My R182 is now straight legged

Discussion in 'Maintenance Bay' started by RandyB, Apr 29, 2019.

  1. RandyB

    RandyB Filing Flight Plan

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    Went flying Friday in my RG but landed in a straight legged 182! After liftoff and in a positive climb with the runway no longer being useful I selected gear up as I always do. Hand still on the gear selector I listened for the usual wine of the gear motor/pump and waited for the thump, thump of the gear snuggling themselves into the belly of plane. Strangely there was no wine and no thump thump. Looking out the window the gear had not budged. I selected gear down and tried again but no joy. I then did all the common checks of circuit breakers and fuses, gear pump handle down and secure, master switch on etc. But everything checked OK. Obviously there was no power to the gear motor. I could see both mains down in the locked position and could also see the nose gear down through the convex mirrors on the wings. The gear light was green so I was comfortable that the gear was locked down. Not wanting to mess with it any further and get the gear to go up and then have the opposite happen of them not wanting to go down I decided to return the airport and land. Now to the shop and up on jacks, I guess, for a diagnosis. I hate to see her up on jacks. Worse thing is my shop is so busy it’s going to be a while before they can get to it.
     
  2. JOhnH

    JOhnH Touchdown! Greaser!

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    That happened to my Bo one time in Arizona (Home is in Florida). Problem was a faulty gear-up switch. They were able to clean and lubricate it, and it got me home safely. But a few months later, the switch started sticking again, so I had it replaced. Only a few AMUs.
     
  3. Clip4

    Clip4 Final Approach

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    Sounds like the squat switch or a bad lead to the squat switch. Usually a popped breaker is associated with motor failures. Very unlikely, but could be the pressure switch or lead.

    Have you decreased the nose gear recently?
     
  4. Unit74

    Unit74 Final Approach

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    Where you at? Perhaps a locale could help get suggestions of shops that can get you fixed up sooner.
     
  5. Clip4

    Clip4 Final Approach

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    A 182RG does not have a gear up switch. The gear handle is hydraulic valve that changes the direction of the fluid flow. A pressure switch senses the pressure loss and engages the pump. A squat switch interrupts the process with weight on the nose gear.
     
  6. JOhnH

    JOhnH Touchdown! Greaser!

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    I believe you.
    I didn't understand that, but I believe you.
     
  7. Clip4

    Clip4 Final Approach

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    upload_2019-4-29_19-8-7.jpeg
     
  8. Timbeck2

    Timbeck2 Final Approach PoA Supporter

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    ^^^

    Clear now? :)
     
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  9. Dan Thomas

    Dan Thomas Final Approach

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    Squat switch or lead, as others have suggested, is most likely. That lead flexes every time the nosegear moves up or down, and it fatigues. The wires also fray right at the switch (vibration) and can fail. Or the nosegear has been dirtied up by a leaking oleo seal or accumulated grease from the torque links, and that gets into the switch and wrecks the contacts.
     
  10. JOhnH

    JOhnH Touchdown! Greaser!

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    Sure is. With that diagram, I feel like I could take my vice grips and duct tape and fix his problem. Oh, I might need a hammer and some wd 40 too.
     
  11. RandyB

    RandyB Filing Flight Plan

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    Thanks for all you guyzes input! The nose gear is ok and has not changed stance/pressure wise. I was thinkin of tracing the wire leads to see if one is broke as suggested because it makes sense that it is an electrical issue. The selector valve was overhauled less than two years ago at the same time I had the electric pump motor replaced due to it letting out the magic smoke! But hey, both were OEM parts. Not bad for a 40 year old. Oddly and I know this is just me but the gear selector handle now seems to have less resistance when I pull it out to select gear up.
     
  12. Landing Fees

    Landing Fees Pre-takeoff checklist

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    I have seen a couple issues recently one was a pressure loss (and ammeter spike) from and o ring leak, landed pulled the CB and flew home with a pink belly.

    On replacement is one of the inspection plates I learned that one of the screws was longer than the other and it was touching the gear limit switch (or whatever those 11 things are) and popping the CB. Over the 40 years the plane has been flying the bolts probably got swapped with one that was 1/8” too long.
     
  13. Zeldman

    Zeldman Touchdown! Greaser!

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    You did a lot trying to get the gear up without knowing if it would go down when needed....:lol::lol:

    Having the gear stuck down is a lot more desirable then having the gear stuck in the up position.....
     
