Well yesterday was a sad day for many as we all heard news of the crash in SFO. The first wind that blew my way about the accident was over Japanese Airspace at about 3:30am Hong Kong time. I had departed Hong Kong just prior to midnight, and was lucky enough to have first rest on our freighter trip to Anchorage. After a few hours of slumber in the bunk I jumped in the left hand seat to take over for the Captain who was now headed for a snooze. The first officer briefed me as per the usual on the aircraft, and flight to bring me up to speed. The next thing I know, Singapore Cargo Flight 2 was getting a re-route via Tokyo ATC. I didn’t think much of that until later in the flight when we first looked at the ATIS for Anchorage. “Ground stop in effect for all San Francisco departures”. It’s 2013 so the first thing that crosses my mind is terrorism, followed quickly of course by, an accident. It must be something major for a ground stop. Although a brief check of the SFO weather confirms that fog/foul weather is not to blame. So we pull up the SFO ATIS via the onboard ACARS (Aircraft Communications Addressing and Reporting System) and discover that there are runway closures, and taxiway closures, much more then usual. Having been to SFO just the day before, it seems obvious that something is wrong. Maybe a disabled aircraft?
Turns out the aircraft was much more then disabled. When we got out of the aircraft in Anchorage, we soon rallied around our customs officer’s computer to see the news. A crash. A bad one by the looks of it. Initial reports suggested an emergency prior to landing. But after a quick search online upon reaching the hotel, it appears the accident WAS the landing. A coworker had a link to the audio tapes and it appears nothing is wrong until the final seconds.
Opinion time. The weather, good. The airplane, also appears to be fully functional. What I do know 9again from having visited SFO the day before in our 747-400) is that Runway 28L had many closures to some of it’s normal navigation aids. The Glide Path for Runway 28L was off the air, and approach lighting was also unserviceable.
One way or the other, I believe that these two items, specifically the ILS glide path, will be found to have contributed to the accident. There are other methods for vertical guidance in this situation, like a LOC/VNAV approach. Where the aircraft uses the lateral guidance as received from a ground transmitter to direct it laterally to the runway centreline, but uses onboard navigation sources to determine the vertical path. On a good weather day such as yesterday at the time of the accident, the operational difference would be little to none. There are certain steps that must occur in the programming of this type of approach that would be different, and could ultimately lead to a mistake if it was something that the crew was not used to.
There are also reports of the aircraft being too slow prior to impact. What I do know of the 777 is that is is normally flown with the autothrottle engaged, whether or not the autopilot is flying. So if a pilot has disconnected the autopilot to “hand fly” the autothrottle computer stays engaged and controls the speed. Perhaps this was not functioning properly on Asiana flight 214, or perhaps as a result of improper programming of the approach, and being too high (also reports of being too high on the approach) the pilots elected to intervene and disengage the auto throttle (non standard).
Like we see in many accidents, there are usually a chain of events that occur to lead to something like this. If those things occur in a short period of time, they are also more likely to lead to an accident or incident.
So my quick analysis is as follows.
Routine services were not available for landing on 28L, which led to a “infrequently used” LOC/VNAV approach method for the crew. The potential unfamiliarity with such an approach could have led to the mismanagement of the approach. This mismanagement appears to have resulted in a speed issue – perhaps from being too high on the approach, which led to the crew disengaging the auto throttle. This removed any speed protection offered form the onboard computers and resulted in a slow airspeed/low altitude situation. Too high, disengage the A/T and cut he power and push the nose down. Perhaps too much so to overcorrect the high on the profile situation. There was not enough time to recover properly from this and the resulting impact just short of the runway occurred.
Again, this is just my two cents, and will very likely be proven wrong. Just hoping to open up some potential discussion amongst anyone who reads this (aviation experts or otherwise) as quite often an education can come from such discussions.