Check that Seat is Properly Latched

[pelmet]

Whenever I get into a light aircraft and make my seat adjustment, I always rock the seat back and forth aggressively(or at the appropriate time on the checklist). Sometimes it turns out that what seems to be a latched seat was in fact not a latched seat and it moves.

Just a short while back, I thought I might get some instruction on a Cessna floatplane and wouldn't you know it. After adding power and getting that second rise with us in that nose high attitude, the instructors seat slides back. I am asking if I should abort but everything else seems OK so I continue and the instructor is able to get the seat forward again once the floats are on the step. Apparently, that seat 'slides back sometimes'. Meant to look at the seat track after the flight but forgot with all the other fun on that flight.

Anyways, I was reminded of this minor incident while reading the TSB reports today.......

"C-GJHD, a privately registered Cessna 172 was on the take-off roll, at Tillsonburg, Ontario
(CYTB), with only the pilot on board. As the aircraft became airborne the pilot's seat slid back on
the rails and the pilot was unable to reach the flight controls. The aircraft stalled and struck the
ground with the left wing and cartwheeled. The nosewheel collapsed and the aircraft came to rest
in an inverted position. The aircraft was substantially damaged but the pilot was uninjured. The
121.5 ELT activated during the impact."

Remember to aggressively check that the seat is properly latched(on sliding seats anyways).

[CpnCrunch]

It's not always the seat rail holes (which has the AD) that are the problem. In my 1970s 172 the holes were fine, but a few times the seat rolled back on takeoff. Luckily it didn't cause any problems as I'm quite tall, and there seems to be some kind of secondary stop installed, so I could still reach the pedals. In my case the issue was that the two pins (on left and right hand seat rails) weren't always lined up, so sometimes one would be in a hole but the other wasn't, and the seat was a bit sluggish moving so even jiggling the seat forward and back sometimes didn't make it latch properly. I got my AME to do his magic, and he worked on it and it's much better now. I also am careful to make sure I hear the DING from the pins latching, but it doesn't seem to be a problem any more.

Replacing the seat rails as per the AD is a PITA due to all the rivets that need removed, but it's worth doing it if your safety is jeopardized.

[pelmet]

It's not always the seat rail holes (which has the AD) that are the problem. In my 1970s 172 the holes were fine, but a few times the seat rolled back on takeoff. Luckily it didn't cause any problems as I'm quite tall, and there seems to be some kind of secondary stop installed, so I could still reach the pedals. In my case the issue was that the two pins (on left and right hand seat rails) weren't always lined up, so sometimes one would be in a hole but the other wasn't, and the seat was a bit sluggish moving so even jiggling the seat forward and back sometimes didn't make it latch properly. I got my AME to do his magic, and he worked on it and it's much better now. I also am careful to make sure I hear the DING from the pins latching, but it doesn't seem to be a problem any more.

Replacing the seat rails as per the AD is a PITA due to all the rivets that need removed, but it's worth doing it if your safety is jeopardized.

Good points. It can be helpful to have on hand on the seat adjustment handle to feel it move downward while it latches.

[gustind]

One of the only times I was genuinely frightened in an aircraft was when my seat slid back unexpectedly as I was entering a loop. It only slid back one or two holes and clicked back in, but my heart absolutely stopped. I don't think I would have reacted as badly had I seen a ghost in that moment. A "seat check" is always part of my aerobatic safety routine and I absolutely remember being quite angry for the whole ordeal even happening given I checked it twice on the flight.

Here is the worst case scenario of a seat sliding on a rail in a Cessna.

The Cessna 172K (registration C-GQOR, serial number 17259052), was returning to the Toronto/Buttonville Municipal Airport after an aerial advertising, banner-towing flight. It flew a low approach parallel to Runway 33, dropped the banner in the grass and commenced an overshoot for landing on Runway 33. Shortly thereafter, the aircraft stalled and spun to the ground. The pilot was fatally injured and the aircraft was destroyed by the impact and a post-crash fire.

