Cessna C337 SID

[Ernie Martin]

Regarding the last two messages:

1. Cessna, not the FAA, is writing the SIDs, but under a mandate from the FAA, who in turn is responding to Congress after the 1988 in-flight failure of a high-time Aloha Airlines Boeing 737, where a section of the upper fuselage ripped away because of fatigue. Initially only transport aircraft were considered but that was later expanded to cover smaller aircraft.

2. But, yes, even though it's being done under FAA auspices, the FAA has made it clear that it doesn't apply to Part 91 -- in fact, it doesn't apply to some Part 135 operations, either (see the FAA’s Final Rule on the matter at http://edocket.access.gpo.gov/2002/pdf/02-30111.pdf). Also, although the referenced letter may apply to large and turbine powered aircraft, the rationale and underpinning for the opinion make it crystal clear that the policy applies to all Part 91 operators. One other point that has not been mentioned: on the Cessna 400-series SIDs, which have been implemented now for several years, Part 91 operators do not have to comply and few do(except for the single SID that became an AD).

In a 1/27/2010 Message in the thread entitled "How are you going to handle the SID?", Herb's point 5 is short and to the point: "Unless these inspections become AD's we will NOT have to comply". Based on all we know -- principally the FAA’s Final Rule and Notices -- he's right.

Ernie

[WebMaster]

When you say "We do not have to comply", what you really mean is that Part 91 operators in the USA do not have to comply. That statement, however, ignores the problem that operators in the rest of the world will face.

They will have to comply. They will have no choice.

Saying that we don't have to comply ignores all those people who don't live in the USA and will have to comply.

[Ernie Martin]

Larry, most of this thread and all of the last message deals only with Part 91 operators. Herb's point 5 also dealt solely with Part 91.

As you note, most foreign operators, won't be so lucky. And some Part 91 operators may have to comply if their insurance companies require it.

Ernie

[Roger]

It may very well be true that operators in other countries need to comply with rules and regulations that are different than those in the US, but that's the way it is with a lot of things. A perfect example is the ELT change. We can't fight everybody's battles for them.

It would seem that operators outside of the US should seek their own clarification or rule changes to be afforded the same protections from these onerous "recommendations" as provided to US operators.

I would imagine that as Cessna continue across all makes and models, they will eventually hit the one model that will cause an uproar casuing a change in how other countries view the implementation of these SIDS. The 337 family is too small to bring about significant change (whihc is mroe than likely why they started here).

I for one can't wait to see the 172 operators reaction

[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