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F/A-22 Raptor crash analysis : flight control system malfunction

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posted on Jun, 11 2005 @ 02:50 PM
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A loss of electrical power and vague instructions helped lead to the crash of an F/A-22 Raptor as it was taking off from Nellis Air Force Base, Nev., on Dec. 20, according to an Air Combat Command investigation released June 8.

The jet’s pilot, Maj. Robert A. Garland of the 422nd Test and Evaluation Squadron at Nellis, survived the crash by ejecting before the stealth jet flipped over and skidded across the ground.

The accident investigation board found that an electrical power interruption caused three sensors that monitor the plane’s pitch, yaw and roll to stop sending information. Without information from the sensors — called “rate sensor assemblies” — the F/A-22 is uncontrollable once it leaves the ground.

Garland didn’t realize the sensors had been turned off because he had done his avionics check, called the “initiated built-in test,” before the power interruption. Garland realized he had lost control of the jet as he took off.

Garland performed his check when the two engines were started, but did not do a second check after he shut down the engines while mechanics fixed an unrelated problem. Garland thought there had been no break in electrical power to the sensors as the plane switched from engine-driven electrical generators to the auxiliary power system, according to the report.

Read more...

Computer simulation of crash

Executive summary of the report




posted on Jun, 11 2005 @ 02:57 PM
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posted on Jun, 11 2005 @ 05:23 PM
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i like the raptor and it is very sad to see one of them meet this fate


i really hope they have addressed the issue and the f22s will not expierance such malfunctions agian



posted on Jun, 11 2005 @ 06:20 PM
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How old is that crash? It keeps coming up again and again and wasn't the Raptor that crashed one of the prototypes?



posted on Jun, 11 2005 @ 10:33 PM
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2 of them crashed, one of them the YF-22 and another one the F-22. It was only known recently that the F-22 crash was due to problems with the flight software.



posted on Jun, 12 2005 @ 02:45 AM
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The latest crash was on December 20, 2004.



posted on Jun, 12 2005 @ 03:27 AM
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Originally posted by WestPoint23
How old is that crash? It keeps coming up again and again and wasn't the Raptor that crashed one of the prototypes?


7 months ago , and it was an operational conversion aircraft .



posted on Jun, 12 2005 @ 07:44 AM
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Sounds like a procedural mistake in the good Major's failure to reinitiate the system and go back through the checklist after turning off the engines, switching to aux power for maintenance, then turning the engines back on. Attitude indicators such as these, that the aircraft can't fly without, are way too important to make assumptions about when there is an interruption of the power-up sequence. In this case the assumption that they were still turned on resulted in the destruction of the aircraft. How much does one of those babies cost? The good Major may not get a chance to fly one again.



posted on Jun, 13 2005 @ 01:57 PM
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Originally posted by W4rl0rD
2 of them crashed, one of them the YF-22 and another one the F-22. It was only known recently that the F-22 crash was due to problems with the flight software.


I think it was only one, and that was six months ago

But 1 crash in 15 years, name me one other aircraft that has accomplished this feat.



posted on Jun, 13 2005 @ 02:12 PM
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Garland performed his check when the two engines were started, but did not do a second check after he shut down the engines while mechanics fixed an unrelated problem. Garland thought there had been no break in electrical power to the sensors as the plane switched from engine-driven electrical generators to the auxiliary power system, according to the report.


Sounds like he ASSUMED too much to me. He had mechanics FIX something and then didn't do a complete flight check after the repair??? Bad move....


[edit on 13-6-2005 by Gazrok]



posted on Jun, 13 2005 @ 03:50 PM
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Originally posted by Hockeyguy567

Originally posted by W4rl0rD
2 of them crashed, one of them the YF-22 and another one the F-22. It was only known recently that the F-22 crash was due to problems with the flight software.


I think it was only one, and that was six months ago

But 1 crash in 15 years, name me one other aircraft that has accomplished this feat.


It was two. I have seen the video.



posted on Jun, 13 2005 @ 04:52 PM
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I have seen the video of only one Raptor crash and this I think was the YF Raptor.



posted on Jun, 15 2005 @ 06:31 AM
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Originally posted by Hockeyguy567

Originally posted by W4rl0rD
2 of them crashed, one of them the YF-22 and another one the F-22. It was only known recently that the F-22 crash was due to problems with the flight software.


