ARROW GEAR MOTOR KEEPS ACTUATING WHEN THE GEAR IS UP, NO LEAKS. WHAT COULD BE THE CAUSE.
1976 ARROW II
I posted a similar question before when I was in the figuring out stage of the problem and I thought it was a loose wire to the alternator.
I flew this week and when I retract the gear, it the gear motor used to intermittently go off for a fraction of a second (by indication of the ammeter ticking every few minutes and sometimes never)
I left the gear up overnight and it only sagged a inch or so. So there are no leaks.
Now when I fly it is doing it every second and I had a passenger take the bulkhead cover off and feel the motor when the ammeter flickers and the motor is coming on and off.
Someone said before it could be the shuttle valve, someone else said it could be a short in a microswitch.
Please help me to determine the cause if anyone has had the same problem.
Also, the gear light is working fine, that doesn't come on when the ammeter flickers. An earlier post said the ammeter will peg if the powerpack motor is activated.
It's not pegging, it's only showing a little flicker when the motor runs for a fraction of a second. It just keeps going on and off, maybe twice a second.
I posted a similar question before when I was in the figuring out stage of the problem and I thought it was a loose wire to the alternator.
I flew this week and when I retract the gear, it the gear motor used to intermittently go off for a fraction of a second (by indication of the ammeter ticking every few minutes and sometimes never)
I left the gear up overnight and it only sagged a inch or so. So there are no leaks.
Now when I fly it is doing it every second and I had a passenger take the bulkhead cover off and feel the motor when the ammeter flickers and the motor is coming on and off.
Someone said before it could be the shuttle valve, someone else said it could be a short in a microswitch.
Please help me to determine the cause if anyone has had the same problem.
Also, the gear light is working fine, that doesn't come on when the ammeter flickers. An earlier post said the ammeter will peg if the powerpack motor is activated.
It's not pegging, it's only showing a little flicker when the motor runs for a fraction of a second. It just keeps going on and off, maybe twice a second.
Comments
It is not proximity switches that turn off the pump on the up swing. They do on the down and locked... but not up. What turns it of on the upside is a single pressure switch on the manifold under the plywood cover of your rear seats.
I have a complete function/diagram/troubleshooting service section on this if you want me to send it to you.
If I can't get this repaired for a few weeks is the plane ok to fly with the gear down. The only problem I see is wasting fuel.
If there are no external leaks, it must be leaking back through the pump or another path. Not really a problem to fly it with the gear up if the pump only bumps occasionally. If it does it every couple seconds, I would get it fixed first.
Good Luck and would like to hear your final solution.
I talked to the Piper sales guy and he said it's more than likely the pressure switch.
And if not that, than possibly the shuttle valve spring, and if not that than one of the gear actuator cylinders leaking internally.
I hope it's just the spring, then it's a $3.00 fix.
I was quoted just about $800 from the parts dept.
First let me ask when was the last time the landing gear actuators were repacked. If its been a number of years, I would start there.
Next, I would go for the shuttle valve. And, although the spring costs only a few dollars the shipping is more. Also, there are a number of mechanics who do not know where the shuttle valve and its associated spring are located. The shuttle valve is inside the mounting manifold underneath the pump and the powerpack is attached to it.
Third, I would consider internal leakage in the hydraulic pump/power pack. This is normally the problem. Try PowerPaks Plus in Reno for the best price.
Fourth is the pressure switch (expensive) and last but not least
The hoof or emergency extension valve ($1200+)
BTW
If your pump is kicking on as often as stated it'll be burned up soon and you'll be replacing it anyway.
It just came in the mail today and I'll install it tomorrow.
Any other advice would be much appreciated. The gear actuators were just rebuilt at last annual and I would think that when I left the gear up overnight and it barely moved at all that would rule out the actuators as a potential problem
also, I work for an airline and had a 747 mechanic look for the shuttle valve and as stated in the previous post couldn't really see it.
I think it's under the mounting bracket but how do you get to it to take the bolt out to check the spring.
Can it be done without moving the pump or does it have to be removed.
I have the service manual with diagrams so if anyone knows detailed instructions to check the spring, that would be great.
Thanks
BUT...
You had said the system pretty much holds over night. Any leak like that will cause the gear to slowly come down.
At this point, I'd bet it is your power pack. Mine was doing the gig where about once every 60 to 90 seconds the pump kicked on. I rebuilt all the actuators... then the auto extend orings... isolated all the gear one at a time... and then put an OH power pack in and it has been fine ever since.
Mine would only hold the gear up about 2 mins and then it started to slowly come down... so it seems my condition was worse then you describe yours as being. Most places seem to get 1000 to 1100 for a power pack. I got one for 900 somewhere. It was a Kelly.
Hopefully this is the problem.
I looked in the logbook and it was overhauled in 2001 and 1,100 hours ago.
I wonder how long they last for.
Someone said it might be the shuttle valve, is that the spring in the manifold. I'm looking in the parts manual and there's no part# for the spring.
Also, somewhere it says that the spring and manifold are matched parts.
Has anyone just changed the spring and that was the problem?
Just curious to see if the spring is the likely cause or the pump is more likely the problem.
The pump was $750 and manifold $350, it'd be nicer if the manifold was the problem.
Also is the shuttle valve in the manifold or the pump reservoir?
I flew from AZ to CA yesterday and my normal 2.5hr flight took us 3hr 10 minutes. I lost about 40kts with the gear down. I would have thought it would be less than that.
I have the pump and manifold to have an appointment Tuesday and get it fixed.
I am renewing my Turbo Arrow tx engine and upspecing the engine to KB specs, and fitting the Merlyn Upper deck auto waste gate Controller and the TurboPlus intercooler and it seems that I should use the Seneca 3 power settings chart but I cannot find them anywhere.
