Monday, July 08, 2013

Seat Belt!

Thanks to a new amateur video (CNN exclusive) shot by an aviation photographer, we were finally able to piece together what had happened to Asiana Flight 214 and what caused the deaths of two Chinese girls en route to a summer camp in the US.

Based on charts of Flight 214's descending path with altitude and speed relative to location and in comparison to other commercial flights with same model airplanes, it was crystal clear that Asiana 214 came too high until they were very close to the San Francisco Airport (SFO). Then between 37.59 and 37.6 degrees, 214 lost several times of altitude and several times speed, in comparison to a 'normal approach'. Its speed dropped to well below 100 knots well before the plane reached the runway. For Boeing 777-200, it should maintain airspeed above 130 knots anytime in air.

The pilot did not realize until it was too late. Survivors noticed the engine suddenly revved up moments before the initial impact, which clipped off the entire tail segment when the airplane hit the seawall. Engines on large commercial airplanes were not designed to provide push instantaneously when increasing throttle. The pilot should have known better.

At any rate, having the airspeed down to 100 knots was simply inexcusable. How did this happened to a commercial pilot was beyond human comprehension.

SFO is marked as a 'special airport' because the runway was extended into the bay. Landing SFO could be challenging because there was little terrain reference above water. However, anyway who had played on a 20 years old Microsoft Flight Simulator should have known that at airspeed less than 100 knts, the jumble jet would drop from the sky.

As the plane lost its tail, it ran out of control, but kept skiing on the runway forward for about ten seconds, until suddenly, as it 'appeared' in the video, 'cartwheeled' with its head shot up to the sky and spun off runway 28. This corroborated to the testimony of a first witness who saw the accident from a hotel window. When he said he saw the airplane cartwheeled, many thought he might not mean it or understand the meaning of the word because the plane was so intact afterwards. Now we know it did happened. The construction quality of the airplane was very impressive to withheld such a great impact with both wings intact and attached and no major damages to the fuselage.

What most likely happened was that some passengers unbuckled their seat belts after the initial impact without realizing what had happened and thought the airplane was taxing on the runway. The ten seconds of time was long enough to make some passengers thought they were finally safe on the ground. They were dropped downwards through the opening caused by the missing tail to the outside the fuselage when the airplane suddenly headed up.

The bodies of the two girls were found outside the airplane on the runway.

Based on the recorded ATC communications, the traffic controlled demonstrated utmost professionalism in handling of the disaster. The pilot of Asiana 214 was totally clueless from the beginning to the end. However, some pilot noticed that the controlled did not issue wind when granting landing permission to 214. It was a flaw but should not contribute in anyway to the crash as there was literally no wind that day.

Update: The official opinion at this time was that one of the victim was ran over by emergency responding vehicles near an evacuate slide. The other girl was ejected at the first impact.

No comments: