The Level Best Campaign

Click here if you have problems playing the Levelbust 2 DVD
(now out of stock, but you can view the video here
courtesy of Scott International Procedures)

Latest updates April 2009 here

A message from Peter Riley, Level Bust Working Group Lead here

The Scale of the Problem:
NATS figures for Level Busts & Losses of Separation
2004 to end of April 2009
Click to enlarge


Source: NATS Division of Safety
SSE Explanation here

The bars represent reported Level Busts – this is not the whole story.

The only statistics we are sure we capture correctly are the Level Busts which cause a loss of separation.

We estimate that the number of reported Level Busts represents approximately 30% of the actual number of Level Busts

During this campaign, we would like to see:

  • An INCREASE in the proportion of level busts which are reported, we want all events to be reported because we need to understand the full scale of the problem

  • Level Busts resulting in a loss of separation DECREASE

You will find articles and posters, which you are welcome to use, as well as other information on Level Busts and tips on how to avoid them.

If you have a comment about Level Busts, or about this campaign, please e-mail us on the feedback form: every piece of information, comment, or experience is very useful to us. We are especially interested in which sector of the aviation industry you are employed in. Please use the drop down box on the feedback page to indicate this. Also, if you'd like to be informed when this website is updated please tick the box on the feedback form.


A message from Peter Riley, Level Bust Working Group Lead:

The graph on the statistics page here shows a rolling total of 427 reported level busts in the last 12 month period. However, this drop from the 450 mark at which we had previously been holding steady for much of the last year, may be due to the recent drop in traffic levels which is also highlighted by the graph.

Causal factors behind level busts are still dominated by Correct pilot Readback followed by Incorrect Action (CRIA) events – often since the actual reasons for why the crew did what they did are not fully understood. You will also note the rise in prominence of altimeter setting error events during 2008.

Below is an update on the workstream activities since the last communication (Dec 08); however, these have been somewhat impacted by the pull for resource to other areas:

Education / awareness:

  • Presentation to an airline's pre-command course

  • Business Aviation article requested for use in FOCUS

  • Quarterly send out of slides to 47 airlines on level bust performance, compared to the average operator

  • Analysis on events provided to particular operators

  • Biz jet safety day planned during March, to include distribution of a DVD regarding TCAS interpretation.


Emerging Trends:

  • Large increase in altimeter setting error events during winter months

  • Numerous level busts reported since May 08 on SW4 types.

SID Phraseology:

  • Several hazards identified both by ATC and Operators with regard to the CAA SRG’s proposed adoption of ICAO phraseology for climbing above a SID. Hazards communicated to SRG and new phraseology temporarily suspended. Hazards are recognised in the planned revisions.

Technology / Airspace:

  • NATS Operations Strategy and Investment (OS&I) report that a Common Transition Altitude for Midlands / Manchester TMA airspace will proceed as planned irrespective of overall airspace development project status.

  • Altimeter Setting Error Tool (using non-mandated downlinked Barometric Pressure Setting from Mode S in conjunction with Mode C data and Selected Flight Level) for use in NATS Swanwick Investigations under consideration.

That’s it for now. Again, thank you to all who continue to contribute to the ongoing work of reducing level busts within airspace in which NATS provides the service.

Pete Riley, March 2009


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