Corroded Torque Tube

[urbanti]

Am looking at a '67 Mooney 20F that is in overall really nice shape.

However, the elevator torque tube has corrosion that my A&P friends all opine is more than surface corrosion. (Rest of plane looks vy clean).

Please let me know your thoughts as to how this might be handled on a prebuy/annual by a hawk-eyed Mooney Service Center - are they going to go straight to replacement option, and if so how much would you guess a used one would cost to obtain and install?

Thanks in advance for any opinions,

Tim

[Marauder]

The elevator control tubes for my F also were showing some signs of rust and I had them pulled and repainted at this past annual. If they are beyond minor surface rust, I don't think you have an option to repair them. And I have no idea of the replacement situation. Do you know with SB 208 has been complied with? If there is some visible rust, I would be worried about the cage as well.

[Seth]

Tim - SB 208 was the one I was worried about when we talked - check the logs to see if it's been addressed.  Other MooneySpacers, please give a better descirption of SB 208.  It's where they roll cage and I think main spar are checked for corrosion/rust.  Basically, the insulation between the airframe and cabin can retain water.  If parked outside in locations with rain, the insulation will suck up moisture if it's getting into the airplane and press that moisture up agains tthe roll cage steel, often near the floor.  If the airplane is SB 208 compliant, there is a much lower chance of major corrosion in the tubes, which are expensive to replace.  The tubes also sit over the main wing spar.

 

Again, other MooneySpacers, please elaborate.

 

-Seth

[1964-M20E]

Which elevator tubes are you refering to?

Teh aluminum ones in the tail or others under the cabin?

[urbanti]

Hi John

In the pictures it looks like a steel tube since it has orange rust on it.

best

Tim

[KSMooniac]

There are tubes that go from the front of the cabin all the way back to the tail, so you need to be more specific.  SB 208 that was already mentioned would be a major concern if rust is visible on control tubes, so if it hasn't already been checked on this plane by your mechanic, you should direct them to remove an interior panel now and check the steel cage.  If you have rust there, it is likely a show stopper.

 

If you can come up with a specific part number for the control tubes, I might be able to help you with a replacement from my salvage plane.  They might be the same on the J.

[Marauder]

Tim - SB 208 was the one I was worried about when we talked - check the logs to see if it's been addressed. Other MooneySpacers, please give a better descirption of SB 208. It's where they roll cage and I think main spar are checked for corrosion/rust. Basically, the insulation between the airframe and cabin can retain water. If parked outside in locations with rain, the insulation will suck up moisture if it's getting into the airplane and press that moisture up agains tthe roll cage steel, often near the floor. If the airplane is SB 208 compliant, there is a much lower chance of major corrosion in the tubes, which are expensive to replace. The tubes also sit over the main wing spar. Again, other MooneySpacers, please elaborate. -Seth

SB 208B: http://www.mooney.com/images/pdfs/sb-pdf/sbm20-208b.pdf Water can get into the cockpit various ways (like the windows and from the roof vent area). The SB addresses the visual inspection requirement for the steel roll cage around our cockpits. As well, the spar area in the back seat area should be inspected.

[Marauder]

Which elevator tubes are you refering to? Teh aluminum ones in the tail or others under the cabin?

The tubes I was speaking about are the ones in the avionics bay that go directly to the elevators. The tubes on mine had rust on them. They did not appear to be made of Aluminum. Not sure what the OP is speaking about.

[47U]

They're all steel.  My IA "encouraged" me to get this taken care of.  I expanded my effort to include the gear control rods, also, but it looks worse in the photos than it actually is.  My airplane was northern IA for 35 years and was hangared, but still showed signs of the humidity.  I didn't have any tubes unairworthy do to the corrosion. 

And yes, I had the IA come back and double check my installation after I put all this back together.   

[KSMooniac]

Very nice work!

[urbanti]

The corroded part in question is called out on the aircraft's previous prebuy by an A&P as "corrosion on elevator torque tube near battery box"

Tim

[rbridges]

They're all steel.  My IA "encouraged" me to get this taken care of.  I expanded my effort to include the gear control rods, also, but it looks worse in the photos than it actually is.  My airplane was northern IA for 35 years and was hangared, but still showed signs of the humidity.  I didn't have any tubes unairworthy do to the corrosion. 

And yes, I had the IA come back and double check my installation after I put all this back together.   

 

just out of curiosity, what year is your plane?  mine is a '65 and it has the yellow-green zinc chromate on the metal.

[47U]

It's a 1963... sn 2552.  Midwestern aircraft it's whole life, until 2008.  I need to check the original airframe log for the exact date and plan a celebration.  It turns 50 years old this month.

[Marauder]

They're all steel. My IA "encouraged" me to get this taken care of. I expanded my effort to include the gear control rods, also, but it looks worse in the photos than it actually is. My airplane was northern IA for 35 years and was hangared, but still showed signs of the humidity. I didn't have any tubes unairworthy do to the corrosion. And yes, I had the IA come back and double check my installation after I put all this back together.

Them are the parts I am talking about as well. My Mooney has zinc chromate theough this area as well, but mine started some rust on the actual tubes. To the original OP, if you got rust here, definitely make sure a rent SB 208B was done.

[Igor_U]

I had to replace one of the elevator torque tubes on my ‘67F during my annual last year. This was as there was a flat spot on it due to rubbing on phenolic block (and possibly still frame). I found out ‘67F has different elevator control system (and p/n’s) then 68 and subsequent models.

Tube I’ve replaced was in the belly – one of the long ones and price was $300 or so. I remember Mooney couldn’t figure a correct replacement p/n and sent me a long one – eventually LASAR found one that is adjustable (from Ovation) that worked.

 

I am surprised with corrosion on those I tail cone. Moisture didn’t enter there by the window so SB208 has nothing to do there; it is good to check, of course.

All original tubes on my plane were sprayed with zinc chromate and I was under impression those were aluminum, but I guess I was wrong.

 

Good luck.

 

Igor

N9514M @ KPAE

[jetdriven]

Those elevator trim pushrods score where they pass through that bulkhead as well.