doug@terak.UUCP (Doug Pardee) (01/23/85)
> Now lets add the certification cost: what is it these days? $10 - $50 > million? I seem to remember that Lear Fan had spent over $100 million > for certification - which it hasn't got yet. The LearFan is certified under a lot more restrictive rules, being a large, turbine-powered airplane. Further, the LearFan is a good example of certification *working*. Turns out that the original "light weight" design of the fuselage was totally unsuitable for a pressurized turbine-powered plane. It failed the original test (broke in two), and a new cabin, with a fix, was built. That cabin ALSO failed, and the fuselage had to be totally redesigned from scratch (and the new fuselage built) in order to be safe. History lesson: The DeHavilland DH-106 Comet-I was the first jet airliner, put into service on England's "Empire routes" in May, 1952. One year later, one "exploded" in mid-air. Over the next year, two more were lost with all aboard. One is known to have "exploded" in mid-air, the other thought so, but it could have been destroyed by a monsoon. In all, 3 of the 9 Comet-I's were lost in one year. Fortunately, the DeHavilland people didn't just give up and scrap the Comet-I. It took them a very long time, but they finally learned the cause: metal fatigue from the pressurize/depressurize cycle at the previously unheard-of altitudes that the Comet-I flew at. So now we know better, and have strength requirements for pressurized turbine-powered planes. -- Doug Pardee -- Terak Corp. -- !{hao,ihnp4,decvax}!noao!terak!doug