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Emergency Landing Gear Extension Cable

Mkruger2021
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A64Pilot Grand Master

A64Pilot

Posted
Posted (edited)

Tru Googling the relay part number and or call an MSC.

Same for the cable.

What shredded the cable? I ask as I don’t want to repeat the mistake is all.

Edited by A64Pilot
Mkruger2021 Enthusiast

Mkruger2021

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  • Author
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We performed the emergency gear extension as planned. We re-engaged the circuit breaker and lever. Nothing happened. It would not go up electrically. IA said to try to drive it up with the crank and:  Well the rest is history.....Thing is: I read this somewhere not to do this.......Darn.....and I cant get the relays to work either for some reason now either.....I need to troubleshoot it more....But I think I have a bad relay....Just bought the bird......

A64Pilot Grand Master

A64Pilot

Posted
Posted (edited)

I just went through replacing both my relays and the issue wasn’t the relays.

‘I would remove one and bench test it, even a 9V transistor battery will power one, if it clicks and gives a good low resistance connection every time, it may not be the relay.

Another way of course is with the airplane on jacks move the gear switch or have someone do it, you should hear a click and of course measure power where it’s supposed to be.

On Edit, it seems relays are made from unobtanium, same as limit switches, and the panel mounted gear switch.

‘I presume as it was hinted to me by an MSC that’s because they are readily available from other sources than Mooney, I hope so anyway, my relays were, but they are different than yours.

Edited by A64Pilot
A64Pilot Grand Master

A64Pilot

Posted
Posted (edited)
2 hours ago, Mkruger2021 said:

If it was not the relays, may I ask what it turned out to be? I ask to give me some guidance what to look for.....

 

MK

Well my issue was way different than your’s, I think, mine was intermittently the gear wouldn’t come down, often there was a few seconds delay and they would, a couple of times I’d recycle the switch and they would come down, they always came up though.

Just about everyone I heard from that had similar problems it was either the relays or the limit switch, none had a bad panel mounted switch, so my issue was of course the panel mounted switch. At least I think it was, I have probably 20 flights since then with no anomalies

‘I think if I were you, I’d check voltage at the relay, the small control wires, if voltage is present when the switch is placed in say the up position and nothing happens, then it’s the relay, you can confirm that by listening for the click and checking if voltage is present at the proper large wires, if there is no voltage,then it’s likely the limit switch or the panel switch or of course no voltage as in a broken wire or bad CB etc. Voltage going to a limit switch, but not coming out is the switch, unless the switch is actuated by the tab of course. Check to be sure, but I’m pretty sure the limit switches are normally closed, meaning that you should have continuity through the switch until the tab pushes it open and then you lose continuity.

You can check continuity with no power applied to the aircraft.

I assume everything was working fine and then you broke the cable, or were you troubleshooting a problem and broke the cable?

Either way, you have two choices, start changing parts and hoping you change the right thing, or get the multimeter out and start troubleshooting.

‘These electrical gear parts are apparently tough to come by and sit down when you see the prices, so I think troubleshooting is they way to go, especially as you have jacks 

The trick is of course getting the schematic and understanding it first, then checking the system, with the aircraft on jacks.

I’m pretty sure that voltage comes from the panel mounted switch to a limit switch, if the switch is open, then it stops, but if it’s closed then voltage goes to the relay, which closes and supplies power to the actuator, and the gear moves either up or down. until a limit switch is opened, power is then removed from the relay and the actuator loses power and stops.

But do not go by what I think as I’m often wrong, get the schematic and figure it out.

Not everyone is an electrician so if schematics aren’t your thing, find an electrician, it’s a simple system and you don’t need an aircraft electrician if your IA is willing, many IA’s and I include myself in this are actually pretty poor electricians.

‘Many times electrical problems are a simple as a loose ground wire.

‘Sorry for all the rambling, it was thinking as I typed.

Best plan I think is get the schematics, then if needed find a friend who knows electrical circuits and trouble shoot the thing

Edited by A64Pilot
Yetti Grand Master

Yetti

Posted
Posted

I believe the E Gear cable is like a speedometer cable which is why you don't try to run it backwards because it will unwind.   The problem is the splined ends that I could never find

 

20161202_093248.thumb.jpg.adb8074011406bfc11e4559f63df0f74.jpg

 

As far as the relays depending they are same as a Ford 8N Tractor.   They have a fourth pole that has power that undoes the brake on the back of the motor.  The brake is supposed to prevent the gear from dropping and chattering.   Some systems use two Solnoids.

 

20161202_094517.jpg

Mkruger2021 Enthusiast

Mkruger2021

Posted
  • Author
Posted
19 hours ago, A64Pilot said:

Well my issue was way different than your’s, I think, mine was intermittently the gear wouldn’t come down, often there was a few seconds delay and they would, a couple of times I’d recycle the switch and they would come down, they always came up though.

Just about everyone I heard from that had similar problems it was either the relays or the limit switch, none had a bad panel mounted switch, so my issue was of course the panel mounted switch. At least I think it was, I have probably 20 flights since then with no anomalies

‘I think if I were you, I’d check voltage at the relay, the small control wires, if voltage is present when the switch is placed in say the up position and nothing happens, then it’s the relay, you can confirm that by listening for the click and checking if voltage is present at the proper large wires, if there is no voltage,then it’s likely the limit switch or the panel switch or of course no voltage as in a broken wire or bad CB etc. Voltage going to a limit switch, but not coming out is the switch, unless the switch is actuated by the tab of course. Check to be sure, but I’m pretty sure the limit switches are normally closed, meaning that you should have continuity through the switch until the tab pushes it open and then you lose continuity.

You can check continuity with no power applied to the aircraft.

I assume everything was working fine and then you broke the cable, or were you troubleshooting a problem and broke the cable?

Either way, you have two choices, start changing parts and hoping you change the right thing, or get the multimeter out and start troubleshooting.

‘These electrical gear parts are apparently tough to come by and sit down when you see the prices, so I think troubleshooting is they way to go, especially as you have jacks 

The trick is of course getting the schematic and understanding it first, then checking the system, with the aircraft on jacks.

I’m pretty sure that voltage comes from the panel mounted switch to a limit switch, if the switch is open, then it stops, but if it’s closed then voltage goes to the relay, which closes and supplies power to the actuator, and the gear moves either up or down. until a limit switch is opened, power is then removed from the relay and the actuator loses power and stops.

But do not go by what I think as I’m often wrong, get the schematic and figure it out.

Not everyone is an electrician so if schematics aren’t your thing, find an electrician, it’s a simple system and you don’t need an aircraft electrician if your IA is willing, many IA’s and I include myself in this are actually pretty poor electricians.

‘Many times electrical problems are a simple as a loose ground wire.

‘Sorry for all the rambling, it was thinking as I typed.

Best plan I think is get the schematics, then if needed find a friend who knows electrical circuits and trouble shoot the thing

Thank you much...I confirmed with the diagram as you said.....The power goes through the limit switches first....I'll get it up on jacks and troubleshoot as you suggested....

Mkruger2021 Enthusiast

Mkruger2021

Posted
  • Author
Posted
14 hours ago, Yetti said:

I believe the E Gear cable is like a speedometer cable which is why you don't try to run it backwards because it will unwind.   The problem is the splined ends that I could never find

 

20161202_093248.thumb.jpg.adb8074011406bfc11e4559f63df0f74.jpg

 

As far as the relays depending they are same as a Ford 8N Tractor.   They have a fourth pole that has power that undoes the brake on the back of the motor.  The brake is supposed to prevent the gear from dropping and chattering.   Some systems use two Solnoids.

 

20161202_094517.jpg

Yup thats the cable that I have....my relays are different....I put a picture in the beginning of this thread....I don't know if you all were able to see that....

all4thekidz Explorer

all4thekidz

Posted
Posted

while you have your panels off for replacement can you send pictures of the layout in the cockpit and under the belly.  I am working on a project that had the cable removed so I amiss at routing.  Additionally I  sent the old cable to McFarlane cables and they were able to duplicate for about 225!  You can send direct to my email if you would like.

Todd

todd.chambers@outlook.com

all4thekidz Explorer

all4thekidz

Posted
Posted

My 2 year struggle continues as I am always in the last 5 to 10% on completion.  right now trying to get this cable correctly installed since the MM is poor on depictions.

Thanks hope to get some detailed photo's

TODD

  • 10 months later...
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