SB218

[donv]

This is interesting, from Flight Levels Online...

https://flightlevelsonline.com/2023/from-the-shop-floor-update-on-service-bulletin-218/

As Twin Commander Aircraft has become aware of reports of cracking in locations previously addressed by Service Bulletin 218, an effort has begun to remedy the situation that preserves the integrity of the fleet. Discussions involving the Twin Commander Factory Service Center network, operators, the factory, the FAA, and outside engineering firms are centered around solving the issue in the most efficient and least disruptive way possible.

SB 218 requires inspection and possible reinforcement of the tail structure of most serial numbers of turbine-powered Commanders. Now in its second revision, the bulletin has been in place since 1994, and has been a mainstay of the fleet for many years. A few years ago the factory became aware of cracking on some airplanes in areas that had already complied with SB 218, and additionally at fuselage station 386, which the current revision of the bulletin doesn’t address. As a result, it became clear an amendment to the bulletin was necessary. Additional cracks recently found renewed interest in properly identifying the problem and working to come up with a complete solution.

[Bruce Byerly]

From everything I’ve ever gathered, the tail is sound if looked after but the lack of maintenance I’ve seen from an Arizona operator, for example, seems a large part of the problem.  Take your plane to someone who knows what they are doing, not just pretending.

[donv]

The wording was sort of vague... are they going to make you open up the tail and inspect it, or re-do the existing doubler, or what?

[Bruce Byerly]

There is nothing really new going on. For many years, my understanding of the goal of a revised inspection scheme in work has been to provide a long term interval. For example, go in, inspect and add a some of the proven repairs (“while you’re in there” before they are needed) and return to service for another 5,000 hours. That would make sense as the design is proven and no one wants a recurring inspection. Of significance.  However, improper Managment of the process could mean something different. And previous and/or current poor maintenance is going to cost us all, I’m sure.  If and when there is a revision, I suspect it will require another look at old poor workmanship, loose bolts on 386 from poor maintenance, etc.

Inconveniently,  the only way to access some of these areas is skin removal, so I would guess there will be some of that to do. Many planes across the country have been inspected and some with the side tail skins removed.

I continue to lobby hard to focus the right and most knowledgeable people on these types of issues but it’s not been really easy lately.

[donv]

Thanks for your work on this!

[Adam Frisch]

Consistently, the pre-690 series are never affected. I'll trade your 1000 model for my 680V smooth.