X-Virus-Scanned: clean according to Sophos on Logan.com X-PolluStop: No license found, only first 5 messages were scanned Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 26 Jun 2006 01:24:36 -0400 Message-ID: X-Original-Return-Path: Received: from cronus.email.starband.net ([148.78.247.54] verified) by logan.com (CommuniGate Pro SMTP 5.1c.1) with ESMTP id 1205360 for lml@lancaironline.net; Sun, 25 Jun 2006 01:43:18 -0400 Received-SPF: none receiver=logan.com; client-ip=148.78.247.54; envelope-from=hwasti@starband.net Received: from [127.0.0.1] (vsat-148-64-23-255.c050.t7.mrt.starband.net [148.64.23.255]) by cronus.email.starband.net (8.13.6/8.12.11) with ESMTP id k5P5gHRi026873 for ; Sun, 25 Jun 2006 01:42:25 -0400 X-Original-Message-ID: <449E2222.9050706@starband.net> X-Original-Date: Sat, 24 Jun 2006 22:41:54 -0700 From: "Hamid A. Wasti" User-Agent: Thunderbird 1.5.0.4 (Windows/20060516) MIME-Version: 1.0 X-Original-To: Lancair Mailing List Subject: Re: [LML] Re: Sterling Ainsworth accident References: In-Reply-To: Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV version 0.86.2, clamav-milter version 0.86 on cronus.email.starband.net X-Virus-Status: Clean colyncase on earthlink wrote:

where does the lack of gyron come in to play? are you saying a CFS doesn't know which way is up if the pitot is blocked?

The CFS system displays what the sensors tell it to display. I believe the aircraft had a Crossbow 520 which to the best of my recollection uses GPS aiding, not air data aiding to compute the attitude. On April 9, I posted the following to the LML, guessing what the pilot may have seen:

While we are talking scary, think about the following scenario:

The pitot tube is blocked due to icing. The windshield may be iced over as well, blocking all outside references even if the airplane does break out into VMC.

The airplane is descending, causing the indicated airspeed to decrease (the difference between the increasing static pressure at lower altitudes and the "high pressure" air trapped in the pitot system is becoming less and less).

The pilot pushes the nose down making the dive steeper and decreasing the ground speed reported by the GPS. The decreasing ground speed correlates with the decreasing indicated airspeed. Even the unwinding altimeter could be interpreted as a stalled airplane in a descent by someone focused on a stall as the main problem.

Can an average pilot assess the situation with enough confidence to overcome all their training and cut the power and pull up when everything is pointing to a stall or an imminent stall? Can an average pilot do that in less time than it took you to read this post?