U.S. News

07.06.13

San Francisco Airplane Crash Landing: What Happened?

A Boeing 777 crashed while landing in San Francisco today, killing two. Aviation expert Clive Irving on what may have gone wrong.

Fire is the thing most feared in an air crash. That's partly why images of the Asiana Boeing 777 that crash-landed on Saturday at the San Francisco airport are so terrifying.

The crash was a shocking and horrible accident. Initial reports indicate that at least two people were killed and dozens injured.

However, the pictures from above showing the plane's fuselage gutted by fire are misleading. The fire seems to have reached the fuselage from the right engine only after the airplane slewed around on the ground. Pictures taken apparently only minutes after the crash show an orderly evacuation of passengers from the left side of the fuselage before the engine fire reached the fuselage. All indications are that the 777 was intact, with no fire, when it reached the runway.

The plane hit the runway with a downward force strong enough to break off its entire tail section, with the rear fuselage, vertical and horizontal stabilizers separating from the main airframe. The impact was strong enough to rip off the left engine from the wing—which prevented an engine fire there—and to collapse the main landing gear.

With the main landing gear gone, the right engine, still attached to the wing, was severely damaged. This is where it seems the fire began.

Descriptions of the 777 cartwheeling on the ground may exaggerate what happened, but the landing would qualify as “extremely heavy,” and this indicates that for some reason the pilots lost control of the airplane’s altitude in the final seconds. For the tail to break off, it must have hit the ground first.

Since it began airline service in 1995, the Boeing 777 has had an impeccable safety record—more than 1,000 are flying, and no passenger had ever been killed on one. However, whether by chance or otherwise, the San Francisco crash is very similar to the only other previous near-disaster with a 777, which occurred at London's Heathrow airport in 2008.

In that case, a British Airways 777 was on its final approach when it lost the power of both engines. With virtually no margin left for error, the pilots glided the airplane over a busy highway and on to the runway, but it was such a heavy landing that the main landing gear pushed up through the wings. Everybody onboard was safely evacuated and there was no fire.

It was later determined that the engines failed because of sudden fuel starvation, traced to the effects of having flown a long flight from Beijing at high, cold altitudes. The Rolls Royce engines were modified to eliminate this problem.

Seoul-based Asiana Airlines has a similarly excellent record, voted “Best Overall Airline in the World” by Business Traveler magazine in 2012, and is one of only seven airlines to be rated at five stars by the Skytrax independent airline rating system.

130707-SFO-plane-01
Marcio Jose Sanchez/AP

One testament to the airline crew is the efficiency of the evacuation from the seriously damaged airplane—reminiscent of the crash of an Air France A340 in Toronto in 2005, in a similar situation, where 297 passengers and 12 crew were safely evacuated before a fire consumed the fuselage of that airplane.

All of which poses the question: How did an airplane with such a stellar record, operated by an highly-rated airline, come to grief in a situation where neither the weather or another airplane were involved?