# ctJ.-ao.EIND

Y1-0300-AC-14-230 August 19,2014 DocketManagementFacility U.S. DepartmentofTransportation 1200 NewJersey Avenue, S.E. West Building Ground Floor Room Wl2-140 Washington. DC 20590 Boe1nq Compary 6001 S PiJrOepot OH2horna Ctty, OK 7J 135

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Subject: PetitionforExemption from Title 14CodeofFederal Regulations (CFR) §25.979(d)(e) inSupportofFAA ProjectST00279MC·T (ODA Project 192) ·- ·····.

The Boeing Company respectfully submits the enclosed Petition for Exemption from Title 14 Code of Fedeml Regulations (CFR) §25.979(d)(e) Arndt. 25-72 from the Certification Basis for FAA Project ST00279MC-T (ODA Projectl92). Theenclosure provides the details ofthe petition in accordance with 14CFR §11.81. DESCRIPTION OFRELIEFSOUGHT: The baseline 767-2C will be modified by the STC to be an in-flight tankerand receiver. The onload and offload installations could experience surge pressures that approach 240 pounds persquare inch gage (PSIG). The baseline767-2C is designed to the maximum burst pressure is 360 PSIG. Higher surge pressures will occurduring onload and offload. The STC modified 767-2C aircraft wiJJ not meet the regulatory requirement of2.0times the ultimate load at maximum pressures, including surge. Thepetitionerrequests the use ofindustry standard pressures foronload and offload installations ofthe STC modified 767-2C which ensures consistency within the current military fleet. As stated in 14 CFR §11.87, the petitionerrequests that this Petition for Exemption notbe delayed by the public process, which includes publication ofthe subjectpetition. Ifthis exemption is not granted, it could lead to delays in the delivery ofthe 767-2C to the USAF at acritical time ofneed. The STC modified**767~2C** approved aircraft will notbe eligible to receive a civil airworthiness approval or standard certificate ofairworthiness. It is intended thatthe aircraft will be maintained as a public use aircraftonly for the life ofthe product. Granting ofthis exemption petition is kindly requested by December 15,2014. Ifyou have any questions, please do not hesitate to contact the undersigned. Sincerely,

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### P. Wehman ODA-501296-CECertification Engineer ODA-501296-CEAdministrator Phone: 405-582-8908 Phone: 425-266-4539 Mail Code: R7-53 Mail Code: R7-53 Enclosure: Petition for Exemption from Title 14 Code ofFederal Regulations §25.979(d)(e) Arndt. 25-72

cc: Joel Ligon (FAA Wichita MCO Program Manager) James Hartley (FAA Wichita ACO OMT Lead) JeffDuven (FAA Transport Airplane Directorate Manager)Enclosure to Yl:D300-AC-14-230 Page 1 of5 Petition for Exemption from Title 14 Code ofFederal Regulations§ 25.979(d)(e) Arndt 25-72

Name and Address ofthe Petitioner
David Hom, ODA Lead Administrator The Boeing Company 6001 S. Air Depot, 

### MIS R7-53 OklahomaCity, OK 73135 Section(s) ofthe Regulations from which Reliefis sought: § 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) must withstand 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 mustbe 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 load that is 2.0 times the load arising from the maximumpermissible de fueling pressure (positive ornegative) at the airplane fueling connection.
The Extent ofReliefSought and Reason(s) Regulation Requires: Reliefis Necessarybecause: 14 CFR § 25.979 (d) "

...withstand an ultimate load The baseline 767-2C will be modifiedby the Amendment 25-72 that is 2.0 times the load STC to be an in-flight tanker and receiver. arising from the maximum The on load installation will exceed the pressures, including surge, that maximum certified surge pressure of 180 is likelyto occur during pounds per square inch gage (PSIG). The on fueling." load installation could experience surge pressures that approach 240 (PSIG). The aircraft will not meet the regulatory requirement ofultimate load of2.0 times the maximumpressures, including surge. 14 CFR § 25.979 (e) "

