U.S. Air Force Retires Last Open Skies Aircraft

 - June 9, 2021, 7:24 AM
OC-135B 61-2670 gets airborne from its base at Offutt AFB for a 2018 mission. (Photo: U.S. Air Force)

On June 4 the 45th Reconnaissance Squadron of the 55th Wing at Offutt Air Force Base, near Lincoln in Nebraska, held a ceremony to officially retire the last of its Boeing OC-135Bs. Aircraft 61-2670 was due to fly into storage in the “boneyard” at Davis-Monthan AFB, Arizona, a few days later.

The tail 670 aircraft was delivered to the U.S. Air Force in April 1962 as a C-135B, flying with the 1501st Air Transportation Wing at Travis Air Force Base in California. After a short spell in the transport role, it was modified to WC-135B standard and reassigned to the 55th Weather Reconnaissance Squadron at nearby McClellan AFB. When this mission ended it was further converted to OC-135B for the Open Skies mission.

A total of three OC-135Bs was produced, beginning with a single aircraft in an interim fit, which entered service in October 1993. It was followed by two aircraft in the full mission configuration. Tail 670 was one of those aircraft and in May 1996 it began flying its peacetime reconnaissance and arms treaty verification flights on behalf of the Defense Threat Reduction Agency (DTRA), many of which were over Russia.

For the treaty monitoring mission, the OC-135Bs were modified with four cameras in the rear fuselage, comprising one vertical and two oblique KS-87E framing cameras used for low-altitude photography, and one KA-91C panoramic camera for high-altitude photography. They typically flew missions with 35 personnel, comprising flight crew, DTRA crew members, representatives from the host nation, and a maintenance crew. The latter was an integral element of the mission as the aircraft often operated for extended periods within the host nation. The OC-135Bs received the Pacer Crag avionics upgrade that ensured compliance with ICAO-mandated global air traffic management regulations.

As well as its Open Skies duties, the aircraft also performed some other survey and humanitarian work, notably in the wake of the earthquake that devastated Haiti in January 2010. By the time of its retirement, ’670 had amassed more than 36,500 flight hours during the course of more than 13,000 sorties. It was one of the last C-135s in U.S. service powered by the Pratt & Whitney TF33 low-bypass ratio turbofans with which it was delivered.

“Over the years [the OCs] have become beloved members of the 55th fleet, new in mission, but old and irritable in spirit,” said Colonel John Litecky, 55th Operations Group commander, who officiated at the ceremony. “They have developed a bit of a reputation as being cranky aircraft, and in their old age they have become notorious for having a higher than normal number of maintenance issues, and just a bear to deal with.”

Open Skies is a multinational treaty that was signed in 1992, covering most of the nations within NATO and the former Warsaw Pact, and effectively covering all of Europe and North America. Under its terms, member states could fly unarmed, dedicated reconnaissance aircraft over the territories of others on an annual maximum quota basis.

Relations between Russia and the U.S. concerning the treaty deteriorated in the late 2010s. On May 21, 2020, President Trump announced that the U.S. would be withdrawing from the treaty, citing alleged violations by Russia, and the official notification was issued on the following day. After the six-month notice period had been served the U.S. officially left the treaty on November 22, leaving the OC-135Bs without a mission. The original interim aircraft had been in inviolate storage for many years, leaving the 45th RS with two operational aircraft. The first of this pair—tail 672—was ferried into storage in mid-May.

As a postscript, Russia announced it would also withdraw from the treaty in January 2021. On June 7, three days after the retirement of '670, President Vladimir Putin signed a law that formalizes Russia’s withdrawal, having earlier hoped—in vain—that President Joe Biden would reverse his predecessor’s decision.