T-Storms Blamed For Jet Crash

[Dennis Dennison]

Judging by Air France move to replace sensors--and the finding of the tail in one piece, and reading all the automated failures that came from the aircraft--I still think and electronic failure happened.
I think they will find (Maybe) that a sensor failed-it began causing computer problems related to the FMC/Autopilot--They claim the autopilot was shutdown-either ny computer or manually-and some sort of rapid climb began to take place.

I am thinking the autopilot was told to shutdown by a computer misread of the speed-resulting in a pitch up, stall and then a dive which resulted in exceeding red line and breakup prior to impact.

In any event--I rather doubt they will ever resolve it, those black boxes are going to be really hard to find

 

[B. Kotcher]

Yeah, an article in the paper said that if the rudder is deflected far enough at high speed, the vertical stabilizer will shear off, so the aircraft's computer constantly checks airspeed and keeps the pilot from deflecting the rudder dangerously far. If there was something wrong with the airspeed sensor and/or the electronics, and the plane was flying much faster than the computer and pilot believed, the pilot could have input enough rudder to cause the vertical stabilizer to shear off, which would cause the plane to crash.

--Bob

 

[George Limpert]

Under normal conditions, Airbus planes operate under normal law. This means that the computer allows the pilot to disengage the autopilot as desired, but the computer still prevents the pilot from doing something unsafe.

Inputs from sensors are constantly verified and if the computer detects invalid input or some other system failure occurs, those systems are disabled. This is referred to as a control law reversion. In that event, control would have been returned to the pilots in alternate law, in which many of the protections normally enforced by the fly-by-wire system are disabled. Should additional failures occur, the fly-by-wire system will disable those protections as well. It is possible for that to happen and for all protections to be disabled, which is referred to as direct law.

If control was returned to the pilots under alternate law, the pilots may simply not have had enough information to react safely. They were also flying very close to the "coffin corner," which is where the stall speed and the critical Mach number are equal. Stalling or going into Mach tuck both would cause a loss of altitude that could eventually lead to a structural failure.

Under those conditions, it wouldn't have taken much to cause Mach tuck to occur. A gust of wind could cause that, which is not at all unlikely under those conditions.

While that doesn't explain what caused the autopilot to disengage and the system to revert to alternate law, it's a plausible explanation of what might have brought the plane down.

 

[MClarkson]

The finding of the vertical stabilizer more or less intact doesn't strike me as particularly significant by itself. The plane could have broken apart in the air from aerodynamic stress after it lost control(for whatever reason), with the separation of the vertical stabilizer being the result of, not the cause of, the crash. Also if the plane did impact the water more or less intact it would have separated then. Sections from the tail are often the largest or most intact debris that remains.

 

[Mike Krzywonski]

Autopsies Suggest Plane Broke Up in Sky :

http://news.aol.com/article/air-france-jet-crash/520205?icid=main|main|dl1|link3|http%3A%2F%2Fnews.aol.com%2Farticle%2Fair-france-jet-crash%2F520205

 

[Stuart Robinson]

Does look like a plane brake up - poor souls

http://uk.news.yahoo.com/5/20090618/twl-jet-victims-injuries-give-clues-to-c-3fd0ae9.html

: "Typically, if you see intact bodies and multiple fractures - arm, leg, hip fractures - it's a good indicator of a mid-flight break-up.

"Especially if you're seeing large pieces of aircraft as well."

Aviation safety consultant Jack Casey agreed multiple fractures were consistent with the plane breaking up in mid-air and that the lack of clothing could be significant.

"In an in-air break up like we are supposing here, the clothes are just torn away," he said.

 

[cdcollura]

Good day all...

Just had to throw this one in (Miami airport)...

Lightning is the LEAST of a commercial airliners' concerns although an airliner and lightning encounter is both frightening and ominous. The "faraday cage" effect, as well as lightning's current flowing AROUND the plane's metal skin and not through it makes these planes safer.

Turbulence and / or icing, on the other hand, is something very few airplanes can handle inside a thunderstorm.

 

[Toni Scholz]

Multiple Failures

As with most airline disasters; a chain reaction of failures is to blame. The backup systems and fail-safe designs that these modern aircraft have are designed to operate when there is a single failure within the given system. The problem is when multiple failures occur across systems that lead to a catastrophe that can't be avoided.

The findings will likely reveal that a number of factors contributed to the disaster. The air speed sensor failure in itself wouldn't have been a fatal flaw if it weren't for the specific weather conditions they encountered and so on. Unfortunately, understanding the causes will not change the end result.