Latest and greatest for type of lube for AD 73-21-01

[Jim Peace]

This is the AD for lube flight controls and landing gear rod end bearings every 100 hours....I am only 16 hours away from this and still over 4 months till annual.

I see there are some dated threads on this but opinions all over the place....

TIA...

[Janat83]

24 minutes ago, Jim Peace said:

This is the AD for lube flight controls and landing gear rod end bearings every 100 hours....I am only 16 hours away from this and still over 4 months till annual.

I see there are some dated threads on this but opinions all over the place....

TIA...

 

[PT20J]

For the rod ends, the AD suggests silicone spray. The good thing about that is that it won't attract dirt which is what wears out the rod ends. The bad thing is that it isn't a very good lubricant. Later Mooney service manuals call for Triflow which is a light oil containing teflon. It's a better lubricant, but the oil remains and can attract dirt. I contacted RBC (manufacturer of Heim rod ends) and their engineering department told me they recommend MIL-PRF- 81322 grease (Aeroshell Grease 22). I think most use Triflow.

Skip

[jlunseth]

I looked at the AD just for the fun of it and came up with a question. It lists the aircraft to which it applies, it specifically lists the M20A-G. The interesting question is that the list starts with "M20" before the M20A." Was there an "M20?" So I looked it up, it was the Mark 20, wood wing, 150 HP, available from 1955-58. Had never heard of it, wonder if there are any still around?

[EricJ]

23 minutes ago, jlunseth said:

I looked at the AD just for the fun of it and came up with a question. It lists the aircraft to which it applies, it specifically lists the M20A-G. The interesting question is that the list starts with "M20" before the M20A." Was there an "M20?" So I looked it up, it was the Mark 20, wood wing, 150 HP, available from 1955-58. Had never heard of it, wonder if there are any still around?

There's a derelict one parked on the north ramp at DVT (Phoenix Deer Valley).   Somebody had apparently just gone through it and did a bunch of restoration on the wing just before it was abandoned.  It's been sitting out in the sun for several years now.

 

Edited December 16, 2020 by EricJ

[47U]

In addition to the 100 lubrication requirement, this AD addresses landing gear link replacement to a newer pn and adding zerks to links that weren’t manufactured with them.  Undoubtedly, by now everyone has complied with this part of the AD.

Is the flight/landing gear rod ends lubrication requirement thrown in as an after thought to standardizing the gear retraction linkage?  The AD is released several years before the J came out.  If the lubrication part of the AD is so important, why are there not revisions to the AD to include the J and subsequent models?  is there any significant difference in the linkages that were built into the J and later models that render the lubrication requirements of the AD as irrelevant?

Probably not high on anyone’s priority list, but I think the AD should be amended to remove the lubrication requirements, or, if it’s that important, add the subsequent models to the AD.  It’s easy enough to hit the exposed gear and flight control rod ends with a shot of Tri-Flow, but who wants to pull the belly and wing panels off one or two months before the annual is due when you pass that 100 hr mark, assuming you’re flying that much (which I’ve only done once since 2008).

https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/AOCADSearch/022EF974FDE32DBA86256A3B006FA1EA?OpenDocument

[cliffy]

Don't forget that paragraph (c) requires you to put the plane on jacks and swing the gear and check the over center torque values   Specific approved tools are required for this check. A&P for the sign off. 

This AD is not just a lube it and forget it deal. 

Many, my self included, have had to do it 2 months before the annual

Being an AD it doesn't qualify for the "overage hrs" to get it to a shop to perform the AD. Its a hard 100 hrs therefore you will always be doing it shy of the 100 hr mark- NOT over (98, 99, but not 100.2). 

Triflow works fine for all the lubrication. For most folks just wiping the exposed rod ends with a rag after lubing keeps a lot of the dust and grim from collecting as they don't live out west in the blowing dust and winds. For that I use 100% silicone spry but I do it about every month on the exposed rod ends just to keep them lubed, Takes about 10 mins for the entire airplane, no panels need to be pulled for that. I wiggle each one also just to make sure they rotate (all except the flap rod ends). 

[47U]

5 hours ago, cliffy said:

Don't forget that paragraph (c) requires you to put the plane on jacks and swing the gear and check the over center torque values   Specific approved tools are required for this check. A&P for the sign off. 

An excellent point, thank you.  

But, is not my question of applicability to later models still valid?  What difference does it make to the landing gear rigging whether the actuator is an electro-mechanical device or the pilot’s arm?

