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A Boeing 767 (B767) aircraft departed Perth for Melbourne on climb to the flight planned level of flight level (FL) 370. The aircraft was being controlled by Melbourne Sector 1. This position was a procedural control position which used flight progress strips (FPSs) to manage aircraft separation. A number of FPSs were required for each aircraft under control. The FPSs designated the planned route of an aircraft. After reporting at RERON, a position southeast of Perth, the crew requested a change of level to FL330. The change of level was approved by the Sector 1 controller. The controller annotated the new level of FL330 on the B767's FPSs. While the Sector 1 controller was receiving coordination on three other aircraft from Perth Flight Service the crew of the B767 requested a change of level to FL350. The Sector 1 controller approved the change of level and then completed the coordination. The controller did not annotate the B767's RUFLE position FPS, the last FPS for the aircraft, with the amended level. This FPS indicated that the B767 was to operate at FL330. The Sector 1 controller transferred the B767 to Perth Flight Service (FS) to maintain communications via High Frequency (HF) radio. The FS operator passed the B767's RIDLE position to the Sector 1 controller after the crew reported at that position. The aircraft's level of FL350 was reported to, and correctly read back by the Sector 1 controller. The Sector 1 controller was then relieved at the position by another controller. The two controllers conducted a handover/takeover of the position. The relieved controller could not remember conducting a final check of the FPSs, as was his normal practice, before leaving the position. The crew of the B767 reported to the new Sector 1 controller that the aircraft was now back on Very High Frequency (VHF) radio and was at position ROMPA at FL350 at 54 (time 1754 UTC). The Sector 1 controller coordinated the position report to Adelaide Sector 4 but read the level of FL330 from the RUFLE FPS. The Adelaide Sector 4 controller read back and annotated the B767 FPS with FL330. During this coordination sequence the Sector 1 controller was interrupted by a transmission from another aircraft. The crew of the B767 subsequently transferred to Adelaide Sector 4 and reported at RUFLE at FL350. There was no breakdown of separation. Sector 1 was combined with Sector 5. Traffic was light and less than normally experienced at the position for the time of day. The first controller had worked until 1300 ESuT that morning and then returned for the evening "Doggo" shift at 2300. He had two hours sleep in the afternoon and felt rested. He operated the position from approximately 0300 to 0445.


There were two opportunities to correct the error after the relieving controller assumed responsibility for the position. The first being when that controller started operating at the position and the second when the crew of the B767 reported at ROMPA at FL350. However, the incorrect annotation on the RUFLE FPS was not detected. The reason for these errors not being detected or why the first controller did not annotate the RUFLE FPS could not be ascertained. It was probable that the physiological effects due to the early time of day and the low level of activity combined to reduce the controllers' vigilance and/or use of standard practices.


1. The Sector 1 controller did not annotate all the B767 FPSs with the approved level of FL350.

2. The relieving controller did not detect the error in the RUFLE FPS during or after the handover/takeover.

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[ Download PDF: 15KB]
General details
Date: 26 March 1997 Investigation status: Completed 
Time: 4:56 ESuT  
 Investigation type: Occurrence Investigation 
 Occurrence type: ANSP info/procedural error 
Release date: 10 October 1997 Occurrence class: Airspace 
Report status: Final Occurrence category: Incident 
Aircraft details
Aircraft manufacturer: The Boeing Company 
Aircraft model: 767-238 
Aircraft registration: VH-EAM 
Sector: Jet 
Damage to aircraft: Nil 
Departure point:Perth WA
Destination:Melbourne Vic
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Last update 15 March 2016