Engine Fuel and Control: Fuel Selector Valve and Fuel Shut Off Cock

FAA Aviation Safety SPECIAL AIRWORTHINESS INFORMATION BULLETIN SAIB: CE-11-59 SUBJ: Engine Fuel and Control: Fuel Selector Valve and Fuel Shut Off Cock Date: September 28, 2011 This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin (SAIB) is to inform the owners and operators of AERMACCHI S.p.A. 260 series airplanes of an airworthiness concern, specifically regarding the fuel delivery system. An investigation following a loss of engine power and forced landing incident revealed that air was being introduced into the fuel system through leakage at either the fuel selector valve and/or fuel shut off valves.

At this time, this airworthiness concern has not been determined to be an unsafe condition that would warrant airworthiness directive (AD) action under Title 14 of the Code of Federal Regulations (14 CFR) part 39.

Background

During an accident investigation involving a SIAI Marchetti 260 series aircraft, the fuel delivery system was inspected and tested. An examination of the fuel selector valve (part number (P/N) SM7672), IPC P/N SM2530, and the fuel shut off valve, P/N SM2513-1, revealed evidence of fuel staining around the valve bodies, and testing of the fuel system with a positive pressure caused fuel seepage at the fuel selector and shutoff valves. With the pumps active, it was evident that air was being introduced into the fuel system. Any air introduced into the system through either valve diminishes fuel flow.

The Ente Nazionale per l’Aviazione Civile (ENAC), which is the airworthiness authority for Italy, and the type certificate holder are working on the issue. Until this issue is resolved, the maintenance requirements as stated in Alenia Aermacchi’s Periodic Inspection List are in effect.

Recommendation

The FAA recommends that you do the following:

 Inspect the integrity of the seals in the fuel shut off and selector valves at the next maintenance inspection. Replace any worn or cracked seals following appropriate procedures.

 Overhaul or replace the fuel shut-off valve every 1,500 flight hours or 5 years as specified in the Alenia Aermacchi’s Periodic Inspection List No. PI 1U-F260/B/C/D-6, Special Inspection List.

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For Further Information Contact

Sarjapur Nagarajan, Aerospace Engineer, FAA Small Airplane Directorate, Room 301, 901 Locust, Kansas City, Missouri 64106; phone: (816) 329-4145; fax: (816) 329-4090; email: [email protected].

For Related Service Information Contact

Alenia Aermacchi S.p.A. Industries, 21040 Venegono Superiore –Via Ing. Foresio, 1, Italy. 2