Return-Path: Sender: (Marvin Kaye) To: lml Date: Sun, 28 Sep 2003 15:55:02 -0400 Message-ID: X-Original-Return-Path: Received: from imo-r05.mx.aol.com ([152.163.225.101] verified) by logan.com (CommuniGate Pro SMTP 4.1.4) with ESMTP id 2607023 for lml@lancaironline.net; Sun, 28 Sep 2003 12:19:37 -0400 Received: from JIMRHER@aol.com by imo-r05.mx.aol.com (mail_out_v36_r1.1.) id q.11a.28cdf2a9 (25305) for ; Sun, 28 Sep 2003 12:19:32 -0400 (EDT) From: JIMRHER@aol.com X-Original-Message-ID: <11a.28cdf2a9.2ca86414@aol.com> X-Original-Date: Sun, 28 Sep 2003 12:19:32 EDT Subject: Re: gliding distance and Loss of Pressurization X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_11a.28cdf2a9.2ca86414_boundary" X-Mailer: 8.0 for Windows sub 910 --part1_11a.28cdf2a9.2ca86414_boundary Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable I have a L4P and have been spending a lot of time at FL 240/250. I also=20 investigated this as much as one can before getting comfortable up there. My= =20 comments are below. Jim Hergert table of "Times of Useful Consciousness" on th= e=20 USAF flight surgeon guide...> =A0 FL 180 20 to 30 Min =20 FL 220 10 Min =20 FL 250=A0 3 to 5 Min =20 FL 280 2.5 to 3 Min =20 =A0 Two things to note are that these are "average" times and also that they are= =20 not to total incapacitation. =A0 From listening to you all and reading on the net, I'd guess that most of the= =20 IV-P owners cruise between FL220 and FL260.=A0 I can't find any specs =20 online about the IVP emergency descent rates--I'd bet it was at least 2500 F= PM=20 when you drop the flaps, gear, and go up on a wing =A0 I'm thinking you= 'd=20 have plenty of time to get down to where you wouldn't have many problems fly= ing=20 your aircraft.=A0 FL200 does seem to be the "magic number"=A0 (I don't smoke= at=20 all.)=A0 But even after that..you would still have to get your bird down on=20= the=20 ground..preferably on an airport w/ paved runways..which brings me back to m= y=20 original question.=A0=20 =A0 How far=A0could you expect to glide if you had to?=A0=A0Also, have any of=20 you=A0gotten=A0your high altitude sign-off in a chamber?=A0=A0I'd be interes= ted in it=20 eventually if you felt=A0that it was worth it as far as=A0future recognition= of the signs=20 of the onset of hypoxia.=A0 IT just seems like a good idea but I've spoken t= o=20 very=A0few GA pilots that have actually gone through the process.=A0=20 =A0 Tom, I'm definately with you on being pumped up on adrenaline--there is=20 nothing quieter than hearing your engine "quit" all of a sudden and then jus= t the=20 whistling wind. =A0 Thank you all for the information, Adam =20 Time of useful Consciousness I was told was less than 2 min. at FL250,=20 However, I had the experience of going through the Altitude chamber at Edwar= ds=20 Airforce Base with 25 other folks. I can briefly say that all the woman had=20= to put=20 on the Ox mask at 10K ft. and one guy had his lips turn blue and could not p= ut=20 on his own mask at 11K ft. I was writing and doing OK until about 19K ft.=20 ,put the Ox mask on, and after that they started asking tricky questions. I=20= had=20 my Ox mask on and was stumped on half the questions. I had a fellow friend=20 there that weighs 110 lbs and is just under 5 foot tall that was sharp and c= ould=20 answer all questions up to 28K ft. where they stopped the test and said he w= on.=20 Then they do a rapid decompression which fogs up the chamber and your ears.=20 But that is why you must take this test in the military so you know your own= =20 tolerance. Night time your affected altitude is lower by at least 5K ft. Another time I was flying my A36 over the Sierra's and while climbing to 14K= =20 ft. I wasn't on Ox, I tried to follow a low ravine to give me more terrain=20 clearance. It was more than 15 min. before I noticed that I had turned 90* f= rom=20 my intended track and I was not crossing the mountains, just flying along a=20 ridge. I was looking at heading and Loran and still not aware. Scary thought= . L4P emergency descents? First, I hang the Ox mask around my neck and have it= =20 plugged in and tested before I take off into the FL's. With the pressurizati= on=20 controller you can select the rate of cabin altitude change you want from 25= 0=20 to 1000 fpm. I have mine on 250 fpm. I normally trim descend at 1K to 2K fpm= =20 without changing any settings. I have tried 4K fpm descents without changing= =20 the engine and guess what? This airplane likes it. There is no problems. You= =20 don't come close to the 274 KIAS Vne. They teach you that you can't go over=20= 225=20 KIAS at FL250 because your Mmo is .6 Mach. However, if you loose an engine a= nd=20 need to get down, don't worry about Mmo. I know two L4 pilots that have seen= =20 way over 300 KIAS (they won't tell me how much over). Also, I talked to one=20 pilot/owner who had the door window blow out two different times at FL250. H= e=20 didn't put on the OX mask just pushed the nose over and got it down to 15K i= n=20 about 2 min. The most likely failure to have is either a window break or a Turbo hose=20 fail. My procedure will be to push over the nose to at least 5K fpm, watch the=20 airspeed, use the speed brakes if needed, close the incoming pressurization=20= valve,=20 and last put on the OX mask. I know that if you pull the engine back to idle you loose pressurization=20 fast. I think the outflow valve will do -250 fpm but the inlet valve will n= eed to=20 be closed very fast to stop the back flow. Has anyone tried this test on the= =20 ground? If anyone is pressure testing on the ground and one is inside the=20 cabin please try to close the inlet and have the outflow set at its lowest r= ate=20 and see how long it takes for the cabin altitude to go down. I would like to= =20 know for sure if closing the inlet value works? The Gliding distance. In the SFS EFIS you put in a ratio that is displayed a= t=20 a round circle modified my winds and terrain. I have 11 to 1 in mine but I=20 know that is with the Prop pulled to course pitch. You must have oil pressur= e to=20 do this. Also, I know that if you have a Full Feathering Prop Stopped, the=20 glide ratio goes up to over 20 to 1. That is a long way when at 250, which I= =20 don't want to test. Inputs appreciated, Jim Hergert N6XE, "An Sex Y" L4P --part1_11a.28cdf2a9.2ca86414_boundary Content-Type: text/html; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable I have a L4P and have been spending a= lot of time at FL 240/250. I also investigated this as much as one can befo= re getting comfortable up there. My comments are below. Jim Hergert

