Seat rail maintenence

sarangan

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Andrew, CFI-I
This might be a naiive question, but is seat rail inspection part of an annual? I have studied the mechanism under the seats, and it appears to be far less beefy than the one under my car seat. The reason I ask is, a seat rail becoming disengaged could cause a serious issue, even catastrophic, especially during takeoff. Has this ever happened, and how reliable are the seat locking mechanisms in GA aircraft?
 
This might be a naiive question, but is seat rail inspection part of an annual? I have studied the mechanism under the seats, and it appears to be far less beefy than the one under my car seat. The reason I ask is, a seat rail becoming disengaged could cause a serious issue, even catastrophic, especially during takeoff. Has this ever happened, and how reliable are the seat locking mechanisms in GA aircraft?
What airplane are we talking about?
 
This might be a naiive question, but is seat rail inspection part of an annual? I have studied the mechanism under the seats, and it appears to be far less beefy than the one under my car seat. The reason I ask is, a seat rail becoming disengaged could cause a serious issue, even catastrophic, especially during takeoff. Has this ever happened, and how reliable are the seat locking mechanisms in GA aircraft?
Heck yeah it's happened. There are airworthiness directives (ADs) on this very subject on Cessna aircraft.
 
Here's where we cover the seat/seat rail inspection during our annual. But since we've got a Cessna the AD has it covered as well.

Title 14: Aeronautics and Space
PART 43—MAINTENANCE, PREVENTIVE MAINTENANCE, REBUILDING, AND ALTERATION
Appendix D to Part 43—Scope and Detail of Items (as Applicable to the Particular Aircraft) To Be Included in Annual and 100-Hour Inspections
(c) Each person performing an annual or 100-hour inspection shall inspect (where applicable) the following components of the cabin and cockpit group:
(2) Seats and safety belts—for poor condition and apparent defects.
 
In our 182 the seat rail inspection is mandatory 100hrs but we rarely hit 100hrs before the annual so its done during the annual.
 
The seats are removed as part of the annual inspection. Your IA should be inspecting the seat and the rails.
 
Tom, that covers it well, 100 hours or 12 months, whichever comes first, I always put that in the maintenance record, also it's not just the seat and rail, well it is the seat, but it's a bunch around the seat, tang, amount of wear and distance between tangs, rollers, it pays to read that AD well, Cessna states no lubrication, Piper said lubricate rails, thanks for the site
 
Tom, that covers it well, 100 hours or 12 months, whichever comes first, I always put that in the maintenance record, also it's not just the seat and rail, well it is the seat, but it's a bunch around the seat, tang, amount of wear and distance between tangs, rollers, it pays to read that AD well, Cessna states no lubrication, Piper said lubricate rails, thanks for the site

The AD forbids lubricating the rollers and bushings, since it just accumulates dirt and forms sludge that eventually seize the rollers. In Cessna's service manuals they tell you that you can rub paraffin (wax) on the seat rails to let the roller housing slide easier, and believe me, that works really well and doesn't attract dust. It will need renewing avery 50 hours or so. It helps prevent galling between the aluminum rail and aluminum roller housings, of which those tangs are a part. Worn tangs mean new roller housings, and they're not cheap.

Don't put the paraffin on the top of the rail where the roller runs. Just along the side edges and under the rail, the places that the housing rubs.
 
You'd be surprised how well dry slide works.
 
The Cessna seat rail issue is due to a couple of things. First off is you have to adjust the seat every time you get in or out of it. Second is the whole mechanism for retracting the pin isn’t the greatest engineering feat ever accomplished and doesn’t work that well a lot of the time. Maybe it gets worn or out of adjustment or just isn’t operated correctly but the result is the pin doesn’t get pulled completely out and you jimmy the seat with your weight so it gets pushed out by the rail and eventually the hole gets enlarged and eroded and the cracks form at the edges and it all goes south from there. You end up with a 25 page AD that has been superseded half a dozen times and just keeps getting longer.
 
As to Piper, what I found on the rails in my Cherokee was kinda spooky to say the least. seat track (4).JPG seat track (3).JPG
 
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