Why Was Asiana Flight 214 Too Low and Too Slow?

Airplane cockpit

The only positive that can come from the crash of Asiana Airlines Flight 214 in San Francisco last summer happened yesterday. The National Transportation Safety Board released its report on what caused the accident and, more importantly, made recommendations to avoid another.

Within hours of the crash we all knew the Boeing 777-200ER was flying too low and too slow. We knew the co-pilot was hands-on and it was his first approach to SFO. He had only logged 43 hours flying 777s. We also knew there was a seawall at the end of the tarmac and that the plane summersaulted and burst into flames after striking it.

We now know a factor was the dronelike auto-throttle going through its programmed motions. Commands the pilots didn’t fully understand.

The crash killed three people and injured 187. There were 307 aboard the flight from Seoul. It was the first fatal crash in the U.S. in four years.

Within 10 days of the crash a Chicago law firm claimed the accident was caused “by a mechanical malfunction of the Boeing 777’s auto throttle.”

Yesterday’s NTSB report doesn’t give heft to that lawsuit. Here it should be noted the agency has a wealth of expertise and is highly regarded around the world. They are not the TSA with plastic badges making $15 an hour telling us to remove shoes.

“Our goal in this investigation is to help prevent similar accidents in the future,” Christopher Hart, acting chairman of the National Transportation Safety Board said in a preamble to the report. “In this instance, the flight crew over-relied on automated systems that they did not understand.”

The NTSB has posted an animation of their vivid archeology of Flight 214 on YouTube. You can follow the NTSB on Twitter.

Asiana acknowledged the too-low-too-slow theory but it’s also citing “inconsistencies” with the auto-throttle, suggesting the pilots believed it was maintaining a safe speed. In fact, the engines were idling in “hold” mode, apparently the way it’s programmed.

“The airplane and all airplane systems were functioning as expected prior to impact and did not contribute to the accident,” Boeing wrote in a submission to the NTSB. They believe the accident was caused by the pilots’ failure to monitor and control the plane’s airspeed and direction.

But an NTSB member with 24 years of experience as a pilot said there was widespread confusion in the industry about the workings of the auto-throttle. Yet another member stated the auto-throttle has been part of Boeing aircraft since the 767 was introduced in 1982. There should be no surprises there, he believes.

Nonetheless, the NTSB is aware of a 2010 incident when one of the FAA’s top-gun test pilots was descending into Seattle’s Boeing Field. He leveled off and thought the auto-throttle would maintain airspeed. It did not so he manually took over.

Therein probably lies the heart of the confusion in the cockpit of Asiana Flight 214. The pilots believed the auto-throttle was taking care of airspeed when in fact it kept the engines only idling.

Boeing told the board “the pilot is the final authority for the operation of the airplane.”

Asiana Airlines blames Boeing and its own pilots, who they say had received “specific instruction about the possibility the airspeed protection would be disabled in a certain mode.”

The airline hangs the crash on the pilots for not ensuring “a minimum safe airspeed,” and Boeing for creating a confusing autopilot system.

The Asiana pilots’ union blames their employer for inadequate training.

The Tarmac’s View:  Aircraft safety, like all science, is an evolving process. The NTSB is one federal agency we should all be proud of.

Other amorphous issues related to the crash involve two evacuation slides that opened inside the cabin and pinned a flight attendant. The aircraft remained mostly intact and so did the seats. Failure there would have resulted in many more fatalities.

Here’s a little background on Flight 214 from The Tarmac.

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