Cessna C337 SID

[WebMaster]

Originally Posted by skymstr02

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.

You are absolutely correct. And when we ask if your airplane is used for low level work, even then we are not getting a good picture of what that means.

Take for example someone doing fire spotting, where they are making tight turns, maneuvering at low altitudes, with lots of thermals. At the other end of the spectrum, some one who is doing polar bear tracking, where, they are flying over a non-thermal environment, basically straight and level, though at a low altitude.

You can't simply say 0-2's had higher stresses. I would argue that the fire spotter gets more stresses, on a continuing basis, than most of the 0-2's in civilian service. Remember that the 0-2's that were beat up pretty badly were simply scrapped.

When you buy a plane, and you look at the log books, you can't tell what kind of use the aircraft had. My former aircraft had lots of hours, but it was a all used as a corp plane for a collection of companies, and for a number of years, was flying every day.

[WebMaster]

This provides an update on the 23 draft Cessna Supplemental Inspection Reports (SIDs) being considered for the Skymaster. If you have read prior messages in this thread you know that Cessna presented these draft SIDs to SOAPA at a meeting on Aug. 27, 2009. Also in attendance at this meeting, beyond SOAPA, were other technical specialists and Skymaster experts, representing themselves. Cessna outlined the proposed draft SIDs at this meeting. SOAPA has requested permission to distribute the draft SIDs but Cessna appears reticent, perhaps because they remain in draft form and are under further consideration within Cessna. Our understanding of the SIDs, as proposed, is that they would not be required for Part 91 operators, but will be for Part 135 and international operators.

The proposed SIDs may be lumped into the following broad groups: fuselage, wing, tail, and engine groups. While some of the proposed SIDs are minor and would normally be easily accessible and be part of an annual inspection, many are significantly more comprehensive and invasive to the airframe. The fuselage SIDs call for visual inspection of the rear spar carry-through and upper rear doorpost bulkheads, nose gear torque link, rudder pedal area, and door lock mechanism. As presently proposed, the wing SIDs involve eddy current inspections of the wing attach bolts area which may require substantial disassembly of the aircraft to complete. Other proposed work on the wings involves removal of fixed panels to gain access to high stress areas for eddy current inspection; and loosening and inspection of the flap cables.(eg jack points, wing strut attach points, aileron hinges). The proposed tail section SIDs require removal of the rudders and elevator for eddy current inspection of the hinge attach fittings among other inspections required once disassembled. As proposed the engine mount SID calls for removal of the tubular engine mounts for inspection. Importantly, as proposed the entire SID package would have a compliance time of 20 (twenty) years from date of aircraft manufacture and every 10 (ten) years thereafter, with varying TTAF hour triggers for certain SIDs. The SOAPA sub-committee investigating this matter has looked at preliminary cost estimates for compliance of various of these proposed SIDs. As proposed the compliance cost would be substantial (exceeding $20,000 or more) and take a considerable amount of time. We would caution members that these estimates are early and based on non-final Cessna documents. If the final Cessna SIDs are modified or allow for alternate means of compliance or inspection, or some are eliminated entirely, then these estimated compliance costs could be substantially less.

SOAPA has organized a Steering Committee (the “Committee”) to address this matter with Cessna. The Committee includes engineers and other technical professionals (A&P, IA) highly experienced with Skymasters and other interested owners. In addition, the Committee has called on others outside the Committee with similar experience (including an FAA DER in structures who has owned 4 Skymasters in the last 20 years) for additional advice and assistance as necessary.

Committee members began a comprehensive review of the FAA Service Difficulty Reports (“SDRs”) for over 35 years of problem reports furnished to the FAA by repair shops. The SDRs have been a focus of Committee work because Cessna has used the SDRs as one of the key sources of information in the development of its proposed SIDs for the Skymaster series of aircraft. First, SOAPA filtered to entire SDR database to extract those dealing only with Skymasters. The resulting 1,773 SDRs were further analyzed and those having nothing to do with the SIDs, fatigue, corrosion or aging aircraft were deleted. The remaining SDRs (over 200) were then arranged by aircraft area and further analyzed against the proposed SIDs presented by Cessna. Each SID was also analyzed in terms of the hardware involved, eg. is this likely where failure would occur, could the proposed inspection result in more harm than good to the airframe?

At this point in time the Committee has not fully completed our examination of the SIDs nor have we submitted final comments to Cessna. To date we have identified a number of areas where we believe compelling engineering arguments exist for us to recommend either deletion or a substantial reduction in the scope of the related SID. Cessna has gone out of its way to solicit our views and has stated that their upper management wants this SIDs to be “for the benefit of the fleet”. We are hopeful that our findings will lead to SIDs which are far less burdensome than the draft versions, but this remains to be seen and will depend on future meetings with Cessna.

The Committee is also reviewing the matter of the 20-year from manufacture compliance period, which for Skymasters will mean immediate compliance for certain operators who are required to comply or for those owners wishing to voluntarily comply with the SIDs. This same 20 year time trigger was used in the SIDs issued previously by Cessna for the 400-series aircraft (despite opposition by 400-series owners and operators and the repair corporation they formed and funded to address compliance). However, in our case, the Committee believes that there are grounds for recommending to Cessna that this provision be modified for Skymasters. Work on this matter continues.

