Research On Turbofan Engine Maintenance Risk Management For Prevention Of IFSD

The engine in flight shut-down(IFSD)becomes the second reason for flight incidents,junior to bird strike damage.And a quarter of IFSD is caused by failure of maintenance management,such as aircraft mechanical failure or maintenance human error.In addition,costs for using and repairing engines are extremely large.Considering both safety and economy,it is necessary to carry out turbofan engine maintenance risk management for prevention of IFSD.Firstly,based on fault tree analysis,ten hazards are passively identified from two IFSD incidents.Then engine maintenance process is analyzed systematically according to the Aircraft Maintenance Manual(AMM),which is divided into ten first flows and thirty secondary flows.Taking the SHELL model as the active hazards identification tool,the engine IFSD maintenance risk factors are classified and analyzed in accordance with Life(L)factors,Life and Life(L-L)factors,Life and Software(L-S)factors and Life and Hardware(L-H)factors,Life and Environment(L-E)factors.107 hazards are found.Thus hazards list is formed,collecting 10 and 107 hazards and then deleting two repetitive.Secondly,as the risk factors are mutually influenced and hard to quantify,the fuzzy analytic network process is applied as the tool of risk assessment to quantitatively analyze the importance of risk factors.The network structure assessment model is constructed after analyzing the relationship among the risk factors,and then triangular fuzzy numbers are applied to calculate or educe the weight of various risk factors.Thus,the assessment rank becomes obvious sorted by weight: violations with weight 0.195,lack of supervision with weight 0.117,poor cooperation between mechanics with weight 0.095,inadequate training with weight 0.081,unreasonable manuals or technical documents with weight 0.079,bad safety culture with weight 0.076,unmatched arrangement with weight 0.064,lack of anti-error design with weight 0.059,shortage of professional skills with weight 0.053,miscommunication with the crew with weight 0.035,bad psychological status with weight0.031,inapplicable tools and equipment with weight 0.029,abnormal but underrated weather with weight 0.025,inapplicable test instrument with weight 0.021,unhandy parts design with weight 0.018,both bad physiological status and unsuitable working environment with weight0.011.Finally,based on the results of risk assessment,the corresponding risk control measuresare put forward such as avoiding habitual violation,process management,improving the coordination,strengthening personnel training,standardizing maintenance manual and making the just safety culture.And responsibilities are assigned to relevant departments and personnel.