To: Genghis
What you said is true. You can account for an exploding tire or the fracture of a fan disc or compressor. But this is only done in the Safety Hazards Analysis (Fault Tree) but these element can't be quantified unless the manufacturer of the engine or tire has provided that information. In the case of the tires the manufacturer will specify how frequently or under what conditions the tires muust be changed in order to maintain reliability. In the case of the engine manufacturer he is allowed to demonstrate the reliability of his engine by test or anaslysis. One manufacturer used analysis and his engine exploded and caused loss of life and property in Manchester, England.
Regarding accounting for bird strikes this is demonstrated in test both for the wind shield and the engines. In the case of the bird strike they normally use one dead chicken but on larger engines I have seen tests where they shot several geese directly into the spinning fan. This type of multiple bird strikes can't be numerically quantified and as such would be difficult to include in the hazard analysis. It could be included but only in combination with other contributing factors that can be quantified. The same is true for the tires.
The failure mode effects analysis EFFECTS THE DESIGN, but only if the manufacturers engineering staff agrees with the analysis.
The Fault Tree REFLECTS THE DESIGN but only after the numbers crunches use their magic Boolean Algebra to prove that the failure would occur no more frequently than 1 10-X hours for the fleet.
In no way does the predicted safety reflect the actual safety or reliability of the actual machine. This is true for a design made under FAA,CAA,DGCA. LBA or any other certification authorities as they all use the same analytical guide lines.
[This message has been edited by Lu Zuckerman (edited 20 November 2000).]
[This message has been edited by Lu Zuckerman (edited 20 November 2000).]