# Gulfstream

A GENERAL DYNAMICS COMPANY

U.S. Department ofTransportation Docket Operations West Building Ground Floor, Room W12-140 1200 NewJerseyAvenue, SE Washington, DC 20590 July 30, 2012 A&C-12-506

Subject: Amendmentto Request for Partial Exemption from Title 14 CFR 25.901(c) Reference: 1) Docket ID

### # FAA-2012-0390 2) Gulfstream LetterA&C-12-227, Requestfor Exemption from Section 25.901(c) ofTitle 14, Powerplant Installation, for Conditions of Uncontrollable High Thrust, dated April 2, 2012
FAA Project No.: TC8700AT-T
Dear Sirs: On April2, 2012, via reference 2), Gulfstream Aerospace Corporation, in accordance with 14 CFR part 11, requested consideration for a grant ofexemption. This petition was submitted to relieve the Gulfstream GVI model aircraftfrom full compliance with 14 CFR 25.901(c) at amendment 46. After additional dialoguewith the Federal Aviation Administration (FAA), Gulfstream requests to amend this petition as follows.
Within Gulfstream's petition we state that ourfailure analysis ofthe final design highlighted that a fuel metering valvejammed condition would preventthe GVI from fully demonstrating compliance for all flight conditions. After consideration ofadditional guidance provided by the FAA, Gulfstream has also identified single failure scenarios within the Throttle Quadrant Assembly (TQA) thatwill also preclude the model GVI from full compliance to 14 CFR 25.901(c). Ifthese single failures were to occurduring a rejected takeoff, orduring a limited portion ofthe landing phase offlight, the resulting condition could be potentially catastrophic. Gulfstream requests these single failures within the TQA also be taken into consideration for our requestfor exemption.
While expanding our request to take into consideration additional single failures implies a greater impacton safety, the use ofa single mechanical leverto control each engine has been the industry norm. Further, Gulfstream has built redundancy into the throttle control system where practical, minimizing the number ofsingle failure points. The small number ofsingle failure points, and the limited window ofexposure, will help ensure a level ofsafety that meets orexceeds the current industry standard. Gulfstream will submitto the FAA a detailed analysis ofthese single failures, their potential effects, as well as an analysis ofthe practicality of redesigning theTQA.

P.O. Box 2206 • Savannah, GA 31402-2206 USA • Telephone (912) 965-3000 • gulfstream.com

### Gulfstream is committed to amending the type design to incorporate revised electronic engine control software that will eliminate all noncompliant, uncontrollable, high-thrustfailures, except forthose due to failures ofthe TQA. Due to the small number ofsingle failures within the TQA, the limited window ofexposure, and the practicality of redesigning the TQAthat currently meets the industry norms, Gulfstream believes permanent relieffrom 14 CFR 25.901 (c) relative to the TQA is appropriate. Furtherwe believe precedent exists with the FAAforthis relief, most recently with FAA Exemption Number 10408.
Ifthere are any questions, or if I can be offurther assistance, please do not hesitate to contact me at (912) 965-6817. Sincerely,

Robert Glasscock Certification Director, G650 Program Gulfstream Aerospace Corporation P.O. Box 2206, M/S R-03 Savannah, GA 31402-2206 robert.glasscock@gulfstream.com (912) 965-6817

cc: N. Berryman, ACE-100G (via email) P. Hatton, EASA (via email) M. Gordon, ANM-113 (via email)

P.O. Box 2206 • Savannah, GA 31402-2206 USA • Telephone (912) 965-3000 • gulfstream.com