Luke Posted September 7, 2018 Report Posted September 7, 2018 Hey all. I'm looking to crowdsource some information about the possible history of the gear actuator in my '84 M20J. The bird is in for annual at a new-to-me shop. My A&P recommended we replace the no-back clutch spring in the gear actuator as it's over 1000 hours. So far so good. While they were in there they found that the gear actuator does not have a down stop. So: I actually knew about the absence of the down stop. The (different) A&P who did my pre-buy pointed it out, said it was not required, and gave me the option to add one. I asked: what's the worst that could happen? His answer: if you did a manual gear extension and pulled way too hard the gear could get stuck down and locked. This didn't seem scary so I didn't have the work done. My current A&P believes the down stop is required, and actually reached out to Mooney who said it's supposed to be there. I'm confused by this, not only because of what my pre-buy A&P said, but because before me the plane passed 15-ish annuals at Mooney Service Centers without a down stop. If anyone knows a bit of history or context, I'm curious! Quote
carusoam Posted September 7, 2018 Report Posted September 7, 2018 If the stop is missing, get it replaced... how hard is that, how expensive is that? The spring is a bit of a gamble... they’re was a history of bad springs that you can look up... the heat treatment and materials conspired to grow cracks with time and use... Losing the spring disables the gear, both electric and back-up system. A GU landing can be expensive.... do a search and read up on the spring... As for the missing stop... I haven’t heard of that one before... why or how did it go missing? PP thoughts only, not a mechanic... Best regards, -a- 1 Quote
Luke Posted September 7, 2018 Author Report Posted September 7, 2018 Absolutely agree about the gear spring, that one is scary. Mostly I'm curious about how the airplane ended up in this state and a bunch of previous A&P's were ok with it. Were some Mooney gear actuators originally made this way, etc? Quote
carusoam Posted September 7, 2018 Report Posted September 7, 2018 Somewhere in there is a decision related to air-worthiness.... If it is not an AW issue, the maintenance item may get deferred.... for another owner... The spring has / had? A 1000hr inspection/replacement cycle.... there are pictures of the spring posted by Andrew, @Hyett6420 New springs may have had the material / hardening issue resolved... confirm that as well. its a mildly expensive PIA to take care of. Kind of like rubber donuts.... It’s been a while since this spring has been discussed around here. Best regards, -a- Quote
N201MKTurbo Posted September 7, 2018 Report Posted September 7, 2018 A mechanical down stop should never be hit. The only use is to keep from bending your actuator tubes too badly in case of a defective switch or overextending it during manual extension. 1 Quote
Guest Posted September 8, 2018 Report Posted September 8, 2018 Here’s the requirement from the maintenance manual. Clarence Quote
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