Installation of Backup Oxygen System In F-22 Combat Fleet Continues

The Air Force Life Cycle Management Center’s F-22 Division is on-track to complete installation of the Automatic Back-up Oxygen System, or ABOS, in the Air Force’s F-22 Raptor combat fleet by December 2014.

In January 2012, following a series of incidents in which a number of F-22 pilots experienced physiological symptoms in flight, the Air Force Scientific Advisory Board made a list of recommendations to improve the aircrew life support system, including the installation of an automatically-activated backup oxygen system.

The F-22 Division, which had already funded a trade study of design alternatives, took the advisory board’s recommendation as well as more specific requirements from the Air Combat Command-led life support system task force, and developed a strategy to tackle the problem.

Mike Connolly, the ABOS program manager, said the F-22 Division and contractor team moved quickly to address concerns.

“When our team received requirements from ACC, the aircraft user, we put together an action plan within a week,” Connolly said. “From there, we got approval to move forward, got funded and we executed. From notification to retrofit of the first test aircraft (the process) took six months to complete.”

According to Connolly, the ABOS is a simply designed system that is integrated into the breathing regulator. It has a control panel in the cockpit within the pilot’s reach so that Airmen can manually turn it on if backup oxygen is needed. The system is typically left in the auto position, which will automatically provide the pilot 100 percent oxygen in the event of a rapid decompression or low primary breathing air pressure.

Lansen Conley, the chief of the F-22 Product Support Management Branch, said that as the division finishes installation of the new oxygen system, he is proud of the team effort.

“When our team was notified of the Scientific Advisory Board’s recommendation, the division here and at Hill Air Force Base worked as one team to quickly develop a plan to address the problem,” he said. “That team’s focus on delivering affordable capability and meeting its commitments were critical to maintaining our nation’s war winning combat advantage.”

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Raptors to Deploy to Japan – Despite Oxygen Issues

A U.S. Air Force F-22 Raptor aircraft with the 1st Fighter Wing in flight. July 10, 2012. (DoD photo by Master Sgt. Jeremy Lock, U.S. Air Force)

The US Air Force says its scientists have identified the root cause of the hypoxia-like events occured in its F-22A Raptor stealth fighters and linked it the supply of oxygen delivered to pilots, rather than the quality of oxygen the pilots are breathing. The Air Force is implementing two changes to correct the oxygen supply issue – removing a diagnostic filter to increasing the air flow and curb high altitude pressure suite, suspected to cause some of the problems. Air Force Secretary Michael B. Donley, Air Force Chief of Staff Gen. Norton A. Schwartz and other Air Force leaders briefed Defense Secretary Leon Panetta last week on this issue. Following the Air Force briefing last week, Panetta decided to lift restrictions on the aircraft gradually. Beginning today, F-22s may resume long-duration flights for deployments, aircraft deliveries and repositioning of aircraft.

As a more permanent solution, the vest will be modified by replacing a valve in the upper pressure garment vest worn by pilots during high-altitude missions. This valve inflates the vest at high altitude, but also cause the vest to remain inflated under conditions where it was not designed to do so, thereby causing breathing problems for some pilots. This garment has been suspended from flight since June 2012 with F-22 missions restricted to low-medium alttudes, where such garments are not required. These restrictions could be removed by early fall, following the testing of the modified upper pressure garment and completion of the Scientific Advisory Board recommendations, and NASA independent analysis.

Increasing the volume of air flowing to pilots will be achieved by removing the diagnostic filter installed after the first reports on hypoxia incidents occured, to determine whether there were any contaminants present in the oxygen system. As Oxygen contamination was ruled out this filter is no longer needed. The Air Force is also exploring improving the oxygen delivery hose and its physical connections. The Air Force also plans to instal a new backup emergency oxygen system, along witha cockpit-mounted oxygen sensor and improved pilot oxygen sensor, all recommended by the NASA and Scientific Advisory Boards. To be on the safe side, the Air Force has surveyed F-22 pilots, and found “the vast majority have expressed confidence in the aircraft”…

The F-22 aircraft have flown more than 7,000 sorties, totaling more than 9,000 hours, since the last unexplained incident involving hypoxia-like symptoms occurred on March 8, 2012. Two incidents involving oxygen-related concerns since then were determined to be mechanical malfunctions, in other words, explained incidents. On June 26, an incident at Langley Air Force Base was caused by a faulty valve in the cockpit. On July 6, at Hickam Air Force Base, indicators in an F-22 signaled a possible oxygen problem, but the issue resolved itself in flight. In other words, these two incidents haven’t clarified why past ‘unexplained’ incidents occured.

