platform to support the Apollo space program and other unmanned space flight operations. In a joint project, NASA and the DoD contracted with the McDonnell Douglas and the Bendix Corporations to modify eight Boeing C-135 Stratolifter cargo aircraft into EC-135N Apollo / Range Instrumentation Aircraft (A/RIA). Equipped with a steerable seven-foot antenna dish in its distinctive "Droop Snoot" or "Snoopy Nose", the EC-135N A/RIA became operational in January 1968, and was often known as the "Jimmy Durante" of the Air Force. The Air Force Eastern Test Range (AFETR) at Patrick AFB, Florida, maintained and operated the A/RIA until the end of the Apollo program in 1972, when the USAF renamed it the Advanced Range Instrumentation Aircraft (ARIA).

Cutaway layout of an EC-135N, showing the nose in the left foreground and the tail in the right background.
Cutaway layout of an EC-135N

Since Patrick AFB was located on the Atlantic Ocean, salt water and salt air-induced corrosion issues and associated aircraft maintenance challenges were problematic for the ARIA while based there. Transferred to the 4950th Test Wing at Wright-Patterson AFB, Ohio, in December 1975 as part of an overall consolidation of large test and evaluation aircraft, the ARIA fleet underwent numerous conversions, including a re-engining that changed the EC-135N to the EC-135E. In 1994, the ARIA fleet relocated again to Edwards AFB, California, as part of the 412th Test Wing. However, taskings for the ARIA dwindled because of high costs and improved satellite technology, and the USAF transferred the aircraft to other programs such as E-8 J-STARS.

Over its thirty-two year career, the ARIA supported the United States space program, gathered telemetry, verified international treaties, and supported cruise missile, ballistic missile defense tests, and the Space Shuttle.[20] ARIA aircraft were equipped to collect data from the Sonobuoy Missile Impact Location System (SMILS) composed of a large sonobuoy field and a fixed bottom transponder. Specially equipped Navy P-3 aircraft were also equipped to collect data from this system which supported the Navy's fleet ballistic missile programs testing.[21][22]

Variant summary


Aircraft on display

See also


  1. ^ ((cite web)): Missing or empty |title= (help)
  2. ^ Hopkins III, Robert S. (1997). Boeing KC-135 Stratotanker: More Than Just a Tanker. Leicester, England: Midland Publishing Limited. p. 115. ISBN 1857800699.
  3. ^ a b c d Hopkins, p. 115, 196
  4. ^ Hopkins, p. 115-117
  5. ^ Men In Crisis: Kennedy vs. Khrushchev. "A grim precaution is carried in this plane. Should the Soviets attack and destroy all land-based SAC installations, the counterattack order will come from this jet, a flying command post airborne 24 hours a day."
  6. ^ "Flying with the A-Bomb on Board: "Looking Glass"". Archived from the original on 12 December 2017. Retrieved 26 August 2022.
  7. ^ Hopkins, p. 114-116
  8. ^ "E-6B Airborne Command Post (ABNCP)". Archived from the original on 2015-09-10.
  9. ^ "EC-135 Looking Glass - United States Nuclear Forces".
  10. ^ "1962 USAF Serial Numbers".
  11. ^ "WC-135 Constant Phoenix Archives". Air & Space Forces Magazine. Retrieved 2023-06-05.
  12. ^ a b c d Hopkins, p. 116-117
  13. ^ Kuehn, Cory (March 2017). "ALCS 50th Anniversary: Celebrating a Proud Heritage" (PDF). Air Force Missileers. Association of Air Force Missileers. 25 (1): 13. Archived from the original (PDF) on July 2, 2017.
  14. ^ a b Kuehn, p. 14
  15. ^ Kuehn, p. 13-15
  16. ^ Kuehn, p. 15
  17. ^ a b Hopkins, p. 116
  18. ^ a b c Hopkins, p. 196
  19. ^ "C-135 Variants Part Five by Jennings Heilig (Artwork, No Scale)".
  20. ^ This section uses public domain text from the National Museum of the United States Air Force. [1]
  21. ^ McIntyre, John W. (1991). "The Advanced Range Instrumentation Aircraft/Sonobuoy Missile Impact Locating System" (PDF). Johns Hopkins APL Technical Digest. 12 (4). Retrieved 12 September 2020.
  22. ^ Cone, Bruce E. (1 July 1976). The United States Air Force Eastern Test Range — Range Instrumentation Handbook (PDF). Patrick Air Force Base, Florida: Eastern Test Range, Directorate of Range Operations. pp. 2–76. Archived (PDF) from the original on February 27, 2021. Retrieved 12 September 2020.
  23. ^ Ranter, Harro. "ASN Aircraft accident Boeing C-135B Stratolifter 61-0331 Hawaii, USA".
  24. ^ Ranter, Harro. "ASN Aircraft accident Boeing EC-135K 62-3536 Albuquerque-Kirtland AFB".
  25. ^ Ranter, Harro. "ASN Aircraft accident Boeing EC-135P 58-0007 Hampton-Langley AFB (LFI)".
  26. ^ Ranter, Harro. "ASN Aircraft accident Boeing EC-135N 61-0328 Walkersville, MD".
  27. ^ Ranter, Harro. "ASN Aircraft accident Boeing EC-135J 62-3584 Fayetteville-Pope AFB (POB)".
  28. ^ Ranter, Harro. "ASN Aircraft accident Boeing EC-135C 63-8053 Fayetteville-Pope AFB (POB)".
  29. ^ "Boeing EC-135E ARIA". National Museum of the United States Air Force™.
  30. ^ "USAF Serial Number Search (61-262)".
  31. ^ "Airframe Dossier - Boeing EC-135C, s/n 61-0262 USAF, c/n 18169". Aerial Visuals. Retrieved 14 November 2016.
  32. ^ "EC-135 STRATOTANKER". Grissom Air Museum. Retrieved 14 November 2016.
  33. ^ "Airframe Dossier - Boeing EC-135L, s/n 61-0269 USAF, c/n 18176". Aerial Visuals. Retrieved 14 November 2016.
  34. ^ "Airframe Dossier - Boeing EC-135C, s/n 61-0287 USAF, c/n 18194". Aerial Visuals. Retrieved 14 November 2016.
  35. ^ "EC-135 "Looking Glass"". Strategic Air Command & Aerospace Museum. Retrieved 14 November 2016.
  36. ^ "EC-135 Looking Glass Restoration – Strategic Air Command & Aerospace Museum".
  37. ^ "STRATOTANKER". Pima Air & Space Museum. Retrieved 14 November 2016.
  • Reference for the Variant Summary list: DoD 4120.14L, Model Designation of Military Aerospace Vehicles, May 12, 2004