Seat Station Weight Limits

Robert Eilers · Post by **Robert Eilers** » Sun Jul 31, 2005 11:10 pm

Reviewing the 1956 C-170 Owner's manual wieght & balance section, I noticed the front seat weight stops at a total of 440 on the loading graph. I have a good friend who will exceed the 440 total when his weight is combined with mine. By extended the loading graph and using a little interpolation I can arrive at an index for our combined weights. What I haven't been able to find is anything that defines what the weight limit is per seat - if there is one (I suspect there is).

Post by **Bruce Fenstermacher** » Mon Aug 01, 2005 1:09 am

Robert

Since your total front seat weight exceeds the graph you would break it down in 2 weights and moments that are added together. If your weight is 260 and your passenger weight is 260 then your total weight for the station would be 520 lb. The index for each of you would be about 9.4 as I see it so your total index would be 18.8.

I have a neat W&B program that will plot your CG on a graph that works with excel. If you PM me your email I'll send it to you.

I've never seen a limit for the front seats but there could be one.

Post by **GAHorn** » Mon Aug 01, 2005 4:47 pm

I've not seen a seat or floor limit published for the 170, although I've seen such limits for later Cessnas like the 206, usually posted as a limit per square inch or square foot for cargo purposes. If memory serves, my '64 206 had a floor limit of 200 lbs per square foot, but that floor may have been more heavily reinforced than our 170's. I don't know.
In any case, it should be mentioned that a primary cause of failed seat tracks due to cracking is overloaded seats, which place a high bending moment thru their track-rollers upon the tracks and floor. It is one reason the seat-track AD note was developed.