Incident Overview

Description
On Jan. 31, 2001, JAL flight 907, a Boeing 747 had departed Tokyo-Haneda (HND) for a flight with destination Naha (OKA). JAL Flight 958, a DC-10-40 was en route from Pusan (PUS) to Tokyo-Narita (NRT). A trainee controller cleared flight 907 to climb to Flight Lever 390 at 15:46. Two minutes later JL958 reported at FL370. Both flights were on an intersecting course near the Yaizu NDB. At 15:54 the controller noticed this, but instead of ordering flight 958 to descend, he ordered the Boeing 747 to descend: “Japan air niner zero seven, descend and maintain flight level three five zero, begin descent due to traffic.” Immediately after this instruction, the crew of flight 907 were given an aural TCAS Resolution Advisory to climb in order to avoid a collision. At the same time the crew of flight 958 were given an aural TCAS Resolution Advisory to descend. The captain of flight 907 followed the instructions of the air traffic controller by descending. The 747 now approaching close to Flight 958, because the DC-10 captain descended as well, following the advisory of his TCAS. A collision was averted when the pilot of flight 907 then put his Boeing 747 into a nosedive. The 747 missed the DC-10 by 105 to 165 meters in lateral distance and 20 to 60 meters in altitude difference. About 100 crew and passengers on flight 907 sustained injuries due to emergency manoevre, while no one was injured on Flight 958. Flight 958 continued to Narita, while flight 907 returned to Haneda Airport. PROBABLE CAUSE: The Aircraft and Railway Accident Investigation Commission concluded that air traffic control’s error in giving the wrong flight numbers when asking the pilots to change course and the pilots’ decision to follow air traffic control instead of the computerized Traffic Alert and Collision Avoidance System (TCAS) were two of the main causes. The commission recommended a.o. that the International Civil Aviation Organization (ICAO) put priority on computer orders over instructions from controllers to prevent similar incidents.
Primary Cause
Air traffic control’s incorrect flight number assignment and the pilots’ subsequent decision to disregard the TCAS advisory led to the collision.Air traffic control’s incorrect flight number assignment and the pilots’ subsequent decision to disregard the TCAS advisory led to the collision.Share on: