It has now been disclosed that Asiana Flight 214 was being flown by a pilot who was new to the 777 under the supervision of a pilot experienced on the plane. This is standard procedure when pilots transition from one type of airliner to another. When the transitioning pilot is making the landing, the pilot supervising is ultimately responsible for the plane's safe operation.
If, at any point during the landing, the trainee allows the speed of the plane, or its path to the runway, to exceed established parameters, it is the supervising pilot's job to take control of the plane, correct the situation, and land the plane safely.
These parameters are fairly wide when the plane is one to two minutes from landing, but as the plane nears the runway, the latitude allowed narrows. When five miles from the airport, the gear should be down, the flaps set for landing, the plane on the proper 2.5 to 3.0 degree glide angle toward the runway touchdown zone, the rate of descent 700 feet per minutes (plus or minus 100 feet per minutes) and the speed within ten knots of target.
Once the plane is less than 1000 feet above the runway, the plane's speed and rate of descent should be within narrow parameters and steady. For example, if the trainee allows the rate of descent even momentarily to reach 1000 feet per minute (as read on instruments in the cockpit), the supervisory pilot should take control of the plane. As the plane nears the runway, if the trainee allows the speed to go even one knot below target speed, or the path of the plane to drop even slightly below the proper glide path, the supervisor must take over the controls.
For safety, the supervisor must hold the parameters actively in mind. If a trainee's performance is outside of parameters - whether minutes before landing or seconds before landing - a trainee must not be allowed to take the plane any closer to the ground. Thus, the question that remains to be answered is - not why the trainee pilot flying the plane landed short of the runway - but why the supervisor allowed the trainee to continue when his performance was unsatisfactory.
The parameters were repeated exceeded long before the plane neared the runway. The supervisor had plenty of time, opportunity, and reason to take control. It has been suggested that problems developed only seconds before the crash; that is incorrect. When the plane was eighty seconds from landing, the trainee allowed the rate of descent to reach a rate of 4,000 feet per minutes, five times the normal rate, and 3,000 feet per minute outside of parameters. From that point on, the trainee was never within acceptable parameters; the plane was too slow or too slow, or both too low and too slow. Had the supervisor done his job, the plane would not have crashed.
Why did the supervisor fail? In some cases, supervisory pilots are chosen based on corporate politics rather than judgment and ability. In some cases, a supervisor's flight skills deteriorate when working mostly in an office setting rather than in a cockpit.
Also, fatigue impairs judgment. Researchers have found that people who drive after being awake for 17 to 19 hours performed worse than those with a blood alcohol level of .05 percent. A flight from Seoul to San Francisco takes about 11 hours. With a scheduled takeoff time of 4:30 PM, if the supervisor woke up at 8:30 AM, he may have have been awake 19 hours when the flight was landing. Though the crew included a relief pilot, a supervisory pilot may have feel a need to remain awake and in the cockpit throughout the flight.
In the United States, periods of accident-free flight are getting longer and longer. Arnold Barnett at M.I.T. says that based on the last five years, a person could fly daily for an average of 123,000 years before being in a fatal crash. But, Barnett has observed, passengers on airlines based in the developing world face thirteen-times more risk than when flying with a First World airline. This may be an example.