X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 19 Feb 2010 13:17:50 -0500 Message-ID: X-Original-Return-Path: Received: from smtp-auth-04.mx.pitdc1.expedient.net ([206.210.66.137] verified) by logan.com (CommuniGate Pro SMTP 5.3.2) with ESMTPS id 4130472 for lml@lancaironline.net; Fri, 19 Feb 2010 00:43:40 -0500 Received-SPF: none receiver=logan.com; client-ip=206.210.66.137; envelope-from=rpastusek@htii.com Received: from HTBOB001 (static-72-66-86-7.washdc.fios.verizon.net [72.66.86.7]) by smtp-auth-04.mx.pitdc1.expedient.net (Postfix) with ESMTPSA id 585A1E4A6B; Fri, 19 Feb 2010 00:43:05 -0500 (EST) From: "Robert Pastusek" X-Original-To: "'Lancair Mailing List'" X-Original-Cc: "'Gunther Todd'" , "'Charlie Kohler'" , , "'Claudette Colwell'" , "'Mark Sletten'" Subject: B&C Regulators X-Original-Date: Fri, 19 Feb 2010 00:43:03 -0500 X-Original-Message-ID: <053f01cab126$689eed80$39dcc880$@com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0540_01CAB0FC.7FC8E580" X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: AcqwLV47LwVSuz0qRxqWRhxJStbJSQA9ZSHA Content-Language: en-us This is a multi-part message in MIME format. ------=_NextPart_000_0540_01CAB0FC.7FC8E580 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable LML Family, =20 Bill Harrelson and I had a chance to review the investigation and preliminary causes of an in-flight fire in a Lancair IV-P that occurred = last spring (2009). The findings and conclusions are not yet established, but = the investigator felt that some of the information discovered was not in question, and would be useful to the experimental community. We agreed = to help spread the word=85as follows: =20 The accident aircraft experienced an in-flight battery fire of the = secondary electrical system shortly after takeoff. The pilot was able to return to = the airport and extinguish the fire in the tail section of the aircraft = after landing. The battery, case, and nearby components were = consumed/destroyed, and the aircraft fuselage sustained significant heat damage from the aft pressure bulkhead to the elevators/rudder. The cause of the fire has not been absolutely determined, but the lead/acid battery vents had = apparently been obstructed, resulting in a case rupture and venting of hydrogen gas into the tail section of the airplane. The exact cause of this apparent = over pressurization and rupture awaits additional information and analysis. = This finding and the final NTSB report are expected within a month and we = will disseminate this report through the LML and LOBO newsletter. =20 One initial result of the investigation was that the B&C regulator for = the secondary electrical system was inoperative upon post-flight analysis. = The NTSB investigator conducted a detailed examination and analysis of the defective unit and determined that the electrical design was robust and appropriate to the task. The unit was mounted to the engine side of the firewall with the spade terminal connectors projecting to the side of = the aircraft. This unit is not sealed, and at some point liquid (probably = water) entered the metal box, most likely through the opening around the spade terminals, and filled it to a depth of =BC to =BD inch. The liquid = allowed arcing among internal components and to the case ground, leaving carbon tracks on the circuit board and case, and destroying the electrical functionality. =20 A review of installation instructions provided with B&C regulators recommends they be installed inside the cockpit or in a similar environmentally-protected area. This regulator was mounted inside the = engine compartment, as we believe are the vast majority of Lancair = installations. When so installed, regulators are subject to additional heat and cooling stresses, as well as water/solvents from engine cleaning and other maintenance when the cowling is removed. If mounted in any position = other than with the spades down, liquid can enter in the area of the spade terminals and will then be trapped within the lower part of the = enclosure, immersing part of the main circuit board. =20 If you are still building and have the option, review the B&C recommendations on mounting location and consider locating your B&C regulator(s) inside the cockpit; preferably with the spades down if = there is any possibility of liquid exposure. No matter the location, mount them = in such a way that they cannot ingest and retain water. =20 If you are not able to locate the regulator(s) as recommended by B&C, consider shielding the terminal strip area from liquids. We expect to contact B&C about the feasibility of other improvements that could be = made, but will refrain from making any recommendations until we receive their comments. =20 =20 Bob Pastusek & Bill Harrelson For the Lancair Owners & Builders Organization (LOBO) ------=_NextPart_000_0540_01CAB0FC.7FC8E580 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

LML Family,

 

Bill Harrelson and I had a chance to review the investigation and preliminary causes of an in-flight fire in a Lancair = IV-P that occurred last spring (2009). The findings and conclusions are not = yet established, but the investigator felt that some of the information = discovered was not in question, and would be useful to the experimental community. = We agreed to help spread the word…as follows:

 

The accident aircraft experienced an in-flight = battery fire of the secondary electrical system shortly after takeoff. The pilot was = able to return to the airport and extinguish the fire in the tail section of the aircraft after landing. The battery, case, and nearby components were = consumed/destroyed, and the aircraft fuselage sustained significant heat damage from the aft = pressure bulkhead to the elevators/rudder. The cause of the fire has not been = absolutely determined, but the lead/acid battery vents had apparently been = obstructed, resulting in a case rupture and venting of hydrogen gas into the tail section of = the airplane. The exact cause of this apparent over pressurization and = rupture awaits additional information and analysis. This finding and the final NTSB = report are expected within a month and we will disseminate this report through the = LML and LOBO newsletter.

 

One initial result of the investigation was that = the B&C regulator for the secondary electrical system was inoperative upon = post-flight analysis. The NTSB investigator conducted a detailed examination and = analysis of the defective unit and determined that the electrical design was = robust and appropriate to the task. The unit was mounted to the engine side of the firewall with the spade terminal connectors projecting to the side of = the aircraft. This unit is not sealed, and at some point liquid (probably = water) entered the metal box, most likely through the opening around the spade terminals, and filled it to a depth of =BC to =BD inch. The liquid = allowed arcing among internal components and to the case ground, leaving carbon tracks = on the circuit board and case, and destroying the electrical = functionality.

 

A review of installation instructions provided with = B&C regulators recommends they be installed inside the cockpit or in a = similar environmentally-protected area. This regulator was mounted inside the = engine compartment, as we believe are the vast majority of Lancair = installations. When so installed, regulators are subject to additional heat and cooling = stresses, as well as water/solvents from engine cleaning and other maintenance = when the cowling is removed. If mounted in any position other than with the = spades down, liquid can enter in the area of the spade terminals and will then be = trapped within the lower part of the enclosure, immersing part of the main = circuit board.

 

If you are still building and have the option, = review the B&C recommendations on  mounting location and consider locating = your B&C regulator(s) inside the cockpit; preferably with the spades down = if there is any possibility of liquid exposure. No matter the location, = mount them in such a way that they cannot ingest and retain water.

 

If you are not able to locate the regulator(s) as recommended by B&C, consider shielding the terminal strip area from liquids. We expect to contact B&C about the feasibility of other improvements that could be made, but will refrain from making any recommendations until we receive their comments.  

 

Bob Pastusek & Bill Harrelson

For the Lancair Owners & Builders Organization = (LOBO)

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