Posted for "Rick Argente" <ricargente@cs.com>:

Hello folks,

We need some direction/input on a problem we recently uncovered a few
weeks ago. When we got the Super ES about a year ago, we were pretty
impressed by the speeds we were getting. Unfortunately, it was simply
too good to be true.

About two weeks ago, Michael and I were flying both the ES and the 360
and we decided to do some formation flying. Indicated airspeed
comparisons showed that the ES, at cruise settings, was indicating 15
knots faster! The slower we got, however, resulted in smaller airspeed
differences. At landing configuration, there was only 3 to 5 knots
difference.

I am pretty confident that the indicated airspeeds that the 360 is
showing is accurate. I have done extensive speed checks/tests during
the testing phase of this aircraft many years ago.

Any ideas what is causing this error? Our AP mechanic tested the
airspeed indicator using some sort of instrument device and he says that
the AI is working fine. He tested the AI by removing the pitot tube and
testing from a point that did not include the pitot tube. Right now, I
suspect two things, either (1) the airspeed indicator is not working
properly, contrary to the test conducted by our mechanic, or (2) there
is something wrong with the pitot tube.

Please feel free to toast our your thoughts on this matter. Thanks in
advance.

Rick Argente
N360ZR - LNC2
N82500 - LNCE

[Hi Rick, if the airspeed indicator is, in fact, working properly it would mean that there is excess pressure being picked up by the pitot tube, and that seems a pretty unlikely scenario. I would be looking for a problem in the static system (ie, a restriction resulting in reduced static pressure reaching the ASI). Are the altimeter and VSI giving proper indications? Have you tried installing a different ASI to compare indications? Do you get an expected result from the ASI when you comapre its indications when operated with the alternate static source? <Marv> ]