Forum: General F-22A Raptor forum

http://www.flightglobal.com/news/articl ... sh-366028/

F-22 oxygen system malfunctioned moments before crash
By: Stephen Trimble Washington DC

A US Air Force report says the regular oxygen system stopped working before a fatal Lockheed Martin F-22 crash in Alaska last November.

The accident investigation board still blames the accident on the pilot, Captain Jeffrey Haney, who failed to activate an emergency oxygen supply that could have saved his life and the aircraft.

....
Haney appeared to be conscious the entire flight. Only 3sec before the crash, Haney suddenly attempted a violent pull-up manoeuvre, but it was already too late.

Damn! Crying or Very sad

I had to stop and sit on my hands for a bit on this one.

This was not the Air force Brass's "Finest Hour"! Embarassed

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Sorry to hear this.

I agree with neptune placing the blame squarely on the pilot who was trying to reach emergency oxygen placed behind him when the F-22 experienced another O.B.O.G.S. malfunction (which to my knowledge still hasn't been fixed properly) doesn't seem right to me. Shocked

But at least now they know.

I knew Captain Haney and he was a great pilot. It is very sad that the AF is placing blame on the pilot for a mechanical malfunction.

This is unacceptable! We should not be losing pilots and planes to a system that has been around for decades. Blaming the pilots of a mechanical failure is just too much.

The official Accident Investigation Board (AIB) report can be found at http://www.militarytimes.com/static/projects/pages/air-force-f22-report-121411.pdf. It contains the following in the Opinion Summary:

"By clear and convincing evidence, I find the cause of the mishap was the MP's failure to recognize and initiate a timely dive recovery due to channelized attention, breakdown of visual scan and unrecognized spatial disorientation.

By preponderance of the evidence, I also find organizational training issues, inadvertant operations, personal equipment interference, and controls/switches were factors that substantially contributed to the mishap."

AIB reports are different than Safety Investigation Board (SIB) reports. The AIB is a legal investigation and its report follows the guidelines in AFI 51-503 (see http://www.e-publishing.af.mil/shared/media/epubs/AFI51-503.pdf). The SIB is a safety investigation and its report is not releasable outside the USAF. Since mishaps are typically the result of a chain of events, safety investigations consider causes of a mishap to be any finding which sustained the mishap sequence. SIB and AIB investigations are both required after a fatal crash. Corrective actions are usually based on recommendations of the SIB.

Last edited by Lightndattic on Dec 15, 2011 - 10:23 PM; edited 1 time in total

If you haven't read the report, then you should. You'll see that it wasn't the OBOGS malfunctioning that caused the problem. The engine bleed air system detected hotter than normal air and <EDIT> Raptor DCTR is correct, this was poorly worded by me <EDIT> closed the bleed air system. This affected everything downstream including cockpit pressurization, OBOGS, avionics cooling, etc. During the decent to lower altitude, he inadvertently made control inputs (speculation was he was trying to activate the EOS, fighting with his survival suit and NVGs) which put the aircraft inverted and nose low. He lost spatial awareness during this time and could not recover quickly enough.

Tragic, but the smoking gun is not the OBOGS (no I don't work for Honeywell). This is another example of the need to get the automatic terrain avoidance software out to the fleet ASAP. This is the second accident where it likely would have saved the pilot and aircraft.

The assumption that the bleed air system shut down completely resulting in the crash of the airplane and death of the pilot, is absolutely wrong in my opinion. Also, an indication of hot bleed air IS NOT usually an indication of fire. There are fire sensors in the engine bays that do that. Bleed air is supplied by both engines through the primary bleed air modulating/shutoff valves (1 ea per engine). In the event there was bleed air was leaking from one of these shutoff valves or the associated plumbing, the pilot would get a L BLEED HOT, R BLEED HOT, or CNTR BLEED HOT ICAW and following his checklist would switch the air source knob on the ECS panel to L, R, or RAM air depending on which engine, or both (EXTREMELY unlikely) was suffering the bleed hot condition. It would take a complete novice pilot (which Captain Haney was not) to not see these indications and follow the associated checklists. It is nearly impossible, in my mind, that a hot bleed air condition caused this problem. A leak in the engine bleed air system is not such a serious problem as to cause the violent maneuvering described unless it was allowed to continue with no pilot actions and possibly melt some wiring harnesses in the engine bay. As stated, Captain Haney was a very good pilot and I have the most confidence that he would have recognized the problem, took actions to correct it, and RTB'd code 3 for ECS and we would have fixed it. There are to many redundancies and fail safes in the ECS system that prevent against a COMPLETE shutdown of the ECS system. There is something else going on here.

Raptor, you are correct in that my post was poorly worded, so I took that part out. I'm only going by what the report stated.

The report states there was a C BLEED HOT ICAW and that the pilot began a descent and retarded throttles to idle. Just 35 seconds after the C BLEED HOT ICAW, the jet began a 240 degree roll through inverted and the nose down pitch attitude increased accordingly. This likely wasn't a violent roll as the pilot apparently didn't recognize that it was occurring. Another 31 seconds passed before the pilot initiated a dive recovery. The recovery attempt came too late and the aircraft impacted the ground just 3 seconds later. Time from C BLEED HOT ICAW to impact was only 69 seconds.

Even the best pilots are susceptible to unrecognized spatial disorientation when they have to deal with abnormal indications/problems in the cockpit. Scenarios similar to this one are all too common. Lightndattic hit the nail on the head with regard to auto ground collision avoidance. The technology has existed for years and it's not in the F-16 yet either.

I'm not sure if I trust that report at all. It does not follow along with ECS theory. Very strange to me.

Raptor_DCTR wrote:

I'm not sure if I trust that report at all. It does not follow along with ECS theory. Very strange to me.

I find it terribly difficult to believe a Raptor driver making a 30+ second-long mistake without some sort of impairment or significant hindrance.

pilotbrah wrote:

I find it terribly difficult to believe a Raptor driver making a 30+ second-long mistake without some sort of impairment or significant hindrance.

So do I. That is why I don't trust the report. He would have heard multiple other audible warnings and tones alerting him to the fact that he was in trouble. And a C BLEED AIR ICAW does not cause a complete shut down of the entire ECS system. He still has RAM air for ECS functionality. I will have to look at the checklist for the C BLEED AIR ICAW as I'm not sure it calls for retarding the throttles to idle, can't remember at the moment. It does not take that long to reach over and switch the air source to RAM air. I don't know, maybe it did take him a while to run the checklist and got spatially D'd. I'm just going off what I know of the ECS system and the events described in the AIB report. Doesn't make sense to me.

The AIB receives all the factual data from the SIB. The AIB has pilot expertise, maintenance expertise, medical/physiological expertise and access to government technical expertise to assess the factual data. You can state your disbelief and distrust; but, the AIB board members and those experts assisting the AIB spent many, many hours of study and deliberation in arriving at their conclusions.

I understand that. I've been part of SIBs in the past. I'm just saying that the AIB report does not add up.