Investigation number
200404707
Occurrence date
Location
278 km NW NIKOM, (IFR)
State
International
Report release date
Report status
Final
Investigation type
Occurrence Investigation
Investigation status
Completed
Aviation occurrence category
Loss of separation
Occurrence class
Incident
Highest injury level
None

On 28 November 2004, a Boeing Company 747-438 aircraft was en route from Sydney to Singapore at flight level (FL) 360. Another Boeing Company 747-400 aircraft was en route from Bangkok to Sydney at FL350. At 1509, the crew of the 747-438 had been issued with a clearance to climb to FL380 with a requirement to reach that level by 1550 and the crew planned to leave FL360 at 1544. At 1521, the crew of the 747-400 requested a clearance to climb to FL370 and were issued a clearance to reach FL370 by 1528. This resulted in an infringement of separation standards.

At 1538, approximately 150 NM north-west of waypoint NIKOM, the crew of the 747-438 observed an aircraft pass overhead. They informed the controller, and confirmed that they had a clearance to climb to F380. The controller acknowledged the crew, but took no further action to resolve the infringement of separation standards.

The controller reported that when he issued the climb instruction to the crew of the 747-400, his mental picture was that the 747-438 was maintaining FL360, and this was reinforced by a simultaneous separation problem with another aircraft. He also reported that it was possible that he may also have mixed up the displayed levels for the 747-438.

The controller indicated that his sleep pattern had been disrupted, and while he had assessed himself as fit for duty, and felt competent to acquit the required task, he felt ‘a bit more fatigued than normal’.

Aircraft Details
Manufacturer
The Boeing Company
Model
747
Registration
HS-TGJ
Serial number
NA
Operation type
Air Transport High Capacity
Sector
Jet
Departure point
Bangkok Thailand
Departure time
0815 UTC
Destination
Sydney NSW
Damage
Nil
Aircraft Details
Manufacturer
The Boeing Company
Model
747
Registration
VH-OJM
Serial number
25245
Operation type
Air Transport High Capacity
Sector
Jet
Departure point
Sydney NSW
Departure time
0815 UTC
Destination
Singapore
Damage
Nil