At this time we are in the process of finalizing our analysis of the SIDs and formulating a report for Cessna. Cessna engineering staff are scheduled to visit a Skymaster service shop that has aircraft in various states of disassembly for inspection. This will allow Cessna to consider the proposed SIDs and possible alternate inspection approaches to address the areas of concern with the benefit of actual disassembled aircraft to examine. SOAPA will have a representative at this meeting as well. We expect to fold any developments that come out of that meeting into our report and are targeting to have our report provided to Cessna by mid October.

We will keep you informed of any further developments or changes to the above as soon as we are able. Should you have any input that you would like to provide to the SOAPA Committee members working on this matter please provide this directly to SOAPA President, Herb Harney hharney@sbcglobal.net or reply openly to this thread.

[skymstr02]

Thanks for the update Larry.

[Alfonso]

Thank you very much for the update. Please remain to the Committee that the Cessna 336s in some areas are better that the C-337s, and that there are very few remaining C-336s.

Thank you for your good work, and best regards,

Alfonso Diazdelcastillo

N695AD - C-336

[Rafful]

I think it's enough for me to say I am grateful, supported and trusted on these people (owners and /or experts) in this type of aircraft, which are operating in this discussion (as a counterpart), and that we are not only at the expense of findings of the Cessna factory. If I am not wrong, the standard owner of this kind of airplane is, at least, solicitous to attend his/her aircraft.
Thank you Larry. I (and I think that a lot of us) will keep in touch.

[WebMaster]

Please understand that there are a LOT of people who have worked diligently over the last few weeks, and who will continue to do so.

[Roger]

First please see: http://www.faa.gov/other_visit/aviat.../info09008.pdf

I had a nice talk today with Rusty Jones at the FAA (listed at the bottom of the attached link). Among other issues I asked him about the previous stated concerns that 14CFR43.19.409(f) might be construed to be applicable to turbin aircraft only, and that 14CFR43.13 (b) may require IA's to comply with inspections as provided by the new service or maintenance manuals as it refers to "structural strenght and deteroration" . Rusty said that in his readings of the points referenced, he can see how the "words" may make it appear that those specific conclusions could be drawn, but he does not beilieve that this is the case. He suggests that SOAPA designate a quesiton or list of quesitons for legal clarification, and submit them through the AFS-300 process for specific clarification.

That being said, we should then perhaps come up with a correctly phrased question or two that the IA' AP's here may help us to clarify, on how they as inspectors and we as owner/operators can best protect our respective intersts going forward so as to not run afoul of regulations.

He likewise made a point of discussing the attached link (which is how I found him) and suggests that we might be well served to take advantage of the answers to these frequestly asked questions. I for one will be making sure that my aircraft maintenance Log clearly states that I am using the maintenance programs for 12 month and/or 100 hour inspections as defined at the time or original manufacture.

Rusty has been around this whole issue for a long time and cut his teeth on Aloha and the 400 series. I might suggest that those who are more knowledgeable about these things contact him direct. That being said, after talking to him about how this has come about with Cessna, and how an AD such as those with the 400 series evolved, I came away with no concern what-so-ever that we will see an AD for the 336/337 on any of these SID issues.

This is essentially a Cessna Protection program, not an Owner/Operator protection program

[hharney]

Good job Roger, the SOAPA steering committee has circulated this document and I was going to call Rusty but hadn't yet. I am glad you talked to him and the steering committee will take some action on your suggestion.

[Skymaster337B]

Ok, so here's the first question that comes to mind.

- Does the term "current" as interpreted for FAR 91.409 that means "current at time of manufacture" apply to all of FAR 91 with respect to "current" maintenance manual and/or inspection programs?

[skymstr02]

Are you operating in accordance with a maintenance program?

[Francisco]

Why are we pilots in the USA surprised by this SID? We are living in a DIFFICULT economic time, most companies are struggling to keep the doors open, a lot of them are in bankruptcy. We have seen our government input billions of dollars into the economy. You don't have to be an economist to realize what Cessna is doing with this "mandate." Cash flow is their primary reason. In order to generate CASH-the needed element in a capitalistic society-Cessna has devised this new revenue source, and the FAA is probably in cahoots (blame it on the lobbyist). To be honest I am surprised that they still let us fly our 30+ year airplanes. But the truth is the economy has to be stimulated and cash has to flow or else capitalism does not have a chance.

I recently had to spend $1000 dollars on a new set of golf clubs... with some discussion about square grooves versus rounded grooves, rendering my good old set useless. How much money are the golf club manufacturers going to make in the coming years with new purchases from individuals? I think I am going to invest my retirement in them, or maybe I should invest in Cessna?

[nick]

who came up with the potential 60k expense? after all to separate both wing and inspect is no more than three or four days work, tops three or four thousand dollars labor! If there is more to it than what I am hearing, guys please elaborate.

[WebMaster]

Nick,
Several people were involved in the review and cost estimates of SID compliance.

Removing both wings from the fuselage is a labor intensive project. Re-assembling them is even more labor intensive. In between, there is the eddy current inspection of each of the attach points, in the fuselage, and the wing. In addition to the wing removal, there are several other items that must be inspected. The cost is real. You may have a lower labor rate, and get eddy current inspection at a lower cost, but the total cost will significant. In addition, there is the very real possibility that the re-assembly will damage the aircraft.

That is why SOAPA has campaigned to have the wing attach inspection removed from the SID inspection.