Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
NM-07-55
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