Asiana Airlines Flight 214

Asiana Airlines Flight 214 was a scheduled transpacific passenger flight originating from Incheon International Airport near Seoul, South Korea, to San Francisco International Airport near San Francisco, California, United States that crashed on final approach into Runway 28L of San Francisco International Airport in the United States on the morning of July 6, 2013. The Boeing 777-200ER operating the flight, registered as HL7742, approached too slowly and crashed at an angle into the seawall before the threshold of Runway 28L. The tail, main landing gear, and left engine separated, while the remaining fuselage slid along the runway before coming to a stop and catching fire.

Of the 307 people on board, three were killed; another 187 occupants were injured, 49 of them seriously. Among the seriously injured were four flight attendants who were thrown onto the runway while still strapped in their seats when the tail section broke off after striking the seawall short of the runway. This was the first fatal crash of a Boeing 777 since the aircraft type entered service in 1995, and the first fatal crash of a passenger airliner on U.S. soil since the crash of Colgan Air Flight 3407 in 2009.

The investigation by the U.S. National Transportation Safety Board (NTSB) concluded that the accident was caused by the flight crew's mismanagement of the airplane's final approach. Deficiencies in Boeing's documentation of complex flight control systems and in Asiana Airlines' pilot training were also cited as contributory factors.

Accident

On July 6, 2013, Flight OZ214 took off from Incheon International Airport (ICN) at 5:04 p.m. KST (08:04 UTC), 34 minutes after its scheduled departure time. It was scheduled to land at San Francisco International Airport (SFO) at 11:04 a.m. PDT (18:04 UTC). The flight was uneventful until its landing.

The instrument landing system's (ILS) vertical guidance (glide slope) on Runway 28L was unavailable, as it had been taken out of service on June 1. A notice to airmen to that effect had been issued. Therefore, a precision ILS approach to the runway was not possible.

The flight was cleared for a visual approach to Runway 28L at 11:21 a.m. PDT and was told to maintain a speed of 180 kn until the aircraft was 5 nmi from the runway. At 11:26 a.m., Northern California TRACON ("NorCal Approach") handed the flight off to San Francisco tower. A tower controller acknowledged the second call from the crew at 11:27 a.m. when the plane was 1.5 mi away and gave clearance to land.

The weather was very good; the latest METAR reported light wind, 10 mi visibility (the maximum it can report), no precipitation, and no forecast or reports of wind shear. The pilots performed a visual approach assisted by the runway's precision approach path indicator (PAPI).

Preliminary analysis indicated that the plane's approach was too slow and too low. Eighty-two seconds before impact, at an altitude of about 1600 ft, the autopilot was turned off, the throttles were set to idle, and the plane was operated manually during final descent. NTSB chairman Deborah Hersman stated the pilots did not "set the aircraft for an auto-land situation... They had been cleared for a visual approach and they were hand-flying the airplane", adding: "During the approach there were statements made in the cockpit first about being above the glide path, then about being on the glide path, then later reporting about being below the glide path. All of these statements were made as they were on the approach to San Francisco..." Based on preliminary data from the flight data recorder (FDR), the NTSB found that the plane's airspeed on final approach had fallen well below its target approach speed. A preliminary review of FAA radar return data did not show an abnormally steep descent curve, although the crew did recognize that they began high on the final approach.

At a height of 38 m, eight seconds before impact, the airspeed had dropped to 112 kn. According to initial reports from the cockpit crew, the plane's autothrottle was set for the correct reference speed, but until the runway's precision approach path indicator (PAPI) showed them significantly below the glide path, the pilots were unaware that the autothrottle was failing to maintain that speed. The instructor pilot stated that the PAPI indicated a deviation below the glide path at approximately 500 ft above ground level, and he attempted to correct it at that time. Between 500 and 200 ft, the instructor pilot also reported a lateral deviation that the crew attempted to correct. Seven seconds before impact, one pilot called for an increase in speed. The FDR showed the throttles were advanced from idle at that time. The instructor pilot reported that he had called for an increase in speed, but that the pilot flying had already advanced the throttles by the time that he reached for the throttles. The sound of the stick shaker (warning of imminent stall) could be heard four seconds before impact on the cockpit voice recorder. Airspeed reached a minimum of 103 kn (34 knots below the target speed) three seconds before impact, with engines at 50% power and increasing. The co-pilot called for a go-around 1.5 seconds before impact. At impact, airspeed had increased to 106 kn.

At 11:28 a.m., the plane crashed short of Runway 28L's threshold. The landing gear and tail struck the seawall that projects into San Francisco Bay. The left engine and the tail section separated from the aircraft. The NTSB noted that the main landing gear, the first part of the aircraft to hit the seawall, "separated cleanly from [the] aircraft as designed" to protect the wing fuel tank structure. The vertical and both horizontal stabilizers fell on the runway before the threshold.

The remainder of the fuselage and wings rotated counter-clockwise approximately 330 degrees as the plane slid westward. Video showed it pivoting about the wing and the nose while sharply inclined to the ground. It came to rest to the left of the runway, 2400 ft from the initial point of impact at the seawall.

After a minute or so, a dark plume of smoke was observed rising from the wreckage. The fire was traced to a ruptured oil tank above the right engine. The leaking oil fell onto the hot engine and ignited. The fire was not fed by jet fuel. All three fire handles were extended; these operate safety equipment intended to extinguish fires on the aircraft (a handle for each engine and the auxiliary power unit). The speedbrake lever was down, showing that it was not being used.

Two evacuation slides were deployed on the left side of the airliner and used for evacuation. Despite damage to the aircraft, "many... were able to walk away on their own." The slides for the first and second doors on the right side of the aircraft (doors 1R and 2R) deployed inside the aircraft during the crash, pinning the flight attendants seated nearby.

According to NBC reports in September 2013, the U.S. government had been concerned about the reliability of evacuation slides for decades: "Federal safety reports and government databases reveal that the NTSB has recommended multiple improvements to escape slides and that the Federal Aviation Administration has collected thousands of complaints about them." Two months before the accident at SFO, the FAA issued an airworthiness directive ordering inspection of the slide-release mechanism on certain Boeing 777 aircraft in order to detect and correct corrosion that might interfere with slide deployment.

This was the third fatal crash in Asiana's 25-year history.