July 07, 2013
Credit: Justin Sullivan
Preliminary analysis of the cockpit voice recorder and flight data recorder from Asiana Flight 214 reveals that pilots had issues with speed control shortly before the 777-200ER hit a sea wall at the approach end of Runway 28L at San Francisco International Airport on the morning of July 6.
NTSB chairman Deborah Hersman, during the NTSB’s first on-scene press conference on July 7, says pilots had discussed a target approach speed of 137 kt. But airspeed just before the crash was “significantly below” that value, “and we’re not talking about a few knots,” she says.
Based on the cockpit voice recorder, Hersman says at 7 sec. before impact, one crewmember called for an increase in speed, and at 4 sec. before hitting the sea wall, the stick shaker is heard. At 1.5 sec. before impact, Hersman says a crewmember called for a go-around. Earlier in the approach, the crew verified that the 777’s landing gear was down and the flaps set to 30 deg.
Based on the flight data recorder, Hersman says that “the throttles were at idle and airspeed was slowed below target airspeed”, adding that the throttles “are advanced a few seconds before impact” and the Pratt & Whitney PW4090 engines “appear to respond normally”.
Two of the 291 passengers were killed in the crash and 182 of the 307 passengers and crew were taken to hospitals with a variety of injuries.
Crash images and video indicate the 777 made an initial impact to the right of the centerline, losing its tail section and parts of the landing gear before sliding down the runway and then ground-looping onto the grass to the south of the normal touchdown area.
Controllers that morning cleared Asiana Flight 214 for a visual approach into San Francisco from Seoul, South Korea with 7 kt. winds from the southwest and 10 mi. visibility. Hersman says there were no reports of windshear “or adverse conditions”.
The Runway 28L glideslope system had been inoperative due to a long-term construction project, but the instrument landing system localizer and a precision approach path indicator (PAPI), a visual-based glideslope, were operational at the time of the accident, Hersman says.
In addition to interviewing the crew in the next few days, Hersman says investigators will look closely at Asiana’s flight training, operations manuals, cockpit configuration and procedures for stabilized approaches.