My only experience is with my manual gear C, so please forgive if I’m out if left field.  I’m just trying to understand.

[carusoam]

23 hours ago, jlunseth said:

I looked at the AD just for the fun of it and came up with a question. It lists the aircraft to which it applies, it specifically lists the M20A-G. The interesting question is that the list starts with "M20" before the M20A." Was there an "M20?" So I looked it up, it was the Mark 20, wood wing, 150 HP, available from 1955-58. Had never heard of it, wonder if there are any still around?

Kind of like the M20D... many got updated to the next level... 180hp and CS prop... + the aluminum tail... 

So... the M20 line started out as just the M20... that makes the M20A really the Bravo!

Speaking of the Bravo... the first Long body was the M20L... which got the Porsche power... nice engine, but like the M20... a bit too little power for the airframe... and how Mooney pilots typically like to fly...

If every airport was 5k’ long... 150hp is a lot..!

PP thoughts only, not a CFI...

Best regards,

-a-

[cliffy]

13 hours ago, 47U said:

 If the lubrication part of the AD is so important, why are there not revisions to the AD to include the J and subsequent models?  

Its just the FAAs way of doing things  :-)

[Vance Harral]

13 hours ago, 47U said:

If the lubrication part of the AD is so important, why are there not revisions to the AD to include the J and subsequent models?

Because the service manuals for the J and subsequent models were written after the AD was issued.  Those service manuals have always required the lubrication in question, hence the issue is addressed for later models without the AD.

Service manuals for the F and prior models were originally composed prior to the AD, and do not require the lubrication in question.  The AD effectively modifies the lubrication guide of these service manuals.  Note that later revisions of the service manual for the F and prior models do require the lubrication in question.  One could argue the AD was made irrelevant when these revisions were published, but that assumes everyone has obtained and is following the later revisions.  I don't think obtaining revision updates to service manuals is actually legally required, but compliance with ADs is.

[47U]

Sure enough, flight control lubrication was added to the 50 hr in the later F and J mx manuals.

A significant change in philosophy.  The A model mx manual has the below statement:

Bearings used in bell cranks, hinge points, and rod-ends are of the sealed type and do not require periodic lubrication.
Avoid excess application of lubricants.

[Jim Peace]

Its all greek to me....plane is going in tomorrow for the ADs and other stuff.....

Its great to have a plane that flys a lot but these 100 hour AD's blow...

Should be 100 hours unless within 4 months of an annual.....

[RobertGary1]

On 12/16/2020 at 10:39 PM, Vance Harral said:

Because the service manuals for the J and subsequent models were written after the AD was issued.  Those service manuals have always required the lubrication in question, hence the issue is addressed for later models without the AD.

 

That just means it’s not regulatory for part 91 in the J. 
 

[Vance Harral]

23 hours ago, RobertGary1 said:

That just means it’s not regulatory for part 91 in the J. 

Not regulatory to do it every 100 hours, agreed.  However, while maintainers are not obligated to follow the schedule in a Service manual, they are obligated to follow the techniques in the service manual any time a service is performed.  So if you ever lubricate a post-J airframe (and note that doing so is required by they annual inspection guide), you must follow the rod-end lubrication guidance.

[DCarlton]

On 12/15/2020 at 8:41 PM, PT20J said:

For the rod ends, the AD suggests silicone spray. The good thing about that is that it won't attract dirt which is what wears out the rod ends. The bad thing is that it isn't a very good lubricant. Later Mooney service manuals call for Triflow which is a light oil containing teflon. It's a better lubricant, but the oil remains and can attract dirt. I contacted RBC (manufacturer of Heim rod ends) and their engineering department told me they recommend MIL-PRF- 81322 grease (Aeroshell Grease 22). I think most use Triflow.

Skip

LPS-2 seems to be the dominate choice in my neck of the woods.  LPS-2 vs. Triflow?   Grease seems like a good choice too but it does seem to harden and cake with grime.  I spent an hour yesterday getting hardened grease and grime off of the U joint associated with the trim system before it could be lubed. 

[PT20J]

48 minutes ago, DCarlton said:

LPS-2 seems to be the dominate choice in my neck of the woods.  LPS-2 vs. Triflow?   Grease seems like a good choice too but it does seem to harden and cake with grime.  I spent an hour yesterday getting hardened grease and grime off of the U joint associated with the trim system before it could be lubed. 

Grease seems a bad choice for the u-joints for the reason you describe. I use LPS-2. Mooney calls for grease on the trim chain which makes no sense since it’s not going to get down into the rollers.