Navigation aid possible clue to crash

2013-07-07 19:37

San Francisco - The shutdown of an important navigational guidance system may provide a clue as to why a South Korean passenger jet crashed in San Francisco, the head of the US oversight authority said on Sunday.

"What we do know is that there was a notice to airmen that indicated that the glide slope was out," Deborah Hersman, head of the US National Transportation Safety Board, told US broadcaster CBS.

The glide slope is an antenna array that sends a signal that helps pilots remain above ground obstacles when bringing planes in to land. Hersman said it had been switched off since June due to construction at San Francisco International Airport.

Witnesses say nothing in the more than ten-hour flight from Seoul suggested it would end in disaster in its final seconds on Saturday. There was no warning from the cockpit, no sound, no rumble - everything was routine.

Asiana Airways Flight 214 was metres from the runway when there was a violent bang and the plane went into a skid. A few minutes later, the seven-year-old Boeing 777 was a wreck next to the San Francisco runway - burned out, surrounded by debris, covered in flame-retardant foam, with one engine and the tail section torn off.

Of the 307 people on board, 305 survived.

"This could have been much worse," San Francisco Mayor Ed Lee, said. "We're lucky we have so many survivors. But we still have many who are injured and our prayers and thoughts go out to them."

Two 16-year-old Chinese students planning a tour of the US were killed. They had been sitting at the back of the plane and died as the tail separated from the bulkhead. Their bodies were found on the runway.

Dozens of other passengers were injured, some with internal bleeding. Five remained in critical condition on Sunday, according to the San Francisco Chronicle.

There has been a great deal of speculation as to how a plane with a near-flawless safety record belonging to a major airline could crash in broad daylight.

The Boeing 777 twinjet first entered service in 1995 and has had a superb safety record. The two fatalities on Flight 214 are the first ever in the plane's history. More than 1 100 of the long-range wide-body planes are in use, with many more on order.

The type's only previous crash took place in 2008, when a British Airways 777 landed on grass 270m before the runway. Ice crystals on a fuel filter that prevented the engines from reaching full power were blamed for the hull-loss incident that injured 47 people. The filter was redesigned.

Several witnesses said the Asiana 777 also touched down too soon, evidently hitting a sea wall that projects into San Francisco Bay.

With no immediate evidence of a mechanical fault, investigators now hope the pilots will be able to bring clarity in the coming days, Hersman said.

  • Harry Boesman - 2013-07-07 20:06

    It's always scary to board an aeroplane, even though it is, statistically, the safest mode of transport. It is truly a miracle that so many survived with most in a relatively good condition. Those with spinal and burn injuries will have years of rehabilitation ahead of them (and, lest we forget, PTSD from which there is virtually no escape), which impacts deeply on them and their families. Our sympathy and best wishes must surround all involved and touched by this tragedy.

  • AndrĂ© C A Jacobs - 2013-07-07 20:24

    I try not to think of it but it stay a scary thought.

  • Crusadersudan - 2013-07-08 04:39

    A taxi is a scary thought.

  • Nathan Govender - 2013-07-08 06:44

    Somebody used a cellphone

  • Elijah Tishbite - 2013-07-08 08:13

    Had the ILS been operational the crash most likely would not have occurred. How can 2 pilots get it so wrong? Answer there is a phenomenon that occurs only in perfect conditions. Wikipedia describes it thus and the very examples they give come from San Francisco:

      Tamlin Van Heerver - 2013-07-08 08:24

      its perfectly legal to do an approach with no glideslope, you just have to cross reference your height with that on the plate... clearly the pilots didn't do that then and were way too low, pilot error.

      Leigh Le Gonidec - 2013-07-09 09:24

      Never mind NTSB, FAA, Boeing, etc etc, no need to continue with your investigations, seems the "experts" have found the problem...again! Should have just come on to this forum for the answers :o any of you recall what caused the Turkish 737 to land short of Amsterdam and is also the subject of Rad Alt OEB's....maybe this was the same deal????? Just saying, but once again, I'll wait for the pro's to publish the findings!

      Leigh Le Gonidec - 2013-07-09 09:31

      @Elija interesting theory, but consider that there is an aircraft landing on that runway and the one next to it, about every's a busy airport, so the air is pretty much permanently "disturbed" by wake turbulence from the landing aircraft, making it unlikely, to quote "In calm weather, a layer of significantly warmer air can rest over colder dense air, forming an atmospheric duct which acts like a refracting lens," but hey anything is possible.

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