Gear Trouble

On May 28, 3:06 pm, Scott Skylane wrote:
wrote:

/snip/

There's a squat switch on the nosewheel scissors that prevents
pump operation if the leg is extended.

Compressed?

Happy Flying!
Scott Skylane

Right. Compressed. If it's extended the switch is closed
and the pump will run. Those oleos can be a little sticky, and the
R182's gear is a little more forward so the load on the nosegear is
low, and the leg might be extended all the way during a normal
rollout. Grabing the the gear lever instead of the flaps right after
landing is a common mistake, and the pump sucks the nosegear up. Mains
too, on low-wing airplanes. Expensive oops. That's why we have a rule
here that the flaps are left alone until the airplane is stopped.


Dan

jeeze....i like a story with a happy ending...way to
keep your cool and not let things "esclate"





On May 27, 9:06*pm, "Kobra" wrote:
Flyers,

This is just a quick flying story some might be interested it.

My plane ('71 Cardinal RG) just came out of annual with a newly over-hauled
prop and hub. *The mechanic and I test flew the plane around the pattern..
The goal was to check the gear horn because it was going off constantly even
with full throttle just prior to the annual.

Everything was fine and the gear horn went off appropriately at about 14 or
15 inches MP. *We put the gear down and landed. *All was normal and I
congratulated him for a job well done. *Not only for the annual and gear
horn, but because he also fixed a very bad main gear shimmy that we've had
since we purchased the plane in 2002 [but I digress and I'll discuss this in
separate post]

The first flight after that I took the plane to Cape May, NJ (WWD) for
dinner with my wife. *After take-off I leveled the plane and as I reduced
the MP past 25 inches the gear horn sounded. *I applied full throttle and it
continued it's serenade for the next 30 minutes despite all attempts to
quell its false protest.

On approach I lowered the gear thankful that at last I would silence that
gear horn's annoying, useless barking. *I noticed that after a respectable
amount of time the gear horn did not silence and upon inspection I observed
the following:

1) I had no Green Light

2) The gear light bulb tested good

3) The pilot-side main gear looked fully extended

4) My wife stated that her gear looked to be in the normal position

5) The amp meter was pegged to the left showing a discharge

6) I did not recall the usual "CLICK / SNAP / THUMP" I am used to hearing
and feeling in the floor boards just prior the green light coming on

I went around, put the gear up, climbed out to 3000 feet and set the
autopilot. *I cycled the gear twice and no joy. *I tried to hand pump it
down and nothing. *I slowed the plane to near stall and tried to lower the
gear, but the horn remained vocally upset and the green light rebellious.

I asked my wife if she could see the nose wheel in the gear mirror. *She
said, "Yea, I see it."

I asked if it looked fully extended and slightly pointed toward the front
and she said, "No...it looks like it's bent back toward the rear."

[hair on neck stands up]

I called down to the Unicom at Cape May's Big Sky Aviation and asked if I
could do a fly-by "because I don't have a gear down light".

On the fly-by I realized that whoever was watching the approach didn't fully
understand what I was asking for and what my problem was. *He radios me and
states, "Yea you're right. *I don't see a light on your gear either." *I
guess I got exactly what I asked for there.

I shook my head and asked if my nose gear look to be down and straight. *He
gave a tentative, "Ah, yea it looked down."

I came back around and did all my pre-landing checks. *The gear horn was
going off and I still didn't have a green gear light. *I cinched up my belts
and *I told me wife to do the same and to crack her door. *I couldn't
believe how calm she was. *She showed no signs of nervousness or hesitancy.
She trusted me completely.hmmm.well anyway she's a keeper!

I put in full flaps, did a power on landing and set down as soft, *slow and
careful as I could. *The mains indeed touched down tenderly and I kept the
nose wheel off as long as possible. *It wasn't until this point that I
suddenly remembered that I have a newly over-hauled prop on it's maiden
voyage. *How ironic! *For a moment I entertained the idea of shutting down
the engine to protect it and engine and quickly realized that that would do
no good at all...or at least it wouldn't halt a tear down inspection (3
blade prop).

I swear it took a lifetime as the nose lowered and I remained keenly aware
of every inch it dropped. *I continually repeated, "come on, come on, come
on, come on!" *I begged for that satisfying "falump" of the nose gear
solidly touching down.

I also was comparing in my memory what was a normal nose attitude at touch
down and at what point it would become painfully obvious that the nose was
too low and a prop strike was unavoidable.

Just as the nose wheel touched down the gear horn muted, the green gear
light came on and the amp meter was back to showing a healthy charge.

[BIG SIGH . WIPE SWEAT OFF MY FOREHEAD AND WALLET]

I couldn't reach my mechanic all night and after dinner I was telling my
wife that we should get a hotel for the night until I could talk to my A&P
or the mechanics at Big Sky Aviation. *She just looked at me stoically and
asked, "Why don't we just fly home with the gear down?"

[face turns red]

"Ah...yea...I was just about to recommend that."

Kobra

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.