Appreciate your help. Thanks, Ian.
Since the gear motor actuates every second, I flew to California Saturday morning tried retracting the gear 4 or times during the flight and ever time the gear motor ran every second. It took 3hrs and 15 minutes to get there.
But left today to come home and tried retracting the gear and it ran as normal. The gear motor did come on but only about 5 times and around every 30 minutes so it was a great short 2.5hr flight home.
Does anyone know why it would work almost as it should again?
I have the OH pump and a manifold and am taking it in tomorrow but I wish I know why it's pretty much working again before I put in a $750 pump.
Thanks for the response.
The gear will always stay retracted when it's supposed to. The pump motor was just coming on and off when it wasn't supposed.
The gear stayed up overnight so there's no leak that I can see.
Something was making the pump come on and making the system think the gear is lowering and needed to build pressure back but in reality the gear was fine.
I want to try taking out the shuttle valve spring and seeing if that's the problem but it just looks too hard to get to the square head nut.
I think the whole pump needs to come out and then take the shuttle valve out too see if that was the problem.
But since it's working now, I don't know how the shop can troubleshoot it.
The only real, easy way to get to the shuttle valve spring is to first remove the whole assemby as one unit, the power pack and the mounting manifold(which contains the shuttle valve & spring.) Also, in an earlier post, the shuttle and manifold are a matched set and not the shuttle valve and spring.
As previously mentioned, I just went through all this with my 1975 Arrow II and the pump and it was the pump that was leaking internally. There is a pressure test that can be performed on the pump which requires 1800 and 3000 psi gauges to perform and the test procedure is in the service manual.
Sadly, when I sold my Arrow the market price, even with my Garmin stack, would not bring what I had invested in the airplane. I was able to recover the cost of the parts, but not the labor.
And someone said there's no limit switches on the upswing, only the down swing and the pressure switch on the manifold under the seats floorboard that turns it off but already tried another pressure switch and that's not the problem.
> Does anyone else think that the problem might be
> with one of the many limit switches in the system?
> If one were defective or loose wouldn't it give
> symptoms like the above?
My thoughts exactly Leigh.... The up limit switches on the nose and/or the mains would be my first area of focus.
When in flight (gear retracted), does the "gear in transit" indicator come on when the gear motor cycles? If so I would focus on the up limit switches on the mains. If not, I would focus on the nose gear up limit switch. If I recall correctly, that indicator is wired to the main gear up limit switches, but not the nose switch. - Joe
Someone posted that there are no up limit switches on the system that would make the pump turn on except the pressure switch that I already tried changing and that wasn't the problem.
> Someone posted that there are no up limit switches
> on the system that would make the pump turn on
> except the pressure switch that I already tried
> changing and that wasn't the problem.
Jasper7821
I was wrong thinking the up-limit switches are connected to the pump circuit and shut the pump off when the gear are fully retracted... After reading through the service manual again and getting feedback from a couple of guys who are knowledgeable about the system, it is clear my assumption about the function of the switches was not accurate.
I chased a similar problem (although my gear in transit light would come on with the gear motor while in cruise flight) with my Arrow about a year ago. After bringing the oil in the reservoir up to the full mark, the problem has not presented itself again. - Joe
It would be great if it was just one of the gear actuators needed to be rebuilt.
It could be the problem because the fluid level was a little low and I topped it off and it's gone down a little bit again. So maybe it's leaking into the actuator. But everything around the actuator is totally dry plus they were rebuilt on the last annual, but hopefully they did fail and my pump is fine.
They TRACED IT TO THE EMERGENCY GEAR EXTENSION VALVE THAT'S CLOSE TO THE MANIFOLD.
An earlier post said it could be
The hoof or emergency extension valve ($1200+)
They cant find a part number in the parts catalog.
I'm also looking at the nomenclature in the parts catalog and see nothing called a valve in the hydraulic system system.
I looked through 3H12-3H15 and cannot find a part called valve.
BTW, the pump is totally fine. But from the earlier post, it looks like the hoof valve cost more than the pump.
Any way to easily disable the emergency gear system, as a lot of Arrows I've seen are like that. and would that take care of the problem if I did that?
Any help would be great.
Since it's the valve in the emergency gear extension system.
Wouldn't disabling the system by the lever and pin bypass the system and make the pump not come on when the gear is up?
Also found SB866A saying that Piper kit 765-303 is a removal kit of the emergency gear extension system.
Found the kit but it's $700.00 plus someone said it took a shop 9hrs to install.
They said the hoof valve is no longer available and you have to buy the kit.
Again, cant i just disable the system by pulling the lever and locking it with the lock pin and it won't actuate the motor when the gear is up?
Did you find a competent Piper mechanic to install it yet? That is really all you need, even if it means flying it to DSM which has a large and knowledgeable Piper service center to fix it once and for all.
I am a big fan of Pipers auto-extend system. It's well designed and easy to overide if needed. Most of its critics don't understand it very well.
PilotKris
Thanks. I did find a big maintenance shop and they have the plane.
They tested the whole system and concluded that the pump and manifold are totally fine and problem they found was loosing pressure in the hoof valve.
To PilotKris,
You say the Hoof valve won't accomplish anything because it's part of the emergency extension system.
Then wouldn't disabling the system by pulling the lever and locking it with he pin disable it?
Velovp,
I hope it's just a O-ring in the hoof valve.
I just read all the threads about leaks and the hoof valve. Everyone's problem was the light would come on and the gear would sag down.
I don't have that problem. The gear stays up and no light comes on, just the pump kept going on and off. The shop traced it to the hoof valve losing pressure. But can that be right since my gear stays up fine.
Thanks everyone, I really appreciate it.