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Airframe certification standards in the case of an uncontained engine rotor failure - EASA and FAA

Issue number: AO-2010-089-SI-13
Who it affects: Airframe certification authorities
Issue owner: European Aviation Safety Agency and the US Federal Aviation Administration
Operation affected: Aviation: Air transport
Background: Investigation Report AO-2010-089
Date: 27 June 2013

Safety issue description

The evolution of the current advisory material relating to the minimisation of hazards resulting from uncontained engine rotor failures was based on service experience, including accident investigation findings. The damage to Airbus A380-842 VH-OQA exceeded the modelling used in the UERF safety analysis and, therefore, represents an opportunity to incorporate any lessons learned from this accident into the advisory material.

Action taken by ATSB

As a result of the identified significant safety issue, coincident with the release of this investigation report, the ATSB has issued safety recommendations to the European Aviation Safety Agency, safety recommendation AO-2010-SR-039, and the United States Federal Aviation Administration, safety recommendation AO-2010-SR-040.

Recommendation

Action organisation: European Aviation Safety Agency
Action number: AO-2010-089-SR-039
Date: 03 January 2014
Action status: Monitor

The Australian Transport Safety Bureau recommends that the European Aviation Safety Agency, in cooperation with the US Federal Aviation Administration, review the damage sustained by Airbus A380-842, VH-OQA following the uncontained engine rotor failure overhead Batam Island, Indonesia, to incorporate any lessons learned from this accident into the advisory material.

The European Aviation Safety Agency (EASA) is responsible for the European Certification standard for large aircraft. The EASA responded to the ATSB recommendation on 13 August 2013, advising that:

The agency is reviewing the available data from this event and is cooperating with the Federal Aviation Administration. Further information on the Agency’s actions and decisions is expected to be provided in an updated response, Status-Open.

In addition to this response from the EASA, the aircraft manufacturer Airbus SAS also responded by advising the ATSB that:

Airbus will support any working group led by Airworthiness Authorities dedicated to possibly enhancing existing guidance and design considerations.

The ATSB acknowledges the actions being taken by EASA and Airbus, and the ATSB will continue to monitor progress of the safety actions.

Recommendation

Action organisation: United States Federal Aviation Administration
Action number: AO-2010-089-SR-040
Date: 27 June 2013
Action status: Released

The US Federal Aviation Administration (FAA) is responsible for the US Certification standard for large aircraft. The FAA responded to the ATSB recommendation on the 04 November 2013, advising that ‘The FAA is working with the European Aviation Safety Agency to evaluate available data from this uncontained engine failure and develop an appropriate course of action. We anticipate providing an update on our progress by March 31, 2014. As a result, FAA Safety Recommendation 13.130 has been classified as: open-awaiting further response.

In addition to this response from the FAA, the aircraft manufacturer, Airbus SAS, also responded:

Airbus will support any working group led by Airworthiness Authorities dedicated to possibly enhancing existing guidance and design considerations.

The ATSB acknowledges the action being taken by the FAA and Airbus, and the ATSB will continue to monitor progress of the safety action.

Correspondence

Date received: 09 December 2013
Response from: FAA
Action status: Monitor
Response text:

The US FAA responded to the ATSB recommendation on the 04 November 2013: ‘The FAA is working with the European Aviation Safety Agency to evaluate available data from this uncontained engine failure and develop an appropriate course of action. We anticipate providing an update on our progress by March 31, 2014. As a result, FAA Safety Recommendation 13.130 has been classified as: open-awaiting further response.’

In addition to this response from the FAA, the aircraft manufacturer, Airbus SAS, also responded ‘Airbus will support any working group led by Airworthiness Authorities dedicated to possibly enhancing existing guidance and design considerations’.

