Aviation safety investigations & reports

Boeing Co 747 , CCA174

Investigation number:
Status: Completed
Investigation completed


The Boeing 747 (B747) was on descent for an arrival at Sydney. The crew was being radar vectored to runway 16R for sequencing behind a SAAB 340 that was being radar vectored to runway 16L. Procedures at Sydney had different air traffic controllers responsible for directing the traffic to each of the parallel runways. The Director West controller positioned aircraft on final for runway 16R and the Director East for runway 16L.

The Director West controller was sequencing the B747 and assigned a heading of 060 degrees magnetic with an instruction to report when the crew had the field in sight.

The crew of the B747 reported the field in sight and the Director West controller told the crew to expect to go right up to the localiser, with a right turn to intercept from the eastern side. The crew acknowledged with a partly unintelligible transmission that included the words "roger" (unintelligible) "localiser into".

Almost immediately, the crew of the B747 turned their aircraft away from the assigned heading onto a heading of 110 degrees to intercept the runway 16R localiser. They advised air traffic control that they were now right heading 110. This particular heading placed the aircraft in potential conflict with the SAAB. The Director West controller instructed the crew of the B747 to maintain a heading of 060 degrees to ensure that the aircraft passed behind the SAAB. The Director East controller passed traffic information regarding the B747 to the crew of the SAAB.

Although the crew of the SAAB reported that they had the B747 sighted, radar separation between the two aircraft was reduced to 2.5 NM during the manoeuvre. The separation standard required was either 3 NM horizontally or 1,000 ft vertically. Analysis of the radar data indicated that vertical separation between the two aircraft was reduced to approximately 800 ft when the 3-NM radar separation standard was infringed.


The instructions passed to the pilot of the B747 may have been unnecessarily complex, given that the pilot was from a non-English speaking background. The controller's transmission was not as definitive as it could have been and included extraneous, non-standard phraseology.

The response from the crew may have indicated to the controller that his transmission was not understood, in that the word "into" indicated a possible turn to intercept the localiser. In addition, the controller did not query the unintelligible transmission.

Safety Action

As a result of this occurrence, the Bureau of Air Safety Investigation is investigating a perceived safety deficiency relating to the use of non-standard language by air traffic controllers during communications with flight crew from a non-English speaking background.

Any recommendation issued as a result of this deficiency investigation will be published in the Bureau's Quarterly Safety Deficiency Report.

General details
Date: 17 March 1998   Investigation status: Completed  
Time: 1015 hours ESuT    
Location   (show map): 20 km NNW Sydney, Aero.    
State: New South Wales   Occurrence type: Loss of separation  
Release date: 01 January 1999   Occurrence category: Incident  
Report status: Final   Highest injury level: None  

Aircraft 1 details

Aircraft 1 details
Aircraft manufacturer The Boeing Company  
Aircraft model 747  
Aircraft registration CCA174  
Type of operation Air Transport High Capacity  
Damage to aircraft Nil  
Departure point Melbourne, VIC  
Destination Sydney , NSW  

Aircraft 2 details

Aircraft 2 details
Aircraft manufacturer S.A.A.B. Aircraft Co  
Aircraft model 340  
Aircraft registration VH-EKG  
Serial number 367  
Type of operation Air Transport Low Capacity  
Damage to aircraft Nil  
Departure point Ballina, NSW  
Destination Sydney , NSW  
Last update 13 May 2014