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  #32  
Old January 12th 05, 11:58 PM
Sriram Narayan
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"Gary Drescher" wrote in message
...
"dlevy" wrote in message
...
I had a pitot/static problem as a new PPL (clear weather) that was very
exciting. Airspeed was fine till about 20 feet off the ground. At that
point airspeed would start dropping. I kept pushing the nose over and
airspeed kept dropping. I then realized rpm's were normal, the propellor
was attached, and everything sounded right. It scared the bejezus outta
me. Turned out to be water in the static line. Afterwards, I realized I
was way too dependant on that one indicator. Had it been IMC, it could
have been very ugly.


Hm, shouldn't a blocked static line cause the airspeed indicator to show

an
increase in airspeed, rather than a decrease, with increasing altitude?


It would indicate a lower airspeed.

The pitot ram air pressure for a given airspeed decreases with higher
altitude. If the static port were blocked (at say, the takeoff altitude),
the airspeed would "indicate" a lower airspeed since the pitot pressure has
dropped for that airspeed as the plane gains altitude. As another poster
commented, the only altitude where the ASI is accurate is at the altitude
where the blockage occurred.