Gear Circuit Breaker Popped
 

On today's flight to four airports I had the gear breaker pop twice upon selecting gear down. The gear "looked" to be down but no green light (obviously). Both times I was able to manually reset the gear breaker and cycle the gear UP then DOWN to get a green light and a successful and happy landing.

I have read through some of the older posts here RE gear problems. Tomorrow I will attempt to pump the gear doors open on the ground and have a good look inside to see if I have any frayed wires or dirty switches or contacts etc. Any other ideas??

Maybe try replacing the circuit breaker first as it's cheaper than the second option would be the pump motor. Doesn't sound like a gear or door issue. Did you have a heavy electrical load at the time?

Electrical load was not heavy. Daytime VFR flight.
Yes to new circuit breaker!! I like cheap fixes IF they work!

TC

Motor
 

Hi Tom,

I am not an expert on the Skymaster, but an AME/A&P for quite a few years, so I will offer a couple other spots to look at that are even cheaper than a CB.

If the gear pops its CB, it means that it is drawing a higher current as it works against electrical resistance, and will not be dependant on any other system. Things that can cause it to work harder to heat up and pop the CB:
- corrosion on connector (or bad connection)
- corrosion in a crimp of a connecter
- bad or loose ground (I always check grounds first - it is the simplest and most often the offending party).

Check the wires on the motor and at the CB. It may take a bit of work, but is cheaper than replacing any parts.

I think you already filled the system too - so that would eliminate any pump cavitation issues (I am really stabbing in the dark here, as I am not well studies on the power pack).

Anyway, hopefully some of this may help.
Jeff

Im a big fan of punting the 40+ year old circuit breakers.
Like Herb said, it's a good place to start. I've found a bunch of CB's that were no bueno. Punt the lot of them. Go to the Klixon's.


The emergency proceedures in the operators manual specifically state to pull the CB if you have to. The Cessna CB's don't allow that.




Leighton.

I like the idea of being able to disable circuits as I wish and I too noticed how most of my CBs do not currently allow this. I will look into upgrading to the Klixon's for sure. Thanks!

Gear Issues Continue...
 

After my initial gear issues things cleared up for a couple of flights but today the problem came back. Today when I went to put the gear down I popped the breaker near what should have been the end of the gear down cycle (12-15 seconds in). Like the previous time I tried cycling the gear but this time I could not get a green light and was not able to reset the breaker right away in order to cycle UP even. Eventually I manually pumped the gear DOWN and got the green light and landed fine. When I look at the mirrors the gear appeared to be down and locked. To me it seems like the gear cycle may in fact be complete and perhaps one of the switches that tell the system that the gear is down and locked might not be functioning which would cause the motor to continue running, heat up and overload the circuit. This is my current best guess.

Obviously this little snag goes to the very top of my list of things to fix!

Low Voltage ?
 

Could it be caused by low voltage in the system creating higher amp draw by the power pack ?

This is a good suggestion. We will look into it. She is going in to my AME tomorrow for a gear swing. Will keep you all posted...

Baggage Pod & Gear Swing..??
 

So, I have the baggage pod which I LOVE. My folding ladder and folding bike live in there 24/7 and it makes my travels so much easier and better while exploring distant lands. However, tomorrow I go in for my first ever gear swing (first since I bought her). I see the two jack points on the wings however the one behind the front wheel is inside the baggage pod. Hum... That can't be good.

The front gear point is not normally used for full lift of aircraft. It's more of a safety and allows you to just lift the nose if desired. Jacking the wings will cause the tail to go down and nose to go up so it should be fine. Check the service manual on jacking aircraft for sure

Except that if while the gear are swinging the aircraft comes off it’s wing points due to inadequate nose point support you will trash your wings, gear and belly, and someone might die…
My Skymaster pod had a door for the front jack point. I have also seen a Skymaster with a pod and no front pod door jacked by partially removing the wings and hoisting the aircraft using straps around the wing attachment points (the shop had an overhead hoist on rails). I have also seen it done using the usual wing points and for the front of the aircraft a strap from a hoist around the the front prop shaft...Whatever way you choose best of luck and stay far away from anywhere underneath the aircraft :)

I was thinking about that very option and how it would be pretty handy. Perhaps a future project.

Gear Swing Results
 

So they jacked her up today and, of course, she totally behaved herself, or rather misbehaved, as the gear worked flawlessly during over 15 cycles. It didn't pop the circuit breaker even once and everything appeared totally normal (of course). Tomorrow they claim to have a technique for putting simulated wind resistance on the gear as it is going down to be better representative of real life. I am going over to supervise (and video) and hope that we find something.

Here is a thought - it was -5C when I was out last time with the dual gear breaker failures. How does temperature affect such things???

Tom, I had a similar problem with my gear. Mine is a 1973 P model and if it is the same gear there are service bulletins on the pump and actuators that I highly recommend if not previously done. You might want to call Rick Cox at Cox Airparts. 316-945-0737

Brent