learning experience - broken mixture cable

[dominikos]

An interesting learning experience today. Went for an IFR training flight with instructor. Run up with no problems, on a take off, the plane felt sluggish, rotated further than usual and the climb was slow. But the density altitude was 2,700 (our field elevation is 275). As we climbed, EGT temp kept raising and we could not get better climb rate than 500 ft/m. The EGT got to 800C and all indicators were sub-par. And noticed that mixture control didn’t have any effect. So, we turned back, landed and opened the cowling.

We found that mixture line detached, picture below. We attached it, tested, and departed again. This time, no issue, got to 3,000 ft, leaned the engine. and again, the same issue. Fortunately, this time the stuck setting was a bit richer . Flew back to the field, landed, and will talk with the field AP tomorrow to get the connector replaced.

Two questions:

1. what should I be looking for on departure to make sure that the engine is performing as expected? As stated, rolled further than usual, but that could have been explained with 97F OTA. I don’t have engine monitor so cannot easily see that engine does not perform at 100%
2. what is the part that I need from Sporty’s to replace it with? I’m still surprised that on the field, when tested, it behaved as expected and was firmly joining cable to mixture control.

 

[carusoam]

There is nothing more dangerous than having an old worn flight control…

In this case engine control…

Read up on replacing engine controls as an owner produced part…

Use the old control as an example of what to have built…

Often the controls get replaced at engine OH…

So… controls over 2000hrs are getting tired… check the hours on yours…

 

Before committing to flight…

MP, RPM, FF…

If you have all three, the engine is producing full power…

It can be a little challenging when you are flying out of an unfamiliar airport at a high altitude, or high DA… but then, you are much more aware of what you are looking for…

My numbers are something like 29”, 2700rpm, 28gph…

A quick glance is all it takes…

Stay on the centerline…

Next glance is at ASI to know how fast your ship is going…

Do you have a FF meter?

PP thoughts only, not a mechanic…

Best regards,

-a-

[dominikos]

I don’t have FF meter. A case for engine monitor is getting stronger and stronger….

[Hank]

35 minutes ago, dominikos said:

An interesting learning experience today. Went for an IFR training flight with instructor. Run up with no problems, on a take off, the plane felt sluggish, rotated further than usual and the climb was slow. But the density altitude was 2,700 (our field elevation is 275). As we climbed, EGT temp kept raising and we could not get better climb rate than 500 ft/m. 

This just happened to me, too. I put the long ground run down to high DA, high weight [loaded for several days at the beach], and forgetting to use flaps on the 5000' runway. But 400 fpm climb with slight roughness was a bad sign, so instead of flying 3 hours to an obstructed grass strip I turned around when nothing made the IVSI change.

Runup was bad on right mag.. Plugs looked good. Marked the exhausts, idled the engine, Cyl #1 was cold. Swapped plugs top to bottom on #1, idled engine--fairly smooth on Both and Left, rough as a cob on Right. Still waiting to hear what the A&P is able to find . . . .

Good luck with yours. Sounds like a simple fix [I replaced my stuck-wide-open carb heat cable a few years ago].

[Mooney Dog]

48 minutes ago, dominikos said:

 

1. what should I be looking for on departure to make sure that the engine is performing as expected? As stated, rolled further than usual, but that could have been explained with 97F OTA. I don’t have engine monitor so cannot easily see that engine does not perform at 100%

So in pulling up a POH for a J model, it says that for a normal takeoff, full throttle at 2700rpm should be expected. 

Now many factors may make it where you're not getting that full power, but i would imagine if you're 2500rpm or less, something might be up, but without being in the actual situation, its hard to tell. Personally i wouldnt have taken off again even if i thought i fixed it, without checking it a few times on the ground for smooth operations. 

22 minutes ago, dominikos said:

A case for engine monitor is getting stronger and stronger….

Its a very very good investment for any airplane imo.

[Shadrach]

With all due respect, given that neither of you are A&Ps, the second flight was a poor decision. Engine controls that have disconnected aren’t likely to be remedied with just a quick reattachment. 
 

part number is 660051-003 swivel joint, mixture.  I can’t find it online.