...withstand an ultimate load The baseline 767-2C will be modified by the Amendment 25-72 that is 2.0 times the load STC to be an in-flight tanker and receiver. arising from the maximum The offload installations will exceed the permissible defueling pressure maximum certified surge pressure of 180 (positive ornegative) at the pounds per square inch gage (PSIG). The off airplane fueling connection." load installations could experience surge pressures that approach 240 (PSIG). The aircraft will not meet the regulatory requirement ofultimate load of2.0 times the maximum pressures, including surge.Enclosure to Yl-D300-AC-14-230 Page 2 of5 Petition for Exemption from Title 14 Code ofFederal Regulations§ 25.979(d)(e) Arndt 25-72 Description ofIssue 767-2C Baseline The Amended Type Certificated (ATC) 767-2C airplane is designed for the ground refueling operating pressures of:OperatingProofBurst120 PSIG 240 PSIG (2x Operating) 360 PSIG (3x Operating, 1.5x Proof) The ATC 767-2C airplane will be certified for the ground refueling operatingpressures of:OperatingProofBurst90 PSIG 180 PSIG (2x Operating) 360 PSIG (2x Proof, 4x Operating)
See Table 1for a summary ofthe 767-2C design pressures. STC Modified 767-2C Thebaseline 767-2C certified pressures are sufficient for ground refueling and defueling ofaircraft in the commercial environment. During onload and offload operations, receivertop offs generate high surges in the receiving aircraft that are reflected backin to the tanker. These surge pressures on other legacyrefueling systems (KC-135, KC-10, and the 767 Global TankerTransport Aircraft (GTTA) can approach 240 PSIG. The onload and offload systems and its operations ofthe 767-2C STC are similar to the aforementioned legacy tanker airplanes. The current fleet ofAir Force tankers and largebodyreceivers 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, Aerial Refueling Systems Advisory Group (ARSAG) specifications, summarily: OperatingpressureProofpressureBurstpressure120 PSIG 240 PSIG (2x Operating) 360 PSIG (3x Operating, 1.5x Proof) See Table 1for a summary ofthe 767-2C design pressures.Enclosure to Yl-D300-AC-14-230 Page 3of5 

### Petitionfor Exemption from Title 14 Code ofFederalRegulations§ 25.979(d)(e) Arndt25-72

Commercial Standard MilitaryOperation KC-46

and Operations Onload Des1gn 767-200 767-2C 767-2C Offload Pressures Design ATC&STC Industry STC Installation Critena Ground Standard Onload Factors Refueling Offload Operating 120PSIG 90PSIG 1X 120PSIG 1X {working)

Proof 240PSIG 180PSIG 2X 240PSIG 2X {limit)
surges s 240 s 180 PSIG =>240 lAW s2X S2X {sproof) PSIG 25.979(d) PSIG

Burst 360PSIG 360PSIG 3X 360PSIG 3X {ultimate)

Notte 360PSIG 360PSIG 360PS/G 360PSIG 360PSIG Exceed Operating (Working) Pressure [IJ A maximum steady state pressure (no-flow and flowing conditions) that the fuel system can continually sustain throughout the life ofthe airframe without any external leakage, fatigue, failures or malfunction. Proof (limit) Pressure [IJ A pressure in which the fuel system may function satisfactorily including pressure transients (surges) up to a value in which the aircraft can continually sustain throughout the life ofthe aircraft without any external leakage, failure and/or malfunction, or deformation. Proofpressures are typically two times greater than operating pressures. Burst (Ultimate) Pressure [IJ A pressure that the fuel system can sustain without external leakage and/orrupture but may not function properly. Deformation without leakage is permitted. Burst pressures are typically 1.5 times greater than proof/limit pressures. SurgePressureLimits & Interpretations [IJ Pressure transients occur as a result ofan interruption offuel flow, a perturbation offuel flow or an abrupt change in flow velocity. Pressure transients shall not exceed proof(limit) pressure in the aircraft.

[IJ ARSAG Document No. 00-03-01, Sections 3.4, 3.5, 3.6, 3.7, Aerial Refueling Pressures Definitions and Terms, Design and Verification Guidance Dec 2010 

### Table 1

FAAregulations in 14 CFR address civil operational use ofthe aircraft These regulations do not envision civil aircraft being modified for onload and offload operations (a non civil function). In 

