Cessna C337 SID

[Ernie Martin]

The above message was moved from an unrelated thread. Here are two responses that followed:

1. I wrote: "Cessna 172s are not subject to SIDs unless in Part 121 operations, a point I made on the thread entitled "AV Web SIDS Article 12-24-09", where I pointed out that the FAA's Final Rule on SIDs clearly specifies that they apply only to Part 121 operations and multiengine Part 129 and 135 operations (see http://edocket.access.gpo.gov/2002/pdf/02-30111.pdf)."

2. Tropical wrote that Cessna 172s can't be in Part 121 operations.

Ernie

[hharney]

AvWeb has a story about the New Jersey Skymaster crash trying to correlate the SID concern with the wing detachment of N12NA. This is not good exposure for our side.

http://www.avweb.com/eletter/archive...ll.html#202067

[Ernie Martin]

I don't know about exposure, but on the merits it's good news. If the NTSB preliminary report is correct, it supports what at least one structural expert with Skymaster knowledge told me when I analyzed the SIDs. Here's the gist:

"If fatigue-tested to failure, no one knows where it will fail. Cessna doesn't know and I don't know. But I know that the wing-fuselage attach points are the least likely to fail. If I had to guess it would be just outboard of the strut, or perhaps the strut itself, but not at the strut attach point with the wing but further down."

He dismissed a failure at the wing-fuselage attach points because of the massive over-design and because the front attachment, which carries the heavier load, is in compression in flight, meaning that the wing is pushing down on the top of the fuselage, rather than trying to pull up (i.e., separate) from the fuselage.

Ernie