X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 28 Mar 2012 09:05:41 -0400 Message-ID: X-Original-Return-Path: Received: from imr-ma06.mx.aol.com ([64.12.78.142] verified) by logan.com (CommuniGate Pro SMTP 5.4.4) with ESMTP id 5459203 for lml@lancaironline.net; Wed, 28 Mar 2012 00:31:18 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.78.142; envelope-from=Sky2high@aol.com Received: from mtaomg-da03.r1000.mx.aol.com (mtaomg-da03.r1000.mx.aol.com [172.29.51.139]) by imr-ma06.mx.aol.com (8.14.1/8.14.1) with ESMTP id q2S4UcSk023299 for ; Wed, 28 Mar 2012 00:30:38 -0400 Received: from core-mtb002a.r1000.mail.aol.com (core-mtb002.r1000.mail.aol.com [172.29.234.197]) by mtaomg-da03.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 60572E000081 for ; Wed, 28 Mar 2012 00:30:38 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: <48e18.4014cedc.3ca3edee@aol.com> X-Original-Date: Wed, 28 Mar 2012 00:30:38 -0400 (EDT) Subject: Re: [LML] LNC2 gear diagnosis X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_48e18.4014cedc.3ca3edee_boundary" X-Mailer: AOL 9.6 sub 168 X-Originating-IP: [67.175.156.123] x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:392149088:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d338b4f7293ee5b23 --part1_48e18.4014cedc.3ca3edee_boundary Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en Danny, =20 From what you reported it would seem that the nose gear actuator is the =20 real problem. How about the door actuators? One possible analysis is tha= t=20 you don't see the 1200 psi because the leak is greater at the higher =20 pressure and then slows a bit as the pressure goes down or the actuator has= its =20 worse leak at full retraction and less when the piston is not at the full = =20 retraction position... =20 Scott Krueger =20 =20 In a message dated 3/27/2012 10:32:25 P.M. Central Daylight Time, =20 danny@n107sd.com writes: =20 If any of you have a suggestion, I=E2=80=99d appreciate your input.=20 On my last flight home, with no early signs of failure, my gear pump was= =20 tripping on about every 2 seconds to maintain pressure. I figured I had a= =20 leaky actuator and would have to rebuild it to resolve this; no big deal. = I=20 found one leaking and figured where there is one, there may be more. So,= =20 I=E2=80=99m rebuilding all of them. But, before doing so, I put a gauge o= n the=20 high pressure side of the pump to see if I had internal leaks there too. = =20 What I found was that my pump will only pressurize to about 950 psi (shoul= d be=20 ~1200 psi) and then it bleeds down slowly. I tried to adjust the =20 pressure switch but it made very little difference. To verify the bleeding= , I=20 isolated all actuators out of the system except the nose wheel. I put the= =20 gauge on the high pressure side of the NW actuator line, selected gear up = to=20 pressurize the system, and then quickly crawled under the plane to look at= =20 the gauge. It was bleeding down so fast that by the time I got down there= to=20 look at it (~2 sec.), it had already lost about 200 psi and then bled down= =20 the rest of the way in about 7 more seconds. So, and here=E2=80=99s the qu= estion,=20 do I have a faulty gear dump valve, a leaky pump, or both?=20 Danny=20 LNC2-360, ~550 hours=20 N 38=C2=B0 43' 25.7"=20 W 77=C2=B0 30' 38.6"=20 --part1_48e18.4014cedc.3ca3edee_boundary Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en

Danny,

From what you reported it would seem that the nose gear actuator is th= e=20 real problem. How about the door actuators? One possible analys= is is=20 that you don't see the 1200 psi because the leak is greater at the higher= =20 pressure and then slows a bit as the pressure goes down or the actuator has= its=20 worse leak at full retraction and less when the piston is not at the full= =20 retraction position...

Scott Krueger

In a message dated 3/27/2012 10:32:25 P.M. Central Daylight Time,=20 danny@n107sd.com writes:

=

If a= ny of you=20 have a suggestion, I=E2=80=99d appreciate your=20 input.

On m= y last=20 flight home, with no early signs of failure, my gear pump was tripping on= =20 about every 2 seconds to maintain pressure. I figured I had a leaky actuato= r and=20 would have to rebuild it to resolve this; no big deal. I found one leaking and figured= where=20 there is one, there may be more. = =20 So, I=E2=80=99m rebuilding all of them. =20 But, before doing so, I put a gauge on the high pressure side of t= he=20 pump to see if I had internal leaks there too. What I found was that my pump w= ill=20 only pressurize to about 950 psi (should be ~1200 psi) and then it bleeds= down=20 slowly. I tried to adjust = the=20 pressure switch but it made very little difference. To verify the bleeding, I isola= ted all=20 actuators out of the system except the nose wheel. I put the gauge on the high pre= ssure=20 side of the NW actuator line, selected gear up to pressurize the system, = and=20 then quickly crawled under the plane to look at the gauge. It was bleeding down so fast th= at by=20 the time I got down there to look at it (~2 sec.), it had already lost ab= out=20 200 psi and then bled down the rest of the way in about 7 more seconds. So, and here=E2=80=99s the ques= tion, do I have=20 a faulty gear dump valve, a leaky pump, or=20 both?

Danny

LNC2-360,=20 ~550 hours

N=20 38=C2=B0 43' 25.7"

W=20 77=C2=B0 30' 38.6"

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