Flight Controls Aileron Boost Bellcrank Lug

FAA Aircraft Certification Service SPECIAL AIRWORTHINESS INFORMATION BULLETIN SUBJ: Flight Controls – Aileron Boost Bellcrank Lug SAIB: NM-07-48 Date: September 11, 2007 This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin advises you, owners and operators of Gulfstream Model G-IV series airplanes, serial numbers 1000 through 1278, that Gulfstream has identified an issue concerning a potentially reduced lug radius dimension on the aileron boost bellcrank clevis.

Background

Gulfstream discovered that the lug radius dimension of the aileron boost bellcrank clevis had been manufactured incorrectly. The hydraulic actuator attaches to the suspect lug. Failure of the bellcrank lug results in loss of hydraulic power to that aileron surface. Control of the aileron is maintained through manual reversion.

Recommendations

Gulfstream has issued GIV Customer Bulletin (CB) 121 to recommend a one-time action to inspect the aileron boost bellcrank lug thickness to lug radius ratio. The lug inspection measures the lug thickness and lug radius using a vernier caliper. We strongly recommend that you accomplish the actions suggested by and detailed in Gulfstream GIV CB 121.

For Further Information Contact

Gerald Avella, Aerospace Engineer FAA Atlanta Aircraft Certification Office One Crown Center, 1895 Phoenix Boulevard, Suite 450 Atlanta, GA 30349 Phone: (770) 703-6066; Fax: (770) 703-6097 E-mail: [email protected]

For Related Service Information Contact

Gulfstream Aerospace Corporation P.O. Box 2206 Savannah, Georgia 31402-2206 Phone: (800) 810-4853 or 912-965-4178; Fax: 912-965-4184