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Limited guidance for block level clearances

Issue number: AO-2012-012-SI-03
Who it affects: Air traffic control – all operation types
Issue owner: Airservices Australia
Operation affected: Aviation: Airspace management
Background: Investigation Report AO-2012-012
Date: 18 October 2013

Safety issue description

The air traffic services provider had limited formal guidance to controllers and pilots regarding the conditions in which it was safe and appropriate to use block levels.

Response to safety issue

Airservices Australia (Airservices) reported that there were existing procedures relating to the use of block level clearances in certain areas. In addition, they advised that further standardisation and guidance would be considered, with the ATSB to be advised of any intended action.

ATSB comment/action in response

The ATSB is not satisfied that Airservices has adequately addressed the identified safety issue. No evidence was provided to the ATSB of the existing procedures relative to certain areas and there remains limited formal guidance to controllers and pilots for the safe and appropriate conditions for the use of block levels. In addition, given Airservices has advised that further standardisation and guidance would be considered, the ATSB issues the following recommendation.

Recommendation

Action organisation: Airservices Australia
Action number: AO-2012-012-SR-018
Date: 18 October 2013
Action status: Released

The Australian Transport Safety Bureau recommends that Airservices Australia takes safety action to address the limited formal guidance to controllers and pilots regarding the conditions in which it was safe and appropriate to use block levels.

Correspondence

Date received: 17 October 2013
Response from: Airservices Australia
Action status: Monitor
Response text:

Airservices notes that the ATSB considers we have not yet demonstrated that we have satisfactorily addressed this issue and the associated recommendation. Prior to receiving the ATSB final report, Airservices had decided to undertake a review to assess the adequacy of the existing guidance material and procedures within Manual of Air Traffic Services (MATS) and National ATS Procedures Manual (NAPM) in respect of block level clearances. The review is anticipated to be completed by the end of November 2013. Airservices will advise the ATSB of the outcome of this review and any intended actions.

ATSB response:

The ATSB recognises that Airservices have done work to review this safety issue and compare their processes with other agencies. The ATSB also notes that no changes have been made to Airservices’ existing guidance. Regardless of the number of ATS-attributable occurrences involving the use of block level clearances, the issue of limited formal guidance for pilots and controllers remains. The Manual of Air Traffic Services states that controllers are to cancel block level clearances if other aircraft request a clearance to operate at levels within the block, but it does not define the proximity parameters of the other aircraft. In addition, there are no formal procedures or guidance to state other conditions under which block level clearances should not be provided, such as when experiencing high workloads, and there are also no time restrictions specified for the use of block levels.

   
Current issue status: Not addressed
Status justification:

The ATSB recognises that Airservices have done work to review this safety issue and compare their processes with other agencies. The ATSB also notes that no changes have been made to Airservices’ existing guidance. Regardless of the number of ATS-attributable occurrences involving the use of block level clearances, the issue of limited formal guidance for pilots and controllers remains. The Manual of Air Traffic Services states that controllers are to cancel block level clearances if other aircraft request a clearance to operate at levels within the block, but it does not define the proximity parameters of the other aircraft. In addition, there are no formal procedures or guidance to state other conditions under which block level clearances should not be provided, such as when experiencing high workloads, and there are also no time restrictions specified for the use of block levels.

 
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Last update 06 November 2014