Aviation occurrence briefs

Tracking deviation during approach involving a Bombardier DHC-8, near Sydney Airport, NSW, on 4 February 2020

Status: Completed
Investigation completed


Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.

What happened

On 4 February 2020 at 0945 Eastern Daylight-saving Time, a Bombardier DHC-8 was conducting a precision runway monitor (PRM) approach[1] to runway 16L at Sydney Airport, New South Wales. The scheduled passenger service comprised of a training captain as pilot monitoring, a first officer undergoing line training as the pilot flying, and a safety pilot. The aircraft was operating in visual meteorological conditions.

During the approach, with another aircraft also on approach to the parallel runway, the aircraft deviated from the runway centreline and the training captain instructed the first officer to re-establish the approach path. At this time, the safety pilot alerted the captain to select the additional PRM frequency to be monitored, as dual VHF is required during PRM operations.

ATC observed the DHC-8 to be within the no transgression zone (NTZ), which is a 610 m-wide safety buffer between the parallel approaches. The controller issued the aircraft with break-out instructions, in order to abort the approach. However, the aircraft continued the approach. It was later determined that the crew had inadvertently delayed selecting the additional PRM frequency and therefore did not hear the break-out instructions issued by ATC.

Safety message

This incident highlights the importance of effective crew resource management and adherence to standard operating procedures, particularly during phases of high workload when vulnerability to error is increased.

Further information on PRM operations can be found on the Airservices Australia website.

About this report

Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.


  1. During periods of the day with peak arrival demand and inclement weather, capacity at Sydney Airport can be maintained with the use of PRM operations. A highly accurate surveillance system allows ATC to precisely monitor aircraft tracking on their approach paths and permit independent visual approaches.
General details
Date: 04 February 2020   Investigation status: Completed  
Time: 0945 EDT    
Location   (show map): 19 km from Sydney Airport    
State: New South Wales    
Release Date: 26 March 2020   Occurrence category: Incident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Bombardier Inc  
Aircraft model DHC-8-315  
Type of operation Air Transport High Capacity  
Sector Turboprop  
Damage to aircraft Nil  
Destination Sydney Airport, New South Wales  
Last update 26 March 2020