Journal of Failure Analysis and Prevention

, Volume 15, Issue 2, pp 205–210 | Cite as

Failure Analysis of an Inter-shaft Bearing of an Aero Gas Turbine Engine

  • R. K. Mishra
  • S. K. Muduli
  • K. Srinivasan
  • S. I. Ahmed
Case History---Peer-Reviewed


Failure of an inter-shaft bearing in an aero gas turbine engine is investigated to determine its root cause. Teardown inspections followed by metallurgical investigations are carried out on the parts of the failed bearing. None of the components of the bearing has shown any discolouration, wear, or overheating marks. But severe flaking is observed on one side of the outer raceway. It indicates progressive fatigue due to overload. Insufficient clearance due to differential expansion of inner ring and contraction of outer ring due to heating and cooling, respectively, can also result in this type of phenomena. Maintaining oil discipline and using correct grade of oil at proper frequency can address these issues. A comprehensive engine-bearing prognostic approach may be followed utilizing available sensor information on-board the aircraft such as rotor speed, vibration, lube system information, and aircraft maneuvers to predict bearing life and incipient bearing failure.


Fatigue failure SEM Spalling 



The authors are very grateful to the Executive Director, Engine Division, Hindustan Aeronautics Limited and Chief Executive (Airworthiness), CEMILAC for their kind permission for publishing this paper.


  1. 1.
    K. Gurumoorthy, B.D. Faye, A. Ghosh, Handling abuse causes premature bearing failures. J. Case Stud. Eng. Fail. Anal. 1, 235–242 (2013)CrossRefGoogle Scholar
  2. 2.
    I. Salam, A. Tauqir, A.U. Haq, A.Q. Khan, An air crash due to fatigue failure of a ball bearing. Eng. Fail. Anal. 5(4), 261–269 (1998)CrossRefGoogle Scholar
  3. 3.
    J.L. Miller, D. Kitaljevich, In-line oil debris monitor for aircraft engine condition assessment, in 2000 IEEE Aerospace Conference Proceedings, vol. 6, pp. 49–56Google Scholar
  4. 4.
    P.J. Dempsey, N. Bolander, C. Haynes, A.M. Toms, Investigation of Bearing Fatigue Damage Life Prediction Using Oil Debris Monitoring, NASA/TM-2011-217117 (NASA, Washington, DC, 2011)Google Scholar
  5. 5.
    A. Tauqir, I. Salam, A. Haq, A.Q. Khan, Causes of fatigue failure in the main bearing of an aero-engine. Eng. Fail. Anal. 7(2), 127–144 (2000)CrossRefGoogle Scholar
  6. 6.
    T.A. Harris, R.M. Barnsby, M.N. Kotzalas, A method to calculate frictional effects in oil-lubricated ball bearings. Tribol. Trans. 44(4), 704–708 (2001). doi: 10.1080/10402000108982514 CrossRefGoogle Scholar
  7. 7.
    T.A. Harris, R.M. Barnsby, Tribological performance prediction of aircraft gas turbine main shaft ball bearings. Tribol. Trans. 41(1), 60–68 (1998)CrossRefGoogle Scholar
  8. 8.
    B.L. Averbach, E.N. Bamberger, Analysis of bearing incidents in aircraft gas turbine main shaft bearings. Tribol. Trans. 34(2), 241–247 (1991)CrossRefGoogle Scholar
  9. 9.
    J. Halme, P. Anderson, Rolling contact fatigue and wear fundamentals for rolling bearing diagnostics—state of the art. Proc. IMechE 224, 377–393 (2009)CrossRefGoogle Scholar
  10. 10.
    N. Ejaz, I. Salam, A. Tauqir, Failure analysis of an aero engine ball bearing. J. Fail. Anal. Prev. 6(6), 25–31 (2006)CrossRefGoogle Scholar
  11. 11.
    M.J. Roemer, G.J. Kacprzynski, Advanced diagnostics and prognostics for gas turbine engine risk assessment, in 2000 IEEE Aerospace Conference Proceedings, vol. 6, pp. 345–353Google Scholar
  12. 12.
    N.H. Forster, K. Thompson, A.M. Toms, S. Horning, Assessing the potential of a commercial oil debris sensor as a prognostic device for gas turbine engine bearings, in AFRL Presentation at IHSM Conference, Aug 11, 2005Google Scholar
  13. 13.
    H. Mao, P. Yang, S. Gai, Bearing condition evaluation and rule extraction. J. Comput. Inform. Syst. 8(18), 7433–7440 (2012)Google Scholar
  14. 14.
    W.K. Yu, T.A. Harris, A new stress-based fatigue life model for ball bearings. Tribol. Trans. 44, 11–18 (2001)CrossRefGoogle Scholar
  15. 15.
    R. Orsagh et al., A comprehensive prognostics approach for predicting gas turbine engine bearing life, GT2004-53965, in Proceedings of ASME TurboExpo 2004, June 14–17, 2004Google Scholar

Copyright information

© ASM International 2015

Authors and Affiliations

  • R. K. Mishra
    • 1
  • S. K. Muduli
    • 1
  • K. Srinivasan
    • 2
  • S. I. Ahmed
    • 3
  1. 1.Regional Center for Military Airworthiness (Engines)BangaloreIndia
  2. 2.Hindustan Aeronautics Limited - Engine DivisionBangaloreIndia
  3. 3.Aeronautical Quality Assurance (Engines)BangaloreIndia

Personalised recommendations