Gulfstream 

A GENERAL DYNAMICS COMPANY 

U.S. Department of Transportation 

Docket Operations 

West Building Ground Floor, Room W12-140 

1200 New Jersey Avenue, SE 

Washington, DC 20590 

July 30, 2012 

A&C-12-506 

Subject: Amendment to Request for Partial Exemption from Title 14 CFR 25.901(c) 

Reference: 1) Docket ID # FAA-2012-0390 

2) Gulfstream Letter A&C-12-227, Request for Exemption from Section 

25.901(c) of Title 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 of exemption. This petition was submitted to 

relieve the Gulfstream GVI model aircraft from full compliance with 14 CFR 25.901(c) at 

amendment 46. After additional dialogue with the Federal Aviation Administration (FAA), 

Gulfstream requests to amend this petition as follows. 

Within Gulfstream's petition we state that our failure analysis of the final design highlighted that 

a fuel metering valve jammed condition would prevent the GVI from fully demonstrating 

compliance for all flight conditions. After consideration of additional guidance provided by the 

FAA, Gulfstream has also identified single failure scenarios within the Throttle Quadrant 

Assembly (TQA) that will also preclude the model GVI from full compliance to 14 CFR 

25.901 (c). If these single failures were to occur during a rejected takeoff, or during a limited 

portion of the landing phase of flight, the resulting condition could be potentially catastrophic. 

Gulfstream requests these single failures within the TQA also be taken into consideration for our 

request for exemption. 

While expanding our request to take into consideration additional single failures implies a 

greater impact on safety, the use of a single mechanical lever to control each engine has been 

the industry norm. Further, Gulfstream has built redundancy into the throttle control system 

where practical, minimizing the number of single failure points. The small number of single 

failure points, and the limited window of exposure, will help ensure a level of safety that meets 

or exceeds the current industry standard. Gulfstream will submit to the FAA a detailed analysis 

of these single failures, their potential effects, as well as an analysis of the practicality of 

redesigning the TQA. 

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-thrust failures, except 

for those due to failures of the TQA. Due to the small number of single failures within the TQA, 

the limited window of exposure, and the practicality of redesigning the TQA that currently meets 

the industry norms, Gulfstream believes permanent relief from 14 CFR 25.901 (c) relative to the 

TQA is appropriate. Further we believe precedent exists with the FAA for this relief, most 

recently with FAA Exemption Number 10408. 

If there are any questions, or if I can be of further 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