Fleet Recovery and Life Extension – Some Lessons Learned

  • Graham Clark
Conference paper


Extending the life of an existing fleet which still has acceptable operational capability can be enormously attractive in economic terms. Ideally, such extension programs will be planned and managed (via an ASI program), although many are urgent “recovery” programs required when substantial problems are discovered. This paper discusses examples of planned and unplanned programs, highlighting the differences in approach required.

Regulatory systems usually demand that we preserve the prevailing “acceptable level of safety” during fleet life extension, although inevitably, progressive life extension must lead to enhanced risk of unforeseen events which are absent from our structural integrity models. We cannot remove this risk, but we can mitigate it. Paradoxically this requires additional (and potentially unwelcome) investment in broad investigative strategies such as teardowns and damage enhancement test programs. This paper will provide examples of a management program that was successful precisely because it contained such strategies.

The paper argues that we may underestimate the extent to which organisational issues may bring an additional (and perhaps more important) threat to the safety of old aircraft. Two examples are provided in which complacency and a perception that the fleet is nearing end-of-service promoted drawing down of maintenance/safety resourcing, leading to maintenance underperformance, increased risk, accidents, and loss of life. These issues will be particularly evident where we have poor corporate culture, weak organisational structure, progressive deferral of fleet withdrawal dates and increased operational demand. The examples suggest that our structural safety models are in themselves of limited value if these broader system/organisational risks are neglected.


