Aviation occurrence briefs

Loss of separation involving a Boeing 737-800 and an Agusta A109S, Sydney Airport, NSW, on 4 October 2019

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 the 4 October 2019, an Agusta A109S helicopter was on approach to Sydney Airport, New South Wales. During approach, air traffic control (ATC) issued the pilot a clearance to track from the clearance limit to overhead the threshold runway 07. The pilot read back, ‘from the clearance limit track overhead the 07 threshold’. The pilot reported to the ATSB that he believed he was cleared to track overhead the 07 threshold (for the heliport).

A Boeing 737 waiting on the crossing runway for an intersection departure was provided with the helicopter traffic and advised ATC that the helicopter was in sight. ATC subsequently issued the take-off clearance.

ATC then advised the helicopter pilot that the clearance limit was the runway 07 threshold and passed traffic on the 737, however the transmission was blocked.

As the 737 began its take-off, ATC observed the helicopter continue past the runway 07 threshold and immediately issued instructions to the helicopter to expedite through the runway intersection.

Safety action

As a result of this occurrence, Airservices Australia advised the ATSB that they are taking the following safety action:

The air traffic controller will be counselled on the appropriate phraseology when issuing a clearance limit.

Safety message

This incident shows the effectiveness of the conflict resolution training received by ATC to resolve loss of separation events resulting from radio transmission errors or miscommunication between controllers and flight crew.

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.

General details
Date: 04 October 2019   Investigation status: Completed  
Time: 1327 EST    
Location   (show map): Sydney Airport, New South Wales    
State: New South Wales    
Release Date: 01 November 2019   Occurrence category: Incident  
Report status: Final   Highest injury level: None  

Aircraft 1 details

Aircraft 1 details
Aircraft manufacturer The Boeing Company  
Aircraft model 737-8FE  
Type of operation Air Transport High Capacity  
Sector Jet  
Damage to aircraft Nil  

Aircraft 2 details

Aircraft 2 details
Aircraft manufacturer Agusta, S.p.A, Construzioni Aeronautiche  
Aircraft model A109S  
Type of operation Charter  
Sector Helicopter  
Damage to aircraft Nil  
Last update 27 November 2019