Servicing Pitot System Drain Valve Assembly

[Schinderhannes]

I have to service the pitot system drain valve located in the front of the left wing close to the fuselage.  I was wondering how to best access the valve. 

 

Thank you,

Frank

[MooneyPTG]

As I recall we drilled out the rivets, removed the inside cockpit pilot side panel and slid it into the cockpit. Mine needed a new o ring. We then held it into position from inside( you reach into the wing) and riveted it in place. Hopes this helps, really not a big deal. While it was out we ran new tubing to the pitot thru the wing...a little tricky but not terrible. Kevin

[Schinderhannes]

Thank you Kevin, this was exactly the information I was looking for. We were able to clean and lubricate the valve in place and replaced all fittings. The static drain valve had the same issue. We also had to replace multiple fitting whit split plastic collars in the system.

All this took a few hours, but at the end the system everything worked fine and the system was IFR certified.

[jamesm]

Where is the  pitot /static  drain valve  physically located on the pilot side ? 

So if I had the pilot side  interior removed would I be able to see it ? it in other words is valve located (lowest point)  between the inboard side of fuel tank  and pilot side seat track in the wing root area ?   or further out the wing or ??? 

I remember seeing the  Service Instruction / Bulletin for the drain valve  but I don't think it  was ever  installed  on mine  airplane.

When you changed the tubing changing the fittings as well ? 

What was the reasoning for changing out the tubing to the pitot tube ?

By chance would happen to pictures ?

 

Thanks in advance,

James

'67M20C

[Marauder]

Where is the  pitot /static  drain valve  physically located on the pilot side ? 

So if I had the pilot side  interior removed would I be able to see it ? it in other words is valve located (lowest point)  between the inboard side of fuel tank  and pilot side seat track in the wing root area ?   or further out the wing or ??? 

I remember seeing the  Service Instruction / Bulletin for the drain valve  but I don't think it  was ever  installed  on mine  airplane.

When you changed the tubing changing the fittings as well ? 

What was the reasoning for changing out the tubing to the pitot tube ?

By chance would happen to pictures ?

 

Thanks in advance,

James

'67M20C

 

James -- the actual drain is within several inches of the leading edge of the pilot's side wing and near the wing root. It is just a little nub stick out of the wing.

[MooneyPTG]

James,

We changed the tubing because the drain valve was out and the tubing to the pitot looked old. We were looking for a leak in the system that was giving me a altitude error of 200 feet at 7000 msl. The problem was a bad o ring at the drain valve. We also replace the o ring in the back as well. Hope this helps.

Kevin

[treebobboy]

Having read this post brings up an interesting question-------I have a '68 M20G and I have two pitot/static drains.  One is same as mentioned above but the second one is aft of the wing on the pilot side of the fuselage.  Any one else two drains??

 

Mike

[Marauder]

Having read this post brings up an interesting question-------I have a '68 M20G and I have two pitot/static drains. One is same as mentioned above but the second one is aft of the wing on the pilot side of the fuselage. Any one else two drains??

Mike

Front one is the pitot tube drain, the rear one is the static ports drain.

[Schinderhannes]

The drain aft of the wings is for the static system and the drain in the leading edge is for the Pitot line.  This seems to be the standard factory set-up.