Andrzej Jeziorski/SINGAPORE
Two packed Japan Airlines (JAL) widebodies narrowly avoided what could have been the worst air accident in history, when they passed within 10m (33ft) of each other some 37,000ft above Shizuoka district, near Tokyo.
The 31 January incident left 30 passengers and crew injured, including nine hospitalised. It involved a Boeing 747-400 carrying 411 passengers and 16 crew from Tokyo to Naha, Okinawa, and a McDonnell Douglas DC-10 carrying 236 passengers and 13 crew inbound to Tokyo from Pusan, South Korea.
The 747 captain had clearance to descend to 35,000ft, and continued descending even when the traffic collision avoidance system (TCAS) sounded a resolution advisory (RA) demanding a climb.
The RA in the DC-10 demanded descent, and the captain took control to comply. JAL says he then halted his descent when he saw that the 747 was at the same altitude but also descending.
The 747 passed below the DC-10. All the injured were aboard the 747, though it is unclear whether the injuries resulted from violent evasive manoeuvring or from wake turbulence.
In his incident report, the 747 captain wrote: "At the closest point, the altitude difference was 10m, lateral distance none." The DC-10 captain reported that the vertical separation was "little", lateral separation zero.
According to JAL, once an RA has been issued, pilots are supposed to give the TCAS advisory priority over air traffic control instructions, but top priority is still given to visual information. This clashes with standard operating procedures adopted by most airlines, which give a TCAS RA priority because of the risk that a visual-based decision taken when aircraft are really close could result in both aircraft turning or pitching in the same direction, which TCAS prevents.
The airline says the 747 captain saw the DC-10 at a range of 74km (40nm), while the DC-10 captain visually spotted the other aircraft at a range of 22-24km when his TCAS first displayed conflicting traffic in the vicinity.
According to Japanese press reports, a trainee air traffic controller had repeatedly given the two aircraft confused instructions with incorrect flight numbers in the minutes leading up to the incident. The third year trainee's supervisor reportedly also used an incorrect flight number when instructing one of the aircraft to descend.
JAL says that ceiling panels in the 747 cabin were damaged by unsecured objects. The aircraft returned to Tokyo's Haneda domestic airport, while the DC-10 landed at Narita.
The near miss has been declared an accident by the Japan Civil Aviation Bureau, and is being investigated by the Bureau's Aircraft Accident Investigation Committee.
Source: Flight International
