Current Events — HabitableZone

Current Events » in reply to Aerospace expert's analysis of Flight 587 crash

Questionable expertise

<"What the NTSB and FBI failed to tell the reporters is that it is not possible for there to be a thrust reverser failure in flight, UNLESS the thrust reverser controls were sabotaged by a terrorist."

Oh, really? Tell that to the people killed in the Lauda Air crash back in 1991. Admittedly, that was a 767 instead of an Airbus A300 but before this incident, everyone was told it was impossible for a thrust reverser to deploy in flight. There was no sabotage in the Lauda Air crash, just a freak accident.

"The Air Force's B-2 Flying Wing stealth bomber is a perfect example to prove that a plane with absolutely NO vertical fin or stabilizer is able to fly and does not instantly become unstable and crash. The B-2 uses modern "fly-by-wire" computers to keep the plane flying straight and level. The original flying wing design from the 1950's also flew but using manual flight controls made it rather difficult to steer with no rudder. The Airbus A300 uses a modern "fly-by-wire" computer system and would fly quite easily with complete loss of the vertical fin and rudder. The NTSB's claim that the loss of Flight 587's vertical fin and rudder might be the cause of the loss of the control of the plane which caused it to crash is both misleading and deceptive."

Several errors here. First, both the B-2 and the earlier XB-35 and YB-49 flying wings achieve yaw control using split ailerons as shown in the photo (left wingtip). The aileron opens both up and down at the same time, causing drag on that wingtip and yawing the plane. Fly-by-wire has nothing to do with it. Earlier Northrup flying wings used the same technique long before fly-by-wire was invented. Lacking something like the split ailerons, losing the complete vertical stabilizer and rudder will lead to a loss of control on most planes.

http://www.fas.org/nuke/guide/usa/bomber/b-2_12.jpg


Furthermore, the Airbus A300 doesn't use fly-by-wire. Airbus first developed that technology for their A320 series. The A300 uses conventional hydraulic technology for control.

"Any theory blaming the failure of the vertical fin and rudder assembly as the cause cannot account for why the engines would fall off the plane.

Wrong. Loss of the vertical stabilizer and rudder would lead the plane to yaw rapidly. That would impart sideloads on the engine pylons in excess of what they were designed to handle, leading to failure. He describes it himself in this paragraph:

"As soon as the tail assembly broke off there is now very little wind resistance to the flat spin. At this point the engines would cause the aircraft to spin even faster with the g-forces away from the center of the spin becoming so great that both engines would be violently ripped off the wings and thrown outward away from the plane. This accounts for why the engines were found so far away from the crash site and why the tail came off first. Thus a single point failure, the in-flight actuation of the left engine thrust reverser, can account for all three observed phenomena of the clean breaking off of the tail and the failure of both engine pylons holding the engines. But how can that happen when there are so many safety devices to ensure that it never occurs?"

The problem is that there is no evidence to support the inflight deployment of a thrust reverser on this flight. From the AviationNow article that I linked earlier, it appears that either the copilot was too agressive with his rudder inputs or that the rudder control system didn't behave properly.

The article goes on with more of the same. Quite frankly, I put a lot more faith in the NTSB than in the self-proclaimed expertise of the "BroJon Gazette."

Log in or register to post.

The whole thread (24 posts)