Analysis of failed components of an aircraft

Venkataswamy, MA and Parameswara, MA and Sujata, M and Suresh Kumar, M and Madan, M and Bhaumik, SK (2005) Analysis of failed components of an aircraft. Project Report. National Aerospace Laboratories, Bangalore.

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Abstract

On April 09, 2005 at approximately 16.00 Hrs, the aircraft force landed in a cultivatable field following the detachment of the propeller during flight. The failed components were examined in the laboratory to establish the cause of failure. Examination showed that out of the six attachment bolts, which held the propeller with the propeller extension flange, four had fractured and the other two had fallen off in the propeller spinner. These two bolts were found in tact without any noticeable damages to the threads. The corresponding bush- nuts of these bolts were found missing. Fractographic examination revealed that out of the four fractured bolts, two had failed by fatigue while the other two had failed by overload. Out of the six bush nuts, four were found with the propeller extension flange. All these bush nuts were either loose or could be taken out of the propeller flange by finger push and/or slight tapping. From the available evidences and the failure patterns, it appears that the bush-nuts were not interference fitted on to the propeller extension flange. Analysis showed that in such a situation, the bush nuts are unlocked and could work their way out due to vibration. Evidences suggest that at least three bush-nuts got loosened in service, which resulted in excessive load on the other three bolts leading to fatigue failure. Hence the most probable reason for the detachment of the propeller appears to be the improper assembly of the bush-nuts on to the propeller extension flange

Item Type: Proj.Doc/Technical Report (Project Report)
Uncontrolled Keywords: Aircraft, propeller detachment, fatigue
Subjects: AERONAUTICS > Aeronautics (General)
CHEMISTRY AND MATERIALS > Chemistry and Materials (General)
Division/Department: Materials Science Division, Materials Science Division, Materials Science Division, Materials Science Division, Materials Science Division, Materials Science Division
Depositing User: Mrs Manoranjitha M D
Date Deposited: 05 Dec 2011 16:52
Last Modified: 05 Dec 2011 16:52
URI: http://nal-ir.nal.res.in/id/eprint/10103

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