Does anyone ever have a problem with their flaps sticking, on either extension or retraction, when it gets very cold outside (below 20 deg F)? On departure today out of Mankato, MN the left flap did not retract on takeoff. After several extensions and retractions, I finally got both flaps to retract. Does this indicate a problem with a weak flap motor or the transmission? I have only had the problem occur when it is really cold! The circuit breaker for the flaps did not pop. However, I did recycle the flap circuit breaker. Any help is appreciated. I have an annual in Februrary and was thinking of getting the flap motor rebuilt.

 

Thanks,

John Wasserburger

Something's dirty froze worn bent or broken! I'd start by going under and check the rollers for dirt and ware. Your not the first with this problem. But don't fly it again till the problem is found and fixed or it could be your last problem! Low airspeed and one stuck down syndrome can make for a bad day! Ray B

Hi John,

 

The flaps are deployed by the gear motor and transmission, but they are retracted by 2 springs located on each flap. So if they are sticking in the down position doubt the motor is the issue. As Ray said, you need to inspect the flaps including the rollers, tracks, and the springs. Have you had the plane painted recently? When mine was painted the morons failed to install the springs and cables correctly which I discovered when the flaps started sticking.

The bride and I both fly the Comanche. One thing we don't agree on is whether to use flaps on take off, I don't, she does. The reason I don't is to avoid an asymmetrical flap retraction on take off. That said we had it happen once and it wasn't a big deal but we were not near the edge of the envelope. Do a no flap take off and go see you mechanic.

Good luck, Don

I have not had the plane painted recently. I will inspect the entire mechanism. I just don't know why it would do this when it is very cold and not any other time.

 

John W.

John,

 

I have vivid recollections of my Multi checkride because it was a cold clear December day and the first task was climb to altitude, do a practice approach to landing and go around - the right flap stuck and felt for all the world like an engine out. I slowed the plane back to 100 and one lowering and raising fixed the problem.

The problem for us was the flap track had been greased. On our twin the flap track was not supposed to be greased. The Twin was only 6 years old at the time and maintained by the same Piper dealer that sold it to my parents. The flap tracks were cleaned and in the next 34 years so far, no further problems. I do specify at annuals that they are not to be greased however since some Twin Comanche flap tracks do get greased, I once had to stop a shop from greasing them anyway.

BTW, do you always take off with flaps? It is rare for us, unless practicing short field or density altitude is very high and we're heavy.

Hope this helps - it may or may not be your problem.

I think Pat has likely hit on it. Grease + cold = very sticky stuff.

 

The flap tracks, particularly if you have the original metal rollers, can also wear causing binding, and the springs can get weaker over time. It it's never been done it wouldn't be a bad idea to replace the springs.

If you have a Robertson conversion there is a kit available from Sierra Industries that provides for positive flap retraction.

Jay

John,

 

I'll also pass along a comment from husband, Ken. I mentioned your post to him as we were driving to an appointment just now. It is the nylon rollers that don't take grease and this is covered on the Maurice Taylor videos available from CFF. If you don't already have the Taylor videos, they are worth the money - we still watch them every so often.

Thanks for the excellent responses! I normally takeoff with flaps 15 at my airport since it is only 3,700' long and has obstacles on both ends. Yesterday, at Mankato, my son was flying and he put the flaps to 15 prior to me telling him to do a no flap takeoff. I prefer a no flap takeoff if I have a long runway and excess stop margin. I am going to check on the grease and I am not sure if I have nylon rollers or steel. Another factor could be that when we were flying to Mankato we went through some visible moisture (snow and snow showers with reduced visibility) and perhaps after sitting a few hours in Mankato it froze and conributed to the problem. However, we did land with flaps extended at Mankato! I'll have everything looked over at the annual in Feb. I am also doing the 1,000 Hr gear AD. Are the nylon flap rollers better than steel?

 

John W.

Where can we purchase nylon flap rollers and new return springs?

 

John W.

Webco for both.
The left flap on my 250 used to stick on the way up, until I installed their nylon rollers.
Then a year or so ago the right one would stick on the way up, until I installed their new springs.

 

Don

John,

 

If you are having your annual done at Heritage in Rockford, Cliff will know where to source all the parts and can likely offer an opinion on the rollers. All I know is, Piper changed to the nylon rollers in the later Twins. I use Webco for most of the parts I buy myself. Be sure to ask if the parts are new or serviceable, both are frequently available. Hope this helps.

John,

 

I have had a similar situation occur. My bird is hangared but there are a few leaks in the roof. About 1 month ago (temp around 32F) took her up for few runs around the circuit. During preflight I noticed a bit of water on the left wing but I wiped it off and bored a hole into the sky. No problem on the first pattern, but the second time I did a touch and go, retracted the flaps on the go and low and behold required more right rudder than usual. Remembering the first rule (Aviate) I flew the plane looked out the pilot side window and there it was stuck flap! Well I continued around the pattern, dared to lower the flap and when the right came down I figured something got stuck.

Once on the ground I checked over both sides and found a bit of binding. Took some approved spray lubricant (already had the nylon bushings installed) and gave em a shot. Now I include a manual flap extension/retraction test before lowering them for preflight.

I have flown since above and below freezing with no further incidents.

Hope this helps.

Paul

As long as I will be taking a good look at the flap system at the annual, is there any opinion on precautionary replacing of other components like the Flap solenoid, Flap sender unit, Flap up/down limit switches etc.?

 

John W.

John,

 

This may be superfluous but you should be able to push the left flap all the way down by hand and have it return to the up position. It is actually a good preflight check. The right flap is of course locked UP because it is the entry step.

John,

 

The flap sender unit is just like the fuel sender units - had the Twin's overhauled by Air Parts of Lock Haven as it was getting sticky after 40 years. May or may not be time for your twin's as well.