Be safe.

[RatherBeFlying]

There's been a number of fatal and serious injury crashes where the seat slid back.

Good reminder.

[TailwheelPilot]

Cessna used to provide (and perhaps cover installation costs?) for their secondary seat stop for the left seat. Also a great idea for the right seat if controls are installed. If not using Cessna's secondary stop (with a retractable belt under the seat), a fixed stop on the seat rail is a good idea.

[I WAS Pez]

One point on this - even with the secondary seat stop (the little seatbelt reel attached to the floor), if the latch mechanism is worn or the spring is broken, both primary and secondary latches can become unlatched easily...even when initially fully latched. So...another thing to check.

[Posthumane]

I had a couple of instances where the seat didn't latch properly on my 172 and slid back a bit when I applied brakes. It got me in the habit of doing an aggressive seat check each time. However, I recently had an exciting moment in my current homebuilt aircraft with Cessna 150 seats and rails. I had meant to add a secondary seat stop since I bought the plane, but it hadn't made it to the top of the priority list. I did an aggressive seat check as I usually do before a flight and everything seemed fine so I went up to do a few circuits. During the fourth circuit while on short final the seat jumped back one or two notches and locked back in again. Scared the crap out of me, especially since I'm pretty short legged and have to have the seat all the way forward on this aircraft to have good control of the pedals. Decided to make that one a full stop landing right away, and then went home and started work on a secondary seat stop. The one I have now physically blocks the seat from moving back unless you remove a pin and take the seat stop off, which is ok for me since I'm currently the only one flying the aircraft so it never needs to be adjusted.

[AirFrame]

My instructor told me that this happened to him once while solo in a 172. Seat slid all the way back on climbout, and he's not a tall guy... Wheel was well beyond his reach. He put his foot on the control column and pushed forward to keep the nose down and wings level enough until he could collect himself and figure out what to grab to claw his way back forward where he could reach things better. I think he pulled himself into the passenger seat and flew the rest of the flight from there.

[hangarline]

Folks, this is why you have to have AD 2011-10-09 performed on your older Cessna every annual inspection or 100 hours. Make sure to have your AME carry it out. There is more to the inspection than just checking the holes on the rails.

[valleyboy]

I have had the seat slide back on more than one occasion and was always lucky to have a passenger or freight behind me. After those I always grabbed the float kit strut and held on after the power was set. A very experience pilot friend of mine was not so lucky and paid the ultimate price.

There is the ability to put a safety bolt through the track to limit the aft range of motion but like any commercial operation this was not installed because the seat was being removed all the time and to save time it was ignored. A privately owned aircraft should always have this installed especially with a single pilot flying it. It can be set for his range of ability to maintain reach of controls. Little less convenient to get in and out but a small price to pay. The seat cleats should also be monitored for wear.

Simply put a piss poor system that has killed several people but no major change ever implemented. Go figure.

[pelmet]

Simply put a piss poor system that has killed several people but no major change ever implemented. Go figure.

I have noticed that the 172S models(one of the types made after Cessna restarted their light aircraft manufacturing again) has a different type of mechanism for the seat track. I assume it is a safer design.

[Donald]

Not just 172's:

http://avherald.com/h?article=4bedd321&opt=0

[CFR]

The secondary seat stop from Cessna is still available. You must pay an approx 2000.00 deposit which is returned once you send them a copy of a log book entry showing the device was installed. With it installed it should be checked for proper operation on a regular basis. With the pins in the holes the belt should lock, with the seat slide lever up, the belt should unlock. The one check everyone forgets is with the pins on the rail between holes (seat lever untouched) the belt should lock. It can be a bit of a finiky install and adjustment, but they work well once adjusted properly. Make sure the release cable is routed so it doesn't put pressure on the plastic part where it attaches to the reel. This is the weak link in the system and that connector can break!