Approved Seat rail stops

[rmorton]

Hello! I’m new to the group and new to airplane ownership having recently purchased a 1955 170B. Coming up to speed on the ADs and looking this plane over really well before I fly it (it’s been sitting for 15 years.)

My plane has no seat stops installed. I’ve read so much about seat stops and secondary seat stops - some of the data seems contradictory. Can someone point me to the correct seat stop that must be installed on the seat rail to prevent the seats from coming off the track? McFarlane kits do not list the 170 for approved aircraft. As far as I can tell, the rails are Cessna rails and the seats are original.

I’ve purchased the Aerostops for backup, but still need to find the correct seat stop for the front and rear of the rails.

Thanks for the help,

Ryan

PS, if anyone has a link or a pdf of the original parts catalog for the 170b, I’d love to have a copy.

[GAHorn]

I’ll be happy to send / email an IPC for the 170B to you but need your email address. (You can use the PM feature to send that to me if you wish.)

I have the Cessna “inertia-reel” auxilliary seat lock on our 172-C, and my 170-B has only the original design (healthy seats, locking pins, and seat rails.)

PLEASE NOTE: Cessna seat rails have mechanical stops pinned at the most-aft desired seat-travel. Make CERTAIN yours are present and installed at a position which allows the pilot seat to remain within arms-reach of the yoke. Most co-pilot seats (if configured as originally intended) will slide farther aft ..almost to the rear seat….than the pilot seat..which is restricted to not slide closer to the rear seat than about 8”.)

The important thing is on EVERY pre-flight to inspect their condition and to ENSURE your seat is locked prior to flight. The Aerostops are fine, the Cessna Inertia-reel system is the best, IMO, and meets Cessna and FAA approvals.

Let me add a point: Take care during pre-flight to see that your cockpit trim wheel is set at the TakeOff position….THEN during your walk-around see that the trim tab on the right elevator is streamlined with the elevator (in a neutral position.)
IF… you then experience an Un-Locked seat during initial climb after take-off….RELEASE THE YOKE… do NOT hang onto it and pull it aft while you and your seat move aft. The neutral trim will continue an ordinary climb attitude…assisted by your aft-shifted C.G. because your seat unlocked…. but will not likely result in an immediate stall. (I’ve deliberately confirmed this with my own 170-B with a safety-pilot. The airplane continued in a near-normal climb.)

[rmorton]

I like the thought process of being prepared to release the yoke. You’re far more likely to react appropriately if you’ve thought it through ahead of time.

If anybody knows of a Cessna service center in the Midwest that can handle the inertia reel install (at Cessnas expense) I’d love to know. I’ve spent an hour on the phone with 2 service centers (listed on Cessnas website) that don’t know what I’m talking about. I live in central Missouri.

I think my highest priority as far as seat stops go is determining and installing the approved stops in the rails.

[Vertical]

By all means put seat stops in. However, if those are original tracks, I’ll wager a guess they could use replacing. Maybe the most important part is not having your seat come loose in the first place.

[dstates]

I definitely recommend adding the Cessna Secondary Seat stop. The parts are still free till the end of 2023 (only for the pilot side). You can have any A&P do the installation (at your cost). I ordered the parts from Yingling (~$1300) and then got a refund after sending them a picture of the logbook entry. The kit part number is SK210-174B for the pilot side. The service bulletin number is SEB07-5R06. If you are having trouble finding someone familiar with the work, send them a copy of the kit instructions (I'm sure they are on this site, if not you can google SK210-174B and get them).

For seat rail end stops I purchased mine from Aircraft Spruce part number 05-00580 (Cessna Seat Stop Kit 1). You will need to order four. I have a 170A so I haven't looked to see if a B model uses anything different or not. McFarlane sells them too. Instead of the cotter pin I use AN416-4 for ease of removal/replacement when having to remove the seat.

Hope that helps.
Doug

[darhymes]

Another good point is that the passenger seat is capable of sliding aft as well. If this happens during takeoff/climb they may be inclined to grab the yoke to arrest their rearward travel. A friend suggested having them hold onto the entry handle on the door post during takeoff (at last they are already holding onto something when if the seat starts moving). Not a bad idea. His other suggestion was adding a Saf-T-Stop to the right seat rail. It works great but I do make sure to brief any passenger on how to exit the aircraft if the seat will not move aft.

Years ago, I had a seat back fail completely during initial climb in a Cessna 152. There was really not a lot to hold onto so I let go of the yoke and was able to manage the climb using the trim from my “reclined” position until reaching a safe altitude. As George mentioned, it was beneficial having the trim set properly before takeoff.

[GAHorn]

Another good point….

Years ago, I had a seat back fail completely during initial climb in a Cessna 152. There was really not a lot to hold onto so I let go of the yoke and was able to manage the climb using the trim from my “reclined” position until reaching a safe altitude. As George mentioned, it was beneficial having the trim set properly before takeoff.

That is yet another important point to consider. The original C-170 seats are constructed of tubular steel and the seat-back is attached to the seat-bottom using a gusset and AN-bolt and bushing.

The tubular steel can rust/corrode internally and the seat back can suddenly FAIL…. usually just above that gusset where the manufacturing process included a weldment which heated that tube internally and created an opportunity for oxidation (rust). Years later that is the point of common failure.

