Tach Time During Annual Inspection

[David_H]

I picked the Mooney up from it's Annual yesterday. Before startup and after shutdown, I always snap a photo of the Tach time from the EI digital Tach to keep track of the hours and oil consumption. When entering the Tach times for yesterday's flight, I noticed the starting Tach time for yesterday's flight was the same as the ending Tach time when it was dropped off for Annual Inspection. 

How is it possible for a plane make it through an Annual Inspection without recording any time on the Tach? I expect the Prop would have needed to make it through an engine warm up and prop cycle in addition to checking RPM... am I wrong? I'm perplexed.

[RLCarter]

I would expect at least a couple tenths just to warm the oil up before changing, couple more to check for oil leaks after, and a few more for run up /prop cycle...etc

Edited March 7, 2019 by RLCarter

[1964-M20E]

Did they change the oil?  Changing the oil is not necessary at annual especially if you just changed it 10 or fewer hours before.

Look at the log book entries to see if they ran the engine and inspected for any leaks.

The run up may have been very brief start run for 30 seconds and shut down not enough to change the tach time.   Tach time of 0.1 is 6 minutes.  Typically when i change the oil or after annual I will run for a couple of minutes doing a normal pre-take off run up.

 

[jetdriven]

 

I dot know about your shop but before I run up an engine I want to warm it up first. cht more than 250-275 or greater.  

Ive seen rental planes crank up and apply takeoff power on the runway 90 seconds later.  Not me. 

That said, we always did the hot compression check as soon at arrives at the shop and the hot oil starts draining right there. I would still think a post-maintenance Runup is needed, it’s on the mooney annual checklist.

Edited March 7, 2019 by jetdriven

[David_H]

The oil and filter was changed. A rocker cover gasket and an oil fill tube lower gasket was also billed.

I couldn't imagine an AI running an engine up before letting the CHTs warm up. It's been cold here in the Mid West.

I sat on the ground for some time yesterday to allow the temperatures to come up before I taxied to do the preflight Runup.

[ArtVandelay]

They may have only ran it for 30-60 seconds, just long enough to verify no leaks.


Tom

[Shadrach]

Tach time is dependent on RPM. I believe 2500 is what yields real time in my plane. So do you consider that it would require six minutes of running at 2500 RPM to register 1/10 of an hour on the tach.

 When we do annual but oil is changed after the airplane has flown. While the oil is draining we do compression checks. It’s entirely possible that your engine was only run for 20 to 30 seconds at low RPM.  This would yield little change in tach time.  It’s also possible that they didn’t run it up afterwards. I think it’s a bad idea to omit the post inspection run up but I don’t think it’s regulatory. He does not need to use Mooney’s list to perform the annual. 

[David_H]

New right-side brake linings were also billed. Time for bedding the brake linings was also expected.

[Shadrach]

42 minutes ago, David_H said:

New right-side brake linings were also billed. Time for bedding the brake linings was also expected.

I just replaced the brake linings on my aircraft. I have to say that “bedding” wasn’t required even though I did it. I did a full power static run up after annual and the parking brake held the aircraft at full power with brand new unbedded brake linings. I did one high-speed taxi test And noted that the brakes were strong. I certainly think it would be a good idea for a shop to test these sorts of things. I think you should call them and ask them about it.

I will add that I’ve had all manner of lousy mx performed by credentialed professionals. But I would never draw a conclusion until the individual I was working with had an opportunity to explain the situation. You might learn something.  There’s also the chance that the owner of the shop might learn something about his staff. 

Edited March 7, 2019 by Shadrach

[David_H]

Just now, Shadrach said:

I just replaced the brake linings on my aircraft. I have to say that “bedding” wasn’t required even though I did it. I did a full power static run up after annual and the parking brake held the aircraft at full power with brand new unbedded brake linings. I did one high-speed taxi test And noted that the brakes were strong. I certainly think it would be a good idea for a shop to test these sorts of things. I think you should call them and ask them about it.I think you should call them and ask them about it.

I agree.

[jaylw314]

2 hours ago, 1964-M20E said:

Did they change the oil?  Changing the oil is not necessary at annual especially if you just changed it 10 or fewer hours before.

Look at the log book entries to see if they ran the engine and inspected for any leaks.

The run up may have been very brief start run for 30 seconds and shut down not enough to change the tach time.   Tach time of 0.1 is 6 minutes.  Typically when i change the oil or after annual I will run for a couple of minutes doing a normal pre-take off run up.

 

I thought changing the oil and filter is part of the regulatory definition of an annual inspection?  It seems silly if you've just changed it, but I think that's the case.

Also, tach time is calibrated for typical cruise RPM, but I'm not sure what that is, maybe 2500 RPM?  So a run up to 1600 RPM would take 9 minutes to make 0.1 on the tach

[Shadrach]

33 minutes ago, jaylw314 said:

I thought changing the oil and filter is part of the regulatory definition of an annual inspection?  It seems silly if you've just changed it, but I think that's the case.

