X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 03 Jan 2012 11:38:18 -0500 Message-ID: X-Original-Return-Path: Received: from imr-db01.mx.aol.com ([205.188.91.95] verified) by logan.com (CommuniGate Pro SMTP 5.4.3) with ESMTP id 5334485 for lml@lancaironline.net; Mon, 02 Jan 2012 13:11:39 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.188.91.95; envelope-from=Sky2high@aol.com Received: from mtaomg-mb01.r1000.mx.aol.com (mtaomg-mb01.r1000.mx.aol.com [172.29.41.72]) by imr-db01.mx.aol.com (8.14.1/8.14.1) with ESMTP id q02IAxOh031838 for ; Mon, 2 Jan 2012 13:10:59 -0500 Received: from core-mta002a.r1000.mail.aol.com (core-mta002.r1000.mail.aol.com [172.29.234.133]) by mtaomg-mb01.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id A5C07E000081 for ; Mon, 2 Jan 2012 13:10:59 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: <4e736.4672004a.3c334d33@aol.com> X-Original-Date: Mon, 2 Jan 2012 13:10:59 -0500 (EST) Subject: Re: [LML] old Lancair maintenance X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_4e736.4672004a.3c334d33_boundary" X-Mailer: AOL 9.7 sub 19 X-Originating-IP: [24.1.9.48] x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:478372416:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d29484f01f333164a --part1_4e736.4672004a.3c334d33_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Chris, All of the flexible fuel and oil hoses on my 1996 LNC2 are originally installed stainless steel braid covered teflon with steel fittings. All such hoses in the engine compartment are fire shielded and the fuel lines from the wings to the header tank are encased in Tygon tubing so that the SS braid will not chafe through anything. Yes, they weigh more that old style hoses, should not be twisted and will take a set over time - However, I have never had to replace any of them. Brake lines are the original Nylaflow, also encased in clear food-quality Tygon tubing for protection, properly supported near the brakes and with an ample curve so that gear retraction will only slightly twist them when everything is sucked up. I see no reason to replace them at this time. Flexible hydraulic lines are another story as the cosmetic covers show some deterioration and I have had to rebuild two of them over these many years. When they actually need service I will use professionally made SS/teflon high pressure lines and will replace all of them at once. Of course, one must remember my airplane rests in a heated hangar far from sea salt misted air when not on flights around the country. Uh, maybe I'll check things more carefully in 2016.... After all, I ignorantly assembled all of the hoses running hither and yon in my plane. I am sure these lines have a service life limit as do I. I am now entering a Zen-like trance seeking guidance from the ether. Scott Krueger N92EX Painfully slow built without the internet. In a message dated 1/2/2012 10:17:20 A.M. Central Standard Time, chris_zavatson@yahoo.com writes: I've been trying to establish criteria for parts replacement on a number of items. The latest of these would be hose assemblies. Manufacturer guidelines place the burden for determining useful life on the end user. It would also appear much more reliance is placed on external visual inspection than I would have expected in determining "condition" (SAE ARP 1658, "Visual Inspection Guide for Installed Hose Assemblies"). Nowhere have I found a criteria for determining the condition of the hose interior. Does anyone have any experience in this area? What do the airlines or maintenance shops use for replacement criteria? from Aeroquip: "The actual service life of a given hose assembly, in a given application, is dependent on many variable factors. These variable factors may include, but are not limited to, operating pressure, pressure surges, flexing, operating temperatures (both fluid and ambient), installed bend radius, cleaning solutions, ozone and assembly routing. Due to the variety of operating conditions and applications, the user, through their own analysis, testing and/or review of maintenance records and data, is ultimately responsible for making the final selection, of or decisions about replacement hose assemblies and assuring that all performance, safety and warning requirements of the application are met. ...... 1. Normal Duty Hoses Typically, these are hose assemblies in less demanding applications, such as in-body, in-wing or other applications not normally exposed to the environment, cleaning fluids, continuous temperature extremes, heavy pressure pulsation, etc., and having infrequent maintenance actions associated with their installation. Recommended Maintenance Approach: On Condition 2. Moderate or Heavy Duty Hoses Typically, these are hoses exposed to more frequent maintenance activity or major system removal, or hoses occasionally exposed to environmental conditions (e.g., upper wheel well hoses, APU hoses) Recommended Maintenance Approach: Either On-Condition or based on user data and maintenance records. 3. Demanding or Severe Duty Hoses Typically, these are hoses continuously or routinely exposed to environmental, cleaning, or other harsh operating variables such as landing gear brake hoses, EDP hoses, etc., and associated with major systems requiring regular removal, repair or overhaul. Recommended Maintenance Approach: Strongly consider replacement at time of major system overhaul." Chris Zavatson N91CZ 360std _www.N91CZ.net_ (http://www.n91cz.net/) --part1_4e736.4672004a.3c334d33_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Chris,
 
