Aviation safety investigations & reports

Cessna Aircraft Company 172, VH-JER

Investigation number:
200202385
Status: Completed
Investigation completed

Summary

On 25 May 2002, at 1157 hours Eastern Standard Time, a Cessna 172 (Cessna) came within approximately 600 m of a departing Boeing 747-300 (B747) while the B747 was climbing through the altitude of the Cessna. The pilot of the Cessna was tracking in accordance with what he believed to be the visual clearance issued by Cairns air traffic control at 1,000 ft AMSL. The B747 crew was tracking via a standard instrument departure (SID) which specified a left turn after take-off.

The aerodrome controller issued the pilot of the Cessna with a clearance to track via the 'southern shores'. The term 'southern shores' was referred to in the Cairns local air traffic control instructions as the 'southern shores of Trinity Inlet'. The aerodrome controller understood that the clearance referred to the shoreline between the Cairns inlet and False Cape along the southern shore of the Cairns harbour. The pilot of the Cessna was not familiar with the term 'southern shores' and thought the controller meant the shoreline on the southern side of Cairns airport (which was the northern shore of the Cairns harbour). The term 'southern shores' was not specified in any document available to the pilot.

The pilot correctly read back the clearance to the aerodrome controller. That correct readback indicated to the aerodrome controller that the pilot could comply with the clearance.

The Cairns local air traffic control instructions stated that a clearance to aircraft to track via the 'southern shores' was meant to provide wake turbulence separation between an aircraft departing Cairns via a runway 15 SID and an aircraft over the southern shore of the Cairns inlet.

The aerodrome controller reported that he had kept both the B747 and the Cessna in sight and that visual separation was maintained between the two aircraft throughout the occurrence. The ADC provided the Cessna pilot with turn instructions, to enable him to avoid the B747, and traffic information about the B747 and a wake turbulence advisory. The B747 crew received a resolution advisory from their traffic alert and collision avoidance system about the Cessna.

The controller issued a clearance to the pilot of the Cessna that was, to the aerodrome controller, a specified route but one that was not known to the pilot. The aerodrome controller was not aware that the pilot's understanding of the 'southern shores' differed from his own. The meaning of the term 'southern shores' was not available to the pilot of the Cessna and therefore the potential existed for the misunderstanding between the pilot and the aerodrome controller that resulted in this occurrence.

Safety Action

Local safety action

As of 28 May 2002, Airservices Australia had removed all references to the 'southern shores' from Cairns local air traffic control instructions.

General details
Date: 25 May 2002   Investigation status: Completed  
Time: 1157 hours EST    
Location   (show map): Cairns, Aero.    
State: Queensland   Occurrence type: Loss of separation  
Release date: 29 January 2003   Occurrence class: Airspace  
Report status: Final   Occurrence category: Incident  
  Highest injury level: None  

Aircraft 1 details

Aircraft 1 details
Aircraft manufacturer Cessna Aircraft Company  
Aircraft model 172  
Aircraft registration VH-JER  
Type of operation Flying Training  
Damage to aircraft Nil  
Departure point Cairns, QLD  
Destination Cairns, QLD  
Crew details
Role Class of licence Hours on type Hours total
Pilot-in-Command Private 34.9 72

Aircraft 2 details

Aircraft 2 details
Aircraft manufacturer The Boeing Company  
Aircraft model 747  
Aircraft registration VH-EBX  
Serial number 23688  
Type of operation Air Transport High Capacity  
Damage to aircraft Nil  
Departure point Cairns, QLD  
Departure time 1127 hours EST  
Destination Nagoya, JAPAN  
Last update 13 May 2014