Details are still emerging about the Asiana Airlines crash at the San Francisco airport on July 6. Investigators only recently examined the aircraft’s black box data and voice recorders and initial interviews with the flight crew. However, investigators and the public are slowly learning more about the minutes and seconds before the crash.
We’ve learned the pilot flying when the plane crashed, though he had more than 10,000 hours in other aircraft (including the Boeing 737, 747, and Airbus 320), had logged only 43 hours in a Boeing 777. The pilot was receiving his initial operating experience (IOE) – a type of “on the job training” with another training captain, and was attempting his first landing in the Boeing 777 at San Francisco. There were a total of four pilots on the flight deck during the crash landing.
A pilot friend of mine suggested another factor which may have led to the crash was the inoperative Instrument Landing System (ILS) and Precision Approach Path Indicator (PAPI) lights for the landing runway. These are systems that give a pilot vertical guidance down to the runway. With initial National Transportation Safety Board (NTSB) reports indicating the aircraft was functioning normally (i.e., there were no identified malfunctions), something clearly went wrong to allow the aircraft to be 30 knots too slow and to collide with the sea wall short of the runway. It seems plausible that the lack of vertical guidance is something the NTSB will examine in its investigation.
But how can four veteran pilots allow this to happen on a clear weather day, like in San Francisco on Saturday? We’ll have to wait for the final NTSB report to come out for the final answer. One factor investigators will likely consider is pilots’ reliance on – and occasional mismanagement of – automated systems in modern jetliners. In other words, extensive use of automated systems during flight and landing or too much reliance on the auto-pilot. The Boeing 777 has auto-throttles, which automatically maintain a pre-selected airspeed and redundant autopilots which are capable of precisely controlling the plane’s flight path, including following on board navigation systems and maintaining selected altitudes (including pre-selected rates of climb or descent). Could this crew’s over-reliance on automation have brought down a high-tech airliner?
The Federal Aviation Administration (FAA) recently issued a Safety Alert for Operators (SAFO) warning pilots of an increase in manual flight-handling errors due to overuse of auto-pilot systems.
The safety bulletin warned that “continuous use of autoflight systems could lead to degradation of the pilot’s ability to quickly recover the aircraft from an undesired state.” In short, pilots can essentially forget how to fly. Because the landing system at San Francisco was turned off for maintenance, the Asiana pilot would have been performing a visual approach with no vertical guidance. If the pilot was too reliant on automation, the manual conditions in a new aircraft at a new airport may have contributed to the pilot’s inability to recover the aircraft from its undesired approach.
NTSB Chairman Deborah Hersman said that Asiana 214 was traveling well below the necessary speed for landing when it crashed. “The speed was significantly below 137 knots, and we’re not talking a few knots”, Hersman said. In fact, the most recent reports indicate the jet approached at speeds as slow as 103 knots, some 30+ knots too slow. At that low airspeed, it would take considerable time for the aircraft to recover after initiating the “go-around” procedure of applying full power and retracting the jet’s landing gear and flaps. The go-around was initiated prior to the crash, but only after the crew received a warning of an impending stall mere seconds before impact.
Fortunately, nearly all of the more than 300 people on board survived the crash, though eight passengers remain in critical condition. Reports suggest that at least one of the two fatalities may have been caused by a collision with a rescue vehicle, rather than the crash itself.
Reports credit improved aircraft design for remarkable lack of deaths and serious injuries from the crash.
While more than 100 people were injured in Saturday’s crash, some seriously, these relatively good outcomes typically happen after what are called “low-impact survivable” incidents when the plane has slowed to 140 or 150 m.p.h., are due in part to changes in airplane construction to include better safety doors, seat technology, exit chutes, fireproofing and incident protocols. “Thirty years of design improvements have made a huge difference in the ability to get everyone off the plane in less than two minutes,” explains Larry Rooney, a veteran pilot, National Transportation Safety Board-trained accident investigator and executive vice president of the Coalition of Airline Pilots Associations.
- Susanna Schrobsdorff at Time
Officials have not yet determined an official cause – and may not for some time. Hersman said investigators will look at all possibilities. “Everything is on the table,” she said.
Read More:
Asiana pilot had little experience flying Boeing 777s [William M. Welch, Chris Woodyard, Doug Stanglin and Gary Strauss at USA Today]
Asiana Crash Victims Possibly Hit By Rescue Vehicle [Christina Ng, Alexis Shaw, Joohee Cho and Anthony Castellano at Good Morning America]
San Francisco’s Boeing 777 Crash: Why It Was Survivable [Susanna Schrobsdorff at Time]
Asiana Crash: Plane Was 34 Knots Below Target Speed, NTSB Says [Bill Chappel at NPR]
FAA Recommends Pilots Spend Less Time Using Autopilot [FAA via National Business Aviation Association]
Autopilot Addiction? Pilots Forgetting How to Steer [Tyler James at CBN News]
© Copyright 2013 Brett A. Emison
Follow @BrettEmison on Twitter.