San Francisco Crash: Asiana Flight 214 crash reconstructed
Hi Captain Lim,
What are the different airlines’ SOP (Standard Operating Procedures) on the use of auto throttles? I believe not using the manual throttle doesn't allow the pilot to keep his hand on them.
What do you think?
On the Boeing 777s, how often do you use the auto throttle for landing? Do you leave it on?
Isn't it better to leave it off to use the power to control your glide path, like basic flying technique?
I have the PMDG 777 for FSX but I have been very interested in heavies (wide bodied planes) for over fifteen years.
I have 25 hours logged real flying though which I think is the best. I want to get back in the skies one day but it will take a bit of work to get a line job.
The Standard Operating Procedure (SOP) of most airlines operating the Boeing 777 is to leave the auto throttle on for all landings. However, if the pilot intends to land the plane using manual thrust, he could do so by switching the system off.
As a matter of airmanship, even if the pilots were to land the plane with auto throttles on; their hands would still be on the levers just in case they fail. This would allow the pilot to apply full power immediately.
An interesting case about the auto throttle issue involved the Asiana Boeing 777 crash in San Francisco recently.
According to the investigation, the instructor who was training the new captain thought the auto throttle was on the Boeing 777 jet when in fact it wasn’t.
What transpired was that they had left their "flight director" system which included the autopilot, partially on. As such, this would prevent a "wake-up" from taking place. Effectively, the lack of ‘wake-up’ meant that the auto throttle was not going to prevent the plane's speed from slowing down. In other words, the pilot needed to manually move the levers. This is Boeing's philosophy to allow pilots to override full automation
Of course, this design by Boeing has its flaw. This ‘wake up’ feature had been raised before during the certification of the Boeing 787 Dreamliner.
According to the NTSB which quoted a FAA report - this was a “less-than-desirable feature and it could be improved upon."
Hence, if the autopilot is disconnected and the auto-throttles are left “armed,” the thrust would hold in idle power and would not automatically increase to the target airspeed.
The auto-throttle is one of the most important devices for the pilots as a back-up to keep their aircraft safe under all circumstances.
Unfortunately, the pilots may have relied on the auto-throttle to maintain a safe speed of 137 knots. They may have failed to notice that the automated system wasn't actually doing its job.
In fact the flight data recorder showed that the speed had already decayed to 134 knots as the aircraft passed through 500 feet and would ultimately drop to as low as 103 knots at 3 seconds before impact.
Having realized that, the captain under training then manually increased engine power from idle power at 125 feet, reaching 50% thrust 3 seconds before impact. Alas, the recovery action was probably too late!
Asiana Airlines Crash: The 7 Seconds of Horror on Flight 214
If you like what you read, more stories are found in my book LIFE IN THE SKIES (Preview here) and you can purchase a copy here. To check for any latest updates or postings, you can follow my Twitter at @CaptKHLim or Facebook here