Interrupting gear mid cycle

[A64Pilot]

I have an 81 J with the Eaton actuator. I’m having trouble getting a couple of zircs to take grease. I’d like to try to unload the gear by stopping retraction soon after it begins and see if that helps the zircs take grease.

I assume I can do this with no harm by releasing the Airspeed override switch soon after the gear begins to move, but thought I’d ask first if this is the proper way as opposed to turning off the master or something.

[KSMooniac]

I would just use the master or pull the circuit breaker. No harm... Just make sure you're jacked up high enough and secured!

Sent from my LM-V405 using Tapatalk

[Fly Boomer]

9 minutes ago, KSMooniac said:

use the master or pull the circuit breaker

Would it work if you released the override button, and then use the master or pull the circuit breaker?

[Vance Harral]

I just pull the circuit breaker a second or two after the retraction cycle starts.  We do this every time we need to remove the landing gear actuator for SB M20-190B.  Have done it dozens of times over the past 17 years and have not (yet) come to any grief by doing so.

[Fly Boomer]

4 minutes ago, Vance Harral said:

have not (yet) come to any grief by doing so.

Thanks.

[A64Pilot]

Thanks, I think I’ll try releasing the button first as I only have two hands, have to be quick to get to the master after letting go of something else

[Ragsf15e]

Or put up the gear, pull the CBs and use the emergency extension?

[mooniac15u]

There's a procedure for partial retraction in the maintenance manual (section 32-60-01).  It specifically cautions against using the circuit breaker as a switch.

[Ragsf15e]

Or just do the emergency extension checklist like you practice during annual and take a break halfway…

[A64Pilot]

I think I have figured out a procedure, gear switch up with power off, then right hand holds red button in, and left hand is free for the Master.

Emergency extension should work too, I’m attempting to release the pressure on the bungees without retracting the gear very far.

It’s only a couple of zircs, I thought I’d try this first before replacing them.

I remember reading don’t use the CB, but can’t figure out why, that’s why I thought I’d ask before I found out that interrupting in mid cycle might bind up something, like maybe the noback spring.

[carusoam]

A64,

Expect that the zircs get blocked at the full extension point…

It should get easier after the stress is off the system…

Essentially, the narrow gap that allows grease to flow between the narrow passageway, between concentric tubes, gets pretty squeezed and becomes non-concentric…. 

PP thoughts only…

Best regards,

-a-

[PT20J]

4 hours ago, A64Pilot said:

Thanks, I think I’ll try releasing the button first as I only have two hands, have to be quick to get to the master after letting go of something else

That’s how I do it. When partially retracted, you can push a wheel up a bit to get the zerk to take grease. It’s an electric circuit and doesn’t matter which switch you use to interrupt it: breaker, master, airspeed — it’s all the same to the motor. Just turn the master off after it stops as a safety measure. 

Skip

[A64Pilot]

That’s the way it works on backhoes, so maybe airplanes are the same.

‘I used to have a tool that you filled with penetrating oil, put it on a zerc, and smacked it with a hammer, smacking it raised the oil pressure very high and it would clean out a blocked zerc.

I don’t think I’ll do that on the Mooney, but it worked on a backhoe or bulldozer.

[A64Pilot]

1 minute ago, PT20J said:

That’s how I do it. When partially retracted, you can push a wheel up a bit to get the zerk to take grease. It’s an electric circuit and doesn’t matter which switch you use to interrupt it: breaker, master, airspeed — it’s all the same to the motor. Just turn the master off after it stops as a safety measure. 

Skip

Yes, I don’t see the logic in prohibiting the CB, must be something I don’t know about, like maybe the relay is still powered but the motor isn’t and over time it could overheat the relay?

[Vance Harral]

4 hours ago, mooniac15u said:

There's a procedure for partial retraction in the maintenance manual (section 32-60-01).  It specifically cautions against using the circuit breaker as a switch.

That's really interesting.  There is no such prohibition in MANUAL 106 for the C/E/F/G models, though on a careful read just now it does prescribe using the manual emergency extension crank to move the gear to partially-retracted positions.

