Return-Path: Sender: (Marvin Kaye) To: lml Date: Sun, 08 Jun 2003 21:04:36 -0400 Message-ID: X-Original-Return-Path: Received: from imo-m01.mx.aol.com ([64.12.136.4] verified) by logan.com (CommuniGate Pro SMTP 4.1b7) with ESMTP id 2407850 for lml@lancaironline.net; Sun, 08 Jun 2003 20:28:57 -0400 Received: from JIMRHER@aol.com by imo-m01.mx.aol.com (mail_out_v36.3.) id q.40.302eabc3 (3850) for ; Sun, 8 Jun 2003 20:28:49 -0400 (EDT) From: JIMRHER@aol.com X-Original-Message-ID: <40.302eabc3.2c152ec1@aol.com> X-Original-Date: Sun, 8 Jun 2003 20:28:49 EDT Subject: Over the line X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_40.302eabc3.2c152ec1_boundary" X-Mailer: 8.0 for Windows sub 910 --part1_40.302eabc3.2c152ec1_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit I had assumed (incorrectly it seems) that it would be OK to discuss data that was consistent with the initial report in the context of improving flight safety Damn, That really bothers me. I want to say a BIG thanks to Brent for sharing this information with us experimenters about an experimental issue. The feds have to worry about being sued or having to change there determination on a preliminary statement but then this wasn't the feds. I for one, flying a L4P for 180 hrs with a SFS am interested in anything that helps. Along that line, I guess I should speak out on my experiences with AHRS and the SFS just to support what Kirk has said about testing each system completely. I think the Chelton Flight System is the best tested and most honest group of folks in the Avionics business. I started with the Watson AHRS and while it worked it had some problems that we and they chased for some time. It had interference from my autopilot servos and even after moving them it required several flights with data gathering computer hooked up to the AHRS to gather enough flight information to reprogram the firmware in the AHRS to be more accurate and therefore unique to my airplane. Even then, making S turns at 2.5 G's would upset the heading and attitude enough to cause a Ghost on the PFD, heading off more than 15*. Not IFR at all. Later, after about 70 hrs, we changed the AHRS to the Crossbow 400. This was markedly better and I came to trust it very much, Until, one day I took a solo flight where I didn't have the wings level for about 15 min. and was pulling 2.5 to 3 G's in turbulent air. When I looked at the PFD it had a left banked horizon by 15* while in level flight. Also, upon landing if you brake hard and then turn off the runway the horizon would tilt maybe 5* almost always. This kept me from considering hard IFR. While flying level on AP the SFS will correct the horizon about 1* per min. Heading seamed OK. At 170 hrs I installed the Crossbow 500 and I must say that it is more steady, less nervous, on the display to where I can't see any jumping of symbols. And I had to fly hard IFR with it. It has not tilted on landing and is calibrated to within 1* of accuracy. I think I can adjust my Mag. compass by my EFIS and be more accurate than using a compass rose. Also, I have to say that my backup AH is a RC Allen electric CERTIFIED IFR unit and it never comes out of those S turns with the horizon level. It has been back to them 3 times. In summary I know you can buy all the sensors for an AHRS for about $400. or spend a lot more. This Crossbow 500 sells for $15,000. and is worth it. Please don't be fooled by the low cost EFIS's until they go through what CFS has gone through, testing and upgrading. I now trust the CFS- Sierra and my TruTrak to do hard IFR. My comment on the crash issue is; Aviate, Navigate, Communicate in that order. If we fill the cockpit with Traffic and Weather Information and we don't deviate from a known danger path until ATC clears us you just may be dead. Fly safely. Thanks to Brent we all know more because he shared this information. My heart goes out to all those who are affected by this tragedy. Sincerely, Jim Hergert N6XE, "An Sex Y" L4P --part1_40.302eabc3.2c152ec1_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
I had assumed (incorrectly i= t seems) that it would be OK to discuss data that was consistent with the in= itial report in the context of improving flight safety




Damn, That really bothers me. I want to say a BIG thanks to Brent for sharin= g this information with us experimenters about an experimental issue. The fe= ds have to worry about being sued or having to change there determination on= a preliminary statement but then this wasn't the feds. I for one, flying a=20= L4P for 180 hrs with a SFS am interested in anything that helps.

Along that line, I guess I should speak out on my experiences with AHRS and=20= the SFS just to support what Kirk has said about testing each system complet= ely. I think the Chelton Flight System is the best tested and most honest gr= oup of folks in the Avionics business.

I started with the Watson AHRS and while it worked it had some problems that= we and they chased for some time. It had interference from my autopilot ser= vos and even after moving them it required several flights with data gatheri= ng computer hooked up to the AHRS to gather enough flight information to rep= rogram the firmware in the AHRS to be more accurate and therefore unique to=20= my airplane. Even then, making S turns at 2.5 G's would upset the heading an= d attitude enough to cause a Ghost on the PFD, heading off more than 15*. No= t IFR at all.
Later, after about 70 hrs, we changed the AHRS to the Crossbow 400. This was= markedly better and I came to trust it very much, Until, one day I took a s= olo flight where I didn't have the wings level for about 15 min. and was pul= ling 2.5 to 3 G's in turbulent air. When I looked at the PFD it had a left b= anked horizon by 15* while in level flight. Also, upon landing if you brake=20= hard and then turn off the runway the horizon would tilt maybe 5* almost alw= ays. This kept me from considering hard IFR. While flying level on AP the SF= S will correct the horizon about 1* per min. Heading seamed OK.
At 170 hrs I installed the Crossbow 500 and I must say that it is more stead= y, less nervous, on the display to where I can't see any jumping of symbols.= And I had to fly hard IFR with it. It has not tilted on landing and is cali= brated to within 1* of accuracy. I think I can adjust my Mag. compass by my=20= EFIS and be more accurate than using a compass rose. Also, I have to say tha= t my backup AH is a RC Allen electric CERTIFIED IFR unit and it never comes=20= out of those S turns with the horizon level. It has been back to them 3 time= s.
In summary I know you can buy all the sensors for an AHRS for about $400. or= spend a lot more. This Crossbow 500 sells for $15,000. and is worth it. Ple= ase don't be fooled by the low cost EFIS's until they go through what CFS ha= s gone through, testing and upgrading.

I now trust the CFS- Sierra and my TruTrak to do hard IFR.

My comment on the crash issue is;
Aviate, Navigate, Communicate in that order. If we fill the cockpit w= ith Traffic and Weather Information and we don't deviate from a known danger= path until ATC clears us you just may be dead. Fly safely. Thanks to Brent=20= we all know more because he shared this information.

My heart goes out to all those who are affected by this tragedy.
Sincerely,
Jim Hergert
N6XE, "An Sex Y" L4P
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