Airspace related - Other involving a Boeing 767-338ER, VH-OGJ, 741 km south-south-east of Manila, on 2 September 1996

FACTUAL INFORMATION

The B767 was flying from Manila, Philippines to Melbourne. The pilot in command reported that, soon after taking off, he attempted to get clearance to leave Flight Level (FL) 290 for FL 370. He attempted to obtain this clearance before leaving Manila airspace as their company had a policy of not changing flight levels in the Ujung Pandang flight information region.

There were frequent communication problems between Manila air traffic control and the flight crews of several aircraft, many of which were also tracking south and attempting to change their assigned flight levels. There were several instances of crews reading back clearances intended for other crews, as well as many instances of either crews or controllers asking for a repeat of the last message. Due to the communication problems, the B767 was only able to reach FL 330.

The flight numbers of several of the aircraft flying south were quite similar, such as Qantas 28, Qantas 86, Qantas 88, Ansett 888, and Air New Zealand 88. In addition, some of the flight crews involved in the incident had just entered the Manila area and they could not hear the controllers but could hear other flight crews. The southern part of Manila's airspace relied on HF radio communications whereas the northern part was equipped with the more reliable VHF equipment.

ANALYSIS