Update to Amsterdam air crash

[Enigma]

From Avweb.com

When a Turkish Airlines 737-800 crashed short of the runway in Amsterdam last week, killing nine people, it was one of those relatively rare accidents where no apparent cause was readily discernible. But on Wednesday, Dutch Safety Board investigators said a faulty radio altimeter fed misinformation to the autopilot. The altimeter registered that the airplane was approaching ground level when in fact it was still at 1,950 feet. The autopilot initiated a power-down of the engines in preparation for landing and the airplane slowed to near stall speed. The pilots responded to the situation too late, and the airplane hit the ground. The 737 data recorder showed that problems with the altimeter had occurred twice before, investigators said.
Boeing has issued a statement to 737 operators reminding pilots to carefully monitor instruments during critical phases of flight. The Dutch Safety Board said in its report that it is "of the opinion that extra attention is needed for the role of the radio altimeter when using the automatic pilot and the automatic throttle system." The board asked Boeing to pay extra attention to a part of a manual for the Boeing 737 in which is stated that in case of malfunction of the radio altimeter(s), the automatic pilot and throttle system that are connected to it may not be used for approach and landing. The board would like Boeing to consider an investigation into whether this procedure is also applicable during other phases of flight.

[Oberon]

Ouch, on a clear day that wouldn't have been a problem, but add some fog and

[Enigma]

I think it was a clear day! (?)

More...

At a new conference in the Hague, Dutch Safety Board chairman Pieter van Vollenhoven said the left radio altimeter registered an altitude of eight feet as the airplane approached Schiphol at around 1,950 feet, causing the automatic throttle system to reduce power and configuring the rest of the systems for an imminent landing. The Boeing slowed to a stall and crashed into a muddy field about a half mile away from the runway threshold.

A conversation recorded between the captain and two first officers in the cockpit indicated they had knew about the altimeter irregularity but did not react until the stall warning system sounded, at which time they tried to power up the engines.

[Oberon]

Aaah, for some reason I recalled it being a bit foggy, but looking at the pictures, yeah, it was quite clear.

I guess that is the down side to automation in modern airliners, it saves the pilot a lot of work and on a good day, is quicker to react to situations, but when it goes wrong

[antikristuseke]

When it goes wrong, the results are the same as they would be with pilot error.

[Oberon]

Originally Posted by antikristuseke

When it goes wrong, the results are the same as they would be with pilot error.

True, true, but would a pilot have cut power thinking they were at eight feet when they were at nearly two thousand?

I'm not saying that the human element is foolproof, but I'm also not 100% happy with putting more reliance on computers, such as the reducing power and automatically preparing for landing because the computer thinks that it's eight feet.

[antikristuseke]

Agreed. They should both suplement eachother.

[GoldenRivet]

Thats why i prefer an autopilot which will keep its hands off my power levers.

poor bastards.

the minute either pilot saw "V-ref" on the airspeed indicator one click of the A/P Disconnect button would have fixed the problem

[Max2147]

Sounds like the inverse of the Sao Paulo TAM crash. From what I've heard, the TAM plane's computers thought it was still in the air when it was on the ground. The Turkish plane's computers thought it was on the ground while it was still in the air.