Ron, I send my condolences on your fine plane.  On the other hand, I congratulate you on your skills that allowed you to survive.  I add my voice to salute your willingness to share.  I’m glad that even your bruised ego is mending…as it should.  I hope that your candor in the LML has helped.

 

I have spent a lot of time considering your experience with the pitot/static system.  Just so that no one thinks that it can’t happen to them, I would like to add my short story.

 

This happened several years ago in deep winter.  I live in northern Ohio so freezing temperatures are the norm, with an occasional thaw.  My Debonair was housed in a non-heated hanger.  The engine was warmed with a Tanis device.  I had been flying in some weather recently, but dodged most of the icing.  One particularly cold morning (18 degrees F) I started a flight to Sporty’s.  The weather was scattered to broken at 3000 with blue above.  The cabin was cold soaked from the night in the hanger and soon so was I.  Preflight, clearances and taxi were all normal.  On the takeoff roll I noticed that the airspeed indicator was “stuck.”  (My interpretation.)  Everything else seemed OK so I continued.  As soon as I lifted off the airspeed indicator “came unglued” from the pin and started to respond.  I’m now dumb and happy.  As I climbed I started to congratulate myself on how good the performance of that dear old Beech was…my airspeed in climb just kept on increasing.

 

OK, so now you know…the pitot was blocked and the static line was open.  I returned and landed.  No GPS or radar altimeter.  I requested “special handling.”  The tower called out my airspeed and altitude every 10 seconds on my approach.  Bless them. 

 

The point of interest here, however, is how the pitot tube came to be blocked.  It was with water…or more accurately, ice.  Water had accumulated in the pitot tubing, but not enough to block it on the last flight I had made.  Perhaps I had flown through a snow shower.  I don’t really remember.  The plane was put away cold.  It may have warmed up slightly, droplets melted, coalesced and refroze completely blocking the pitot channel.  The fix was easy.  Heated hanger overnight and blow out the lines.

 

Other than a heated hanger and a preflight drain of the pitot/static system, anybody have a viable plan to avoid the same thing happening to my Lancair IV-P when I finish it in 2022?  Should I be building in sumps and drains for the pitot/static system?  Where?  Should a dessicant be used in the system?  Is there a way to ensure that the AOA system doesn’t fall victim to the same mechanism?  Snow has been known to fall on my wings when I’m “on the road” and therefore, not hangered.  After brushing the wing off, should the upper AOA port be alcohol washed?  Do I need a cap for the upper port to keep rain & snow out?  It would need to be marked with a tag: REMOVE BEFORE FLIGHT.  Jim?

 

Thanks for your thoughts.

 

Barry Knotts

LIV-P, Conti TSIO-550, 15%, Perrysburg, Ohio