Aviation safety investigations & reports

Loss of separation between VH-TFK and VH-PDP, 6 km N Cairns, QLD, 23 November 2011

Investigation number:
AO-2011-147
Status: Completed
Investigation completed

Summary

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What happened

On 23 November 2011, a loss of separation occurred 6 km north of Cairns, Queensland, between a Cessna Aircraft Company 402C (C402), registered VH-TFK, and a Cessna Aircraft Company T210N (C210), registered VH-PDP.

The C402 was conducting an instrument landing system (ILS) approach for runway 15 and was 1.8 NM (3.3 km) from the airport when the pilot initiated a missed approach from a height of 1,000 ft in instrument meteorological conditions. At the time the C210 was on the same ILS approach and was 6.4 NM (11.9 km) behind the C402. About 1 minute after the pilot of the C402 turned left to establish the aircraft on the missed approach track, the distance between the two aircraft reduced below the required air traffic control separation (ATC) standard.

What the ATSB found

The Australian Transport Safety Bureau identified that a local ATC procedure, published in part to assist ATC in separation management during a missed approach event, was not clear and subject to varying interpretation. This resulted in the spacing between the two aircraft being closer than intended at the point when the pilot of the C402 commenced the missed approach.

The local ATC procedure did not fully consider all operational aspects that may lead a pilot to initiate a missed approach in instrument meteorological conditions above the procedure-defined minimum cloud base height.

What has been done as a result

In response to this occurrence, Airservices has initiated a number of safety actions including amending the local procedure to assist with the clarity and intent, changing the Cairns local instructions to enforce minimum flow (distance) spacing and updating controller missed approach procedures refresher training. This updated training will increase controller awareness of separation assurance issues relating to consecutive approaches and ensure that due consideration is given by controllers to the broad mix of aircraft types using straight-in approaches.

Safety message

This occurrence reinforces the need for all local procedures, in particular those that assist controllers in separation management, to be unambiguous and to encompass all possible operational circumstances. The importance of effective radar navigation guidance when positioning an aircraft for an approach is also highlighted.

Download Final Report
[Download  PDF: 1.42MB]
 
 
Alternate: [Download  DOC: 5MB]
 

Safety Issues

Go to AO-2011-147-SI-01 - Go to AO-2011-147-SI-02 - Go to AO-2011-147-SI-03 -

Local procedure intent and understanding

The Cairns air traffic control procedures on the management of missed approaches and the management of successive arriving aircraft were unclear in intent and function, increasing the risk of their incorrect application.

Safety issue details
Issue number: AO-2011-147-SI-01
Who it affects: All Cairns based Airservices Australia air traffic controllers
Status: Adequately addressed

Cairns air traffic control procedures

The Cairns air traffic control procedures that defined a minimum spacing of 5 NM to be established when there were no departures (when the cloud base is less than 1,000 ft and/or visibility is less than 2,000 m) were inadequate to assure separation during a missed approach event and may result in future loss of separation occurrences.
Safety issue details
Issue number: AO-2011-147-SI-02
Status: Adequately addressed

Cairns missed approach procedure note

The missed approach procedure note on the Cairns runway 15 instrument landing system (ILS) or localiser (LOC) approach chart may inadvertently influence a pilot to commence a turn on the missed approach procedure prior to the published missed approach point.
Safety issue details
Issue number: AO-2011-147-SI-03
Status: Adequately addressed
General details
Date: 23 November 2011   Investigation status: Completed  
Time: 0007 AEST   Investigation level: Complex - click for an explanation of investigation levels  
Location   (show map): 6 km N Cairns    
State: Queensland   Occurrence type: Loss of separation  
Release date: 04 February 2013   Occurrence category: Incident  
Report status: Final   Highest injury level: None  

Aircraft 1 details

Aircraft 1 details
Aircraft manufacturer Cessna Aircraft Company  
Aircraft model 402  
Aircraft registration VH-TFK  
Serial number 402C1011  
Type of operation Air Transport Low Capacity  
Damage to aircraft Nil  
Departure point Mareeba, QLD  
Destination Cairns, QLD  

Aircraft 2 details

Aircraft 2 details
Aircraft manufacturer Cessna Aircraft Company  
Aircraft model 210  
Aircraft registration VH-PDP  
Serial number 21063636  
Type of operation Charter  
Damage to aircraft Nil  
Departure point Mareeba, QLD  
Destination Cairns, QLD  
Last update 14 November 2018