X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml Date: Tue, 01 Aug 2006 00:18:42 -0400 Message-ID: X-Original-Return-Path: Received: from mxsf27.cluster1.charter.net ([209.225.28.227] verified) by logan.com (CommuniGate Pro SMTP 5.1c.2) with ESMTP id 1330721 for lml@lancaironline.net; Mon, 31 Jul 2006 17:39:37 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.225.28.227; envelope-from=troneill@charter.net Received: from mxip16a.cluster1.charter.net (mxip16a.cluster1.charter.net [209.225.28.146]) by mxsf27.cluster1.charter.net (8.12.11/8.12.11) with ESMTP id k6VLcpq6030741 for ; Mon, 31 Jul 2006 17:38:51 -0400 Received: from 68-184-229-22.dhcp.stls.mo.charter.com (HELO axs) ([68.184.229.22]) by mxip16a.cluster1.charter.net with SMTP; 31 Jul 2006 17:38:51 -0400 X-IronPort-AV: i="4.07,199,1151899200"; d="scan'208,217"; a="655418080:sNHT33458124" X-Original-Message-ID: <02c901c6b4e9$b68ecf70$6501a8c0@axs> From: "terrence o'neill" X-Original-To: "Lancair Mailing List" References: Subject: Re: [LML] Re: response to Terrence O'Neill's posting.. X-Original-Date: Mon, 31 Jul 2006 16:38:50 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_02C6_01C6B4BF.CD4DD0A0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2905 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2869 This is a multi-part message in MIME format. ------=_NextPart_000_02C6_01C6B4BF.CD4DD0A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable My apologies, Brent. Sorry. I didn't mean to offend anyone. My = statistics were from more than 20 years ago, before computers. I hyave = since checked the 2004 data on one responder's suggestion, and found = GenAv has three times as many fatalities per aircraft hour flown than = airliners. I expe3ct that saying this will also poffend someone. My = apologies beforehand. Terrence ----- Original Message -----=20 From: Brent Regan=20 To: Lancair Mailing List=20 Sent: Sunday, July 30, 2006 11:25 PM Subject: [LML] Re: response to Terrence O'Neill's posting.. Terrence writes: <> Don't you just love statistics. Of the "lower" branches of mathematics = it is one of the least understood, and consequently, most abused. For = example, it is statistically accurate to say that everyone in the United = States has slightly less than one testicle. The average is skewed from a = whole number by the slightly higher population of females, and not = because of Lance Armstrong. Likewise, Terrence's statistical argument may be accurate (which it = does not seem to be for 2004 data) but it is not relevant. His is taking = the actuary's perspective where the insurance company is insuring the = entire airframe and the actuary must compute the death per flight hour = coefficient in order to determine the insurance premium. This is a risk = calculation, not a personal safety calculation. For the calculation to = have relevance to you it must be expressed in terms of your probability = of being one of the fatalities. As an individual I only care about my personal risk in evaluating = safety. How many hours do I need to fly before death is a near = certainty. If I happen to be the sole occupant or one of 200 passengers = it is irrelevant as I am just as dead, not 1/200 or 200 times as dead, = just dead. So, from the perspective of my safety I must evaluate the = probability of an accident in terms of my exposure over time, that = being passenger miles. If we were to take Terrence's argument that the metric it is aircraft = flight hours then it would also be argued that, among commercial = aircraft, the larger the aircraft the less safe it is. Given that any = particular accident would expose more passengers to risk the you would = be wise to fly on carriers with as few passengers as possible. I = believe the raw statistics would run counter to this logic. Safety must be evaluated in terms of the individual. Consequently the = "event" based evaluation is skewed by the average passenger load of the = compared group. If the average for GA is 2 passengers and the average = for commercial is 50 passengers then the relative ratio between the two = is 25. I did look up the statistics for 2004 as reported by the NTSB for the = US. I also found this site for a more comprehensive analysis: http://www.ntsb.gov/Aviation/stats.htm In 2004, GA had a total of 24 million total flight hours and = Commercial (10 seats or more) totaled 23 Million with flight hours = (about the same) GA killed 321 people in airplanes and another 241 on = the ground (562 total) and commercial killed 14 passengers and 26 on the = ground (40 total) (14 times more for GA). GA had a total of 1,669 = accidents and commercial had 111 (15 times more for GA). It seems that = in the US it is ~15 times safer to fly commercial vs. GA based on = flight hours and perhaps 20 to 50 times that if evaluated by passenger = miles. Remember, with statistics two plus two can be any number you want it = to be, depending on how you define the conditions. Regards Brent Regan ------=_NextPart_000_02C6_01C6B4BF.CD4DD0A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
My apologies, = Brent. =20 Sorry. I didn't mean to offend anyone.  My statistics were from = more than=20 20 years ago, before computers.  I hyave since checked the 2004 = data on one=20 responder's suggestion, and found GenAv has three times as many = fatalities per=20 aircraft hour flown than airliners. I expe3ct that saying this will also = poffend=20 someone.  My apologies beforehand.
Terrence
 
