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View Full Version : Stealth bomber down... due to a few small technical problems !!!


jmig29
20th Apr 2009, 19:10
Telstar Logistics: Photos and Video of a Crashed B-2 Stealth Bomber (http://telstarlogistics.typepad.com/telstarlogistics/2008/08/photos-and-vide.html)

This is the link and next is the text

Small errors, it now turns out, caused a large accident. A B-2 has four computers, called the flight control system (FCS), that translate the pilot’s cockpit inputs into movement of the plane’s control surfaces. The $1.4 billion warplane was brought down by a few drops of water in three of the 24 air-pressure sensors that feed data to the FCS. The moisture distorted the plane’s air-pressure readings and confused the FCS badly enough to cause the crash, the first one of the B-2’s career.

February’s crash was caused by maintenance crews trying to do the right thing: They saw the wrong data and recalibrated the sensors. However, once the moisture evaporated, the sensors “fixed” by the crew were actually set incorrectly and were feeding the flight computer false data on airspeed and air pressure, which is used to measure altitude. “The pressure differences were miniscule, but they were enough to confuse the FCS, ” Maj. Gen. Floyd Carpenter, who headed the Air Force’s investigation, tells PM.

The FCS then took control; triggering a premature takeoff, automatically driving the airplane into a 30-degree, nose-up pitch and overruling the pilot’s efforts to regain control.

spannersatKL
20th Apr 2009, 20:58
Actually a wonderful illustration of how aircraft maintenance has moved in to the new era.....from my experience (30 years Licence Holder) people often look at the 'highly technical' answer to a defect, particularly if the problem is highlited in some form of maintenance computer. (CMC), when in fact some good old fashioned common 'dog' would show the problem for what it really is.

In a past life one of our contracted maintenance crews on B744, one aircraft returned from flight, gear would not raise when selected...problem shows up in CMC saying an issue with the PSEU (black box interpreting the switches on the gear)....So lots of cards changed and test OK....off you go again.....gear not go up......should have tried to look for the hole in the pipe line to one of the truck tilt actuators, but not in the book...so not looked at ....an expensive error if you ask me as this problem was common on the Classic 747 and a bit of common sense would say truck not tilting stopping gear from raising......

jmig29
20th Apr 2009, 21:07
Yeah, you're right.

Also reminds me of a probe heat computer (this situation did not happen to me, but to a lame on another airline, who's response was targeted to an award for enhancing level of safety) getting continuously burned out, but only after raining. A/C in the hangar, floor out floor in A/C out next day same thing. Turned out to be a covered stair used by handling staff, not completely covering door 1 LH, originating that water ingress! It looked like there was a water conduit buid specifically for that purpose lol :eek: