Brent Posted September 3 Report Posted September 3 At the end of the second leg of a cross-country yesterday I moved the landing gear switch to "Down" and nothing happened. I toggled the switch a couple times and got nothing. No motor motion, no circuit breakers popped, the low RPMs gear alarm continued (along with airspeed...), the "Gear Unsafe" annunciator light was lit, and the floor window showed red-stripe gear up. I lowered the gear using the manual extension and landed safely. Luckily, the issue happened at my home airport, so there's that. Ahead of the troubleshooting on jacks with my mechanic tomorrow, I thought I would solicit info from anyone with prior experience on this issue. Areas I assume we'll look at: actuator motor, breakers, relays (one for up, one for down), any loose wiring. (I did have some rain and turbulence on that leg.) (Side note for others: when you lower the gear via manual extension, be careful NOT to over-pull that ripcord cable. Lower the gear until the Gear Unsafe light goes off and you have normal green in the floor window, and that's it. If you force-pull the cable after you have a gear-safe condition, you will bend the long linkage rod in the belly. I almost learned that the hard way in a hangar with the plane on jacks a couple years ago.)
PT20J Posted September 3 Report Posted September 3 If there was no motion of the motor and no circuit breakers popped, then the problem is most likely the down limit microswitch or the down relay. When mine did this (but on retraction rather than extension) I isolated it to the relay by jacking the plane, removing the belly panel and tapping the relay with a screwdriver handle which caused the gear to operate. 3 1
EricJ Posted September 3 Report Posted September 3 +1 that it is most likely one of the relays or a loose wire to a relay or something like that. It should be reasonably easy to diagnose on jacks. 1
Brent Posted September 3 Author Report Posted September 3 16 minutes ago, PT20J said: If there was no motion of the motor and no circuit breakers popped, then the problem is most likely the down limit microswitch or the down relay. When mine did this (but on retraction rather than extension) I isolated it to the relay by jacking the plane, removing the belly panel and tapping the relay with a screwdriver handle which caused the gear to operate. No breakers popped. I clarified the original entry. Is the down-limit micro-switch that button with a little paddle clamped to the linkage rod? Thanks for the info. 1
EricJ Posted September 3 Report Posted September 3 3 minutes ago, Brent said: No breakers popped. I clarified the original entry. Is the down-limit micro-switch that button with a little paddle clamped to the linkage rod? Thanks for the info. Yes, and they're very easy to test. If one is sticky, contact cleaner will sometimes rehab it, but it is also telling you that it will need to be replaced eventually. 1
Ragsf15e Posted September 3 Report Posted September 3 57 minutes ago, Brent said: No breakers popped. I clarified the original entry. Is the down-limit micro-switch that button with a little paddle clamped to the linkage rod? Thanks for the info. There are the limit switches and the relays (which are near the actuator i think). Limit switches are exactly as you described- paddles on the rod. 1
PT20J Posted September 3 Report Posted September 3 The relays are bolted to the floorboard ahead of the left rear seat. 3 1
N201MKTurbo Posted September 3 Report Posted September 3 I’ve told this a few times. I think people think it is silly, but it is not. In your situation, if it is a contactor, they are mounted to the floor under the pilots seat. If the gear does nothing, stomping on the floor or bouncing on the seat may knock it loose and get the gear going. I also had this happen once and found one of the motor brushes fell out. 2 2
Brent Posted September 4 Author Report Posted September 4 Tapping on the relay restored downward movement. The other parts of the system (motor, actuator gear, limit switches, down/up panel switch, breakers test ok. So now I’m going on the hunt for the relays. PN 940050-501 is the applicable PN I see in the IPC. I’ll search today. If anyone has a sourcing idea, I’ll appreciate the advice. 2
Brent Posted September 4 Author Report Posted September 4 UPDATE: I found two used relays from BAS Parts, PN 940084-501, which are the Mooney retrofit parts for the original but now obsolete/unavailable 6041H53 and 70-311221 parts. I couldn't find new anywhere. LASAR had history from several years ago showing $3000 and 18 weeks lead-time. Worst case, even though used, these retrofit parts must be decades newer than my originals. We'll see. Thanks for the advice above.
Fritz1 Posted September 4 Report Posted September 4 If the limit switches are same vintage as relays, might as well replace them while you are at it if you can find new switches and are planning to keep the plane for a while, food for thought... 1
Will.iam Posted September 4 Report Posted September 4 Would not this relay since not available new anywhere be a prime candidate for owner produced part? How specialized can that relay be? Where is radio shack when you need one?
N201MKTurbo Posted September 4 Report Posted September 4 55 minutes ago, Will.iam said: Would not this relay since not available new anywhere be a prime candidate for owner produced part? How specialized can that relay be? Where is radio shack when you need one? I had one go bad. Found a new old stock of the OEM part number. There are plenty of Chinese knock offs.
EricJ Posted September 5 Report Posted September 5 Also look for crosses to other part numbers, or a MS number or such that might expand the part search. Also, if you can find a manufacturer name and PN on it, sometimes that can help. 1
201Steve Posted September 5 Report Posted September 5 Food for thought, I had an intermittent issue with gear going UP. I tapped on the contactors and voila! It went up! I replaced both for good measure. And then, it still didn’t work right. Long story short, the light tap of a hammer in the general area created enough vibration to break loose the real problem, that turned out to be a limit switch actuator. YRMV. 1
PT20J Posted September 5 Report Posted September 5 I would buy a used electrical component only as a last resort - who knows how much life is left in it? The Safran catalog still lists the 6041H53 (p 26). I might contact them. I replaced my 28v 6041H220 relays with Safran parts. SE&P_Relay_Catalog.pdf 2
Ragsf15e Posted September 5 Report Posted September 5 I agree with the guys above. Instead of looking for the Mooney part number (unless it’s actually available, which in this case it’s not), pull the original manufacturer and part number off the part. If it’s been superseded, you’ll need that part number. Search by that manufacturer and part. It’s amazing what you’ll find. Make sure your mechanic is ok with using parts that are from the original manufacturer instead of being blessed by Mooney (even though they are the correct part). 1
Brent Posted September 5 Author Report Posted September 5 12 hours ago, PT20J said: I would buy a used electrical component only as a last resort - who knows how much life is left in it? The Safran catalog still lists the 6041H53 (p 26). I might contact them. I replaced my 28v 6041H220 relays with Safran parts. SE&P_Relay_Catalog.pdf 2.19 MB · 3 downloads Yes, I wasn't keen on used since that's what I have now, but I wasn't having any luck on any of the part numbers new. So thanks for the OEM catalog. I didn't know that. I did contact Safran's distributor. They had no stock go the 6041H53 (14v) but will check with the OEM. We'll see. 1
Ragsf15e Posted September 5 Report Posted September 5 43 minutes ago, Brent said: Yes, I wasn't keen on used since that's what I have now, but I wasn't having any luck on any of the part numbers new. So thanks for the OEM catalog. I didn't know that. I did contact Safran's distributor. They had no stock go the 6041H53 (14v) but will check with the OEM. We'll see. I have had good luck with “electronic warehouses” that stock all kinds of old-new parts. Found a microswitch that had been superseded, but the newer one had a slightly different actuator that wouldn’t work. I would possibly expand out past the distributors if needed…
Ragsf15e Posted September 5 Report Posted September 5 43 minutes ago, Brent said: Yes, I wasn't keen on used since that's what I have now, but I wasn't having any luck on any of the part numbers new. So thanks for the OEM catalog. I didn't know that. I did contact Safran's distributor. They had no stock go the 6041H53 (14v) but will check with the OEM. We'll see. I have had good luck with “electronic warehouses” that stock all kinds of old-new parts. Found a microswitch that had been superseded, but the newer one had a slightly different actuator that wouldn’t work. I would possibly expand out past the distributors if needed…
Fly Boomer Posted September 5 Report Posted September 5 13 hours ago, PT20J said: I would buy a used electrical component only as a last resort - who knows how much life is left in it? The Safran catalog still lists the 6041H53 (p 26). I might contact them. I replaced my 28v 6041H220 relays with Safran parts. SE&P_Relay_Catalog.pdf 2.19 MB · 4 downloads Were you able to buy directly from Safran? If not, who?
PT20J Posted September 5 Report Posted September 5 24 minutes ago, Fly Boomer said: Were you able to buy directly from Safran? If not, who? I got mine from peerlesselectronics.com 4 1
Brent Posted September 5 Author Report Posted September 5 2 hours ago, PT20J said: I got mine from peerlesselectronics.com That's who I called. They have my RFQ. We'll see. 1
blaine beaven Posted September 8 Report Posted September 8 On 9/3/2025 at 11:06 AM, PT20J said: The relays are bolted to the floorboard ahead of the left rear seat. I am amazed at how shiny your floorboards are. 1
Yetti Posted September 8 Report Posted September 8 On 9/5/2025 at 1:51 PM, Brent said: That's who I called. They have my RFQ. We'll see. A quick google search on 6041H53 shows it to be a Cutler Hammer which was bought by Eaton. This looks like a pretty good fact sheet. http://www.aeroelectric.com/Reference_Docs/Misc_Pdf/6041SeriesPowerRelays.pdf 28V 2PDT Has an MS number MS25031-D1B I found the F model flap relay NOS at like Relays.com or something. I should probably sell it.
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