Mailing List lml@lancaironline.net Message #44167
From: <Sky2high@aol.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Airspeed Indicator Consult
Date: Wed, 26 Sep 2007 08:22:17 -0400
To: <lml@lancaironline.net>
In a message dated 9/25/2007 11:56:07 P.M. Central Daylight Time, Lancair1@bellsouth.net writes:
So, we have here a situation in which the AS tested out fine on the ground, and bad in the air. Any idea why?
Doug,
 
If one believes that the pitot side (all the way from the pitot tube to the AS) is good, then the static side should be checked. Did the mechanic actually test the pitot part of the system by pressurizing the wing mounted pitot tube as opposed to supplying pressure to the AS pitot port?  Can you test the pitot system with the engine running as vibration might expose the problem.  Was it tested with the cockpit pressurized?
 
The pitot/static systems only come together in possibly 3 places - AS indicator, air speed driven squat switch and an AOI system (if any).  Is it possible that air pressure related to air speed is getting into the static side - i.e. was your VS or altimeter operating properly during the takeoff roll and the short flight?  Is it possible that there is water in the static line?  Could you try to pressurize (lower) the static system at the static port and check that the VS and altimeter are operating properly?  
 
Scott Krueger AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL (KARR)

Darwinian culling phrase: Watch This!




See what's new at AOL.com and Make AOL Your Homepage.
Subscribe (FEED) Subscribe (DIGEST) Subscribe (INDEX) Unsubscribe Mail to Listmaster