USAF Grounds F-22 Fleet
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USAF Grounds F-22 Fleet
Defense News: USAF Indefinitely Grounds F-22 Raptors
The U.S. Air Force has grounded all of its F-22 Raptors until further notice because of potential malfunctions in the fighter jets' oxygen-generation system.
Gen. William Fraser, commander of U.S. Air Combat Command, ordered a stand-down of the 165-plane fleet May 3, ACC spokeswoman Capt. Jennifer Ferrau said. Ferrau didn't immediately know how long the Raptors will be out of service.
The On-Board Oxygen Generating System (OBOGS) has been under investigation since an F-22 crashed in November just outside Joint Base Elmendorf-Richardson, Alaska. Until the stand-down, Raptor sorties had been restricted to an altitude of 25,000 feet or below for training missions because of the potential malfunctions.
The limits were "designed for mishap prevention and is a prudent measure to ensure the OBOGS are operating safely," ACC spokesman Col. William Nichols said in March, when the command first publicly disclosed the investigation.
An OBOGS malfunction can be potentially life-threatening, said Hans Weber, who sat on the U.S. Federal Aviation Administration's Research, Engineering and Development Advisory Committee, and is president of Tecop International, a San Diego consulting firm.
"It's a big deal if you're at high altitude and you run out of oxygen," Weber said in a March interview.
At 50,000 feet, a human being has less than 10 seconds of useful consciousness, he said. The 25,000-foot altitude restriction would allow the pilot to quickly dive below 18,000 feet, where the atmosphere has enough oxygen to ensure prolonged survival in case of an emergency.
"It would take you so long when you're way up high, you may black out before you make it to a safe altitude," Weber said.
The U.S. Air Force has grounded all of its F-22 Raptors until further notice because of potential malfunctions in the fighter jets' oxygen-generation system.
Gen. William Fraser, commander of U.S. Air Combat Command, ordered a stand-down of the 165-plane fleet May 3, ACC spokeswoman Capt. Jennifer Ferrau said. Ferrau didn't immediately know how long the Raptors will be out of service.
The On-Board Oxygen Generating System (OBOGS) has been under investigation since an F-22 crashed in November just outside Joint Base Elmendorf-Richardson, Alaska. Until the stand-down, Raptor sorties had been restricted to an altitude of 25,000 feet or below for training missions because of the potential malfunctions.
The limits were "designed for mishap prevention and is a prudent measure to ensure the OBOGS are operating safely," ACC spokesman Col. William Nichols said in March, when the command first publicly disclosed the investigation.
An OBOGS malfunction can be potentially life-threatening, said Hans Weber, who sat on the U.S. Federal Aviation Administration's Research, Engineering and Development Advisory Committee, and is president of Tecop International, a San Diego consulting firm.
"It's a big deal if you're at high altitude and you run out of oxygen," Weber said in a March interview.
At 50,000 feet, a human being has less than 10 seconds of useful consciousness, he said. The 25,000-foot altitude restriction would allow the pilot to quickly dive below 18,000 feet, where the atmosphere has enough oxygen to ensure prolonged survival in case of an emergency.
"It would take you so long when you're way up high, you may black out before you make it to a safe altitude," Weber said.
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They should all be sent to museums at Microsoft, Intel, Google, et al.
They had to use a chainsaw to cut the $275K canopy on one, because a software glitch wouldn't let the pilot open it.
The Nav computers got lost when the first pair crossed the Intl Dateline.
At $350 Million each, we don't have an enemy worthy of risking them in combat. Notice they weren't used over Libya.
GB
They had to use a chainsaw to cut the $275K canopy on one, because a software glitch wouldn't let the pilot open it.
The Nav computers got lost when the first pair crossed the Intl Dateline.
At $350 Million each, we don't have an enemy worthy of risking them in combat. Notice they weren't used over Libya.
GB
Wonder if the flight sims that enthuse a million US gamers into 'Raptor screws other fighters of the world debates' can factor that limitation in?
Sorry terminology edit. Please substitute 'Owned' or 'Raped' for 'screws' as your age/background dictates.
Sorry terminology edit. Please substitute 'Owned' or 'Raped' for 'screws' as your age/background dictates.
Last edited by AR1; 6th May 2011 at 14:12. Reason: Inappropriate terminology
Notice they weren't used over Libya.
Limitations keep F-22 from use in Libya ops - Air Force News | News from Afghanistan & Iraq - Air Force Times
Last edited by BEagle; 6th May 2011 at 14:29.
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OBOGS is standard on the Hawk T Mk 2, but sensibly there is a back up compressed O2 supply that would get the pilot/s down to breathable altitudes.
Interesting how often 'dramatic' statements like 'so-and-so fleet grounded' appear here though.
