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Enhanced risk factor analysis of the external fire following an uncontained engine rotor failure on the A350XWB
KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
2012 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

The risk factor study of the external fire following an uncontained engine rotor

failure on the A350 XWB has been performed in this report. As a background, the

engine failure model is presented as well as the way the EASA certification

requirements lead to a risk factor creation to moderate the risk. Key in-service

events were then investigated giving information relative to the engine failure and

the emergency evacuation following an external fire in order to set the model of

the external fire and its hypotheses. Four main scenarios were pointed out: single

wing shots, cross wing shots, own pylon impacted and opposite pylon impacted. In

a second time, risk factors were developed taking into account the flight phase

exposure, the fuel tank filling, the fuel ignition, the engine detachment direction

and finally the emergency evacuation. The residual risk quantification process was

then performed through the risk volume creation, the impact trajectories

simulation, the logical combination of targets and the risk window exploitation with

the new risk factors for all scenarios. The external fire total isolated contribution

has been calculated equal to 8.7% of 1 in 20 probability thanks to the enhanced

risk factor approach that refine the risk. The scenarios cross wing shots, own and

opposite pylon have catastrophic trajectories hitting the targets but not the cabin at

the same time unlike the single wing shots scenario that sees most of its

catastrophic trajectories impacting also the cabin, which prevents from performing

an easy emergency evacuation. The design precaution on the fuel tanks with the

distinction center tank/wing tank in the fuel filling risk factor has also shown

effective results because one-third-disc fragments never impact the wing tanks.

This study gathers many opportunities about the external risk factors development

but it shows also that the risk factors have a deep impact on the residual risk

quantification in the certification process.

Place, publisher, year, edition, pages
Keyword [en]
risk factor UERF uncontained engine rotor failure fire
National Category
Aerospace Engineering
URN: urn:nbn:se:kth:diva-116588OAI: diva2:596170
Subject / course
Aeronautical Engineering
Educational program
Master of Science - Industrial Engineering and Management
2012-09-04, 10:00 (English)
Available from: 2013-01-28 Created: 2013-01-21 Last updated: 2013-01-28Bibliographically approved

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