Damage Tolerance Applied on Metallic Components
Abstract
New requirements including damage tolerance were inserted in FAR 29.571, amendment 28 in 1989 to increase the safety level of helicopters. Flaw tolerance safe life" and fail safe" - or a combination thereof, were proposed to fulfill the damage tolerance requirements. If unpractical, safe life "evaluation was acceptable. A working group called TOGAA was mandated by the US Senate to propose modifications to the FAA rules. Harmonized recommendations from rotorcraft manufacturers (RCWG) had been gathered in a "White Paper". The TOGAA commented this methodology and concluded in mid 1998, that the "flaw tolerant safe life" concept should be purged in FAR 29, and advocated the exclusive use of crack propagation for single and multiple load paths. This paper presents EUROCOPTER's statistical analyses of the root causes of accident in flight. EUROCOPTER's philosophy in reply to FAR & JAR 29-571 is detailed, showing a significant and measurable improvement over conventional "safe-life" methodology. This philosophy has already been applied to several current projects (EC 155, NH 90), and the RCWG simply wanted it to be left in the current rules.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2000
- Accession Number
- ADP010646
Entities
People
- Alain Struzik
- Thierry Marquet