Fuel drip from cockpit ceiling vent

[DaveAnderson]

1981 M20K...At 9k, saw a drip out of corner of eye from the passenger ceiling vent..smelled of fuel.  How in the world does that happen? I was about 20 miles from home and it dripped about 5 times.

The cockpit vents are supplies by the tail intake..so...the only thing I can think of is that I was flying through/above a layer of smoke from the fires in California while I was coming back from San Francisco to San Diego.  I can't believe that would be it though,but I have no clue. 

Thoughts?

 

[M20S Driver]

Since I am known to be paranoid, i would look for fuel leak all over and investigate the engine fuel drain lines.

How full were the tanks?  Did you notice abnormal fuel consumption or flow?

[DaveAnderson]

Full at takeoff but had been flying for 1.5 to 2 hours already. Fuel flow was spot on the whole way. 9gph +/- 0.3. 

[carusoam]

Liquid draining out of the overhead air vents?

The following is a PP guess....

It is normal to have a method of separating water from air in the ventilation system.

See if you can find the drain tube that allows moisture to exit the system.  The M20C has a simple tube that originates at the ceiling and exits at the bottom of the fuselage.  It stops up pretty easily...

See if it is possible to see if it is blocked, if yes, see if you can snake the tube.

It may smell like something, but probably not fuel..?

The MM should have some drawings.  I think Byron may have posted photos of the installation of a modern air system in his Better than new J.

Hope that helps generate an idea or two...

Best regards,

-a-

[DaveAnderson]

Yeah, the more I thought about it I was thinking...hot, condensation build up, blockage. I'll keep digging and I'm going up tomorrow so I'll see if it happens again. Totally weird. 

 

Thanks!