  14. RandyB

    RandyB Filing Flight Plan

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    You are correct. Down is a whole lot better than up. That’s why on second attempt to retract and finding the “at hand” items to be OK I returned to the airport and landed. Gladly I was able to look at a complete airplane:D
     
  15. sarangan

    sarangan Cleared for Takeoff

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    How weird. I had the exact same issue, but the mechanic did not find anything wrong. I am going to print out your post and discuss it. Thanks.
     
  16. SoCalPilot88

    SoCalPilot88 Pre-takeoff checklist

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    Same thing happened in my R182. It was the squat switch.
     
  17. RandyB

    RandyB Filing Flight Plan

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    So on the nose gear of the R182 there are three switches Squat Switch, Nose Gear Down Switch (located on the actuator) and Up Switch. Why a down switch and a squat switch?
     
  18. GRG55

    GRG55 Final Approach

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    "Down" shows the gear is extended in flight (green light). Squat switch is so the gear can't be inadvertently retracted when the airplane is on the ground (disables the hydraulics when it senses there is weight on the nose gear).

    If the squat switch fails and continuously senses "weight on the gear", even when the plane is airborne, the gear won't retract (because it thinks it's still on the ground).
     
    Last edited: May 1, 2019
  19. RandyB

    RandyB Filing Flight Plan

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    Thank you!
     
  20. Dan Thomas

    Dan Thomas Final Approach

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    That's because there's no hydraulic pressure in the system. Takes a bunch of friction off the valve. That system is pressure-controlled; when you move the lever UP you dump the DOWN pressure and apply UP pressure, and the pressure switch senses the drop in system pressure and turns the motor's contactor on. It shuts the contactor off once the pressure recovers to around 1650 psi. When you first turn the master on you'll sometimes hear the motor run, as tiny internal leaks in the system will bleed off the pressure while the airplane sits. So you never feel that slackness in the valve unless you're in flight and the pressure is gone, or the airplane is on jacks and pressure has been bled off for various checks.
     
  21. RandyB

    RandyB Filing Flight Plan

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    While on the ground, simply turning on the master will not pressure the system if any one of the many switches in the system is in op i.e. squat switch, down switch etc. Is this correct? All the stars must be aligned for every thing to work?

    Also, what locks the gear down in place? A mechanical lock or hydraulic pressure? If a mechanical lock how is it released when the gear lever is moved to a new position?
     
    Last edited: May 1, 2019
  22. Dan Thomas

    Dan Thomas Final Approach

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    Only the squat switch would stop the pump. The UP and DOWN switches just fire the lights on the panel.

    There are mechanical downlocks. The mains have small hydraulic cylinders that pull the lock out of the way when the UP pressure is applied. They're shown in that diagram Clip4 posted, at the bottom. The nosegear cylinder has a downlock that unlocks when the cylinder starts retracting. A clever little design, but those latching pins in the cylinder fork are known to break sometimes at the roll pin groove, and I used to check them for tightness in the fork at inspection.

    If you get down under the airplane, on your back, with a flashlight and inspection mirror, you can see the downlocks.

    The gear is held UP by pressure only in this system. The old 210s had a lot more stuff in them.
     
    Last edited: May 4, 2019
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  23. RandyB

    RandyB Filing Flight Plan

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    Dan. Thank you very much for the information! Very informative and very much appreciated.
     
  24. Jamie Kirk

    Jamie Kirk Line Up and Wait

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    Own a set of jacks? Jack or up and manually press the squat switch and if the gear retracts there is your problem. On my Commander the squat switch is adjustable.
     
  25. RandyB

    RandyB Filing Flight Plan

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    If all goes as planed, she'll be on jacks tomorrow morning.
     
  26. CMongoose

    CMongoose Pre-takeoff checklist

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    I had the same happen to me last year. We tested the squat switch and the pressure switch in the pump, both were fine. It turned out to be worn brushes in the motor.
     
  27. RandyB

    RandyB Filing Flight Plan

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    Hoping for a better outcome. I replaced / rebuilt the power pack, motor, pressure switch and selector valve about two years ago.
     
  28. Clip4

    Clip4 Final Approach

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    The motor would be a better outcome than the pressure switch @ $2500.
     
  29. donjohnston

    donjohnston Cleared for Takeoff

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    I don’t think this is correct. But I’m not an expert.

    When I had my R182, if the plane sat for a while, when I turned on the master, the pump would run momentarily. My A&P said it was because the system lost pressure while sitting.

    The squat switch just prevents the gear from being retracted. It does not disable the hydraulic system.
     
  30. GRG55

    GRG55 Final Approach

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    Hooo boy. Nobody can argue semantics like we PoAers. :D

    If the gear is retracted using hydraulic cylinders you can be absolutely certain the hydraulic system circuit(s) to those cylinders must be disabled in one fashion or another, if the squat switch is active (and working properly).

