Auto Gear Extender

Jim WellsJim Wells
in General Discussion
I recently had a new diaphragm installed in my system on my Arrow in an attempt to return the system to working order. Everything went well except when I flew with the AI on board he ran out of adjustment and could not get the drop down speed below about 75 kts. When the system was working originally the drop down speed was about 90 kts which was ideal. Other than running out of adjustment the system appeared to working nominally watching it visually while flying.

Does anyone have any ideas as to why the adjustment screw would reach it's limit at such a low air speed? Could it have anything to do with the tightness of the diaphragm? Any ideas or suggestions would be greatly appreciated.

Thank you,
Jim

Comments

  • Piper TechPiper Tech
    Maybe a small leak in the line, or the part you installed is bad from stock.
  • flyguydonflyguydon
    A leak would make the system deploy at a higher speed. Is the spring on correctly?
  • CaptPeteCaptPete
    Jim, I'm trying to understand your problem. Did you mean to say:

    "...he ran out of adjustment and could not get the drop down speed ABOVE about 75 kts."?

    Or am I really misunderstanding the problem?

    I've played around with mine quite a bit to get familiar with how it works, so once I understand what is happening, I can probably suggest some things to check.
  • Jim WellsJim Wells
    "...he ran out of adjustment and could not get the drop down speed ABOVE about 75 kts."? Yes, that is what I was trying to say. Thank you.
  • CaptPeteCaptPete
    There are a number of linkages and a teflon sleeve between the spring/screw adjustment point (2) and the pressure housing (10) (that contains the seal/bellows) that may need to be checked for binding and adjusted or lubricated as the case may be.

    The other thing to have checked is the adjustment of the screw (20) stackup which is expanded in Detail A. There is an eccentric bolt in that stackup that needs to be adjusted properly. By changing the tightness of that bolt, the difference between the gear-up and gear-down speeds is adjusted (ie. the spread). So it could be that your spread is too wide which means your gear-up speed is too high and your gear-down speed is too low. By narrowing the spread, you may be able to get the gear-up speed where it should be. Then you would have to check the gear-down speed to see if it jives with the specs.

    I believe the spring/screw adjustment will just shift both speeds in one direction or the other, so between the two adjustments, you should be able to find something that works.

    The PA32 maintenance manual provides directions on how to adjust all of this. Not for the faint of heart, I warn you.

    mini_backup-gear-extender.JPG
  • Jim WellsJim Wells
    Update: Today I was IMC in heavy winds and as I decended into the Tampa Bay area I began slowing to smooth out the ride. Inteestingly, as I approached 110 kts. the gear began dropping. I was taken by surprise since the highest drop down speed we could obtain while adjusting the system was about 75 kts. I am going to try readjusting. Stay tuned.
  • Jim WellsJim Wells
    I tested the system again today and did not get a gear drop as low as 65 kts. IAS. I just figured out why I got the gear drop at 110 kts. the other day. Icing. I was picking up rime ice and it must have accumulated on the airspeed sensor mast reducing the effective airspeed.

    QUESTION: I am in central Fl. Does anyone know a knowledgeable person in this area that could help troubleshoot this system. I have a new diaphragm installed and there is no reason it should not function properly. I would really appreciate any refferrals to someone who might be able to help.

    Thank you very much.
  • 78TARROW78TARROW
    Jim - I'm curious about your icing incident. Does your mast warm up when you turn on the pitot heat? Mine does but I haven't the foggiest as to its effectiveness.
    Regards,
    Jim
  • Jim WellsJim Wells
    Good question. I'm really not sure. I'll check it.
  • flyguydonflyguydon
    The last little ice I got made it to where I had to bypass the system... I will see if it gets hot. I did not turn on my heat till after the incident as it happened so fast and was not real bad.
  • flyguydonflyguydon
    Jim,

    I hope the repair to your auto gear extender meets your approval. You have a real nice plane! Nice to have met you.

    Don
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