Cessna's Free Seat-Stop Installation -- Any Downside

Paul462 · #1 12-24-08, 04:10 PM

Cessna Pilots Association technical support suggested three downsides to this installation:

1. Cost. Although the initial install may be free, belt fraying will occur over time due to the angle of the belt relative to the reel housing. When the time arrives to replace the reel/belt assembly, it probably won't be cheap, and that cost will be borne by the owner.

2. Removal of existing effective retrofit stop. One previous back-up stop design involved a spring-loaded clip which was removably attached to the rail, and apparently it worked well. Installation of the belt mod requires removal of this stop.

3. Reliability. When the belt eventually frays and hangs up inside the reel, it could prevent the original rod from fully descending into its rail bore, because the belt and the original rod are mechanically interconnected. The frayed belt could thus defeat both the "free" mod itself AND the original seat lock, causing the seat to slide backwards upon takeoff.

The CPA rep I talked with knew of one pilot who had never had his seat slide backwards on takeoff UNTIL he installed the belt mod. The seat slid backwards twice on takeoff. He took his plane back to the pilot center, which pronounced the install fixed. Shortly thereafter the pilot's seat slid back yet a third time! The pilot ended up removing the mod.

4. Bonus draw-back: you can't store stuff under the pilot seat anymore because of the reel.

Conclusion: I decided not to install the belt mod. The CPA rep noted that if the entire original system (rollers, rail, rod, etc.) is kept in good condition and within tolerances, it'll work just fine.

I make it a habit to push my seat forward and backwards at the very start of my take-off run, to confirm the seat is well-locked into place. If I were ever to note any movement at this point, I would simply abort the take-off.

This is a good habit to get into whenever flying a SE or light twin Cessna, be it a C150, C172, C182, P210, C337, etc. - one can't be assured that they all have back-up stops installed. :-)

hharney · #2 12-26-08, 12:06 AM

Did I miss something here? I thought this was discussing the seat rail stops? Where does fraying the seat belt come in on this issue? These are the units I have installed. I can't see where these would affect the belt web.

http://www.aircraftspruce.com/catalo...s/saftstop.php

JeffAxel · #3 12-26-08, 12:31 AM

Herb,
I believe the question was relating to the inertia reel seat stops Cessna released this year. I can't recall the service bulletin number, but Cessna paid for this for the pilot's seat, if you installed them on the co-pilot's seat as well. Basically a 50% off sale. I put them on, and they work fine. Basically they are an inertia reel seat belt that attaches to the seat frame on one end and the other end of the belt bolts to the floor in front of the seat.

hharney · #4 12-26-08, 09:37 PM

Is this referring to the lap belt or a shoulder belt?

JeffAxel · #5 12-26-08, 10:24 PM

Quote:

Originally Posted by hharney

Is this referring to the lap belt or a shoulder belt?

neither. It attaches the base of the seat to the floor and keeps it from slipping back unless you release the inertia reel with the seat release. It is described in Cessna SK337-77 for the pilot's seat and SK337-78 for the copilot's seat. MEB07-2 also describes this installation.

Paul462 · #6 12-27-08, 07:43 AM

Herb,

I highly reccomend the BAS 4-point seat restraint system, and have it installed on our T337C (and it was also installed on our last Skymaster).

My comments above were intended to be directed to the backup seat stop system which Cessna came up with. As Jeff notes above, this seat stop system attaches an inertial reel to the floor of the airplane under the seat, and the free end of the belt to the seat itself. The inertial reel is pre-set to dispense a pre-determined length of belt, after which it stops the seat from moving backwards. Actuation of the conventional seat release lever simultaneously releases the belt, so the seat can slide backwards. :-)

JeffAxel · #7 12-27-08, 01:48 PM

Quote:

Originally Posted by Paul462

Herb,

I highly reccomend the BAS 4-point seat restraint system, and have it installed on our T337C (and it was also installed on our last Skymaster).

My comments above were intended to be directed to the backup seat stop system which Cessna came up with. As Jeff notes above, this seat stop system attaches an inertial reel to the floor of the airplane under the seat, and the free end of the belt to the seat itself. The inertial reel is pre-set to dispense a pre-determined length of belt, after which it stops the seat from moving backwards. Actuation of the conventional seat release lever simultaneously releases the belt, so the seat can slide backwards. :-)

actually, the inertia reel attaches to the seat base, the free end of the belt bolts to the floor in front of the seat. I agree with your comments about the BAS 4 point restraints as well BTW. Someone alluded to the possibility of damage to the belt. I hadn't thought of this. The belt on the pilot's side is not likely to have this happen, but the co-pilot's seat does slide back further, and the pilot has to crawl over it and could step on the belt since it is just off the floor. Something to keep in mind I suppose. My question is why did Cessna put the door on the wrong side of the plane?? My P210 had only one door and it was by the pilot who could easily open and close it and thus be sure it was operated correctly. This seems like a better set up to me, unless of course your co-pilot is really attractive.....