From here (it may or may not have been the factor) this seems a persistent source of accidents over many years.
Are some airframe types more known for this, and isn’t it a much bigger risk with rental (school/aeroclub) aircraft where the mechanism is constantly getting moved?
It’s a known problem with all the older small Cessnas (152, 172, 182). The locking mechanism is failure-prone and it has caused accidents. There’s an AD which requires it to be checked at every annual. Sensible Cessna pilots do an energetic wriggle after adjusting the seat.
Probably. But the Robin seat lock actually works well but it does need to be checked and not just by jiggling back and for. The lever needs to be properly located in the slot and then slid forward to lock it in place. Some forget this and treat it like a car seat.
I had only one encounter with a seat unlocking and that was in the Caravelle. To say it was scary was putting it mildly.
We had just climbed trough 1000 ft and the pilot flying was reducing power to climb power while in a manual 270 degee climbing turn with about 30 degrees bank, when his seat shot back towards the cabin. He instinctively held onto the yoke and he still had his other hand at the throttles. Next thing I knew, the seat hit the front of mine (thankfully not my leg), the airplane had a 30 degree pitch up and the engines went to idle. The bank angle also did not help and we got a stall warning.
Thankfully by then, the PF had released both the controls and the throttles, mainly because from the extreme aft position of the seat he could not reach either, while the PF first pushed the yoke and throttles forward simultaneously. Within a relatively short time we were back in normal flight regime. And as the days of FDM were still some 20 years in the future, all the tech log said was “seat lock opened during flight”.
The situation recovered quickly, yet all of us had a heightened pulse and I learnt a few French expressions I had been unaware of they existed.
Now, the main reason this did not end in a disaster was that it was a multi crew airplane where the 2nd person in reach of the controls could counteract immediately. In a GA plane, I can only imagine that the effect must be horrendous, particularly in an airplane with stick controls, as the other hand may well be on the throttle at the same time. Add to that a significant movement of CG to the aft.
Not a situation which would under any condition be very pleasant nor easy to recover.
Mooney_Driver wrote:
In a GA plane, I can only imagine that the effect must be horrendous, particularly in an airplane with stick controls, as the other hand may well be on the throttle at the same time.
You should not grab on the throttle in the climb but push on it. Then at least the engine will still be on full power if the seat moves backwards.
Good advice, A_A, but I think you will instinctively grab whatever is close to your hands if your seat suddenly slides back. Unfortunately the two things closest to your hands are the yoke and the throttle.
It’s a known problem with all the older small Cessnas (152, 172, 182). The locking mechanism is failure-prone and it has caused accidents. There’s an AD which requires it to be checked at every annual.
I remember this happening as a kid with my dad flying a Cessna. It was a lot less challenging given that he could ask me to push the yoke forward and get the nose down, at which point it was easy to slide the seat forward again. A incident when solo would be more dangerous, especially with a shoulder harness. We had only lap belts and this was long before the 1987 AD was in effect but the seat wiggle became a personal preflight item anyway.
Neither of my planes has had adjustable seats and they aren’t something I’ve missed. One less thing to break.
The type I owned until recently, an Escapade, has a movable seat mechanism. I never moved it in anger during my ownership as even at 6’ the most forward position was fine for me, and I only ever flew one passenger (who was fat) that needed to move their seat back.
However in a syndicate owned Escapade, one pilot took off with his seat pin not properly engaged. The outcome is here:
On the 182 I rented recently it was hard to get the seat locks to engage, interestingly that plane had an inertia reel thingy under the seat that had been disconnected.
Also @Peter the reason Cessnas are more susceptible to this is that the cabin design means you need to move the seat back every time you get in and out – not just to adjust the seat for different pilots. You can’t get in or out of a 172/182/206 without actually moving the seat back.
I once had a Cessna’s seat slide one notch backwards on take off and having read about the AD beforehand, I envisioned myself crashing almost before the seat locked again. Since then I do the seat check even more thoroughly.
Peter wrote:
Are some airframe types more known for this, and isn’t it a much bigger risk with rental (school/aeroclub) aircraft where the mechanism is constantly getting moved?
Don’t you slide your seat back every time you get into or out of your TB20? I can do it without but then there will be only few centimeters left between my foot and aircraft parts that are not meant to come in contact with shoe soles. No such risk in a Cessna but there the forward end of the seat almost lines up with the door frame and leaves little room for feet and legs. For me it’s therefore either sliding (the seat) or scraping (aircraft interior and upholstery). I try to keep as much distance as possible between my body and the aircraft interior and try not to bother parts like flap levers (Pipers) or autopilots (Mooney) with the weight of my body like many others do. At least this keeps the wear in only one component: the seat rail.
