7
$\begingroup$

The Piper Archer (PA-28) i had this morning had issues returning flaps to normal after being fully extended ON THE GROUND. It required a non trivial amount of push on the air-frame itself to restore the flaps to the original position after having retracted the flaps using the stick in the cockpit.

I was told that "this is normal" and that the spring might be a little worn but that it wouldn't cause any safety issues, but none of the other Piper Archers I've flown have had this issue. I would add that it was a cold day (just above freezing) but the plane fully fully de-iced.

Is it reasonable the fly the plane? Would you be worried? If you refused to fly the plane in that condition despite booking, would you accept the rental to be charged partially?

$\endgroup$
1
  • $\begingroup$ I would think about the outcome if the airflow for whatever reason wasn't enough to retract them. What's the density altitude like at your destination - if they are stuck down would you be able to survive a go-around? $\endgroup$
    – Ben
    Feb 21 at 5:42
11
$\begingroup$

The main thing to be concerned with, is that the spring tension is important for keeping the bicycle chain segment secure on the eccentric sprocket (item 17 below) that drives the torque tube. If there are issues with spring tension in the return spring (item 32), I'd be concerned that slack could result in the chain potentially coming off, but that would require the tension spring on the bottom (item 22) to be not doing its job.

The top return spring should be a fair bit stronger than the tension spring, which is only there to keep the chain from going slack when the cable from the cockpit lever is slack. There is likely a combination of a weakened return spring and some binding in the bushing blocks for the torque tube.

There isn't any risk of flap asymmetry unless the torque tube itself breaks or a control rod lets go, so a problem with the chain arrangement where it jams up or disconnects will, in a worst case scenario, just leave you stuck with flaps partially extended or at zero.

So what to do about it? Depends.

I'm assuming they went almost fully up and you had to push them a bit to get them to move the last little bit. If I knew the plane well, and if the panels came up almost all of the way and just needed a little nudge to overcome some friction, and they stayed up after the nudge, and every thing otherwise felt smooth and solid (when you do a walkaround, you shouldn't just be looking at stuff; you should be gently tugging and moving bits as part of your inspection to detect unusual play), it should be ok and air loads will do the job fine at retracting them as soon as you are moving with some speed, although I would snag it and expect it to be fixed the next time I saw it.

On the other hand, technically it shouldn't be doing that and if there is significant friction, or slop, or you are just uncomfortable with it, you should refuse it and shouldn't be charged for it. A weak return spring and/or binding in the mechanism that prevents retraction on the ground is still a "defect" and needs to be rectified.

If you have access to the A&P that maintains the airplane it might be a good idea to mention it. They may not be aware of the problem.

enter image description here

$\endgroup$
3
  • $\begingroup$ Thanks John, this is an awesome reply! I appreciate you mentioning how some could feel comfortable flying it but not everybody would be expected to. The flight school is forcing me to pay for the rental despite sitting it out, I think it's time to find another one. $\endgroup$
    – Jake
    Feb 21 at 14:38
  • 4
    $\begingroup$ Yeah if the mechanic inspected it and said the components were all fine and it was a little bit stiff and just needed a little help going up, I'd probably live with it temporarily. The problem is when you don't know the source of the binding and they just ASSUME it's something benign. Could be, or could be something more serious, like something is cracked, and the binding is an early warning sign. $\endgroup$
    – John K
    Feb 21 at 15:29
  • $\begingroup$ I hate places that use such a policy. I understand that the school is a business, but a flight SCHOOL should't be trivializing pilot concerns. You KNOW what a proper walk-around looks like, and you correctly identified something that seemed wrong. And it was. If it were your personal plane, you'd have canceled your trip that day and have had it checked out. So you were completely in your rights to avoid using a "defective" plane. Ask them to show you in the POH/service manual the acceptable amount of play in the flaps. They're not even motorized! $\endgroup$ Mar 2 at 20:49

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.