By Andy Pasztor
Pilot mistakes in monitoring airspeed and undue reliance on automated systems they didn't understand caused the
July 2013 crash of an Asiana Airlines Inc. jet trying to land at San Francisco International Airport, U.S. investigators
said Tuesday at a hearing that capped an 11-month probe.
In its final conclusions about the accident, which killed three people and injured more than 180, the National
Transportation Safety Board determined that the crew made more than two dozen separate errors during the approach and
failed to respond to numerous visual and instrument warnings about serious problems with the approach.
The pilots, among other mistakes, violated mandatory Asiana procedures regarding how fast the jet was sinking,
didn't make required verbal calls as they got closer to the landing strip and then waited some 11 seconds after
realizing the imminent hazard--much too long to initiate a go-round and climb away safely, NTSB officials have said.
The safety board's official report--similar to previous statements and a prior public hearing--mentioned poor
manual-flying skills, inadequate training and confusion about the design and operation of automatically controlled
throttles as factors contributing to the accident.
Capping an 11-month probe that already has prompted significant international rethinking of cockpit design and
pilot training, the safety board on Tuesday approved more than 40 findings and recommendations.
The NTSB formally determined that pilot "mismanagement" was the primary cause of the Asiana jet crash, with cockpit
fatigue and "complexities" of the auto-throttle system likely contributing to the accident.
"As the approach proceeded" in good weather and under visual flight conditions, "the errors seemed to cascade and
became more egregious," Roger Cox, a senior NTSB investigator, said during the hearing.
In addition to raising questions about the airline's training programs, the accident highlighted the hazards of
undue pilot reliance on automation and erosion of manual-flying skills.
"We believe the National Transportation Safety Board has properly recognized the multiple factors that contributed
to the accident, including the complexities of the autothrottle and autopilot systems, which the agency found were
inadequately described by Boeing in its training and operational manuals," Asiana Airlines, based in South Korea, said
in a statement.
"The NTSB made four training recommendations to Asiana, all of which Asiana has already implemented," the airline's
The pilots haven't commented publicly on the accident.
During what should have been a routine approach to San Francisco with all airplane systems functioning properly,
the pilots made a fundamentally wrong assumption, according to the board. They mistakenly believed that by arming the
auto-throttle system, they were assured it would maintain safe approach speed, according to the board.
But when the pilot flying the plane switched the mode of the computerized flight controls--without understanding
the effect of the change or alerting other crew members--the automatic throttle controls became inactive and the
widebody jet's speed fell dangerously low, according to the board's findings. The crew failed to keep track of airspeed
for more than two dozen seconds during a critical phase of the approach, the board said.
The board said during the hearing it adopted recommendations focused on eliminating potential pitfalls stemming
from the auto-throttle's design, including calls for improved training manuals and additional cockpit-warning systems to
alert pilots about dangerously slow approaches.
An attempted emergency go-round came too late to prevent the Boeing 777's tail from smacking into the sea wall in
front of the runway at San Francisco International Airport. The plane broke apart and burst into flames. Despite the
captain's initial decision to delay an evacuation, the flight attendants initiated an evacuation about 90 seconds after
In explaining reasons for the poor performance of the experienced pilots, NTSB officials said that fatigue may have
contributed to poor decision-making. Investigators also said that poor crew communication was exacerbated by the fact
that it was a training flight and that both of the aviators sitting at the controls were captains.
This "led to confusion about who was responsible for initiating a go-round," according to the board.
The only point of suspense during the hearing focused on how far the board would go in urging Boeing and the FAA to
redesign the 777's auto-throttle system to explicitly alert pilots when it is deactivated; and whether it would call for
developing new instrument warnings to ensure that crews realize when planes are flying too slowly to reach and safely
touch down on a strip.
After the hearing, an FAA spokeswoman said the agency remained confident that the original approval of the 777's
auto-throttle system was sound, but the agency "supports a broad review" of measures to enhance pilot understanding of
its operational features.
While recommending additional cockpit alerts to let pilots know about dangerously low-speed landing approaches, the
board also made it clear the current systems already provide adequate warnings. The Boeing 777 offers pilots "plenty of
cues," about such approaches, according to Mr. Cox, "but you have to look at them." Boeing said it disagreed with the
board's conclusion that the plane's automation contributed to the accident.
In the end, the board agreed that the accident was significant enough--and it raised basic questions about
automation issues--to warrant a broad re-examination of certain computerized flight-control features of Boeing's
"The pilot must always be the boss," said Christopher Hart, the board's acting chairman. The experienced pilots at
the controls of Asiana Flight 214 got into trouble because "they misunderstood the relationships" between various
computerized systems and failed to properly work together when an emergency loomed.
Asiana Airlines previously acknowledged the crew's mistakes, and the carrier beefed up training for manual-flying
skills and automation awareness.
Write to Andy Pasztor at firstname.lastname@example.org
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