In response to Ed de Chazal's plea for the listers to share their
"bloopers", let me share this one with you.

Some years ago, I was forced to leave my LNC2 at an airport when I
encountered unforecast weather that I didn't choose to penetrate (sometimes
referred to as: "A wall of water"). I had to be somewhere so I landed and
rented a car to continue, and didn't get back to pick up the airplane for
about a week during which, the airplane sat outside on a tie-down. During
that week, there was several days of extremely heavy rain and high winds and
apparently, rain water was driven into the static ports.

When I finally retreived the airplane, I did what I thought was a very
thorough pre-flight and launched. I hadn't installed drains on the
pitot/static system and because I had never had a problem before, and it was
such a pain to check it, I didn't. Big mistake!

Initial A/S indication during the take-off roll looked entirely normal, that
is, it began responding in what looked like a normal fashion as I
accelerated to lift-off. Immediately after take-off and after raising the
gear, when I checked the A/S indicator, it was obvious that something was
screwed up as it was bouncing up and down (maybe +/- 10 MPH) around 90 MPH.
The hair on the back of my neck (and on the top of my scalp) stood up so
stiffly my cap and headset almost came off! I immediately called the tower
(I was then still climbing straight out) and declared an emergency. Thank
whatever Gods there are, the several hundred hours I had accumulated in my
Lancair allowed me to get it back on the ground by "feel"! At that time, I
was running a fixed pitch wooden prop so had only RPM, approximate throttle
position and control "feel" to guide me - also hadn't installed a GPS yet,
so no G/S either!

Once down, I went over the pitot and static system and blew out what
amounted to no more than a few tablespoons of water - some from the static
lines and a little from the pitot lines. I had expected to see a lot more
than that - so it doesn't take much to ruin your day!

My point here is that apparently, a small amount of water will move enough
by the differential pressure that develops in the lines to allow initial A/S
indications to look "normal" until something blocks the water from moving
(like having to flow up hill). In my case, things looked fairly normal until
I reached about 90 MPH and already airborne, at that point (and I'm
theorizing here) the water encountered something in the tubing where it
could no longer move and the A/S indicator stopped reporting accurately
(probably the other instruments that rely on pitot/static as well, I just
don't remember paying much attention to anything but A/S). I'm also
theorizing that it was the water in the static lines that caused the problem
as there was only a few drops blown out of the pitot lines.

Bottom line: Water in the p/s system can sometimes allow things to look
normal at the beginning of a take-off run, only to have things go awry at
some indeterminate A/S - maybe right after getting airborne. So check it out
if you've been in precip - and be sure your drain system really works since,
as I've found out the hard way, it doesn't take much to mess up the system
and it may not even become obvious until too late!

Dan Schaefer