Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Wed, 27 Oct 2004 00:28:48 -0400 Message-ID: X-Original-Return-Path: Received: from [203.220.32.147] (HELO relay01.mail-hub.kbs.net.au) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 487586 for lml@lancaironline.net; Tue, 26 Oct 2004 19:02:02 -0400 Received-SPF: none receiver=logan.com; client-ip=203.220.32.147; envelope-from=goconnell@dodo.com.au Received: from [10.2.3.72] (helo=DodoInternetWebmailServer) by relay01.mail-hub.kbs.net.au with smtp (Exim 3.36 #2) id 1CMaJm-00063R-00 for lml@lancaironline.net; Wed, 27 Oct 2004 09:01:30 +1000 Received: from client 203.220.142.166 for UebiMiau2.7 (webmail client); Wed, 27 Oct 2004 9:01:30 +1000 X-Original-Date: Wed, 27 Oct 2004 9:01:30 +1000 From: "Gerard O Connell" X-Original-To: "Lancair Mailing List" Reply-to: "Gerard O Connell" Subject: LNC2 Leaking Wing X-Priority: 3 X-Mailer: Dodo Internet Webmail Server X-Original-IP: 203.220.142.166 Content-Transfer-Encoding: 8bit X-MSMail-Priority: Medium Importance: Medium Content-Type: text/html; charset="iso-8859-1"; MIME-Version: 1.0 X-Original-Message-Id:

Dear all, though you might be interested in the following findings of a Neico build Lancair. Fortunately, it is not my aircraft, but another which came in for a tyre change. The work shop asked if I could share the info with the forum and ascertain if anyone has had a similar (unfortunate) experience or heard of such an occurence.

During an unscheduled tyre and tube change, it was discovered that fuel was dripping out of the R/H wing at the wing attach point . Initially a faulty drain was suspected but further investigation found the fuel to be weeping out of the leading edge rib past proseal which has been used to seal around an electrical wiring conduit. So the fuel was drained from the fuel tanks and the wiring removed. As removal took place it was noticed that a substantial amount of fuel was sloshing around in the leading edge, so a hole was cut in the inboard rib to investigate. Approximately 7 litres of fuel drained out of the leaking edge.

We suspect the fuel got into the leading edge by passing through some defective part of the integral fuel tank, through the skin or spar and into the leading edge.

The reason the defect was not discovered until now was that the leading edge is almost completely sealed apart from the conduit, which allows the wires for the strobe light to pass through. Upon drilling the hole in the leading edge and draining the fuel we inserted a optical fibre scope for inspection, the result was inconclusive. We also inserted the probe into the fuel tanks (both inboard and out board and found some signs that look like tears starting to form in the fibres and defective resin. But until the wing is cut open it may be impossible to determine if these were actual defects or just darken spots in the layup of the spar. Several of our engineers and trained technicians from the Australian NDT services all viewed the possible defects in the wing with optical fibre scope.

Our engineers have expressed concerns for this type of design and in particular the previous history of AD/Lancair/2.this particular aircraft appears to be a Neico build not an Avtex.

Because this aircraft has had a sloshing compound in the R/H wing at least three times over the years.
Because there are no inspection panels in the leading edge
Because the leading edge is totally sealed, apart from the electrical conduit it was only a matter of time before the fuel level in the wing made it up to the strobe light and possibly an explosion with the right fuel air mixture. The only other way in which this may have been discovered is if fuel was running out of the conduit, which finishes up near the cockpit.
The fuel has been sitting in the leading edge for an unknown time- what effect does this have on the resins, fibres and honeycomb, already there are small delaminations appearing under the paint and inside the fuel tank.
The imbalance fuel effect on control during high wing loadings/slow speeds. We estimate that the amount of fuel could have doubled before any signs may have been evident.

Aircraft history:

Date

17.1.1994ЕЕ Statement of Compliance.

17.1.1994ЕЕ.C of A carried out by Angus Aviation

7.12.1994ЕЕ.AD/Lancair /Z carried out by Go-Air Products PTY LTD with nil defects found.

30.9.1997ЕЕ.RH Wing Re Sealed with slushing compound by Aquila Aviation PTY LTD Job no 6896

12.5.1998ЕЕ.RH Wing Fuel pickup replaced and RH wing resealed with slushing compound, RH wing fuel line section replaced by Aquia PTY LTD job no 7148

Nil other Log book entries regarding RH fuel tank.

12.10.2004 Fuel leak observed from RH wing. Investigation found fuel in leading edge fwd of main wing spar (approx 8 litres) same cavity for electrical wires from Nav and strobe lights.

Unable at this stage to determine how fuel getting from wet wing behind main spar, to forward of main spar due unable to access area forward of main spar

The AD carried out in 1994 was for avtex manufactured aircraft (unsure if the wings were assembled at their plant in Ballina Australia then sent out to builders ). Apparently the initial "sloshing" process was found to be faulty and wings were required to be re-sloshed.
--
Gerard O Connell
Melbourne, Australia

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