Elevator alignment

[AJ88V]

During annual, we noticed that my elevators were not exactly aligned.  Maybe a 2 or 3 degrees of offset - noticeable by holding one elevator horn flush with the horizontal stabilizer and then checking the alignment of the other to the horiz. stab.

My IA first asked if the plane flew straight hands off (it does), and thought maybe it was intentionally rigged that way to tweak for some other aerodynamic twist.  We checked the HStabs and they seemed well aligned using a inclinometer. We also checked the ailerons and they lined up to book.  Flaps likewise appear correct.  Not wanting to become a test pilot, we opted to leave well enough alone (even though I'm sure this is worth at least 3 kts in cruise!!!! :D)

Will post the actual offset next time I see the plane and measure it with my phone.

Curious if anybody else has theirs rigged with a bit of offset.

Any other ideas why the elevators might be rigged this way?

 

[N201MKTurbo]

Rig them per the maintenance manual.

Its possible you have a broken spring in one of your bungees.

[EricJ]

I've not seen that before, but I agree there's no reason to change it unless there's an issue.

[cliffy]

As it doesn't meet the BOOK for alignment technically some future IA could question it on an annual

(and maybe should to protect his license as it is visible on a walk around ramp check).

The actual rerig is not too hard to do but the fly off retrim for hands off flying might be. 

My question would be - if its that far off visibly how far off are the actual deflection settings and stab pitch limits as

prescribed in the TCDS?

It could affect your recovery from a stall or even worse a spin. 

 

[Hank]

24 minutes ago, cliffy said:

My question would be - if its that far off visibly how far off are the actual deflection settings and stab pitch limits as

prescribed in the TCDS?

It could affect your recovery from a stall or even worse a spin. 

The overwhelming majority of GA spins are in the pattern, and recovery is not possible there (especially in a Mooney).

[cliffy]

Just had a hangar neighbor 2 hangars down spin in on a base to final turn yesterday in Provo Utah 

in a Cirrus 

[AJ88V]

On 9/27/2024 at 9:37 PM, cliffy said:

As it doesn't meet the BOOK for alignment technically some future IA could question it on an annual

(and maybe should to protect his license as it is visible on a walk around ramp check).

The actual rerig is not too hard to do but the fly off retrim for hands off flying might be. 

My question would be - if its that far off visibly how far off are the actual deflection settings and stab pitch limits as

prescribed in the TCDS?

It could affect your recovery from a stall or even worse a spin. 

 

Part of the reason I started the thread was to see if others have this situation with the elevators slightly offset - and it's very slight.  I've owned the plane 26 years and never even noticed it until a new mechanic pointed it out to me.  (He's also a new Mooney owner, having bought a practically abandoned Mooney ('64 C?) on the field for a song, and then bringing her back to flying condition.)

The Check:  Line the elevator horn up with the horizontal stabilizer on one side and see if you have any offset on the other. 

[PT20J]

48 minutes ago, AJ88V said:

Part of the reason I started the thread was to see if others have this situation with the elevators slightly offset - and it's very slight.  I've owned the plane 26 years and never even noticed it until a new mechanic pointed it out to me.  (He's also a new Mooney owner, having bought a practically abandoned Mooney ('64 C?) on the field for a song, and then bringing her back to flying condition.)

The Check:  Line the elevator horn up with the horizontal stabilizer on one side and see if you have any offset on the other. 

I believe the answer is that it’s not right. But, if it’s been that way for 26 years, it may not be worth fixing. In rigging, often if you change one thing you mess up another. 

[A64Pilot]

Known as the rule of unintended consequences, can drive you nuts, also known as perfection is the enemy of good enough. 
My bet is at some time in the past one elevator was changed due to damage and in order to prevent the dreaded damage history wasn’t recorded, or that record lost.

19 hours ago, PT20J said:

often if you change one thing you mess up another. 

 

[PT20J]

In engineering we have a saying that there is no such thing as a single change.

[MikeOH]

5 hours ago, PT20J said:

In engineering we have a saying that there is no such thing as a single change.

LOL!

Every time production would approach me with, "we need you to just make a simple change" I would shudder uncontrollably!

[hammdo]

Amen to that!

[Jcmtl]

Yes mine used to not be perfectly aligned and the plane had a tendency to roll to the right.  The first shop i brought it to fixed the roll by adjusting one of the flaps.  I then had another mechanic rig the elevators so they were flush with each other and then we also lined up the flaps so they were even.  The plane now flies perfectly straight. 

[Kelpro999]

If you’re still dealing with this, you know the out of position it is so fly it, adjust it and fly again.

 Could be nothing. May be compensating with the rudder tab and not know it. You can always put it back out of position.