Ailerons on 170A

[MickP170A]

Question for the people that know. A friend contacted me and said he is conducting an annual on a 170 A and he has discovered It is fitted with two different Ailerons. The difference being that the spar on one aileron has lightning holes along the length of the spar, the other aileron only has lightning holes in the hinge areas. Question is what is the correct aileron and secondly is there a problem with having the two different types provided that balance etc is ok.

[Bruce Fenstermacher]

First it is important to understand that lots of parts on a 170A wing, are specific too and not interchangeable with, any other wing Cessna made. The aileron would not be one of them.

A quick look in both the A and B IPC shows for example that the left aileron assembly on both is part 0523800 and both right aileron assemblies is 0523800-1. So any aileron right or left from any A or B model 170, and every 172 till at least 1986, the latest year I checked, and also the L-19, would be a suitable replacement aileron on an A model.

Yes the balance would have to be for the 170A spec but as the assembly includes the weight, I suspect your set of ailerons are no more mismatched in weight or balance than any other set found on a Cessna that looks the same.

Yes Cessna make changes to parts look over the run of the parts. Usually having the changes had something to do with simplifying and decreasing the cost of manufacture. But if the part number is the same or the assembly number is the same then the part, is the same and all parts in the assembly are the same. They may look different. Many of these mods we are finding are not documented and therefor unknown to Cessna if you called and asked tech support.

[ghostflyer]

Thanks for that Bruce , it’s appreciated information as I have to change my left hand aileron as it looks like a dog has chewed it . BUT it flys perfectly ,no hands on and just sits there. That’s why I haven’t changed it but would consider it if a reasonable priced one came along . Plus I was told [TOLD] recently that the Cessna 182 aileron is the same also.

[GAHorn]

Thanks for that Bruce , it’s appreciated information as I have to change my left hand aileron as it looks like a dog has chewed it . BUT it flys perfectly ,no hands on and just sits there. That’s why I haven’t changed it but would consider it if a reasonable priced one came along . Plus I was told [TOLD] recently that the Cessna 182 aileron is the same also.

The 100 Series Cessnas share many assemblies.

0523800 is the “base” part number also for the 182 series. The differences are minor and are determined by “dash no”. For example, 180 AND 182 serials 30000 thru 51213 ... ALL use the same LH ailerons PN 0523800-15 “until exhausted then use -16”.
The RH aileron assy’s are 0523800-14 “until exhausted then use -17”.

Note that the “dash no” convention customarily used (even numbers LH and odd numbers RH are not followed.

There are LOTS of oddities in the Cessna assemblies.... some differences are so small as to be almost unnoticeable...for example a dash-no change might indicate nothing more than an end-rib being reversed “flange out” instead of formerly “flange in”.... simply because it might save a few minutes of assemblyman time on the line. Nevertheless...they are still fully interchangeable.

When Mort Brown, Cessna Chief Production Test Pilot attended our 2008 Convention (Branson) he pointed out the up-turn at the outboard ends of ailerons, which was intended to streamline the trailing edges to conform with wing washout (twist). He said that during/after the production test flight it was common for the pilot, on his own authority, to “tweak” that upturn spontaneously to improve or affect wing-heaviness and aileron-position in-flight. He said it was almost an expected thing since 100 Series Cessnas do not use aileron trim tabs.... ever!

The lightening holes can be a production-line effort to change the amount of lead needed for the counterweights.... or it may be nothing more than a sub-assembly supplier alternate.

Speaking of counterweights on Cessna ailerons.... Winter is approaching. Those of you who leave your airplanes out in weather...or wash it and unthinkingly plan a flight in cold altitudes..... be sure to closely pre-flight your counterweights and attaching rivets regularly. Water can seep beneath the weights and freeze/expand and loosen the weights and pull the rivets. HOLD that aileron UP with your hand (to prevent a wind gust from smashing your fingers) and run another hand along the counterweights to feel for looseness and pulled rivets. Loosing a weight in flight can cause flutter in a high-speed descent and flutter can lead to loss of the aileron and wing. This makes the world look very crazily spinning in the windshield and will mess up your upcoming landing.

[n2582d]

The C-140A and the C-150 share the same aileron part numbers as the 170A and 170B — 0523800 and 0523800-1.