All of the flexible fuel and oil hoses on my 1996 LNC2 are originally= =20 installed stainless steel braid covered teflon with steel=20 fittings.  All such hoses in the engine compartment are fire shielded = and=20 the fuel lines from the wings to the header tank are encased in Tygon tubin= g so=20 that the SS braid will not chafe through anything. Yes, they weigh mor= e=20 that old style hoses, should not be twisted and will take a set over= =20 time - However, I have never had to replace any of them.
 
Brake lines are the original Nylaflow, also encased in clear=20 food-quality Tygon tubing for protection, properly supported near the= =20 brakes and with an ample curve so that gear retraction will only slightly t= wist=20 them when everything is sucked up.  I see no reason to replace them at= this=20 time.
 
Flexible hydraulic lines are another story as the cosmetic covers show= some=20 deterioration and I have had to rebuild two of them over these many years.&= nbsp;=20 When they actually need service I will use professionally made=20 SS/teflon high pressure lines and will replace all of them at once.
 
Of course, one must remember my airplane rests in a heated hangar far = from=20 sea salt misted air when not on flights around the country.
 
Uh, maybe I'll check things more carefully in 2016....  Afte= r=20 all, I ignorantly assembled all of the hoses running hither and yon in my= =20 plane.
 
I am sure these lines have a service life limit as do I.  I = am=20 now entering a Zen-like trance seeking guidance from the ether.
 
Scott Krueger
N92EX
Painfully slow built without the internet.
 
In a message dated 1/2/2012 10:17:20 A.M. Central Standard Time,=20 chris_zavatson@yahoo.com writes:
=
= I've been=20 trying to establish criteria for parts replacement on a number of items.&= nbsp;=20 The latest of these would be hose assemblies. =20 Manufacturer guidelines place the burden for deter= mining=20 useful life on the end user.  It would also appear much more relianc= e is=20 placed on external visual inspection t= han I=20 would have expected in determining "condition" (SAE ARP 165= 8, "Visual=20 Inspection Guide for Installed Hose Assemblies"). Nowhere have I fou= nd a=20 criteria for determining the condition of the hose interior.  Does a= nyone=20 have any experience in this area?  What do the airlines or=20 maintenance shops use for replacement criteria? 
 
from Aeroquip:
"The actual = service=20 life of a given hose assembly, in a given application, is dependent on ma= ny=20 variable factors. These variable factors may include, but are not limited= to,=20 operating pressure, pressure surges, flexing, operating temperatures (bot= h=20 fluid and ambient), installed bend radius, cleaning solutions, ozone and= =20 assembly routing. Due to the variety of operating conditions and applicat= ions,=20 the user, through their own analysis, testing and/or review of maintenanc= e=20 records and data, is ultimately responsible for making the final selectio= n, of=20 or decisions about replacement hose assemblies and assuring that all=20 performance, safety and warning requirements of the application are=20 met.
......
1.= Normal=20 Duty Hoses
Typically, these are hos= e=20 assemblies in less demanding applications, such as in-body, in-wing or ot= her=20 applications not normally exposed to the environment, cleaning fluids,=20 continuous temperature extremes, heavy pressure pulsation, etc., and havi= ng=20 infrequent maintenance actions associated with their installation. Recomm= ended=20 Maintenance Approach: On Condition
2. Moderate or Heavy Dut= y=20 Hoses
Ty= pically,=20 these are hoses exposed to more frequent maintenance activity or major sy= stem=20 removal, or hoses occasionally exposed to environmental conditions (e.g.,= =20 upper wheel well hoses, APU hos= es)=20 Recommended Maintenance Approach: Either On-Condition or based on user da= ta=20 and maintenance records.
3. Demanding or Severe D= uty=20 Hoses
Ty= pically,=20 these are hoses continuously or routinely exposed to environmental, clean= ing,=20 or other harsh operating variables
such as landing gear brake hoses, E= DP=20 hoses, etc., and associated with major systems requiring regular removal,= =20 repair or overhaul. Recommended Maintenance Approach: Strongly consider= =20 replacement at time of major system overhaul."
 
 
Chris Zavatson
N91CZ
360std
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