Also, tach time is calibrated for typical cruise RPM, but I'm not sure what that is, maybe 2500 RPM?  So a run up to 1600 RPM would take 9 minutes to make 0.1 on the tach

Oil change is not required during annual inspection.  You are indeed correct about tach time (as I stated earlier). 2500 rpm yields the closest thing to an accurate measure of real time in my airplane.

Edited March 7, 2019 by Shadrach

[PT20J]

2 hours ago, jetdriven said:

I want to warm it up first. cht more than 250-275 or greater.

On the radials, the standard has always been minimum oil temp 40 deg C and CHT 100 deg C before applying significant power. I've always used that. Happens reasonably quickly in our small engines. Lycoming seems to be much more concerned with overheating during ground operation than low temps before takeoff. The IO-360 Operator's Manual says, "The engine is warm enough for take-off when the throttle can be opened without the engine faltering." Still, I think 90 seconds from startup to takeoff is a bit quick, but rentals and flight school airplanes get abused a lot. Still, many such engines make TBO and beyond because, in spite of any abuse, they get used a lot and don't get a chance to rust.

Skip

[Guest]

Down load your engine monitor and see if it got run up.

Clarence

[PT20J]

Oil change is on the annual inspection list in the Maintenance Manual.

[Hank]

7 minutes ago, PT20J said:

Oil change is on the annual inspection list in the Maintenance Manual.

I've always been told that oil change isn't part of the annual, beginning with my first one when I didn't change the oil right before because the annual was due, and it wasn't changed.

 

Edited March 7, 2019 by Hank

[PT20J]

I believe that the annual is supposed to follow the manufacturers Maintenance Manual, but perhaps one of the A&Ps can weigh in.

 

[jaylw314]

57 minutes ago, PT20J said:

Oil change is on the annual inspection list in the Maintenance Manual.

Thanks, I got it backwards then, it's not required under the part 43 definition, but is in the MM.

[David_H]

44 minutes ago, PT20J said:

I believe that the annual is supposed to follow the manufacturers Maintenance Manual, but perhaps one of the A&Ps can weigh in.

 

That is a very good question.

[Andy95W]

45 minutes ago, David_H said:

That is a very good question.

Tricky question.  Appendix D to Part 43 doesn't require an oil change for an Annual or 100 hour Inspection.  Most mechanics (at least the ones who were taught like me) were told to use the manufacturer's maintenance manual to perform the inspection, and to note that in the logbooks:  "Aircraft inspected IAW FAR 43 App. D and Mooney Service Manual dated ______."  

If I sign it off that way, then I changed the oil, or I will note it as such ("except for changing oil which was changed at ______ hours.")

Honestly, I think the Mooney Service Manual was written that way because it also has 50 hour requirements, one of which is to change the oil.  Obviously, then, you would change the oil at 100 hours also.  But how many of us actually change our oil at 50 hours?  I bet it's not too many.

[jaylw314]

26 minutes ago, Andy95W said:

Honestly, I think the Mooney Service Manual was written that way because it also has 50 hour requirements, one of which is to change the oil.  Obviously, then, you would change the oil at 100 hours also.  But how many of us actually change our oil at 50 hours?  I bet it's not too many.

I do.  personally, I find swearing at safety wire therapeutic 

[Guest]

An oil change and a run up are both on the Mooney inspection guide.

https://cdn2.hubspot.net/hubfs/4147179/TECHNICAL PUBLICATIONS DOCUMENTS/100_Hour_2018.pdf

Clarence

[Rick Junkin]

7 hours ago, David_H said:

I picked the Mooney up from it's Annual yesterday. Before startup and after shutdown, I always snap a photo of the Tach time from the EI digital Tach to keep track of the hours and oil consumption. When entering the Tach times for yesterday's flight, I noticed the starting Tach time for yesterday's flight was the same as the ending Tach time when it was dropped off for Annual Inspection. 

How is it possible for a plane make it through an Annual Inspection without recording any time on the Tach? I expect the Prop would have needed to make it through an engine warm up and prop cycle in addition to checking RPM... am I wrong? I'm perplexed.

From the EI RPM (R-1) manual:

Tach Time:

The tach timer keeps a running total of time the engine is above 1300 RPM.

It's likely that a leak check run-up never exceeded 1300RPM, or if it did, only for a few 10's of seconds.

 

Not a mechanic, just spit-balling. I think someone suggested downloading engine monitor data to see if anything shows there - good idea.

Cheers,
Rick

[N201MKTurbo]

If you inspect the suction screen with a sump full of oil, it makes a big mess in your hangar!

[Andy95W]

5 hours ago, N201MKTurbo said:

If you inspect the suction screen with a sump full of oil, it makes a big mess in your hangar!

I stand corrected!  This is the best point and answers the question.  Per FAR 43 Appendix D:

(3) Internal engine - for cylinder compression and for metal particles or foreign matter on screens and sump drain plugs. If there is weak cylinder compression, for improper internal condition and improper internal tolerances.

Since you can't inspect the filters and screens without draining the oil, you really can't do an annual inspection without doing an oil change.  (I suppose you could put the old oil back in, but that's kind of dumb.)