May 17, 2006

This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin (SAIB) alerts you, owners and operators of Raytheon Aircraft Company (RAC) Model 390 Premier 1 airplanes (serial numbers RB-4 through RB-101 and RB-103 through RB-123), of an airworthiness concern.

Background

An omission of fuel drain holes may exist on Model 390 airplanes, which could allow fuel vapors to collect in the event of a fuel leak in the main landing gear bay. The holes may have not been added during fabrication of the machined auxiliary bulkhead (P/N 390-110100). The fuel from a leaking fuel fitting or hose is collected in either the wing vapor box or main gear bay auxiliary bulkhead forward vapor box. The fuel is then intended to drain overboard through the omitted drain holes. As a result of our investigation, we suspect that the same condition may exist on other airplanes of the same type design.

Recommendation

Raytheon has released Service Bulletin (SB) 53-3726, which contains the procedures to inspect the main landing gear bay auxiliary bulkhead and to verify the presence of the drain holes. We recommend that you perform the actions in the SB.

For Further Information Contact

Anthony Flores, Aerospace Engineer, FAA Wichita Aircraft Certification Office, 1801 Airport Rd, Room 100, Wichita, KS, 67209; phone: (316) 946-4174; email: anthony.flores@faa.gov

For SB Information Contact

Raytheon Aircraft Company, 9709 E. Central, Wichita, KS 67201-0085; phone: (800) 429-5372 or (316) 676-3140.