On Sat, 21 Aug 2004 00:54:46 -0400, An Metet
wrote:

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I was flying from Green Bay, Wisconsin to the Upper Peninsula of
Michigan. Very shortly after takeoff I noticed that my air speed
indicator said over 200 mph. That's just not bad in a Cessna 150!

Further investigation showed that my air speed indicator was actually
reading NEGATIVE!! It had wrapped around below zero.

My plane has a small cover over the pitot tube that should lift off the
pitot tube hole at flying speed. Normally as I begin my takeoff role the
cover 'pop's off at about 40 mph. On this takeoff roll the thing stayed
stuck, and I had an inoperative ASI.

I continued my climb, making sure to keep my climb shallow.

Once I had some altitude I tried doing shallow dives to increase the
airspeed and maybe 'pop' off the cover. No joy. I considered more
agressive dives, but decided that was a dumb idea.

I decided to continue to my destination. My destination is a quiet
airport with 11,000 foot runways, and that seemed a better place for my
first no-ASI landing than the rather busy Green Bay airport.

Many people would probably just land by feel, but I'm a numbers guy and
now I didn't have any numbers.

My plan was to come in with just below cruise power, keeping more than
90 mph on the GPS. Once over the runway I would cut the throttle and
wait for speed to fall. When the plane felt like landing I'd let it
touch down, being careful not to let the wheels hit the pavement at
90mph. With 11,0000 feet to use this should all be possible. I would
avoid the use of flaps since I was not sure when the plane would be in
the white arc, and no-flaps landings are easy in a Cessna 150.

To finish the story, the dang cover popped off after two hours of flying
and five minutes before landing. I never got to try my plan.


So, how would you deal with your first no-ASI landing?

Pitch and power will get you most of the way there, especially when
you have a long runway, and a draggy plane. For example, I know that
1900rpm, level, and 2 notch of flaps ~= 90mph in my plane. Trim for
this, and the plane will try to keep 90mph on the approach.

You can also fly the final approach course inbound & outbound, note
the groundspeeds, average them to get the winds, and then use this to
derive airspeed. Gotta be careful with this approach as winds aloft
are usually different than the winds at the surface.

I think your procedure was fine. Find a long runway, and be generous
with the speed.

As a sidenote, a check of the airspeed indicator should really be part
of your takeoff roll. As well, if it is a windy day, you can often
see if the ASI is working just by pointing the plane into the wind.