    Just because your pump was running does not mean the hydraulic system to the gear actuators is live (once again, assuming everything is working properly).

    The hydraulic system on my Aztec is a bit different from the electro-hydraulic system in the Cessna, but the principle around how the "squat switch" works is exactly the same. In my case there are mechanically driven hydraulic pumps on both engines. That means the pumps are running continuously and there is pressure in the system when the engines are turning. But on the ground, with weight on the gear (squat switch active) the hydraulic system to the retraction side of all three of the gear actuators (and all of the gear door actuators) is disabled...even though both pumps are running.

    Trust that clarifies my comment in the earlier post. :)
     
    Last edited: May 4, 2019
  31. Dan Thomas

    Dan Thomas Final Approach

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    Go back up to post #7. In the R182, that squat switch is in the power line between the breaker and pressure switch, which fires the contactor, which controls the pump motor. If your R182's pump motor ran when you turned on the master, you had either a miswired system, or the nosegear is fully extended, which is easily possible in those airplanes if you have a bunch of weight in the back seat or baggage compartment and the oleo is a bit overinflated. Or the switch is seized in the closed position.

    We used to test our R182 squat switch on the jacks by bleeding off the nose oleo pressure and holding the nosewheel up a bit to open the switch. Another person would turn on the master and select gear up. Nothing would happen until the nosewheel was dropped and the pump started.
     
  32. hindsight2020

    hindsight2020 En-Route

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    Dayum, my arrow's powerpack OH, R/R, plus gear swing came under that figure. Textron Aviation sure is helping the Chinese get all our aviation money. The selloff of American sovereignty continues.....
     
  33. GRG55

    GRG55 Final Approach

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    I don't buy much in the way of parts from Piper, for reasons you already know ;)

    But Piper hasn't raised their prices to the stratospheric level of Beech or Cessna. Yet...
     
  34. hindsight2020

    hindsight2020 En-Route

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    I know I can't prove it, but they want those piston products gone yesterday frankly. Reference the current V-tail fiasco for a good example of this. Now, I'm not suggesting this was a concerted snipe at mothballing support for the museum pieces, but when my wife nags me about the trash bag, I seem to have a problem putting one foot in front of the other in a manner that would reflect my current age and not that of an octogenarian. Sometimes to the degree she ends up beating me to the damned thing, whilst I enjoy plausible deniability for "trying". Textron strikes me as the latter when it comes to these pricing shenanigans and support's lack of sense of urgency. Just sayin'.....:D
     
  35. Dan Thomas

    Dan Thomas Final Approach

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    There's usually the name of the manufacturer on the pump motor. A little Googling often turns up a lead to those folks, and much more reasonable prices. You can sometimes make hundreds of dollars per hour in savings just by running a search engine.
     
  36. GRG55

    GRG55 Final Approach

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    Cessna/Textron has a wide range of non-piston products in the family (with another coming soon in the form of the Denali turboprop).

    Except for the M500/600 turboprops, Piper does not.

    I sometimes think this may be one reason for the difference in behavior wrt piston aircraft.

    I'm surprised Textron continues to produce the Bonanza and the Baron. They sold only 15 and 19 of them, respectively, last year.

    Not sure what you meant by "the current V-tail fiasco"? I must have missed that.
    But do note one of the new crop of Flying mag columnists is having a Bo totally refurbished from the airframe up, after trashing his last one at Telluride after a botched high density altitude take-off.
     
  37. RandyB

    RandyB Filing Flight Plan

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    Finally got my plane to the shop to trouble shoot the issue. A broken wire from the pressure switch to ??? I will find out which wire when I pick it up tomorrow. Thankfully not expensive and yes I probably could have found it myself but not enough time to do it correctly. Besides, I'm sure it needed to go on jacks to test anyway. YIPEE!! Now, how did the wire get broken? Probably from me kickin and screamin each time I have to land and can't play anymore
     
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  38. Dan Thomas

    Dan Thomas Final Approach

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    That wiring is right above your right foot and can indeed get kicked.
     
  39. Clip4

    Clip4 Final Approach

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    Actually the gear pump can run momentarily in a R182 upon turning on the master as the pump bring the system pressure back. It does not indicate the squat switch is not working. Re-examine the wiring and the gear down switches in series.
     
  40. Dan Thomas

    Dan Thomas Final Approach

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    Back to the schematic you posted.
    The squat switch is in the pressure switch circuit and the pump's contactor will not close if the squat is open.