Edited August 12, 2021 by Shadrach

[KSMooniac]

I replaced my early J cables with the later versions that use a real rod end and bolt instead of that ball/socket arrangement like yours that are subject to wear and catastrophic failure. I strongly suggest you get some new cables from McFarlane and the modern ends. Look in the IPC for part numbers from a later model. Minor mod/logbook entry IMO since the later J parts are certified/approved.

I wouldn't own a plane without an engine monitor unless it were a sailplane! It cannot be emphasized enough how much of a safety enhancer and diagnostic helper they are. Even a used EDM-700 is worth the effort! If you have a forever plane, go for the EDM-900 and ditch the old instruments... It fits well in any Mooney. If you're DIY inclined, it is a great opportunity for sweat equity installing probes and routing the harnesses under supervision.

Sent from my LM-V405 using Tapatalk

[ArtVandelay]

I replaced my early J cables with the later versions that use a real rod end and bolt instead of that ball/socket arrangement like yours that are subject to wear and catastrophic failure. I strongly suggest you get some new cables from McFarlane and the modern ends. Look in the IPC for part numbers from a later model. Minor mod/logbook entry IMO since the later J parts are certified/approved.

I wouldn't own a plane without an engine monitor unless it were a sailplane! It cannot be emphasized enough how much of a safety enhancer and diagnostic helper they are. Even a used EDM-700 is worth the effort! If you have a forever plane, go for the EDM-900 and ditch the old instruments... It fits well in any Mooney. If you're DIY inclined, it is a great opportunity for sweat equity installing probes and routing the harnesses under supervision.

Sent from my LM-V405 using Tapatalk

I agree 110%…I changed out all my engine control cables during overhaul, and would discount a planes value by $10k if it doesn’t have a engine monitor.

[EricJ]

That's the old, crappy kind of end.   You can replace that easily with a good spherical rod end, and this has been done on many airplanes that had those janky ends that would come off like you experienced.

It's an easy repair.   Get your A&P/IA to replace it with a proper spherical rod end.   It's a common repair/alteration.

 

[DMM]

Here's a link to an old discussion that includes the retro-fit part number (PN660051-005).  As stated above the old ends need to be swapped out for the new heim bearing type ends. 

 

[Yetti]

6 hours ago, EricJ said:

That's the old, crappy kind of end.   You can replace that easily with a good spherical rod end, and this has been done on many airplanes that had those janky ends that would come off like you experienced.

It's an easy repair.   Get your A&P/IA to replace it with a proper spherical rod end.   It's a common repair/alteration.

 

There is an SB/AD for that cable end.  There are mechanics that should be scolded.  You should be able to tell mixture based on the run up at 2700.   Also you should lean on the ground to the point that if you pour on the coals the engine dies.  At 2700 and heat you should be adjusting mixture to DA prior to takeoff.  Do your throttle cable also.   McFarland is the cable people call them and they will tell you what you need to do.

[Yetti]

When was your fuel servo rebuilt last?  Might as well do it too.

[dominikos]

4 minutes ago, Yetti said:

When was your fuel servo rebuilt last?  Might as well do it too.

I need to check. The list is building up for another visit to MSC.

Makes me wonder… is there a list of best preventative practices?

[Yetti]

14 minutes ago, dominikos said:

I need to check. The list is building up for another visit to MSC.

Makes me wonder… is there a list of best preventative practices?

Checking to see if my buddy wants to work on it.

[EricJ]

For M20J with the push-pull controls there is a note in the IPC that says either the -003 or -005 assemblies can be used, and lists the parts for the -005 assembly (with the spherical rod end, aka heim bearing).   It is note 1 on p4 of section 76-00-01.     The rod end is an HF-3-M.

 

[Yetti]

46 minutes ago, Yetti said:

Checking to see if my buddy wants to work on it.

He is busy doing pilot stuff.   This is an easy mechanic thing you don't need an MSC.   You can just do the rod ends.    Don't feel bad he had an F with the old ends on it just recently.   At least check the the finger screen in the fuel servo while you are there.

I do maintenance like this.  Focus on one system at a time each annual.    Like brakes.  Or fuel system,  Keep rebuilding and redoing each annual and eventually everything will be redone and not 30 years old.