Aviation safety issues and actions

Ambiguity in documentation

Issue number: AO-2009-080-SI-02
Who it affects: All Airservices Australia en route air traffic controllers and All flight crews operating in controlled airspace
Issue owner: Airservices Australia
Transport function: Aviation: Airspace management
Background: Investigation Report AO-2009-080
Issue release date: 24 June 2011
Current issue status: Adequately addressed
Issue status justification:

MATS had no requirement for a radar controller to establish that a pilot request for a non standard level was due to an operational requirement, whilst AIP required pilots to state the requirement. MATS and AIP are required to reflect the same information so ATC and flight crew have the same understanding of procedures. MATS and AIP have now been updated to relfect the same information and require flight crew to state that a non standard level request is due to operational requirements, and advise ATC when the non standard level is no longer required.

Safety issue description

Ambiguity existed between the Manual of Air Traffic Services and the Aeronautical Information Publication in relation to the assignment of non-standard cruising levels and the definition of an ‘operational requirement’.

Proactive Action

Action number: AO-2009-080-NSA-066
Action organisation: Airservices Australia
Date: 24 June 2011
Action status: Closed

Since the release of this report in 2003, Airservices has been investigating the issue of non standard routes and non standard levels in respect of recommendations R20030056 and R20030057. As you would be aware, flight planning errors of this type are routinely and reliably tracked through the ESIR [electronic safety incident report] application. Airservices analysed this data and ascertained that non standard routes are not normally a significant contributory factor to Breakdown of Separation. Nonetheless, over the past several years we have invested significantly in examining technical solutions that would detect flight planning errors and highlight them to the controller. Our investigations determined that it was not feasible to use either NAIPS (Airservices' flight planning system) or to develop a separate database to process flight plans prior to entering the Eurocat system.

Further, we determined that the cost of implementation in Eurocat for a warning system is high, and as Airservices has now commenced work on its future ATS [air traffic services] system the lead time and cost does not support further work in this area We discussed the use of non standard levels with CASA [Civil Aviation Safety Authority] a number of years ago and it was determined that the number of changes of level that would be incurred if standard levels were required to be utilised in all cases would introduce an increased level of risk into the system.

In addition, since this incident a number of changes have been introduced to improve instruction to both pilots and air traffic controllers on the use of non standard levels. The Aeronautical Information Publication (AlP) was updated on 18 November 2010 and now specifically states that a pilot must only request a non conforming level when it is determined by the pilot in command to be essential to the safety of the flight and its occupants. [In such circumstances, the phrase ‘DUE OPERATIONAL REQUIREMENTS’ must be included in the level change request.]

ATSB comment:

The ATSB notes the action by Airservices related to R20030056 and R20030057 and in response to the issues identified in this investigation. The ATSB is satisfied that, the combined action in response to R20030056 and R20030057 and that recommended by the Airservices investigation will, when implemented, adequately address the identified safety issues.

Last update 30 January 2014