UNITED STATES OF AMERICA DEPARTMENT OF TRANSPORTATION FEDERAL AVIATION ADMINISTRATION RENTON, WASHINGTON 98057-3356

In the matter ofthe petition of Exemption No. 12733

The Boeing Company Regulatory Docket No. FAA-2014-0661
for an exemption from§ 25.979(d) and (e) ofTitle 14, Code ofFederal Regulations

GRANT OF EXEMPTION
By letter dated August 19, 2014, Mr. David Hom, ODA Lead Administrator, The Boeing Company, 6001 S. Air Depot, Oklahoma City, Oklahoma, 73135, petitioned the Federal Aviation Administration (FAA) for an exemption from the requirements of§ 25.979(d) and (e) ofTitle 14, Code ofFederal Regulations (14 CFR). This exemption, ifgranted, wouldpermit the use of industry standard pressure loads for onload and offload fueling installations on supplemental type certificate (STC) modified 767-2C tanker airplanes instead ofthe regulatory requirement ofan ultimate pressure of2.0 times the limit load at maximumpressures, including surge. The requested exemption would apply to military use only and would ensure consistencywithinthe current military fleet.
The petitioner requests relieffrom the following regulations: Section 25.979- Pressure fueling system Forpressure fueling systems, the following apply: (d) The airplane pressure fueling system (not including fuel tanks and fuel tank vents) mustwithstand an ultimate load that is 2.0 times the load arising from the maximumpressures, including surge that is likelyto occur during fueling. The maximum surge pressure must be established with any combination oftank valves being either intentionally or inadvertently closed. (e) The airplane defueling system (not including fuel tanks and fuel tank vents) must withstand an ultimate loadthat is 2.0 times the load arising from the maximumpermissible defuelingpressure (positive or negative) at the airplane fueling connection.The petitioner supports its request with the following information:
This section quotes the relevant information from the petitioner's request, with minor edits for clarity. The completepetition is available at the Department ofTransportation's Federal Docket Management System, on the Internet at http://regulations.gov, in DocketNo. FAA-2014-0661.
STC Modified 767-2C
The baseline 767-2C certified pressures are sufficientfor ground refueling and defueling ofaircraft in the commercial environment. During onload and offload operations, receivertop-offs generate high surges in the receiving aircraftthat are reflected back in to the tanker. These surge pressures on other legacy refueling systems (KC-135, KC-10, and the 767 Global Tanker Transport Aircraft [GTTA]) can approach 240 pounds per square inch gage (PSIG). The onload and offload systems and its operations ofthe 767-2C SIC are similarto the aforementioned legacytanker airplanes. The current fleet ofAir Force tankers and large body receivers are builtto the following industry standards for fuel pressure consistent with the Joint Service Specification Guide (JSSG), Joint Service Board (JSB), Standardization Agreements (STANAGs), Mil-Specs, and Aerial Refueling Systems Advisory Group (ARSAG) specifications: Operating (normal/working) pressure Proof(limit) pressure Burst (ultimate) pressure 120 PSIG 240 PSIG (2x operating) 360 PSIG (3x operating, 1.5x proof) FAAregulations in 14 CFRaddress civil operational use ofthe aircraft. These regulations do not envision civil aircraftbeing modified for in-flight onload and offload fueling operations (a non-civil function). In orderto meet§ 25.979(d) and (e),the 767- 2C would be required to meet a burstpressure of480 PSIG (2 x 240 PSIG). The 767-2C fuel system as modified by the SICwill add additional functionality to the existing baseline fuel system. The certified 767-2C amended type certificate (ATC) fuel systems are designed for a max burst pressure of360 PSIG. Increasing the burstpressure to 480 PSIG to the baseline 767-2C fuel system would require redesign, requalification, and recertification at the system level. Additional component level requalification and recertification will be requiredto pump shutoffvalves, check valves, nozzle,reception couplings, receptacles, plumbing, hose, interconnects, etc

. Itis impractical and not economically viable to make the design changes to increase the burstpressure to 480 PSIG. Historical operation oftankers (KC-135, KC-10, and GTTA) and large body receiver aircraft (C-5, C-17,E-3 ,B-52, and B-1) indicate no event offuel system leaks with surge pressures that may approach 240 PSIG. This stellar operational record incorporates fuel system design features carried forward to the 767-2C onload and offload installations. The 767-2C onload and offload installations have the ability ofwithstanding 240 PSIG surges and 240 PSIG in a steady state condition indefinitely

