From: email@example.com (Terrell D. Drinkard) Organization: The Boeing Company Date: 25 Sep 96 13:40:13 References: 1 2 3 4 Followups: 1
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In article <airliners.1996.1910@ohare.Chicago.COM>, Karl Swartz <kls@ohare.Chicago.COM> wrote: >> >From a regulatory standpoint, if the '747-700' has a totally new wing >> and a totally new fuselage, how can it be certified on the 747 type >> certificate? Of course, I'm wondering the same thing about the new >> 737s. They are exactly like the old 737 family except for the wing, >> tail, engines, landing gear, systems, horizontal tail, vertical fin, >> and other 'bits'. Looks to me like the only thing they share in >> common with a 737-300/400/500 is the basic fuselage shell... Um, not really. The new 737s have had the structure upgraded to damage tolerant standards, so it isn't interchangeable with the current production aircraft. >I think I heard that even the 747-400 has a new TC, and I'm pretty >sure the new 737 series does as well. No, not a new Type Certificate. Those are the same, even on the 747-400. What you do have there is a new Type Rating for the 747-400. The 737s all have the same Type Rating, last I heard. We fought quite hard for that one. >With derivatives, the border >is somewhat fuzzy -- recall that the FAA made MacDAC get a new TC for >the MD-90 even though it has the MD-80 (DC-9-80) wing, fuselage (with >a plug, maybe two, to stretch it), and the modified tail of the MD-87. >The FAA said they weren't sure at what point it stopped being the same >plane as the original DC-9-10, but they were sure that the MD-90 was a >new plane! I'm pretty sure that all the MD-80/90 aircraft have the same type certificate as the DC-9. Could you double check your references? [snip] >Perhaps a better question is how they manage to certify a new type >with the old design rules, which is part of the advantage us doing a >derivative type. For example, as I understand it, the current 737 is >not certifiable under the current regulations, and there are some odd >regulartory quirks that have allowed the BAE 146-200 and -300 to ride >on the coattails of the -100 even though the later models don't meet >the regulations in question. (Noise and/or weight in the case of the >146 -- neither the -200 nor the -300 could serve LCY, for example, >but for the *type* being allowed in.) Actually, I think the 737 meets or exceeds all the current regulatory requirements. There was a lot of early scuffling over exactly what would bring added safety, but with a few zillion hours of inservice experience, the 737 folks can show what failures they are subject to and what they aren't, so they could point out that in a couple of cases, what the FAA asked for would not actually increase safety because there had never been a failure in that area (jammed flight controls on one side jumps to mind). Given the fact that there are more 737s flying than any other type of heavy jet transport in the world, and the fact that it is a short-haul airplane flown by every concievable kind of airline in every part of the world, if it hasn't happened to them by now, it probably isn't going to happen. -- Terry firstname.lastname@example.org "Anyone who thinks they can hold the company responsible for what I say has more lawyers than sense."