On Saturday, the 6th of July, 2013, an Asiana Airlines flight from Seoul crashed on landing at San Francisco airport, hitting the sea wall in front of the runway.
Two passengers were killed, more than 160 were injured, and dozens of frightened passengers and crew had to evacuate the heavily damaged aircraft before it was engulfed in smoke and flames.
So what caused the Asiana Airlines crash? And what could have been done to prevent it?
Asiana Airlines Crash: What Was the Cause?
There has been speculation that the cause of the crash was that the aircraft was travelling at a speed significantly below its required approach speed.
According to Deborah Hersman, Chairwoman of the U.S. National Transportation Safety Board, information collected from the plane’s cockpit voice recorder and flight data recorder indicated that there were no signs of trouble until seven seconds before impact, when the crew tried to accelerate.
Apparently, a stall warning sounded four seconds before impact, and the crew tried to abort the landing and initiate what is known as a ‘go around’ manoeuver (missed approach) just 1.5 seconds before crashing. Hersman said that “air speed was significantly below the target airspeed.”
Why Would This Cause the Aircraft to Crash?
All aircraft from small four-seater piston aeroplanes to massive jet airliners rely primarily on lift in order to fly. Airflow over the wings produces lift, which means the engines must produce enough power for the aircraft to travel fast enough to produce the required lift to keep the plane aloft.
Every aircraft has a stated speed for approach to landing. If the speed is reduced too much below this, there will not be enough lift to keep the plane in the air. If this happens the wing ‘stalls’. This is not at all the same as an engine stall in a car – what it means is that the lift over the aircraft becomes too low, and the aircraft begins to literally fall out of the sky.
All aircraft have a ‘stall warner’, usually an auditory signal, which warns the pilot to increase speed to prevent a stall. If the speed isn’t increased, the aircraft will crash.
Click to Read Page Two: Why Didn’t the Pilots Prevent the Stall?
© 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.