Any manufacturer/operator is being prudent by ensuring the safety of both the company (vicarious liability, duty of care etc etc) and operators (crews and pax when carried).
It's not a particularly dramatic event, it's actually putting safety first - for whatever the reason (I'm a cynic).
I suppose the worst thing about hypoxia is its insidious nature, so the (cabin) or altitude limit is eminently sensible.
Interesting how often 'dramatic' statements like 'so-and-so fleet grounded' appear here though.
Any manufacturer/operator is being prudent by ensuring the safety of both the company (vicarious liability, duty of care etc etc) and operators (crews and pax when carried).
It's not a particularly dramatic event, it's actually putting safety first - for whatever the reason (I'm a cynic).
I suppose the worst thing about hypoxia is its insidious nature, so the (cabin) or altitude limit is eminently sensible.
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Another example of inter-service non-communication.
F-22 problem may be identical to F/A-18 problem identified and fixed by the USN years ago!
Carbon monoxide suspected in F-22 grounding - Air Force News | News from Afghanistan & Iraq - Air Force Times
F-22 problem may be identical to F/A-18 problem identified and fixed by the USN years ago!
Carbon monoxide suspected in F-22 grounding - Air Force News | News from Afghanistan & Iraq - Air Force Times
Carbon monoxide suspected in F-22 grounding
By Dave Majumdar - Staff writer
Posted : Thursday Jul 21, 2011 14:17:42 EDT
The prolonged grounding of the Air Force’s F-22 Raptor fleet may be due to carbon monoxide entering the cockpit via the aircraft’s oxygen system, two sources said.
.....
Part of the problem may be the procedures used at Elmendorf Air Force Base, Alaska, where most of the known incidents have occurred. Because of the harsh climate, pilots often start their jet engines inside a hangar before taking off. Investigators suspect that exhaust gases are getting trapped in the building and subsequently sucked back into the engines, where they enter the bleed air intakes that supply the OBOGS, sources said.
.....
If the carbon monoxide is being ingested because the engines are being started in confined spaces, a fix could be as simple as moving the jet outside, Weber said. If the engine must be started inside the hangar, the startup of the oxygen system might be delayed until the jet is out in the open, he said.
.....
The Navy has had similar problems with the OBOGS on its F/A-18 Hornet, which sucked carbon monoxide into its oxygen system during carrier operations.
Between 2002 and 2009, Hornet aviators suffered 64 reported episodes of hypoxia, including two that killed the pilots, according to the July-August 2010 issue of “Approach,” a Navy Safety Center publication.
.....
According to Navy documents, “Prolonged exposure to jet engine exhaust while sitting behind another aircraft waiting to take off and operating with low bleed air pressures can result in carbon monoxide (CO) breaking through … into the pilot’s breathing gas.”
The Navy modified the planes’ OBOGS to fix the problem, has had no recent similar incidents, and is not currently investigating the systems, Naval Air Systems Command officials said.
By Dave Majumdar - Staff writer
Posted : Thursday Jul 21, 2011 14:17:42 EDT
The prolonged grounding of the Air Force’s F-22 Raptor fleet may be due to carbon monoxide entering the cockpit via the aircraft’s oxygen system, two sources said.
.....
Part of the problem may be the procedures used at Elmendorf Air Force Base, Alaska, where most of the known incidents have occurred. Because of the harsh climate, pilots often start their jet engines inside a hangar before taking off. Investigators suspect that exhaust gases are getting trapped in the building and subsequently sucked back into the engines, where they enter the bleed air intakes that supply the OBOGS, sources said.
.....
If the carbon monoxide is being ingested because the engines are being started in confined spaces, a fix could be as simple as moving the jet outside, Weber said. If the engine must be started inside the hangar, the startup of the oxygen system might be delayed until the jet is out in the open, he said.
.....
The Navy has had similar problems with the OBOGS on its F/A-18 Hornet, which sucked carbon monoxide into its oxygen system during carrier operations.
Between 2002 and 2009, Hornet aviators suffered 64 reported episodes of hypoxia, including two that killed the pilots, according to the July-August 2010 issue of “Approach,” a Navy Safety Center publication.
.....
According to Navy documents, “Prolonged exposure to jet engine exhaust while sitting behind another aircraft waiting to take off and operating with low bleed air pressures can result in carbon monoxide (CO) breaking through … into the pilot’s breathing gas.”
The Navy modified the planes’ OBOGS to fix the problem, has had no recent similar incidents, and is not currently investigating the systems, Naval Air Systems Command officials said.
The F-22 grounding is a very good reason whey air forces need at least two combat types [or engines???] to remain operational. The RAAF thinks it can hang its hat on only the F-35 going forwards [maybe!]. The USAF can cover the F-22 grounding with other types, the RAAF would not be in a position to do so. Bad planning methinks.
