Cessna C337 SID

[Ernie Martin]

No idea, but my guess is that all the manufacturers have been tasked and funded to do the same.

Ernie

[Ernie Martin]

We had a productive meeting with Cessna yesterday. There were 9 people from Cessna and these 7 guests/users: 3 owners (Steve Keller, Steve Walz and me, all very familiar with the aircraft), 2 from Commodore Aerospace (Don Nieser and his structures person, Larry Good) and 2 from AirScan (which operates 23 late-model Skymasters).

For context let me mention that this SID exercise is FAA driven and is expected to be followed by similar exercises for other Cessna aircraft models.

Here, in brief, are my impressions:

1. Cessna has been working on this for roughly 6 months or more. Some of the documents date to March and some of the Cessna people at the meeting visited Steve Keller about 6 months ago to get a first-hand look at his airplane (most of these people were unfamiliar with Skymasters because they were not around when they were designed, built and tested, and Cessna does not have a significant database of experience with the aircraft).

2. Unlike the 400-series SID program, this is an experience-based, not analytically-based program. No finite-element structural analysis of the aircraft is planned. Instead, the Cessna people went to the FAA's Service Difficulty Reports (SDRS) database and used that as the basis for the proposed SIDs. At the time of the meeting, Cessna had written draft SIDs and the meeting was in part intended to get the users’ inputs on these proposed SIDs.

3. Approximately 23 proposed SIDs were reviewed, some in more detail than others.

4. For some, the guests were surprised by, and expressed disagreement with, the area in question and/or the initial compliance requirement (for instance, 7,500 hrs or 20 years).

a) As an example, one may call for an inspection for cracks in a wing area where none of the users have ever seen a crack, either on very-high-time aircraft or aircraft that have seen high-load accidents, yet there were no SIDs for other areas of the wing which are susceptible to damage due to fatigue or excessive loads.

b) Or one may call for inspection at 20 years (from manufacture) when it’s a fatigue (not corrosion) issue, so that an aircraft which has sat in a hangar since manufacture and never flown would be subject to this SID looking for fatigue cracks. Or the SID may call for an inspection requiring massive aircraft disassembly even if there is no corrosion evident in easy-to-inspect adjacent/comparable areas.

5. As a result of these user comments, Cessna agreed to look more closely at the SDRS data (some of which are 15 – 20 years old) to try to determine whether they may have come from questionable aircraft or sources (e.g., an aircraft which may have had an earlier accident and/or improper repair) or misidentified the aircraft or part. Inquiries I performed after the meeting suggest that FAA SDRS data is generally considered suspect in the aircraft maintenance business. If true, then Cessna’s re-examination may bear fruit.

6. Moreover, Don (a retired Air Force Lt. Col. who has over 20 yrs experience with our aircraft, worked for years on aging aircraft and corrosion research for the Air Force, has disassembled and restored dozens of Skymasters, and has many Skymaster aircraft and parts which Cessna can examine) invited Cessna to visit him and see first-hand why he believes that some of the proposed SIDs need re-examination. Roughly, his words were “When you see this item, especially one removed from a high-load, high-fatigue aircraft, you’ll see right away that this item can’t fail that way, that other parts will fail first, that the SDRS data must be from a suspect aircraft or refer to a different part”.

7. Cessna also agreed to re-examine the initial compliance requirements, including the possible removal of years-since-manufacture requirement.

8. We were asked to estimate the manpower requirement for each SID.

9. I don’t have at this point a schedule of future activities. There wasn't enough time to review all of the proposed SIDs, so we are continuing their review. We talked about the next meeting of this group perhaps held both in person and as a WebEx Internet meeting. With the caveat that all of these points are my impressions, I believe that such a meeting will likely come after we have submitted our views on the unreviewed SIDs and after points 4 – 6 above are addressed. I’m hoping that Cessna goes to Don’s shop (it’s a 3 hour drive) and that Don (and perhaps AirScan and others) can furnish point 7 after that. I expect to contact Cessna and hope to get a better feel for future activities.

In summary, there are some issues that we’re all working through, but I found the Cessna people competent, professional and receptive to considering our points. The attendance of Don and Larry was crucial and I hope that they can continue contributing.

Ernie

[WebMaster]

One of the concerns is that while these may not be applicable to part 91 aircraft here in this country, in some countries these may be treated as if they were AD's. In fact, there are 400 series aircraft, in other countries, where they advertise that "SIDS are complete".

So, we have a duty to all Skymaster Owners, both here and in other countries.

[skymstr02]

At least our input is valued by Cessna. I don't think that the 400 series owners had that luxury.

We, as a collective unit, need to be smart and educate the OEM as anyone there that was on the 337 program has long retired or gone west.

[ipasgas1]

Our partnership 337 has been sold and I was looking at getting my own but I am now thinking I should hold off until this is all sorted out so I don't end up getting an aircraft that becomes too expensive to maintain???? How long do they feel this process will take before we know what the new recommendations / requirements are going to be?

[Roger]

Well assuming you are at least 16 years old, it will probably happen in your lifetime, but I wouldn't count on it. I certianly wouldn't delay a purchase based on waiting for a governtment ok, or a "Cash for Airplane" program.

Life is what happens while you let other people decide your fate.

[Shalimar]

I recommend that ipassgas take and underline Roger's final point, "Life is what happens when you let other people decide your fate". This is an on going issue with all aging aircraft. SOAPA is doing a superb job representing us all and the issue should sort itself out. That said, since the concern seems to be for the higher time airframes, i would suggest finding one with 3000 hours or less (this becomes academic if they base it on calendar years which seems even more senseless).
A bigger issue facing all of us is the possible future demise of 100LL but we can't let that stop us either.
Recommendation: Find a lower time 337 that has been well taken care of, has good logs and a knowledgeable owner. Find an A&P/IA that knows and loves Skymasters and pay him/her for a complete pre-buy (suggest not the same shop that performed the last annual).
Since you are experienced with the type you probably already know many of the foibles and should have an idea what to look for. if not this website has many knowledgeble and experienced pilots, mechanics and owners. That can offer some suggestions.
But don't wait on this issue.
Good Luck

[SkyMac]

Hi Everyone

I need some thoughts on this matter from other members of the forum, last week all SID's were completed on my plane with the exception of the front and rear spar bolts / screws.

Aircraft is 33701575 (1974)

In my aircraft these two bolts / screws do not exist, they are rivits and are factory. The SID's which my aircraft S/N falls into still specifies the removal of the bolts /screws to complete the stated eddy current inspection of the bolt hole. They even show the photograph of the bolts / screws.

1. Does anyone have information or documentation from Cessna regarding this?

2. Has anyone completed the SID's on their aircraft which has rivits, and what did you do?

A previou post mentioned a discussion with Cessna had taken place regarding this particular issue - the response was remove the rivits and replace with bolts / screws.

I have a window of opportunity to finalise this last remaining SID tomorrow, do I remove the rivits?

Appreciate and assistance with this.

Dave

[hharney]

Dave

Are you referring to the bolts that attach the wing, to the fuselage? These points would be the spar attachments

The parts book does not refer to anything other than the bolts.

I am thinking that your airplane already has the wings removed (based on photos I have seen) so you must be referring to some other area?