Aircraft crash caused by stress corrosion cracking
- National Aerospace Lab., Emmeloord (Netherlands). Dept. of Materials
An aircraft crash in the Netherlands was caused by disintegration of a jet engine. Fractography showed that the chain of events started with stress corrosion cracking (SCC) of a pin attached to a lever arm of the compressor variable vane system. Such a lever arm-pin assembly costs only a few dollars. Investigation of hundreds of pins from the accident and a number of identical engines revealed that this was not an isolated case. Many pins exhibited various amounts of SCC. The failed pin in the accident engine happened to be the first fractured one. SCC requires the simultaneous presence of tensile stress, a corrosive environment, and a susceptible material. In this case the stress was a residual stress arising from the production method. There was a clear correlation between the presence of salt deposits on the levers and SCC of the pins. It was shown that these deposits were able to reach the internal space between the pin and lever arm, thereby initiating SCC in this space. The corrosive environment in Western Europe explains why the problem manifested itself in the Netherlands at a relatively early stage in engine life. The main point is, however, that the manufacturer selected an SCC-prone material in the design stage. The solution has been to change the pin material.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 207761
- Report Number(s):
- CONF-940626-; ISSN 0742-4795; TRN: IM9616%%89
- Journal Information:
- Journal of Engineering for Gas Turbines and Power, Vol. 118, Issue 1; Conference: 39. international gas turbine and aeroengine congress and exposition, The Hague (Netherlands), 13-16 Jun 1994; Other Information: PBD: Jan 1996
- Country of Publication:
- United States
- Language:
- English
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