If you have the “successful look”….. (beer belly acquired thru years of hearty meals and beverage)…. you probably TEST that seat back every time you Board the cockpit and lean back firmly to connect the seat belts. But if you are one of the young and/or “trim” set…. you can probably sit in the seat without such gymnastics and your seat back may never have been “restored” or properly inspected during the last re-upholstery job for condition in that area. Many “bargain” planes have original seats in “experienced” condition and DESERVE CLOSE INPSECTION.

At Take-Off …the failure of a seat-back is just as dangerous or MORE SO than the failure of the seat-track locking system.


Then there are those who have REPLACED their seats with seats from another, often unknown, airframe-source. BEWARE of substitute-seats…THEY TOO have weakness in this area. The method of construction may be aluminum extrusions or forgings which are subject to cracking and again …the seat back can fail. It is truly SHOCKING when it occurs. NO AMOUNT of sit-ups excersize can prepare you for the tummy-strength needed to recover from it.
(Once, while sitting in the hangar doing some instrument panel work on a friends Baron the co-pilots seat-back failed… I almost had to ROLL out of that airplane onto the wing to get out of it!)

[n2582d]

Ryan,
First, welcome to the forum. Not sure if you've joined the Association or not, but if so, you'll find a lot of helpful stuff that's been stored in the Mx Library section here like a link to download for free all of Cessna's Illustrated Parts Manuals (IPC's).

Can someone point me to the correct seat stop that must be installed on the seat rail to prevent the seats from coming off the track?

My understanding is that the various seat stops which attach to the rails don't help in preventing the seats from coming off the track, they only limit how far the seat can slide back if the locking pin doesn't seat properly in its hole. Cessna's inertia reel for the seat may help if the seat comes off the track -- haven't really thought about that. AD 2011-10-09 is designed to prevent both the seat from sliding back and the seat from coming off the track. Before this AD and AD 87-20-03 -- the seat track AD which was superseded by AD 2011-10-09 -- I got my initial taildragger training in a 180 HP C-170B at MAF. As I recall, they used a rope tied to the front inboard seat leg with a clip like you'd find on a dog leash attached to the other end. Once the pilot or front passenger was in position with the seat scooted forward, the clip would be attached to a D-ring which was bolted to the side of the forward center tunnel. Cheap and effective.

I've been reviewing AD 2011-10-09 and two AMOC's (Alternative Methods of Compliance) related to it. One can find that research here.

[dstates]

Can someone point me to the correct seat stop that must be installed on the seat rail to prevent the seats from coming off the track?

My understanding is that the various seat stops which attach to the rails don't help in preventing the seats from coming off the track, they only limit how far the seat can slide back if the locking pin doesn't seat properly in its hole.

It sounds like Ryan has the secondary seat stops to deal with the pin coming out of the hole in the rails. I believe he is looking for the stop at the end of the rails. The seat rail end stops I mentioned above (Aircraft Spruce PN 05-00580) are to keep the seats from coming off the ends of the rails. They are simple u-shaped pieces that pin through the rails. Simple and effective. Looks like they are made by McFarlane. The 170 is not listed in McFarlane's info (similar to how the 170 is not in the 100 series service manual), but I use "Seat Stop Kit 1" on my 170A.

[n2582d]

Dang, I should know better than to post at 1:00 am! I was interpreting “seat coming off the tracks” incorrectly. Thanks for getting the thread back on track Doug (no pun intended). Sorry about the obfuscation.

[rmorton]

Thanks to each of you for the replies and links to research. Very helpful. Yes, Doug, I believe you nailed what I was looking for. I am under the impression that those clips are required to be airworthy, but I wasn’t finding the 170 listed on the approved airplane lists. At any rate, I’ve ordered those.

I’m going to continue pursuing the inertia reels as well. So is the consensus that Cessna will only provide the parts for the pilot side? We are responsible for labor on the pilot side and both parts and labor for the right seat?

Thanks again for responses,

Ryan

[dstates]

Thanks to each of you for the replies and links to research. Very helpful. Yes, Doug, I believe you nailed what I was looking for. I am under the impression that those clips are required to be airworthy, but I wasn’t finding the 170 listed on the approved airplane lists. At any rate, I’ve ordered those.

I’m going to continue pursuing the inertia reels as well. So is the consensus that Cessna will only provide the parts for the pilot side? We are responsible for labor on the pilot side and both parts and labor for the right seat?

Thanks again for responses,

Ryan

Correct. If you read through the service bulletin, Cessna only covers the cost of their secondary seat stops for the pilot side, just parts not labor. If you want it on the passenger side as well that is all on you. Due to the cost, I chose to only put it on the pilot side. I still use the Safe-T-Stops on both pilot and passenger side. Belt and suspenders I guess for my seat.
Doug

[GAHorn]

The ridiculous price for seat-rail (U-shped) stops provoked me to make my own out of Home Depot 1/2” U-channel and clevis pins and “ring cotters” instead of cotter-pins. A 4-foot piece of aluminum channel was less than $8 IIRC and will make about 100 of the stops. The AN-392 clevis-pin from Spruce was about 50-cents so $2 takes care of an entire airplane. The ring cotters from Spruce are about ten-cents each.

Easy and fun project for Owner Produced Parts.

Another alternative: http://www.aerotwin.com/products/cessna_seat_stop.html