 Gear Trouble
Unbelievable.
>
> The 182RG (R182) should be similar to the 177RG. We have
> the R182, and the pump has a pressure switch that shuts off around
> 1600 psi. There are two relief valves in the system, one that relieves
> the electric pump at 1800 psi and the one that relieves the manual
> pump at 2200. Both valves and the pressure switch are supposed to get
> checked at the 100-hour inspections, as does the gear swing ("Five
> fault-free cycles," as Cessna puts it). This requires jacking the
> airplane to a ridiculous and scary height, so a lot of mechanics won't
> do it.
> The gear warning horn has two switches: One in the flap
> mechanism and the other on the carb, operated by a cam on the throttle
> shaft. The horn will sound if the throttle is reduced below a certain
> point or if the flaps are lowered below 23 degrees. The flap switch
> will make sure the horn sounds even if the throttle is in all the way.
> The green light system is wired to stop the horn when it fires. (Or
> you could turn off the master.)
> The gear-down light is operated by three microswitches, one
> for each leg, wired in series. The yellow gear-up light is wired to
> three others. The gear-down switch on the nosegear is actuated by the
> downlock mechanism, and so the nosegear must be down and locked for
> the circuit to close. The mains don't absolutely have to be locked for
> their switches to close, since they're not going anywhere after weight
> is on them anyway.
> The OP's complaint, as I think about it, is probably due to
> the nosegear's switch not closing because the hydraulic cylinder
> wasn't pulling hard enough to yank the lock into place. It wasn't
> pulling hard enough because it is bypassing fluid internally, making
> the system pressure low and keeping the pump running. The hydraulic
> systems is supposed to be overhauled every five years to replace the
> rubber bits that do this, but guess how many of them are within THAT
> limit? There's another R182 on the field here that has had that same
> bypassing problem. Fixed, now.
> So, as I see it, that OP's nosegear downlock was not locked
> (and its switch not closed) until the vibration of the wheel touching
> down shook the hydraulics a bit and made the piston seal finally catch
> and bring the pressure up, pulling the lock into place. He is SO
> lucky, especially considering that he flew the thing home again with
> no guarantee that the system would hold pressure to keep that lock
> from jumping out. And that's why the Regs require grounding an
> airplane when a defect is present.
>
> Dan
> There's a squat switch on the nosewheel scissors that prevents
> pump operation if the leg is extended.
| 
