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Despite bleed air failure and multiple system shutdown, bleed air system not blamed in crash

Now that its investigation is complete, the USAF has come back and handed down its decision on what caused the pilot of an F-22 Raptor to crash his aircraft in November 2010. According to sources and other pilots, the issue that led to the death of Capt. Jeff "Bong" Haney was a malfunction of the Raptor's bleed air intakes.
 
The report has now been issued and according to the USAF Accident Investigation Board, the cause of the accident was Haney, not the malfunctioning bleed air system in the stricken Raptor. The AIB found that while the bleed air system on the F-22 had failed, Haney didn’t react quickly enough to save the aircraft.
 
President of the AIB, Brig. Gen. James Browne wrote in the AIB report, "I find the cause of the mishap was the MP's [mishap pilot] failure to recognize and initiate a timely dive recovery due to channelized attention, breakdown of visual scan and unrecognized spatial disorientation."
 
Fingers were pointed early on at a failure of the On-board Oxygen Generating System or OBOGS as a cause of the accident. The accident report has determined that the OBOGS was functioning and was not a contributing factor to the accident. However, the OBOGS did shut down due to the bleed air problem the F-22 encountered.
 
The report read, "The MP most likely experienced a sense similar to suffocation." Despite that statement, the report also rules out hypoxia as a contributing factor to the accident. The report continues, "Due to the high affinity of oxygen to hemoglobin, the MP would have had adequate blood oxygen supply after the OBOGS failed. It was concluded that the late recognition of the MA's [mishap aircraft's] unusual attitude and appropriate corrective actions attempted by the MP demonstrates that hypoxia was not a factor in this mishap."
 
Defense News cites a source that claims that Haney would not have succumbed to hypoxia fully, though he would have had symptoms. The source notes that the hypoxia would have been a contributing factor even if the pilot were still conscious. Along with the OBOGS system on the stricken Raptor, the environmental control system, air cycle system, and On-board Inert Gas Generating System as well as cabin pressure were also shut down.
 
The recovered aircraft memory unit reportedly showed that the "partial pressure to the MP's [mishap pilot] oxygen stopped shortly after 19:42:37 L, which would lead to severely restricted breathing."
 
Haney was conscious enough to attempt to recover from the steep dive his Raptor was in right before the crash. The F-22 hit the ground three seconds after Haney first attempted to recover. The report notes that for 39 seconds Haney did nothing to address the flight condition of his aircraft.
 
The report reads, "The fact that the [mishap pilot] went from a controlled flight regime to an unusual attitude and did not take corrective actions for 30 seconds suggests he had unrecognized spatial disorientation. At 19:42:24L the [mishap pilot] recognized the [mishap aircraft's] position and attempted to perform a dive recovery."
 
This was the second F-22 lost in service since the aircraft went operational. In March of 2009, another Raptor crashed killing the pilot. This accident was a contributing factor to the Raptor stand down that lasted months.
 
This week the final F-22 Raptor rolled off the assembly line and will replace the aircraft lost in the fatal crash that took Haney's life.

Source: Defense News



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If I read this correctly...
By HoosierEngineer5 on 12/17/2011 11:11:00 AM , Rating: 2
At 19:42:24 the mishap pilot attempted to perform a dive recovery.

Slightly after 19:42:37, partial pressure to the pilot's oxygen stopped. If the F-22 hit the ground three seconds after the recovery was attempted, the oxygen system was working ten seconds after impact.

If the aircraft had already impacted the ground, I would expect the oxygen system to stop if the impact was severe enough.




RE: If I read this correctly...
By static1117 on 12/17/2011 12:52:03 PM , Rating: 2
Im not sure exactly how the oxygen system works on the F-22 as I have 12 years experience on F-16's, but when you lose bleed air, your lose alot of fuctions in the A/C.

1. Cabin pressure
2. G-Suit pressure
3. Cooling Air

and not paticularly in that order. Also, once you lose G-Suit pressure, you also lose the PBG (Pressure Breathing Group) function of the jet. (PGB is a function of the Oxygen regulator that, under G, forces air into the pilot. And I mean it FORCES air)

Not arguing for one side or another, just a little clarification


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