table of "Times of Useful Consciousness" <after losing pressurization>= on the USAF flight surgeon guide...>
=A0
FL 180 20 to 30 Min
FL 220 10 Min
FL 250=A0 3 to 5 Min
FL 280 2.5 to 3 Min

=A0
Two things to note are that=20= these are "average" times and also that they are not to total incapacitation= .
=A0
From listening to you all an= d reading on the net, I'd guess that most of the IV-P owners cruise between=20= FL220 and FL260.=A0 I can't find any specs <anyone> online about the I= VP emergency descent rates--I'd bet it was at least 2500 FPM when you drop t= he flaps, gear, and go up on a wing <of course assuming that you do it th= e same in a lancair as in a piper or cessna>=A0 I'm thinking you'd have p= lenty of time to get down to where you wouldn't have many problems flying yo= ur aircraft.=A0 FL200 does seem to be the "magic number"=A0 (I don't smoke a= t all.)=A0 But even after that..you would still have to get your bird down o= n the ground..preferably on an airport w/ paved runways..which brings me bac= k to my original question.=A0
=A0
How far=A0could you expect t= o glide if you had to?=A0=A0Also, have any of you=A0gotten=A0your high altit= ude sign-off in a chamber?=A0=A0I'd be interested in it eventually if you fe= lt=A0that it was worth it as far as=A0future recognition of the signs of the= onset of hypoxia.=A0 IT just seems like a good idea but I've spoken to very= =A0few GA pilots that have actually gone through the process.=A0
=A0
Tom, I'm definately with you= on being pumped up on adrenaline--there is nothing quieter than hearing you= r engine "quit" all of a sudden and then just the whistling wind.
=A0
Thank you all for the inform= ation,
Adam

