Post by skyking on Jan 25, 2008 22:05:36 GMT
British Airways flight BA 038 -
The Air Accidents Investigation Branch (AAIB) published this statement on its website regarding the crash-landing of a British Airways flight at Heathrow.
".....At approximately 600ft and two miles from touch down, the autothrottle demanded an increase in thrust from the two engines, but the engines did not respond.
Following further demands for increased thrust from the autothrottle, and subsequently the flight crew moving the throttle levers, the engines similarly failed to respond.
The aircraft speed reduced and the aircraft descended onto the grass short of the paved runway surface....."
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At about the same time, the BBC News said:
....."As the handling pilot, first officer John Coward would have been preparing to take manual control below 1,000 feet.
Warning signs
The trouble started two miles out at 600 feet, as the plane was slowing down in its landing configuration.
At this point the engines would have required more power to keep the plane from sinking below the glideslope - an invisible three degree path down to the runway, generated by radio waves.
The plane had not run out of fuel, and there is no mention of birds being sucked into the engines, or violent blasts of wind throwing it off course.
When the automatic throttle demanded more power, the engines initially responded. Then first the right engine, followed eight seconds later by the left, powered down - to a level below the thrust needed.
Warnings would have flashed up on engine monitoring screens in the centre of the control panel, showing the power was below that required.
A lower screen would have shown more detailed information about the flow of fuel around the aircraft. Other displays would show the likely speed and height the plane would achieve over the next minute.
Faced with the knowledge that a disaster was in the making, the crew had around 40 seconds to save their aircraft. It's understood the captain Peter Burkill quickly reduced the amount of wing flaps deployed.
This was as important as the skilful manipulation of the control column by John Coward, in saving the aircraft. It cuts drag, speeds the plane up a little, and when a pilot has speed, he can maintain altitude.
But it would only delay the inevitable - the plane would have been losing both speed and height, a potentially catastrophic situation....."
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If the foregoing statement about the Captain reducing the flap setting is true, I offer the following:
I'm not so sure that reducing the flap setting is a good idea within 600 feet of the ground. It might well reduce drag, but it also INCREASES the stall speed.
They were already descending AND decelerating at an increasing rate because of loss of power, and reducing flaps at an already reduced speed (VREF + ? at that phase of the approach), could only magnify the situation.
The natural instinct of the Co-Pilot (the one flying at that point) would have been to increase back pressure on the stick which would have further reduced the speed, yet closer to stall.
No, the thing to do in that situation is hold on to what you have for a flap setting and increase back pressure ever so slightly to reduce speed toward VSO, increasing the gliding distance, and hope for the best.
I'm sure this will be shown in the simulator to every pilot of British Air, and perhaps others as well. And like many other accidents, others will learn from this.
The Air Accidents Investigation Branch (AAIB) published this statement on its website regarding the crash-landing of a British Airways flight at Heathrow.
".....At approximately 600ft and two miles from touch down, the autothrottle demanded an increase in thrust from the two engines, but the engines did not respond.
Following further demands for increased thrust from the autothrottle, and subsequently the flight crew moving the throttle levers, the engines similarly failed to respond.
The aircraft speed reduced and the aircraft descended onto the grass short of the paved runway surface....."
---------------------------------------------------------
At about the same time, the BBC News said:
....."As the handling pilot, first officer John Coward would have been preparing to take manual control below 1,000 feet.
Warning signs
The trouble started two miles out at 600 feet, as the plane was slowing down in its landing configuration.
At this point the engines would have required more power to keep the plane from sinking below the glideslope - an invisible three degree path down to the runway, generated by radio waves.
The plane had not run out of fuel, and there is no mention of birds being sucked into the engines, or violent blasts of wind throwing it off course.
When the automatic throttle demanded more power, the engines initially responded. Then first the right engine, followed eight seconds later by the left, powered down - to a level below the thrust needed.
Warnings would have flashed up on engine monitoring screens in the centre of the control panel, showing the power was below that required.
A lower screen would have shown more detailed information about the flow of fuel around the aircraft. Other displays would show the likely speed and height the plane would achieve over the next minute.
Faced with the knowledge that a disaster was in the making, the crew had around 40 seconds to save their aircraft. It's understood the captain Peter Burkill quickly reduced the amount of wing flaps deployed.
This was as important as the skilful manipulation of the control column by John Coward, in saving the aircraft. It cuts drag, speeds the plane up a little, and when a pilot has speed, he can maintain altitude.
But it would only delay the inevitable - the plane would have been losing both speed and height, a potentially catastrophic situation....."
-------------------------------------------------------------------------------
If the foregoing statement about the Captain reducing the flap setting is true, I offer the following:
I'm not so sure that reducing the flap setting is a good idea within 600 feet of the ground. It might well reduce drag, but it also INCREASES the stall speed.
They were already descending AND decelerating at an increasing rate because of loss of power, and reducing flaps at an already reduced speed (VREF + ? at that phase of the approach), could only magnify the situation.
The natural instinct of the Co-Pilot (the one flying at that point) would have been to increase back pressure on the stick which would have further reduced the speed, yet closer to stall.
No, the thing to do in that situation is hold on to what you have for a flap setting and increase back pressure ever so slightly to reduce speed toward VSO, increasing the gliding distance, and hope for the best.
I'm sure this will be shown in the simulator to every pilot of British Air, and perhaps others as well. And like many other accidents, others will learn from this.
