Dg. Astridge, DESIGN SAFETY ANALYSIS OF HELICOPTER ROTOR AND TRANSMISSION-SYSTEMS, Proceedings of the Institution of Mechanical Engineers. Part G, Journal of aerospace engineering, 210(G4), 1996, pp. 345-355
Design safety analysis (DSA) is an element of the certification proces
s having the objective of determining whether the design can satisfy t
he required safety objectives. Analysis methods traditionally applied
to aeroplane control systems include numerical procedures that are bas
ed upon the standard rules of probability theory. In this paper it is
shown from a detailed examination of accident data that helicopter rot
or and transmission systems do not confirm to this theory in respect o
f catastrophic failures. Practical solutions are offered for this prob
lem, and for that posed by the lack of meaningful component failure da
ta. Details are also given of procedures tailored to produce effective
analysis of such systems, and for the structuring of failure modes, e
ffects, and criticality analysis (FMECA) to improve their space effici
ency by several orders of magnitude.