Cessna Seat
- Thread starter pnancoz
- Start date
PaulMillner
Line Up and Wait
Could be slippped roll pins, or broken aluminum links... I've had both!
If you pick up on the seat bottom does it seem to be separated from the lower mount structure that is connected to the tracks? Here's a diagram for reference. FYI: If you're in a bind most 172 seats can be swapped between the pilot and co-pilot.
Dan Thomas
Touchdown! Greaser!
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Dan Thomas
The crank that reclines the seat back has an Acme thread that runs in an aluminum nut that moves a bellcrank that turns a shaft that turns a cam on each end of that shaft. the cams push against clevis pins in the set back lower arms to change the tilt.
That aluminum nut is stripped. They do that when they're either high-time, or they haven't been properly lubricated at annual. If you buy a used nut it might be nearly shot, too. There's another nut on the other crank, the one that raises and lowers the seat, and they fail as well.
There are other critical things to check in that seat: those clevis pins in the seat back lower arms wear out. I have found them worn more than halfway through. If they wore much more they would break and the seat back would flop right down almost flat. Imagine that happening when you're on takeoff; what is the immediate, conditioned response? To pull yourself back up. And what will you pull on? The control wheel and throttle knob. And what will happen then? All because two little pins weren't inspected?
AD 2011-10-09 demands that the seats be removed every 100 hours/annual for inspection of the seat rails, locks, rollers and tangs. I wish they had added a line to that AD: "Inspect the entire seat for wear, cracks and distortion before reinstalling." There are so many places, especially on those infinitely-adjustable seats, that need checking.
That aluminum nut is stripped. They do that when they're either high-time, or they haven't been properly lubricated at annual. If you buy a used nut it might be nearly shot, too. There's another nut on the other crank, the one that raises and lowers the seat, and they fail as well.
There are other critical things to check in that seat: those clevis pins in the seat back lower arms wear out. I have found them worn more than halfway through. If they wore much more they would break and the seat back would flop right down almost flat. Imagine that happening when you're on takeoff; what is the immediate, conditioned response? To pull yourself back up. And what will you pull on? The control wheel and throttle knob. And what will happen then? All because two little pins weren't inspected?
AD 2011-10-09 demands that the seats be removed every 100 hours/annual for inspection of the seat rails, locks, rollers and tangs. I wish they had added a line to that AD: "Inspect the entire seat for wear, cracks and distortion before reinstalling." There are so many places, especially on those infinitely-adjustable seats, that need checking.
Clip4
Final Approach
Get bell crank #2 of the chart from RobAir. Better than OEM.
kgruber
Final Approach
Robair.........for sure. Send him the seat for overhaul.