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To: Mac from Cleveland
I’m not familiar with the 1991 thrust reverser incident-did the pilot deploy it in error?

Lauda Air Flight 004 on May 26, 1991. According to the black box and the flight recorder the flight crew did nothing. They just deployed.

The 1989 incident-don’t recall it, but I don’t see how an “electrical short” can cause deployment of a door. There are interlocks built in those systems to prevent such a thing-not to mention mechanical locks. I’d have to know more about the specific incident before I could discuss it.

United Airlines Flight 811, occured on February 24, 1989. Final cause was identified as improper wiring and deficiencies in the door design.

I said in my original post that what the official line is improbable—but when you couple it with the non-technical big picture, lots of different big and small facts, plus eyewitness reports—hell, wasn’t July 19th Baathist Independence Day?—it seems kind of fishy.

Why is that fishy and none of the other ones?

81 posted on 01/09/2009 8:07:19 AM PST by Non-Sequitur
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To: Non-Sequitur

As I said before-I don’t know all the details of every aircraft mishap in history. I don’t have a lot of time at the moment but I did look up the NTSB report about the United flight in 1989

http://amelia.db.erau.edu/reports/ntsb/aar/AAR92-02.pdf

Here’s an excerpt:

2.6.3 Possibility of Electrical Malfunction
“Due to the lack of physical evidence, the Safety Board was unable to
conclude that an electrical short caused the cargo door actuator to move the latch
cams to the nearly open position, allowing the door to separate when the cabin
pressure exceeded the load-carrying capability of the door latches. Neither could
this possibility be eliminated. A momentary actuation of the door open switch by
someone on the ground in the presence of a faulty S2 switch could also have
caused the latches to open through the closed lock sectors. However, no evidence
has been found that someone actuated the switch after the door was initially closed
and locked.
The Safety Board concludes that it was not possible for the cargo door
to have opened electrically at the time of the loss of the door. There was no power
to the ground handling bus to power the actuator, even if there had been an
electrical short. Further, the Safety Board concludes that it is highly improbable
that an electrical short could have caused the latches to open after the airplane was
airborne. Although the ground handling bus could conceivably have been
powered, failures of other components that were tested as functional would also
have been necessary.
The Safety Board believes that the electrical operation of the latch
actuators from the fully closed and locked position most likely occurred before the
engines were started when the ground handling bus was powered. The precise
source of the electrical actuation could not be determined. Once the engines were
started, the possibility of an electrical short decreases significantly because the
ground handling bus is disengaged from the APU when the engines start. There
was no evidence that the flightcrew reengaged the ground handling bus.
Because the preaccident condition of the S2 master latch lock switch
could not be determined, it could also not be determined whether its proper
functioning would have prevented the accident. The Safety Board did not
determine whether damaged cargo door wires or a malfunctioning S2 switch could
have been found by UAL maintenance had they been more aggressive in troubleshooting
the cargo door problem in the weeks prior to the accident”

In other words-they don’t know.

If the aircraft that went down in 1996-Flight 800-had had existing issues, etc-it appears both the Lauda Air and united Flights you reference both did have prior issues with the affected systems, then I might be more inclined to go with the party line on Flight 800-it just seems unlikely, and, as I said, there isn’t any conflicting info on those other flights to indicate foul play, but 800 has a lot of questions/gray areas.


82 posted on 01/09/2009 8:16:01 AM PST by Mac from Cleveland (Joe Biden behind a microphone is like Ted Kennedy behind a steering wheel)
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