The J and later models have the no-back-spring type actuators, correct?  If so, I wonder if this prohibition on using the breaker as a switch is related to that, or if Mooney just decided using the breaker as a switch while the gear is moving is generally not a good idea.  Wonder if there was an "incident" at some point.

[PT20J]

3 minutes ago, A64Pilot said:

Yes, I don’t see the logic in prohibiting the CB, must be something I don’t know about, like maybe the relay is still powered but the motor isn’t and over time it could overheat the relay?

There are some documents from the FAA around that caution against using a circuit breaker as a switch out of concern that it will weaken the breaker. I did some research on this and it turns out that circuit breakers work better when exercised occasionally to clean the contacts. Recommendation was to exercise every breaker once annually. While it is true that circuit breakers are not rated for as many manual operations as switches, they are all rated for many thousands of operations. 

Skip

[A64Pilot]

I’m betting the big CB removes motor power, but unless you pull the little one to, the relay remains powered, and maybe some of the relays aren’t continuous duty?

On CB’s though, every annual pull and reset every one, I got embarrassed doing my first phase on an OH-58 40 years ago, when it was ready for its test flight the test pilot tried to pull each CB and there were a couple that wouldn’t.

It wasn’t in the manual, but apparently if a CB is never pulled, maybe even for decades, it can seize, and can’t be pulled, so they need to be pulled and reset every so often

I’m just proud that Mooney uses the kind you can pull, and not those like Cessna does that you can’t.

[philiplane]

"unloading" the gear rarely helps. What does work, is heat. Use a heat gun to warm the offending area up to 200-250 degrees, and that usually softens the old grease so that the new grease will flow.

[N231BN]

There is really no reason to overthink this, just use the safety switch and then shut off the master when done.

When I'm doing an annual by myself I'll just gently squeeze some air in the pitot tube so I can watch them move.

[A64Pilot]

12 hours ago, philiplane said:

"unloading" the gear rarely helps. What does work, is heat. Use a heat gun to warm the offending area up to 200-250 degrees, and that usually softens the old grease so that the new grease will flow.

I’ll try that if unloading doesn’t work , thanks

[KB4]

On 3/31/2022 at 1:47 PM, A64Pilot said:

I have an 81 J with the Eaton actuator. I’m having trouble getting a couple of zircs to take grease. I’d like to try to unload the gear by stopping retraction soon after it begins and see if that helps the zircs take grease.

I assume I can do this with no harm by releasing the Airspeed override switch soon after the gear begins to move, but thought I’d ask first if this is the proper way as opposed to turning off the master or something.

Don’t over think it.  Use the POH. Failure of gear to retract section.  
Little red button allows gear to stop where you release.  It’s enough to get the ones that won’t take grease otherwise.  

[A64Pilot]

To report back the red button does in fact stop the gear the moment it’s released and pressing it again has it start moving again, so the red button does for me work perfectly.

I’m able to stand beside of the aircraft and reach in through the storm window and turn on the master, then place gear switch in up position, then push red button while watching nose wheel. One hand operation. 

I’ve not yet tried to grease it yet though.

Edited April 1, 2022 by A64Pilot

[PT20J]

7 minutes ago, A64Pilot said:

To report back the red button does in fact stop the gear the moment it’s released and pressing it again has it start moving again, so the red button does for me work perfectly.

I’m able to stand beside of the aircraft and reach in through the storm window and turn on the master, then place gear switch in up position, then push red button while watching nose wheel. One hand operation. 

I’ve not yet tried to grease it yet though.

For me it worked to just raise it enough to get the downlocks over center and then pump the grease gun with one hand while gently rocking the gear up and down with the other hand.

[larrynimmo]

12 hours ago, PT20J said:

For me it worked to just raise it enough to get the downlocks over center and then pump the grease gun with one hand while gently rocking the gear up and down with the other hand.

This is what I use…I highly recommend…it makes the job really easy…I put the plane on jacks, pull down the tail and pump my grease and do so every 25 hrs when I change my engine oil…and at least at annual I stop the gear half way to better lube the MLG 

[A64Pilot]

13 hours ago, PT20J said:

For me it worked to just raise it enough to get the downlocks over center and then pump the grease gun with one hand while gently rocking the gear up and down with the other hand.

That’s what I’m going to try right after I get off my lazy butt this morning