Fuel system selector valves

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FAA Aircraft Certification Service SPECIAL AIRWORTHINESS INFORMATION BULLETIN http://www.faa.gov/aircraft/safety/alerts/SAIB

SAIB: CE-06-11R1 Date: March 14, 2007 This is information only. Recommendations aren’t mandatory.

Introduction

This Revised Special Airworthiness Information Bulletin (SAIB) informs you, a registered owner or operator of Sierra Hotel Aero, Inc. “Navion” airplanes (all models) of the following information concerning warn out or defective fuel system selector valves and fuel system selector valves that may have received unauthorized repairs.

There have been two (2) field service reports of fuel leaking from a Navion model airplane fuel system selector installed as part of the original Type Design or subsequent FAA Approved certification process. Defective fuel selector valves may have been the cause of engine power loss that resulted in airplane accidents. Since 1978, thirty six (36) “Navion” accident reports appear to be related to fuel selector valve problems, possibly due to unauthorized repairs on these selector valves. Since the July 2006, EAA AirVenture Forum where this concern was highlighted, three more Navion accidents have occurred that can be attributed to improperly functioning fuel selector valves or defective fuel systems.

Background

There are now six reported airplane accidents in the last couple of years associated with leaking or improperly operating fuel system selector valves, one of which involved serious injuries. These valves may have had field repairs/rebuilding attempted as part of routine continued airworthiness maintenance. It is believed that one of the valves had a repair attempted prior to the accident. In that case, the preliminary investigation has determined that the fuel selector valve was allowing air to be introduced into the airplane fuel line potentially disrupting the flow of fuel to the engine. The fuel selector valves were/are manufactured by the following companies: • Imperial Valve Company - P/Ns 108-HD, 114-HD, and 115-HD • Navion - P/N 147-30013-28, P/Ns 145-48001-11, 145-48066-1, 145-48076-1, and 145-48031 (various manufacturers) • Whittaker - P/N 6235 • Any fuel selector valves supplied with STC Fuel System changes • Equipment Items 110, 113, 116, or 131 of the “Navion” Aircraft Specification No. A-782 • Any similar valve installed on a Navion

In SAIB CE-06-11, issued November 29, 2005, we noted that we were unaware of any FAA Approved field instructions/procedures to repair these fuel selector assemblies. This is still the case. Fuel selector valves have all been superseded by “Navion” Fuel Selector P/N 147-30013-201, -202, or -203. New valves are available so there is no valid reason to consider unauthorized fuel selector valve repairs. The FAA is considering further airworthiness action.

2 Recommendation To prevent potential fuel disruption that can cause an engine power loss and a potential airplane accident, we recommend that the Navion fuel system selector valve be inspected for proper operation and checked to ensure the valve cannot introduce air into the fuel line system. The Inspector Authorized (IA) representative or appropriately rated mechanic should inspect these units for binding, leakage, or improper operation and replace any defective fuel selector valves with a serviceable unit. In addition, on February 27, 2007, Sierra Hotel Aero, Inc. issued a NEW Service Bulletin No. 106 which describes a Fuel System Inspection program to help ensure that the Navion fuel system is airworthy and does not introduce air into the fuel lines. Also refer to Sierra Hotel Navion Service Bulletin 101A or later revision for more information (www.navion.com)

For Further Information Contact FAA, Chicago Aircraft Certification Office, Propulsion Branch, ACE-118C, 2300 East Devon Avenue, Des Plaines, IL, 60018; Facsimile (847) 294-7834, Tim Smyth, Senior Propulsion Engineer, Telephone (847) 294-7132 or by e-mail: [email protected]