Advertisement

NH90 Qualification According to Damage Tolerance

  • Alain Struzik
Conference paper

Abstract

The NH90 is the first military helicopter in the world to be qualified according to the new Damage Tolerance requirements, FAR 29 amendment 31.

For all Principal Structural Elements, a Retirement Time and repetitive Inspection Intervals, approved by the Authorities, are included in the Airworthiness Limitation Section of the Instruction for Continued Airworthiness.

The Retirement Time is based on the conventional “Safe Life” concept.

The repetitive Inspection Interval is established by using one of the three offered concepts (“Flaw Tolerance”, “Crack Tolerance” and “Multiple Load Path”). The advantage of this pragmatic approach is to improve what exists today, i.e. the substantiation of repetitive Inspection Intervals with full-scale tests and/or analysis, formerly based on in-service experience.

This paper presents the necessary research program undertaken by EUROCOPTER to deal with these new concepts and the full qualification process for some dynamic components.

It is concluded that the Damage Tolerance philosophy is viable and should contribute to enhance the flight safety of helicopters.

Keywords

Fatigue Crack Flaw Tolerance Load Path Damage Tolerance Main Rotor 
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.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Foulquier, J., Aliaga, D., Lachaud, B.: Fatigue crack growth under in-service loading-Description and evolution of PREFFAS model. In: ICAF, vol. 18 (1995)Google Scholar
  2. 2.
    Pouradier, J.M.: Helicopter flight safety enhancement: a Eurocopter continuing action. In: ICAS (2002)Google Scholar
  3. 3.
    Edwards, JP.R., Darts, J.: (eds.), Standardised Fatigue Loading Sequences for Helicopter rotors - Helix and Felix - Part 1: Background and fatigue evaluation. NLR TR 84043 U (1984); Also published as RAE TR 84084, LBF FB-167 PT 1, IABG B-TF 1425/1, ICAF Doc. No. 1441 Google Scholar
  4. 4.
    Edwards, P.R., Darts, J.: (eds.) Standardised Fatigue Loading Sequences for Helicopter rotors - Helix and Felix - Part 2: Final Definition of Helix and Felix. NLR TR 84043 U (1984); Also published as RAE TR 84085, LBF FB-167 PT 2,IABG B-TF 1425/2, ICAF Doc. No. 1442 Google Scholar
  5. 5.
  6. 6.
    Fatigue evaluation of transport category rotorcraft structure (including flaw tolerance) AC29MG11 issue on 30/09/1999 Google Scholar
  7. 7.
    Roesch, J., Adams, D., Krasnowski, B.: Rotorcraft Fatigue and Damage Tolerance. White paper presented to TOGAA, Lake Oswego, Oregon (January 1999); It is referred as FAA–2009–0413 in FAA documentation Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  • Alain Struzik
    • 1
  1. 1.EurocopterFrance

Personalised recommendations