----- Original Message -----
From:=20 Brent=20 Regan
Sent: Sunday, July 30, 2006 = 11:25=20 PM
Subject: [LML] Re: response to = Terrence=20 O'Neill's posting..

Terrence = writes:
<<Have you=20 researched accidetn data (like I did) and found that the airlines = report=20 safety in terms of passesnger miles?  Is a 747 with 500 = passengers 500=20 times safer than one with jujst crew?  And since that's abviously = a lying=20 statistic,  = >>

Don't you just=20 love statistics. Of the "lower" branches of mathematics it is one of = the least=20 understood, and consequently, most abused. For example, it is = statistically=20 accurate to say that everyone in the United States has slightly less = than one=20 testicle. The average is skewed from a whole number by the slightly = higher=20 population of females, and not because of Lance = Armstrong.

Likewise,=20 Terrence's statistical argument may be accurate (which it does not = seem to be=20 for 2004 data) but it is not relevant. His is taking the actuary's = perspective=20 where the insurance company is insuring the entire airframe and the = actuary=20 must compute the death per flight hour coefficient in order to = determine the=20 insurance premium. This is a risk calculation, not a personal safety=20 calculation. For the calculation to have relevance to you it = must be=20 expressed in terms of your probability of being one of the=20 fatalities.

As an individual I only care about my personal risk = in=20 evaluating safety. How many hours do I need to fly before death is a = near=20 certainty. If I happen to be the sole occupant or one of 200 = passengers it is=20 irrelevant as I am just as dead, not 1/200 or 200 times as dead, just = dead.=20 So, from the perspective of my safety I must evaluate the probability = of an=20 accident in terms of  my exposure over time, that being passenger = miles.

If we were to take Terrence's argument that the metric = it=20 is aircraft flight hours then it would also be argued that, = among=20 commercial aircraft, the larger the aircraft the less safe it is. = Given that=20 any particular accident would expose more passengers to risk the you = would be=20 wise to fly on carriers with as few passengers as possible.  I = believe=20 the raw statistics would run counter to this logic.

Safety must = be=20 evaluated in terms of the individual. Consequently the "event" based=20 evaluation is skewed by the average passenger load of the compared = group. If=20 the average for GA is 2 passengers and the average for commercial is = 50 =20 passengers then the relative ratio between the two is 25.

I did = look up=20 the statistics for 2004 as reported by the NTSB for the US.  I = also found=20 this site for a more comprehensive analysis:
http://www.ntsb.gov/Aviat= ion/stats.htm

In=20 2004, GA had a total of 24 million total flight hours and Commercial (10 seats or more) totaled 23 Million=20 with flight hours (about the same) = GA killed 321 people in airplanes and another 241 on the = ground=20 (562 total) and commercial killed 14 passengers and 26 on the ground = (40=20 total) (14 times more for GA). GA had a total of 1,669 accidents and=20 commercial had 111 (15 times more for GA).  It seems that in the = US it is=20 ~15 times safer to fly  commercial vs. GA based on  flight = hours and=20 perhaps 20 to 50 times that if evaluated by passenger = miles.

Remember,=20 with statistics two plus two can be any number you want it to be, = depending on=20 how you define the conditions.

Regards
Brent=20 Regan
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