The ATSB considers the response from US FAA and the actions by Airbus SAS as appropriate and classifies the recommendation as open. The ATSB will monitor progress from the FAA in respect to the recommendation and will publish web updates as new information becomes available

Date received: 05 May 2014
Response from: FAA
Action status: Monitor
Response text:

The European Aviation Safety Agency obtained a report from Airbus which details the damage caused by multiple fragments and trajectories in the uncontained rotor failure of VH-OQA. The information in the report has been given to the FAA William J. Hughes Technical Center so that the uncontained engine debris model can be revised to include lessons learned from this event. FAA Technical Center report, "Large Engine Uncontained Debris Analysis" (DOT/FAA/ AR-99111 ), will be revised to include this data. A copy of this report is publicly available using the following link http://www.tc.faa.gov/its/worldpac/techrpt/ AR99-ll .pdf

Once the revisions are complete, compliance guidance contained in FAA Advisory Circular AC 20-128A, "Design Considerations for Minimizing the Hazards Caused by Uncontained Turbine Engine and Auxiliary Power Unit Rotor Failure," will be revised to include consideration of the enhanced engine debris model. We expect to provide an update on our progress by March 31, 2015. As a result, FAA Safety Recommendation 13.13 0 remains classified as open.

 

 

ATSB response:

At the end of May 2015, the FAA responded that ‘they are expecting a response from their action office at the end of this month. After receipt, the FAA will review the response and provide an update to the ATSB’

Date received: 01 September 2015
Response from: FAA
Action status: Monitor
Response text:

The ATSB received advice from the FAA on the 01 September 2015 that:

The FAA is evaluating recent uncontained engine failure events, including the 2010 Airbus A380 event in Indonesia, to update the uncontained engine debris mod el included in FAA Advisory Circular (AC) 20-l 28A, Design Considerations for Minimizing the Hazards Caused by Uncontained Turbine Engine and Auxiliary Power Unit Rotor Failure. Specifically, we are updating the multiple fragment methodology and tool kit referenced in this AC to provide guidance on evaluating design change effectiveness and system routing, and means of compliance that would allow for consideration of shielding.

Additionally, the FAA Technical Center tasked China Lake Weapons Center to update the uncontained engine debris model defined in DOT/ FAA/AR- 99/11, Large Engine Uncontained Debris Analysis, and to develop computer modelling of more recent uncontained engine failures to reflect in-service events.  DOT/FAA/AR- 04/16, Uncontained Engine Debris Analysis Using the Uncontained Engine Debris Damage Assessment Model, will also be revised to highlight tool kit and runtime improvements available today.

The FAA expects these tasks to be completed by July 31, 2016, and plans to review our approach with the European Aviation Safety Agency. [The FAA expects] to provide an updated response to Safety Recommendation 13.130 [ATSB safety recommendation AO-2010-089-SR-040] by August 30, 2016.

Date received: 30 December 2016
Response from: Federal Aviation Administration (FAA)
Action status: Monitor
Response text:

The ATSB corresponded with the US FAA on several occasions during 2016 regarding ATSB ‘Safety Recommendation AO-2010-089-SR-40’. The ATSB received a response from the FAA-Office of Accident Investigation and Prevention on 30 December 2016.

The response stated:

…’the Federal Aviation Administration (FAA) is evaluating uncontained engine failure events, including the 2010 Airbus A380 event in Indonesia in order to understand the failure effects of these events and use this information to update the uncontained engine debris model included in FAA Advisory Circular 20-128A, “Design Considerations for Minimizing Hazards Caused by Uncontained Turbine Engine and Auxiliary Power Unit Rotor Failure.” The FAA Technical Center tasked U.S. Naval Air Weapons Station China Lake to update the uncontained engine debris model defined in DOT/FAA/AR-99/11. “Large Engine Uncontained Debris Analysis,” to include multiple fragments and means of compliance that would allow consideration of shielding, and to develop computer modelling of more recent uncontained engine failures to better reflect in-service events.

In addition, we are updating the multiple fragment methodology and tool kit referenced in Advisory Circular 20-128A to provide guidance on evaluating design change effectiveness and system routing.

We expect to complete these tasks by July 31, 2016. However, the update for the uncontained engine debris model has taken longer than anticipated. We now expect to complete the update to DOT/FAR/AR-99/11, and the draft revision to AC 20-128A by the end of calendar year 2016. As previously indicated, we plan to review our approach with the European Aviation Safety Agency thereafter. We expect to provide an update by June 30, 2017.’

ATSB response date: 06 January 2017
ATSB response:

The ATSB will monitor progress by the FAA in respect to the recommendation and will publish web updates as new information becomes available.

   
Current issue status: Partially addressed
 
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Last update 06 January 2017