Nevertheless, the secretary has approved the Air Force planned sequence of actions to remove flight restrictions over time, after receiving assurances that these corrective measures would minimize hypoxia-like events in the aircraft. The F-22 has been flying under restrictions ordered by Secretary Panetta since May 15 of this year. These restrictions have limited the deployment of Raptors overseas. A unit of F-22A has been deployed in the UAE for some time, but a forward deployment to Japan has been delayed sofar. Following the decision to return to normal operations, Secretary Panetta has authorized the deployment of a squadron of F-22s to Kadena Air Base in Japan. The aircraft will fly to Japan under altitude restrictions via the North Pacific transit route. If all goes well on that flight, the Air Force will recommend resuming most long-duration flights.

As the altitude and range restrictions are still in effect, the Air Force is planning this trans-oceanic deployment to Japan with extreme caution. The planes will fly at lower altitude, which means that pilots won’t have to use the problematic upper garment vest. In addition, at anytime on their route aircraft will have to be within 30 minutes of a landing field (even when flying over the ocean).

Following the completion of these corrective actions and the installation of the backup oxygen system, the Air Force will request resumption of the aerospace alert control alert missions in Alaska. Until that time, this mission will continue to be flown by other aircraft.

F-22 Raptors park on the ramp after landing at Kadena Air Base, Japan, May 27. F22A arrives at Kadena AFB in Okinawa, Japan on its first international deployment in 2010. The aircraft were deployed from Holloman Air Force Base, NM as part of an air expeditionary force rotation. (U.S. Air Force photo/Senior Airman Amanda Grabiec)

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US ‘confident’ F-22 jet oxygen problems solved

By Agence France-Presse on Wednesday, July 25th, 2012

The US Air Force is “confident” it has identified the problems that led some pilots to complain of dizzy spells and blackouts while flying its most advanced fighter jet, the Pentagon said Tuesday.

The “root cause of the issue is the supply of oxygen” — necessary for pilots flying at high altitudes — “not the quality of oxygen delivered to pilots,” Pentagon spokesman George Little told reporters.

To fix the problem, Little said the Air Force will replace a valve that was causing inflation in a vest pilots wear at high altitudes, impeding breathing for some.

The Air Force will also increase the flow of oxygen to pilots by removing a filter that monitored whether the oxygen contained any contaminants, after determining there were none.

A new emergency oxygen supply system will also be installed on the planes.

“We have very high confidence that we have identified the issue,” Little said, but “it’s going to take us a while to ensure that all of the relevant components are replaced.”

The fleet of 187 F-22 Raptors was grounded last year for four months after a spate of incidents of pilots saying they had passed out or suffered a lack of oxygen.

Engineers were still trying to solve the problem when flights resumed in September 2011. But pilots continued to express concerns over oxygen issues on the F-22s, leading Defense Secretary Leon Panetta to restrict the stealth fighters to lower altitudes and shorter ranges, within easy reach of a runway.

Panetta has now approved lifting those restrictions over time, after “receiving assurances that these corrective measures would minimize” the risk of further dizzy spells or blackouts, Little said.

A squadron of F-22 Raptors is going to be deployed to Japan, flying there via a low-altitude route. “Following completion of the flight to Japan, the Air Force will recommend resuming most long-duration flights,” the Pentagon spokesman added.

The F-22, the most expensive aircraft in the US fleet at $143 million each, flies at a higher altitude than other jets, above 50,000 feet. It also relies solely on pressurized oxygen instead of a mixture of oxygen under pressure and air in the cockpit, according to the Air Force.

The plane is faster and more agile than older fighters, with the pilot facing more gravitational forces than in other planes, officials say.

But the F-22 has yet to be deployed in combat, and its cost overruns became a long-running political controversy until the program was curtailed.

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