### order to meet the 14CFR 25.979(d) and (e) the 767-2C wouldbe required to meet a burst pressure of 480 PSIG (2 X 240PSIG). The 767-2C fuel system as modified bythe STC will add additional functionality to the existing baseline fuel system. The certified 767 -2C ATC fuel systems are designed for a maxburst pressure of360 PSIG. Increasing the burst pressure to 480 PSIG to the baseline 767-2C fuel system would require redesign, requalification and recertification at the system level.Enclosure to Yl-0300-AC-14-230 Page 4 of5 Petition for Exemption from Title 14 Code ofFederal Regulations § 25.979(d)( e) Arndt 25-72 Additional component level requalification and recertification will berequired to pump shutoff valves, check valves, nozzle, reception couplings, receptacles, plumbing, hose, interconnects, etc. Itis impractical and not economically viable to make the design changes to increase the burst pressure to 480 PSIG. Historical operation oftankers (KC-135, KC-10 and GTTA) and large bodyreceiver aircraft (C-5, C-17, E-3, B-52 and B-1) indicate no event offuel systemleaks with surge pressures that may approach 240 PSIG. This stellar operational record incorporate 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 PSIGin a steady state condition indefinitely. Testing will be done simulating normal operations and single failures that generate high surge pressures to verify that all surges experienced on the 767- 2C during onload and offload operations remain below 240 PSIG. Statement ofPublic Interest The single aspect of§ 25.979(d)(e) that the 767-2C onload and offload installations do not meet is the 2 times the load arising from the maximumpressures. This regulation is specifically written for ground refueling operations and not onload and offloadinstallations. Maintaining the industry standards for onload and offload installations utilized on programs such as the KC-135, KC-10 and the GTTA will provide for the most economical option for the STC modified 767-2C and provide consistency within the industry for onload and offload installations. Boththe baseline 767-2C and the STC modified 767-2C maintain a 360 PSIG Burst pressure maximum. Anychange to the 767-2Cbaseline fuel system would cause significant modification to the airplane that would provide no netbenefit inthe configuration and no commensurate increase in safety. Ifthe reliefis not granted, it could lead to delays in the delivery ofthe 767-2C to the USAF at a critical time ofneed. Itremains inthe public's interest to agree with the Boeing Company decision to utilize industry standards for onload and offload operating pressures which ensure consistency within the current military fleet. Statement ofNoAdverse Effect on Safety The ground refueling installations on the 767-2C will be certified in accordance with§ 25.979(d)(e). The STC modified 767-2C onload and offload refueling installations will meet industry standards for fuel pressure. Bothelements ofthe operations shall assure that the aircraft will not exceedthe maximumburstpressure of360 PSIG and to operate safely within the design standards. The 767-2C mustbe operationally compatible with othertanker airplanes for onload and offload with currentreceivers 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 in the AFM that states that onload and offload operations are limited to militaryuse only as allowed by Order 8110.101. This will prohibit civil in-flight onload andEnclosure to Yl-D300-AC-14-230 Page 5 of5 Petition for Exemption from Title 14 Code ofFederal Regulations§ 25.979(d)(e) Arndt 25-72 offload system operations. Additionally, due to the aforementioned limitation and other limitations as a result ofthe STC alterations, the aircraft will notbepermitted to carry commercial passengers.
Request to Waive Publication and Comment
As stated in 14 CFR §11.87, the petitionerrequests that this Petition for Exemption notbe delayed bythe public process, which includes publication ofthe subjectpetition. Ifthis exemption is not granted, it couldlead to delays in the delivery ofthe 767-2C to the USAF at a critical time ofneed. The STC modified 767-2C approved aircraft will notbe eligible to receive a civil airworthiness approval or standard certificate ofairworthiness. Itis intended that the aircraft will be maintained as apublic use aircraft only for the life ofthe product. Privileges ofthe Exemption Outside the United States
Not requested Conclusion Since §25.979(d)(e) considers ground refueling operations only, the STC modified767-2C aircraft will remain compliantto §25.979(d)(e) for ground refueling operations. Itis requested that the FAA grant an exemption to Boeing allowing the use ofindustry standardpressures for the onload and offload installations on the STC modified767-2C. The STC modified 767-2C will add an operating limitation inthe AFM that states that onload and offload operations are limited to military use only as allowedby Order 8110.101. This will prohibit civil in flight onload and offload system operations. Boeing is requesting this exemption which adequately and appropriately addresses this special purpose of767-2C airplane. Summary to be Published in the Federal Register PETITIONER: The Boeing Company SECTION OF 14 CFR AFFECTED: 14 CFR §25.979(d)(e) DESCRIPTION OF RELIEF SOUGHT: Thebaseline 767-2C will be modifiedbythe STC to be an in-flight tanker and receiver. The onload and offload installations could experience surge pressures that approach 240 pounds per square inch gage (PSIG). Thebaseline767-2C is designed to the maximumburst pressure is 360 PSIG. Higher surge pressures will occur during onload and offload. The STC modified 767-2C aircraft will not meet the regulatory requirement of2.0 times the ultimate load at maximumpressures, including surge. The petitionerrequests the use ofindustry standard pressures for onload and offload installations ofthe STC modified 767-2C which ensures consistency within the current military fleet.