SAIB NM-07-55

FAA Aircraft Certification Service

SPECIAL AIRWORTHINESS

INFORMATION BULLETIN SUBJ: Air Conditioning – Pack Inlet Valve Operation SAIB: NM-07-55 Date: September 24, 2007 This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin advises you⎯owners and operators of Gulfstream Model GV series airplanes, serial numbers 501 through 686, and 699, equipped with pack inlet valves having part number 396610-1 or -2⎯that two operators experienced loss of normal cabin pressurization control due to a pack inlet valve failure.

Background

During one event, the cabin altitude increased at approximately 1,000 feet per minute while descending from flight level (FL) 450 to FL 430. The increase in cabin altitude was accompanied by a “CPCS LOW AIR FLOW” message annunciated in the Crew Alerting System (CAS) as the engine power levers were retarded to idle. Troubleshooting has revealed that this incident was the result of both Environmental Control System (ECS) pack inlet valves failing to operate normally.

Recommendations

Gulfstream has issued GV Customer Bulletin (CB) 84 to recommend a one-time action to inspect the left and right pack inlet valves for proper operation. We strongly recommend that you accomplish the actions suggested by and detailed in the Gulfstream GV CB 84. At this time, we have not yet determined whether or not the airworthiness concern is an unsafe condition that would warrant Airworthiness Directive (AD) action under Title 14 of the Code of Federal Regulations (14 CFR part

39).

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: Gerald.Avella@FAA.gov

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