30-03-2009, 12:37 PM
I recieved some extra background information in the crash of the 737 at A'dam Airport Schiphol.
This could be very interesting for our simmers.
As we all know, the throttle went to idle as one altimeter was faulty. Throttle going idle at that stage of the approach is normal. However,
there was at that time only one way to notice this was a fault.
On the instruments an annunciation of MCP should appear, but a retard annunciation actually did appear.
The pilots did not notice this.
At my company the pilots must always have one hand on the yoke and one on the throttle levers on approach when the automatic pilot is
flying.
This way they can always 'feel' what the autopilot is doing and correct it if necessary.
The Turkish pilots probably did not do this.
The plane was losing speed, but remained on the glideslope.
Only 25 seconds (not 100 according to the media) after the retard the stickshaker activated.
(The pilots did probably not look at their instruments during those 25 seconds because of a checklist and checking outside conditions).
The co-pilot responded by applying full throttle and pushing the yoke forward with both hands.
In respond to that, the captain took over and pushed the yoke forward with both hands to lower the nose.
This is a normal stall recovery procedure for the 737.
However, the co-pilot forgot to disengage the autothrottle.
Immediately after the stall recovery procedure was initiated, the throttles went slowly back to idle.
Because both pilots did not have their hands on the yoke (what is not necessary at a stall recovering procedure) they did not notice this.
Because of all the warnings, all three pilots could not 'hear' that the engines were going to idle:
'Stickshaker'
'Too low gear'
'Too low flaps'
'Terrain, terrain'
'Whoop whoop, pull up'
Just seconds after that, the plane impacted the ground with a vertical speed of -4000ft/m.
Boeing 737 pilots of my company tested this in the simulator.
If the stall recovery procedure was executed normally they would have come out of this stall.
The 737 pilots in the simulator only lost 100 feet of altitude after the stickshaker was activated and after waiting two seconds before
initiating the stall recovery procedure.
At this time it looks like the crash is caused by technical faults at Boeing in combination with pilot error.
Anastasios.
Post Edited ( 03-30-09 14:00 )
This could be very interesting for our simmers.
As we all know, the throttle went to idle as one altimeter was faulty. Throttle going idle at that stage of the approach is normal. However,
there was at that time only one way to notice this was a fault.
On the instruments an annunciation of MCP should appear, but a retard annunciation actually did appear.
The pilots did not notice this.
At my company the pilots must always have one hand on the yoke and one on the throttle levers on approach when the automatic pilot is
flying.
This way they can always 'feel' what the autopilot is doing and correct it if necessary.
The Turkish pilots probably did not do this.
The plane was losing speed, but remained on the glideslope.
Only 25 seconds (not 100 according to the media) after the retard the stickshaker activated.
(The pilots did probably not look at their instruments during those 25 seconds because of a checklist and checking outside conditions).
The co-pilot responded by applying full throttle and pushing the yoke forward with both hands.
In respond to that, the captain took over and pushed the yoke forward with both hands to lower the nose.
This is a normal stall recovery procedure for the 737.
However, the co-pilot forgot to disengage the autothrottle.
Immediately after the stall recovery procedure was initiated, the throttles went slowly back to idle.
Because both pilots did not have their hands on the yoke (what is not necessary at a stall recovering procedure) they did not notice this.
Because of all the warnings, all three pilots could not 'hear' that the engines were going to idle:
'Stickshaker'
'Too low gear'
'Too low flaps'
'Terrain, terrain'
'Whoop whoop, pull up'
Just seconds after that, the plane impacted the ground with a vertical speed of -4000ft/m.
Boeing 737 pilots of my company tested this in the simulator.
If the stall recovery procedure was executed normally they would have come out of this stall.
The 737 pilots in the simulator only lost 100 feet of altitude after the stickshaker was activated and after waiting two seconds before
initiating the stall recovery procedure.
At this time it looks like the crash is caused by technical faults at Boeing in combination with pilot error.
Anastasios.
Post Edited ( 03-30-09 14:00 )
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