Why Did the Pilots Not Take Action to Prevent a Stall?
This is the $64,000 question, the answer to which we don’t know at present.
Airspeed is actually produced by both the speed of the aircraft through the air plus the speed of the wind over the wing, so that sudden alterations in wind speed (windshear) can be responsible for a stall.
At this time, however, there has been no suggestion in any of the reports that this is what happened here. The pilot at the controls during the flight, Lee Kang-kuk, was making his first attempt to land a 777 at San Francisco’s airport, although he had flown there 29 times previously on other types of aircraft. However, there was a highly experienced senior pilot in the other seat, and all airliners have dual controls.
It is not, at present, clear whether the senior pilot tried to abort the landing. It is also not clear whether the pilots were ‘hand flying’ the plane, or using some form of automatic pilot, which could perhaps make a difference, although it should not.
The pilots’ command of English might also have affected their affected their understanding of what was going on; there have been reported incidents of pilots not understanding auditory commands such as ‘pull up’. However, this is mere speculation at present, and again, it should make little difference.
There is also the possibility that what is known as ‘human factors’ came into play here, such as the co-pilot not wanting to criticise an older or apparently more experienced colleague who was about to make a mistake. Again, this sort of thing has caused accidents in the past.
Will We Ever Know What Actually Happened?
Authorities investigate every air crash in great detail. Once they have interviewed pilots and done some additional research, it is likely that we will better understand what happened. Meanwhile, the cause of the crash appears to be some element of ‘pilot error’ or in other words, human error – rather than any kind of mechanical failure. Perhaps this should be seen as proof that however experienced professionals are, occasionally they can still get things wrong. Food for thought, perhaps…
© Copyright 2013 Helen Krasner, All rights Reserved. Written For: Decoded Science
Read the report on the Turkish plane that crashed in Amsterdam. Read the report on the French airliner that fell out of the sky into the Atlantic.
SAME: nose up, stabilisers over-trimmed, engines on idle, full stall.
It’s a combined auto-pilot and auto-throttle error (they don’t communicate too well apparently) which is crashing more and more planes, of all sizes. By the time the auto-pilot hands control to the humans, they often don’t have time to fix the errors.
Until that is fixed, all planes should fly manual from 5000 feet to prevent further “accidents”.
Despite the apparent Q&A format, no one really knows what caused the crash and it is still premature to offer conclusions about the causes. Some of the speculation in this article is inappropriate and not based on any published disclosures specific to this incident.
Stall, low speed, and insufficient lift are all different things. A stall can occur at any speed. An airplane can not have enough lift even though it is not stalling. An aircraft can descend with the same amount of lift that it takes to keep it flying level. The article would be better if it explained those distinctions.
The early indications are that those three problems came together and combined with low altitude to set the stage for this crash.
I’ve been passenger on many flights. Landing seemed to be very challenging and most pilots took pride for soft, smooth landing. I could hear them say it over the PA.
The “new” pilot of Asiana 214 might have tried to prove to his senior pilot that he could manually perform a soft touchdown in his first landing of a 777-300. Unfortunately, slower speed was a totally wrong mental judgement for his attempted soft landing. The senior pilot got no seconds left to react.
If the plane did not carry 300 people with carry-on luggage to add 50,000 pounds of weight, they might have made it smoothly over the seawall.