Cessna C337 SID

WebMaster · #1 08-19-09, 09:05 PM

I have received a request from Cessna for a gathering of a few people to discuss the SID that is upcoming for Cessna 337 aircraft.

The text of the message is this

I am looking to locate some experienced 337 owners in Kansas and the surrounding near by states to have a meeting to discuss and get customer feed back for the SID’s program coming up for the aging Cessna 337 aircraft.

Could you help me with this?

Thank You for your time

Cameron Miller

We have had a flurry of Email's going back and forth, and the upshot is that Herb Harney, our President, has offered to spearhead the contact with Cessna.

Anyone wishing to be involved in this discussion, please contact Herb by email, at hharney@sbcglobal.net

edasmus · #2 08-19-09, 09:19 PM

Please forgive my ignorance, but what is the "SID" program?

hharney · #3 08-19-09, 10:35 PM

Supplimental Inspection Documents

http://www.casa.gov.au/airworth/info/CessnaSIDs.pdf

The link above is a good description of the program.

Ernie Martin · #4 08-19-09, 10:46 PM

Further to Herb's message above, the Supplemental Inspection Document addresses inspections and modifications required for aging aircraft to remain airworthy. The most infamous is the one for 402 Cessnas, which for aircraft with over 15,000 hours requires the installation of wing-spar straps in a procedure that is so expensive that it threatens grounding much of the fleet. Cessna is now working on other models, including the 337.

But please note:

1. The 402s are low-wing aircraft with wing mounted engines and some have a dry wing with the fuel in tip tanks, so the loads at the root of the wings are quite different than for a 337.

2. Many (most?) of the 400s have spent much of their life in charter operations, accumulating thousands of hours per year, so fatigue cycles are much greater than for the typical 337.

It's possible that the difference in loads and designs will result in an SID for the 337 which is considerably less costly and may be applicable even later in life (say, 25,000 hours). Since most 337s have far less hours, few aircraft may be affected over the next decade.

But we need to stay on top of this.

Ernie Martin

WebMaster · #5 08-20-09, 09:21 AM

The SID program calls for inspections. It is no different than the requirement for wing spar x-rays on Beech 18's, or the spar inspection or other mandatory service bulletins for twin commanders. While Ernie is correct that it has been applied to 402's, it has also been applied to 414's, and the 425 and 441 turbo props. On the 441's, they determined that the fleet averaged 8000 hours. The initial requirement for the SID was extremely invasive. It consumed so many hours that the centers that could do the SID were overloaded, and they extended and modified the requirements. Incidentally, the initial SID for 425's was anticipated to cost $150K to $250K, depending on the findings.

Cessna has obviously decided to extend the program to other aircraft. The initial implementation may not be the final outcome. As Ernie says, it's important to stay on top and be aware.

Between now and the initial implementation, the input from users should have a major impact on how it is implemented. It behooves everyone to be as involved at this point as possible. If you live in Kansas, or would like to be involved in the discussions, please send Herb an email.

K337A · #6 08-20-09, 01:36 PM

C337 SID ?

Is there a public database of documented failure/failed inspections of C337 spars? I have the 5000 hr. AD. on my desk and have wondered about the failure rate of this inspection and the incidents which required it. What has caused this at this time? I have checked the NTSB database the best I could and the incidents of Spar problems causing a accident beside repeated aerobatic flight is non existent. It would be good science to be able to compare failure rates with other aircraft in a logical process. God help the GA owner if the FAA Legal Department has chosen this avenue to demonstrate their authority to the lowly taxpayer/owner.

WebMaster · #7 08-20-09, 01:41 PM

I really like your avatar.

K337A · #8 08-20-09, 02:50 PM

Unfortunately I have been through this dog and pony show before. Please refer to this article from Mike Busch from 2004. Cessna will sit and listen but the course of action is already determined by Cessna with the FAA blessing. The sad part about this is that there is no, nada, zero determination by investigation if aircraft was abused or g limits routinely exceeded. And don't ask Cessna for the Analysis data or you will be hustled out by the TSA,Homeland Security, FBI or Marv Nuss personally.

twin.cessna.org/reference/twnc400nprms2.pdf

http://www.avweb.com/news/features/189243-1.html

K337A · #9 08-20-09, 03:25 PM

- Mr Truman Sparks and his fine flying machine. Best line in the film as he picks up the chicken ...."No flying today Agnes". Then Mr. Sparks does a a little field approved Duct tape repair. Aircraft is now owned by Randy Deluca's son. Still fly's it out in California.

edasmus · #10 08-20-09, 05:17 PM

Thanks for the info gentlemen. I tell ya, I must be getting old and crabby, but between the FAA (who happens to be my employer incidentally), the TSA, Cessna, and others, flying my Skymaster on a sunny day to play a round of golf is getting to be more and more challenging. It shouldn't be so complicated.

Thanks again! Ed

WebMaster · #11 08-20-09, 05:34 PM

I couldn't agree with you more Ed. Just be thankful you weren't planning on going to Martha's Vineyard real soon.

Roger · #12 08-25-09, 11:58 AM

I would hope that if Cessna decides there is a potential SID issue with the 337's they make it a point to exclude any 336/02 data from their data base. It would hardly seem logical to mix the standard catageory historical use and condition of the 337 and non military 336's in with the condition of aircraft that were used in military service.

skymstr02 · #13 08-25-09, 05:41 PM

Quote:

Originally Posted by Roger

It would hardly seem logical to mix the standard catageory historical use and condition of the 337 and non military 336's in with the condition of aircraft that were used in military service.

Like I mentioned in another thread, some civillian 337's were used in aerial survey, fish spotting, powerline and pipeline patrols, and some 337's are still used for this purpose, so you cannot exclude any airplane from this effort.

For instance, if you own a 1966 model, and you bought the airplane in 2002, you have a history of who the airplane was registered to, but you don't how it was operated up to the point that you became familiar with it.

tropical · #14 08-25-09, 08:38 PM

Quote:

Originally Posted by skymstr02

Like I mentioned in another thread, some civillian 337's were used in aerial survey, fish spotting, powerline and pipeline patrols, and some 337's are still used for this purpose, so you cannot exclude any airplane from this effort.

Yes you can delineate it. Separate by O-2, 336 and civilian 337. It's not a matter of "exclusion" but rather model. And it's a known fact the O-2's lived a harder life and also had wing hard points.

skymstr02 · #15 08-25-09, 10:56 PM

Quote:

Originally Posted by tropical

Yes you can delineate it. Separate by O-2, 336 and civilian 337. It's not a matter of "exclusion" but rather model. And it's a known fact the O-2's lived a harder life and also had wing hard points.

What I'm saying is that some civil registered 337's may have experienced the same stresses that an O-2 has. If you are not the original purchaser from Cessna on your aircraft, you do not know what kind of stresses have been accumulated on the airframe. i used to work on a 337G, N200ZF, that was a fish spotter. It had a 175 gal fuselage fuel tank to give it 22 hour endurance. It was not uncommon for that airplane to take off at 6100 lbs, and seven leg it from Houston to Cape Town South Africa. What kind of stresses have been placed on that wing structure?

Fatigue is cumulative on aluminum and it doesn't matter if Lt. Hamfist or commercial pilot Hamhand is at the controls.

O-2A wings are different from 337 wings, as there is additional structure on the rear spar to absorb the firing loads from the hard points. The wing spars and center carry thru spars are also physically larger than its civillian cousins. Even the wing attach bolts are two sizes larger than its 337 counterpart. An O-2 wing will not mate up to a civil fuselage.

There's no way that a prudent engineer could simply dismiss a portion of the population just because if was never in military service.