. Testing will be done simulating normal operations and single failures that generate high surge pressures to 2verify that all surges experienced on the 767-2C during onload and offload operations remainbelow 240 PSIG. Statement ofPublic Interest
The single aspect of§ 25.979(d) and (e) that the 767-2C onload and offload installations do not meet is the 2.0 times the load arising from the maximumpressures. The regulations are specifically written for ground refueling operations and not onload and offload installations. Maintainingthe industry standards for onload and offload installations utilized onprograms such as the KC-135, KC-10, and the GTTAwill provide for the most economical option for the STC modified 767-2C and provide consistencywithinthe industry for onload and offload installations. Boththe baseline 767-2C and the STC modified 767-2C maintain a 360 PSIG burst pressure maximum. Any change to the 767-2C baseline fuel system would cause significant modification to the airplane that would provide no net benefit in the configuration and no commensurate increase in safety. Ifthe reliefis not granted, it could lead to delays inthe delivery ofthe 767-2C to the United States AirForce (USAF) at a critical time ofneed. It remains in the public's interestto agree with The Boeing Company decisionto utilize industry standards for onload and offload operatingpressures whichensure consistency within the currentmilitary fleet. Statement ofNo Adverse Effect on Safety
The ground refueling installations on the 767-2C will be certified in accordance with § 25.979(d) and (e). The STC modified 767-2C onload and offload refueling installations will meetindustry standards for fuel pressure. Bothelements ofthe operations shall assure that the aircraft will not exceed the maximum burstpressure of360 PSIG and to operate safely within the design standards. The 767-2C must be operationally compatible with othertanker airplanes for onload and offload with current receivers and tankers which operate with surge pressures up to 240 PSIG. Along with meeting industry standards for onload and offload refueling installations, the STC modified 767-2C will add an operating limitation inthe airplane flight manual (AFM) that states that onload and offload operations are limited to military use only as allowed by Order 8110.101. This will prohibit civil in-flight onload and offload system operations. Additionally, due to the aforementioned limitation and other limitations as a result ofthe STC alterations, the aircraft will not be permittedto carry commercial passengers. Federal Register publication Althoughthe petitionerrequested that action on its petition notbe delayed for publication in the Federal Register, the FAAfound thatthe petition, ifgranted, would set a precedent. Therefore, to allow an opportunity for the public to commentonthe petition, we published a summary ofit in the Federal Register onJuly 6, 2015 (80 FR38505). No comments were received.

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### The FAA's analysis Aerial refueling is not an approved operation ofcommercial airplanes and the requested exemption only applies to military refueling operations. The 767-2C airplane is not currently commercially available; however, we recognize that future sales orconversions could include airplanes that are the subject ofthis exemption and these airplanes could be used in commercial service. Boeing addresses this concern by providing operating limitations in the AFM that will prevent aerial refueling operations in commercial service. In addition, Boeing will demonstrate thatthe maximum surgepressure during failure conditions will maintain a safety factor of 1.5. This safety factor margin has been adequate on previous military refueling aircraft and the proposed fuel system burstpressure limits provide the capabilityproven in other military aerial refueling airplanes. Granting this exemption will not adversely impactpublic safety. Itwill enhance the United States militarybyreplacing older, less efficienttanker airplanes and ensure consistency within the currentUSAF fleet.


### The FAA's decision
In consideration ofthe foregoing, I find that a grant ofexemption is inthe public interest. Therefore, pursuantto the authority contained in 49 U.S.C. 40113 and 44701 delegated to me by the Administrator, I grant The Boeing Company an exemptionfrom 14 CFR25.979(d) and (e). The exemption is granted to the extentnecessaryto allowThe Boeing Company to use industrystandard designpressures that have a lower factor ofsafety than is required by§ 25.979 on STC modified 767-2C military tanker airplanes. This exemption is subjectto the following condition(s): 1. The fuel onload and offload installations on the STC modified 767-2C must withstand an ultimate load that is 1.5 times the load arising from the maximum pressures, including surge that is likely to occur during onload and offload fueling operations

. 2. The STC modified 767-2C must add an operating limitation in the AFM that states that onload and offload operations are limited to military use only as allowed by FAA Order 8110

.101. This will prohibit civil in-flight onload and offload system operations.

Michael Kaszycki Acting Manager, Transport Airplane Directorate Aircraft Certification Service

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