Preflighting the Horizontal Stabilizer

[Flocker]

I took my plane in for an annual this week and one of the findings was a worn out bushing in the horizontal stabilizer. Apparently it has been an on-going issue as the hole where the bushing resides had also worn out. It is now egg shaped as opposed to being circular. We're having to replace the stabilizer torque tube as well as the bushings.

When preflighting, the stabilizer should have no movement front to back or up and down from the tip. If it does, it may be a worn out bushing.

[Flocker]

Here's the area in question.  Part #33

[TiPi]

Had the same problem on my P92 Eaglet. The LAME who assembled the tail after a repair didn't tighten the 2 bolts from the torque tube to the bearing correctly. I could feel some minor movement during preflight, so investigated and found the problem. Luckily, the bolt holes were good, just had to get new bolts. They don't wear out if the bolts are torqued correctly.

[timb]

My P2008 had the same issue last annual (around 700 hours) the shop listed - stabilator has fore/aft movement.  Action:Removed elevator and worn stabilator brackets, prepped & painted new elevator brackets and reinstalled.

Parts listed were left and right stabilator fittings and stop nut.

[Cluemeister]

Just to be clear timb, was the movement up and down on the elevator, or a horizontal left to right movement?

[timb]

My horizontal stabilizer moved slightly forward and aft, meaning if you pulled on the tip forward or pushed rearward there was play. I do not recall movement up & down.

[Flocker]

Apr 18, 2019 14:51:30 GMT Flocker said:

When preflighting, the stabilizer should have no movement front to back or up and down from the tip. If it does, it may be a worn out bushing.

Replaced the torque tube today.  Annual completed; however, this is still some (slight) movement on the stabilizer.  Apparently the bushing is a type that swivels.  I've been told that some (slight) movement is normal...  the bushing we replaced was clearly worn out.  As Mark said, they should be tightened on a regular basis.

[stroudj]

Flocker, how many hours do you have on your P2008? I checked my stabilizer I just have a slight movement. I have 670 hrs on mine.

Thanks, Jim

[Flocker]

Apr 23, 2019 3:26:45 GMT stroudj said:

Flocker, how many hours do you have on your P2008? I checked my stabilizer I just have a slight movement. I have 670 hrs on mine.

Thanks, Jim

568

[Cluemeister]

I’m having mine checked today, as I have an upcoming PPL checkride. Will report back what’s found. 183 hours currently.

[Cluemeister]

The stabilizer had up and down movement, none side to side. The hole had been elongated by wear, so the tube connecting the elevators was replaced.

IMG_0116.mov (1.64 MB)

[ChiMike]

I tested my H.S. today—no issues. Thanks for the tip on how to check it.

[TiPi]

The prevent the costly replacement of the elevator torque tube, any movement needs to be investigated and fixed pronto. Most of the time, just re-tighening the 2 axis bolts will fix it.

[Flocker]

Apr 23, 2019 1:54:16 GMT Flocker said:

Apr 18, 2019 14:51:30 GMT Flocker said:

When preflighting, the stabilizer should have no movement front to back or up and down from the tip. If it does, it may be a worn out bushing.

they should be tightened on a regular basis.

After 10 hours on my new torque tube, I started getting movement on the stabilizer.  Both up and down and forward and back.  We tightened up the 10mm bolts and were able to get to zero movement.  Like Tipi said, any movement should be investigated pronto.

[ChrisConnor]

Had the same issue on my P92. I caught the problem before any damage was done by the bolt(s) coming loose. Contacted Tecnam about it, but never recieved a fix. What I did (and it works perfectly) is add a second Nylock nut to the end of the bolt, as a jam nut. I had plenty of bolt there. Niether side have come loose since. I added a paint line to visually verify it's where I left it during each preflight.