I think it was only one, and that was six months ago

But 1 crash in 15 years, name me one other aircraft that has accomplished this feat.


I got one Better for you! NO Crashes in 17 years (and Counting)! Not a single B-2 Spirit has ever crashed.

Second, the First YF-22 Prototype crash landed during a touch and go exicise in 1992. The plane survived the crash and was repaired 8 months later. So for the record, this is the second crash in the F-22 program.

What can I say? you DID ask!



posted on Jun, 15 2005 @ 06:40 AM
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For the first one, there was a video. That was the YF-22 crash.

For the second one, that is this one, there are no videos.



posted on Jun, 15 2005 @ 07:14 AM
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What's the record of SR-71 Blackbird? I don't think that aircraft Thad many crashes in its history.



posted on Jun, 15 2005 @ 07:28 AM
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The americans need to do some serious work on that craft, it aint worth jack if the flight control screws up at the wrong time.



posted on Jun, 15 2005 @ 10:25 PM
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This is why pilots have checklists they're supposed to use everytime they start engines, or shut them down, and before they take off....... talk about a "D'OH!"



posted on Aug, 5 2005 @ 06:01 AM
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A known defect in a ... flight-control system component is blamed for causing the crash of a $133 million US Air Force Lockheed Martin F/A-22 Raptor late last year.

The F/A-22 crashed 11s after take-off on 20 December at Nellis AFB, Nevada, the first production Raptor to be lost. The pilot ejected with the aircraft in a near-inverted attitude. The aircraft struck the end of the Nellis runway going backward. The USAF Accident Investigation Board (AIB) has traced the crash to the failure of all three rate sensor assemblies (RSA), which provide feedback on yaw, roll and pitch status to the flight-control system.

The pilot inadvertently triggered the failures of the RSA during pre-flight operations, according to the AIB report released on 8 June. The pilot shut down the engines during a maintenance check, believing the flight control systems were continuously powered by the auxiliary power unit (APU). The AIB attributed the pilot’s mistake to “ambiguous” language in the aircraft’s technical orders. In fact, the flight-control system momentarily loses power during an engine shutdown. This interruption in the power supply then is linked to a known quirk in the RSA unit, which is programmed so that it could interpret a momentary power loss as an instruction to enter test mode, which freezes or “latches” the unit, according to the AIB report.


full..

I pity the F-22

[edit on 5-8-2005 by Stealth Spy]



posted on Aug, 5 2005 @ 06:05 AM
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And this is from a WASHINGTON POST article in 2004.


The Air Force originally wanted to see the plane's sophisticated avionics, or electronics gear, achieve 20 hours of uninterrupted flying time without a software failure. When the plane couldn't achieve that, the Air Force changed its goal to flying five hours without a software failure. As of January, the plane could average no better than 2.7 hours.

In addition, the plane's microprocessor is an obsolete model no longer manufactured.

It's no surprise, then, that watchdog groups like the Project on Government Oversight are asking the Pentagon to put this sick puppy of a program to sleep.



Link

Very sad ...



posted on Aug, 5 2005 @ 06:11 AM
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2004 article again ... but not too outdated



.. [F/A-22, which has already cost some $40 billion and could cost another $40 billion to complete.


Development costs have risen as well -- by 127 percent, the report said.


What's more, the Air Force plans to add extra air-to-ground missions to a plane designed for air-to-air combat, which could push costs up another $8 billion or more, the report said.

The GAO also found that the F/A-22's computer-based maintenance system has suffered glitches that cause the plane to miss a significant amount of test-flying time. The Air Force had hoped to get the plane to fly nearly two hours between maintenance events by this point in the program, but has been unable to do better than an average of 30 minutes, the report said.

The avionics gear is close to flying five hours between failures, he said. While the microprocessors are outmoded, they are ample for current mission requirements, and the plane has plenty of room to add computer gear.


www.washingtonpost.com...

another 40 billion $
.. what the ??



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