Trying to grasp the AD for wing spars

[hharney]

The SID development by Cessna was a proactive approach on their part. It all comes from Congress passing the Aging Aircraft Bill. This document is primarily pointing to the airliners but will eventually catch up to all aircraft. Cessna is just getting ahead of the game you might say.

Bottom line is liability. Cessna never intended that their aircraft should still be flying 50 years after construction. They really don't care about selling parts for the old ones either otherwise they would make the parts. They would in my opinion rather see the aircraft retired. They would like to sell you a new one.

Personally I think we can learn a lot from the SID's. They do identify key areas to inspect and be aware of potential weaknesses of our aircraft. Use them as guides and they may make some sense. I would suggest that everyone that owns a Skymaster buy a copy of the SID's to use along with the service manual. They are available from Cessna through companies like Yingling Aircraft.

[Ernie Martin]

I agree with Herb, and some of the SIDs make sense and should be used as guides, but if we focus on the big-ticket item -- the wing-attach points SID -- there are two additional factors to consider:

1. There is NO indication that there has ever been a problem in the area. If you read the entire SID thread you will learn that Cessna's stated methodology for areas needing SID attention was the FAA Service Difficulty Reports (SDRs, over 35 years of problem reports furnished to the FAA by repair shops, with about 1,000,000 reports, of which 1,773 involve Cessna 337 aircraft), BUT there were no relevant SDRs in this area. More importantly, Don Nieser's Commodore Aerospace has disassembled numerous Skymasters -- some with well over 5,000 hours -- and has never found corrosion or stress in this area.

2. If not done properly -- and that's likely with an inexperienced shop -- the SID may cause more harm than good, putting undue stress in the inspection area.

Ernie