Asiana Flight 214 made no distress calls and appeared to be operating smoothly moments before it slowed to a near-stall, crashed into a seawall near the runway and broke apart, a federal official said Sunday.
“There is no discussion of any aircraft anomalies or concern with the approach,” Deborah Hersman, chairwoman of the National Transportation Safety Board, said at an afternoon news conference that included reporters from all over the world.
Then, at seven seconds prior to impact, a call is heard from one crew member “to increase speed,” Hersman said. At four seconds before impact, the sound of the "stick shaker" – which noisily vibrates to warn pilots of an impending stall – can be heard, she said. Then, one and a half seconds before impact, the cockpit crew sought to initiate a “go-around,” hoping to power back up and circle back to the runway.Asked if pilot error may have been a factor, Hersman stressed that the investigation would probably take more than a year and that “everything is on the table right now. It is too early to rule anything out.”
The cockpit voice recorder offered two clear hours of good quality and indicated that the Boeing 777 was cleared for visual approach to the 2-mile runway 28L. The flaps were configured at 30 degrees and the landing gear was down. Target speed was 137 knots and the approach “proceeds normally as they descend,” Hersman said.
But then Hersman said that during the approach, “the data indicate that the throttles were at idle and airspeed was slowed below the target airspeed.”
“The speed was significantly below 137 knots,” she said. When questioned further, Hersman said, "we’re not talking about a few knots,” but she declined to give exact speeds.
The engines appeared to be working properly. Throttles were advanced “a few seconds prior to impact and the engines appear to respond normally,” she said.
Hersman confirmed that part of the so-called glide path system that assists pilots with instrument based landings had been out of commission since June 1. The glide slope – which “can give you a constant approach to the airport on an approach down” has been sidelined until Aug. 22 due to runway construction, and all pilots had been notified.
Another part of that system – known as a localizer – that lines up an aircraft horizontally around the runway’s center line, was working correctly, a test flight revealed, she said. So were precision approach indicator lights, which were then “significantly damaged” during the crash.
Hersman said the aircraft may have also had GPS-based technology that offers vertical guidance to pilots.
The unavailability of the glide scope is part of the investigation, as is a detailed look at all the technologies the aircraft had deployed, Hersman said. But she stressed that “this was a visual approach.”
The skies were clear and wind was blowing at 7 knots, with a visibility of 10 miles. “What a visual approach means is that you can fly it visually,” she said. “You do not need instruments. It was a clear day. They were cleared for a visual approach.”
Handling of the aircraft “appeared routine until the controller noticed that the aircraft hit the seawall,” she said.
The aircraft’s engine is manufactured by Pratt & Whitney. About 168 other Boeing 777s use the same model of engine.
Hersman offered a glimpse at the far-reaching scope of the investigation and said crews should be on scene for at least a week. Korean airline safety investigators as well as Asiana’s own investigators arrived Sunday and have joined the team, and FBI evidence response and hazardous materials teams are also assisting.
The investigation includes an operations group, which will evaluate the airport geography, the cockpit instruments, seats, windshields, flight plans, training and experience of the crew, whom investigators hope to interview “in the next few days.”
“They can tell from examinations whether the engine was rotating at the time of the crash, so they will look at that, and whether any fires originated in the engines,” Hersman said.
A site survey will locate the “four corners of the wreckage” and search for key parts. Investigators are also probing the seating positions of those killed and injured, deployment of the chutes, and use of seat belts and child safety seats. They will soon interview survivors.
A separate “human performance investigator” will perform drug and alcohol testing, and probe fatigue, medication use, sleep disorders and what Hersman called “crew resource management -- how they work together and communicate.”
The NTSB is seeking video footage and photographs from eyewitnesses, which can be uploaded on its website, she said.