Return-Path: Sender: (Marvin Kaye) To: lml Date: Wed, 18 Sep 2002 17:53:42 -0400 Message-ID: X-Original-Return-Path: Received: from [148.78.247.23] (HELO cassiopeia.email.starband.net) by logan.com (CommuniGate Pro SMTP 4.0b7) with ESMTP id 1736407 for lml@lancaironline.net; Wed, 18 Sep 2002 12:28:27 -0400 Received: from starband.net (vsat-148-64-23-255.c050.t7.mrt.starband.net [148.64.23.255]) by cassiopeia.email.starband.net (8.12.4/8.12.4) with ESMTP id g8IGSEJH022250 for ; Wed, 18 Sep 2002 12:28:19 -0400 X-Original-Message-ID: <3D88AAC0.4050805@starband.net> X-Original-Date: Wed, 18 Sep 2002 09:33:04 -0700 From: "Hamid A. Wasti" User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 X-Accept-Language: en-us, en MIME-Version: 1.0 X-Original-To: " (Lancair Mailing List)" Subject: Re: [LML] Need Help - Which Lancair is capable of "safe" IFR? References: Content-Type: multipart/alternative; boundary="------------030609040607050809010405" --------------030609040607050809010405 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Bill wrote: > So, I would like to hear from those who are flying IFR in non carbon > fiber Lancairs as to what risk you think actually exists with > structural failure due to lightning strikes. While I have no knowledge of specific incidents of lightning strikes in Lancairs and I did not stay at a Holiday Inn last night either, I did spend quite a bit of time in recent weeks at a lightning test facility doing lightning certification for the Sierra Flight Systems EFIS and have picked up a few tidbits from the folks that do this testing for the FAA. According to the tester, a full blown lightning bolt has about 200,000 Amps (yes, that 200 Kilo-Amps) of current. The bad news is that no composite plane is going to survive that. The good news is that most lightning bolts carry much less punch. The even better news is that a composite plane does not provide an attractive target for a lightning bolt looking to pounce at something. Most lightning strikes that we hear about are a small splinters of the main bolt and hit with significantly less power, in the 1000's of amps or less, not 100s of thousands of amps. Even then, 1000 amps going through your airframe is not going to be pleasant or inconsequential. Then there is the issue of induced currents in your airplane's wiring from a lightning bolt passing near the airplane. For flight critical hardware, the regulations call for all the pins to be injected with several hundred volts with up to 100+ amps of current. That corresponds to a lightning bolt happening somewhere close to the airplane and not actually hitting the airplane. I will bet my bottom dollar that there is no COTS hardware out there that can sustain that kind of a test. Think about that before you decide to go flying IFR in your home brewed EFIS with no backups. Hamid P.S. For our non-US membership, the "Holiday Inn" comment refers to a very lame TV add running in the US where a person goes around offering advise to everyone about everything because he feels extremely smart because he stayed at a Holiday Inn last night. --------------030609040607050809010405 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit Bill wrote:

So, I would like to hear from those who are flying IFR in non carbon fiber Lancairs as to what risk you think actually exists with structural failure due to lightning strikes.

While I have no knowledge of specific incidents of lightning strikes in Lancairs and I did not stay at a Holiday Inn last night either, I did spend quite a bit of time in recent weeks at a lightning test facility doing lightning certification for the Sierra Flight Systems EFIS and have picked up a few tidbits from the folks that do this testing for the FAA.

According to the tester, a full blown lightning bolt has about 200,000 Amps (yes, that 200 Kilo-Amps) of current. The bad news is that no composite plane is going to survive that. The good news is that most lightning bolts carry much less punch. The even better news is that a composite plane does not provide an attractive target for a lightning bolt looking to pounce at something. Most lightning strikes that we hear about are a small splinters of the main bolt and hit with significantly less power, in the 1000's of amps or less, not 100s of thousands of amps. Even then, 1000 amps going through your airframe is not going to be pleasant or inconsequential. Then there is the issue of induced currents in your airplane's wiring from a lightning bolt passing near the airplane.

For flight critical hardware, the regulations call for all the pins to be injected with several hundred volts with up to 100+ amps of current. That corresponds to a lightning bolt happening somewhere close to the airplane and not actually hitting the airplane. I will bet my bottom dollar that there is no COTS hardware out there that can sustain that kind of a test. Think about that before you decide to go flying IFR in your home brewed EFIS with no backups.

Hamid

P.S. For our non-US membership, the "Holiday Inn" comment refers to a very lame TV add running in the US where a person goes around offering advise to everyone about everything because he feels extremely smart because he stayed at a Holiday Inn last night.

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