Time of use= ful Consciousness I was told was less than 2 min. at FL250, However, I had t= he experience of going through the Altitude chamber at Edwards Airforce Base= with 25 other folks. I can briefly say that all the woman had to put on the= Ox mask at 10K ft. and one guy had his lips turn blue and could not put on=20= his own mask at 11K ft. I was writing and doing OK until about 19K ft. ,put=20= the Ox mask on, and after that they started asking tricky questions. I had m= y Ox mask on and was stumped on half the questions. I had a fellow friend th= ere that weighs 110 lbs and is just under 5 foot tall that was sharp and cou= ld answer all questions up to 28K ft. where they stopped the test and said h= e won. Then they do a rapid decompression which fogs up the chamber and your= ears. But that is why you must take this test in the military so you know y= our own tolerance. Night time your affected altitude is lower by at least 5K= ft.

Another time I was flying my A36 over the Sierra's and while climbing to 14K= ft. I wasn't on Ox, I tried to follow a low ravine to give me more terrain=20= clearance. It was more than 15 min. before I noticed that I had turned 90* f= rom my intended track and I was not crossing the mountains, just flying alon= g a ridge. I was looking at heading and Loran and still not aware. Scary tho= ught.

L4P emergency descents? First, I hang the Ox mask around my neck and have it= plugged in and tested before I take off into the FL's. With the pressurizat= ion controller you can select the rate of cabin altitude change you want fro= m 250 to 1000 fpm. I have mine on 250 fpm. I normally trim descend at 1K to=20= 2K fpm without changing any settings. I have tried 4K fpm descents without c= hanging the engine and guess what? This airplane likes it. There is no probl= ems. You don't come close to the 274 KIAS Vne. They teach you that you can't= go over 225 KIAS at FL250 because your Mmo is .6 Mach. However, if you loos= e an engine and need to get down, don't worry about Mmo. I know two L4 pilot= s that have seen way over 300 KIAS (they won't tell me how much over). Also,= I talked to one pilot/owner who had the door window blow out two different=20= times at FL250. He didn't put on the OX mask just pushed the nose over and g= ot it down to 15K in about 2 min.

The most likely failure to have is either a window break or a Turbo hose fai= l.

My procedure will be to push over the nose to at least 5K fpm, watch the air= speed, use the speed brakes if needed, close the incoming pressurization val= ve, and last put on the OX mask.

I know that if you pull the engine back to idle you loose pressurization fas= t. I think the outflow valve will do  -250 fpm but the inlet valve will= need to be closed very fast to stop the back flow. Has anyone tried this te= st on the ground? If anyone is pressure testing on the ground and one is ins= ide the cabin please try to close the inlet and have the outflow set at its=20= lowest rate and see how long it takes for the cabin altitude to go down. I w= ould like to know for sure if closing the inlet value works?

The Gliding distance. In the SFS EFIS you put in a ratio that is displayed a= t a round circle modified my winds and terrain. I have 11 to 1 in mine but I= know that is with the Prop pulled to course pitch. You must have oil pressu= re to do this. Also, I know that if you have a Full Feathering Prop Stopped,= the glide ratio goes up to over 20 to 1. That is a long way when at 250, wh= ich I don't want to test.

Inputs appreciated,

Jim Hergert=
N6XE, "An Sex Y" L4P
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