Fatigue Life Fatigue Test Life Extension Safe Life Bolt Hole 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. 1.
    Johnston, C.: Commander, Naval Air Systems Command, JACG Principals Panel. In: 7th Joint DoD/FAA/NASA Conference on Aging Aircraft, New Orleans, Louisiana, USA (September 2003)Google Scholar
  2. 2.
    Clark, G., Jackson, P.: Structural integrity and damage type in military aircraft. Fatigue and Fracture of Engineering Materials and Structures 33(11), 752–764 (2010)Google Scholar
  3. 3.
    Heller, M., Burchill, M., Wescott, R., Waldman, W., Kaye, R., Evans, R., McDonald, M.: Airframe Life Extension by Optimised Shape Reworking –Overview of DSTO Developments. In: Bos, M. (ed.) Proceedings of the 25th ICAF Symposium Bridging the Gap between Theory and Operational Practice, pp. 279–299. Springer, Heidelberg (2009)CrossRefGoogle Scholar
  4. 4.
    Iyyer, N.P., Phan, N.: Durability Issues and Management of Aging P-3C Aircraft. In:11th International Conference on Fracture, Turin, Italy (2005)Google Scholar
  5. 5.
    Teunisse, B., Mongru, D., Jackson, P., Matricciani, E., Hartley, D.: P-3C service life assessment program - Australian test interpretation report for the USN wing/fuselage/landing gear test articles. DSTO Report, Melbourne, Australia (2006)Google Scholar
  6. 6.
    Hartley, D., Jackson, P., Matricciani, E., Teunisse, B., Phillips, M.: P-3C service life assessment program Australian test interpretation report for the empennage test articles. DSTO Report, Melbourne, Australia (2005)Google Scholar
  7. 7.
    Iyyer, N., Sarkar, S., Merrill, R., Phan, N.:Managing aging aircraft using risk assessment models-lessons learned from P3-C fleet. In: 24th ICAF Symposium, Naples, Italy, May 16-18 (2007)Google Scholar
  8. 8.
    Jackson, P., Cardrick, A.W.: The Challenge of Conducting a Meaningful Fatigue Test on a Transport Aircraft Empennage. In: Proc. 22nd Symposium of the International Committee on Aeronautical Fatigue, Lucerne (May 2003)Google Scholar
  9. 9.
    Ministry of Defence. Design and Airworthiness Requirements for Service Aircraft. Defence Standard 00-970 (2), Part 1, Section 3, Leaflet 35 (December 1999)Google Scholar
  10. 10.
    Jackson, P., Mongru, D., Hartley, D.: Durability and Damage Tolerance Substantiation of a Transport Aircraft Metal Tailplane Structure. In: Australia 24th ICAF Symposium Napoli, Italy, May 16-18 (2007)Google Scholar
  11. 11.
    Final report of Fatigue Test on Wing and Centre Section Structures MB- 326H Aircraft. Aermacchi report No. 1945 (September 1975)Google Scholar
  12. 12.
    Clark, G., Jost, G.S., Young, G.D.: Recovery of the RAAF MB326H Fleet; the Tale of an Aging Trainer Fleet. In: Poole, P., Cook, R. (eds.) Proceedings of the 19th ICAF Symposium Fatigue in New and Ageing Aircraft, pp. 39–58. EMAS, Warley (1997)Google Scholar
  13. 13.
    Clark, G., Barter, S.A., Goldsmith, N.T.: Influence of initial defect conditions on structural fatigue in RAAF aircraft. In: Blom, A. (ed.) Durability and Structural Reliability of Airframes, vol. I, pp. 281–304. EMAS, Warley (1993)Google Scholar
  14. 14.
    Goldsmith, N.T., Clark, G.: Analysis and interpretation of aircraft component defects using quantitative fractography. In: Bernard, S.M., Susil, P.K. (eds.) Quantitative methods in fractography, STP, vol. 1085, pp. 52–68. American Society for Testing and Materials, Philadelphia (1990)CrossRefGoogle Scholar
  15. 15.
    Goldsmith, N.T.: Fractographic examinations relevant to the F+W Mirage fatigue test. Dept. Defence Aeronuatical Research Laboratory Materials Tech. Memo 371 (August 1978)Google Scholar
  16. 16.
    Anderson, B.E., Goldsmith, N.T.: Prediction of crack propagation in Mirage wing fatigue test spar. Aeronuatical Research Laboratory Structures Note 448 (1978)Google Scholar
  17. 17.
    Frost, N.E., Marsh, K.J., Pook, L.P.: Metal fatigue. Clarendon Press, Oxford (1974)Google Scholar
  18. 18.
    Frost, N.E., Dugdale, D.S.: The propagation of fatigue cracks in test specimens. J. Mech. Phys. Solids 6, 92–110 (1958)CrossRefGoogle Scholar
  19. 19.
    Head, A.: The growth of fatigue cracks. Phil. Mag. 44(7), 925–938 (1953)zbMATHGoogle Scholar
  20. 20.
    FAA Transport Airplane Risk Assessment Methodology Handbook, Federal Aviation Administration, Transport Airplane Directorate, document ANM-100 draft 22-12-10Google Scholar
  21. 21.
    Health and Safety Executive (HSE), UK Government, Report: The Tolerability of Risk from Nuclear Power Stations (1992)Google Scholar
  22. 22.
    Health and Safety Executive (HSE), UK Government, Report: Reducing Risks, Protecting People (“R2P2”) (2001)Google Scholar
  23. 23.
    Knott, J.F.: The integrity and durability of structures and machines. In: Proc. 9th International Conference on Engineering Structural Integrity Assessment, October 15 - 19, vol. 51180, pp. 1–21. ESIA Publication, Beijing (2007)Google Scholar
  24. 24.
    Athiniotis, N.A., Lombardo, D., Clark, G.: Simulation, assessment and technical conclusions from a major accident investigation. Engineering Failure Analysis 17, 353–360 (2010)CrossRefGoogle Scholar
  25. 25.
    Royal Australian Navy. Nias Island Sea King Accident Board of Inquiry Report, released June 21 (2007)Google Scholar
  26. 26.
    Debrincat, J., Bil, C., Clark, G.: Assessing organisational factors in aircraft accidents: methodologies and limitations. In: Proc. 27th Congress of the International Council of the Aeronautical Sciences, Nice, France, September 19- 24 (2010)Google Scholar
  27. 27.
    Haddon-Cave, C.: An independent review into the broader issues surrounding the loss of the RAF Nimrod MR2 Aircraft XV230 in Afghanistan in 2006, HC, vol. 1025. HM Stationery Office, London (2009)Google Scholar
  28. 28.
    Nimrod Airworthiness Review Team report 1998; quoted in [27] p. 359Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  • Graham Clark
    • 1
  1. 1.Aerospace DesignRMIT UniversityMelbourneAustralia

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