## AUG 2 6 

## 2013

RA-13-03942
U.S. Department ofTransportation Docket Operations John A. Hamilton Lead Administrator Regulatory Administration Commercial Airplanes

West Building Ground Floor, Room W12-140 1200 NewJersey Avenue, S.E. Federal Aviation Administration Washington DC 20590

Dear Sirs: The Boeing Company P.O. Box 3707 MC 03-56 Seattle, WA 98124-2207



### Subject: Petition for Exemption from Title 14 CFR 25.961(a)(5) Fuel System Hot Weather Operation 

### Model: 767-2C 

### RA Project No.: PS09-0863 

### Response Requested: December23, 2013



### This letter is to submit: (X) Petition for Exemption 

### This letter is being sent for: (X) Posting to the Federal Docket The Boeing Company herebypetitions for an exemption for relieffrom Title 14 CFR 25.961(a)(5) as amended by Amendment 25-57,with respect to the critical fuel temperature for hot weather operations.
To support the 767-2C program schedule, The Boeing Companyrespectfully requests that the enclosed information be processed byDecember 23, 2013. Furthermore, The Boeing Companyrequests to be notified when the encloses petition processing has been completed_

# rtJ--_BDE,NG
Page 2 Mr. A:Xidias RA-13-03942 

### Pleasecontact this office orthe following individuals ifyou havefurther questions: · Project Administrator (PA): Program Manager

. CertificationLead/Specialist: S. Gordon T.Howorth M. Darnen 425-237-:6068 425-717.,9847 425-717-8775
Theinformation being forwarded to the FAA by orwith this correspondence is for the exclusive purpose ofsupport ofapplicationsfor or amendments to Type Certificates.

Sincerely, ·

· Douglas M. Lane

Dire.ctor CommercialAirplanes (425) 237;.1383, MC**03~56** FAX: (425)**294~9340**
Enclosure: 

### Petition for Exemptionfrom 14**CFR25~961(a)(5)**

cc 

### Name·
•Jim Cashdollar

Angelos Xidias 

### Letter 

### EDT EDT 

### Enclosures 

### EDT EDT Comments



### . ANM-:lOOB

ANM-IOOBEnclosure RA-13-03942 Page 1 of4

Petition for Exemption from Title 14 CFR25.961(a)(5) Fuel System Hot Weather Operation


### Name and Address ofthePetitioner Douglas M. Lane, Director The Boeing Company PO Box 3707 Seattle, Washington, 98124 

### (a) Section(s) ofthe Regulations from which Reliefis sought: §25.961(a)(5) Fuel System Hot Weather Operation.: "(a) The fuel system must perform satisfactorily in hot weather operation. Thismust be shown by showingthatthe fuel system from the tank outlets to each engine is pressurized, under all intended operations, so as to prevent vapor formation, ormust be shown byclimbing from the altitude ofthe airport elected bythe applicant to the maximum altitude established as an operating limitation under Sec. 25.1527. Ifa climb test is elected, there maybe no evidence of vapor lock orothermalfunctioning during the climb test conducted underthe following conditions: (5) The fuel temperature must be at least 110° F." 

### (b) ExtentofReliefand Reason Boeing is requesting relieffrom the requirements of 14 CFR25.961(a)(5), Amendment [25-57], for the Pratt & Whitney-powered 767-2C. The regulation requires thatthe airplane and engines perform satisfactorily with the critical fuel at a temperature ofat least 110°F. Boeing requests thatthe FAA approve a set oflimitations for JP-4** and Jet B fuels on the Pratt & Whitneypowered 767-2C in lieu ofcomplianceto the specifiedtemperature of 110°F. The limitations consist ofrestricting the fuel temperature to 85°F, restricting the initial cruise altitude vs. fuel temperature ifrequired, and making use offuel tanktemperature indication to allowJP-4 usage in any tank. Similar limitations were approved for the Rolls Royce-powered 757-300 and 747- 400/-400F. This exemption from the 11OoF requirement is required because the properties ofJP4 will not support operation at that temperature under all intended operations. Boeing submits this petition for the following reasons: (1) It is in public interest. The customer for the 767-2C requires their aircraft be able to operate with JP-4 and JetB fuels. A maximum temperature of85°F will meet their operational requirements. (2) The 767-2C will demonstrate fuel feed performance under normal and abnormal conditions with JP-4 at the maximum temperature allowed underthis exemption. (3) The 767-2C will demonstrate fuel feed performance undernormal and abnormal conditions to cover all other approved fuels to temperatures in excess of 110°F. (4) The proposed limitations on fuel temperature and maximum altitude for initial cruise (if required) provide a level ofsafety equal to that intended by 14 CFR25.961(a)(5). (5) The FAA has granted similarexemptions in the past:Enclosure RA-13-03942 Page 2 of4

(a) for the Rolls Royce-powered 757-300 (FAA Exemption No. 6867, issued 2/12/1999) (b) for the Pratt & Whitney-powered 757-300 (FAA Exemption No. 7790, issued 6/3/2002) (c) for the Rolls Royce-powered 747-400/400F (FAA ExemptionNo. 7496, issued 4/12/2001) (d) the RollsRoyce-powered 757-200 has had an 85°F temperature limitation for JP-4 and Jet B fuels since entry into service in 1983.

**JP-4 is a military designation for a Jet B type commercial grade fuel with additives. 

### Description ofIssue Boeing is introducing a 767-2C airplane model powered byPratt & Whitney PW4062 engines. The 767 with Pratt & Whitney PW4000 series engines was introduced in 1986, and has accumulated over 15.1 million flight hours ofrevenue service. The 767-2C will offeronlythe PW 4062 engine atthis time. The customerhas requested the aircraft be certified to operate with JP-4 fuel. The 767 with PW4000 series engines is currently certified to operate with JP-4 fuel, as listed on the Type Certificate Data Sheet, however, there is an Airplane Flight Manual limitationthat does not allow it for revenue flights.
With regard to 14 CFR25.961(a)(5), the ability ofan airplane to operate with JP-4 and Jet B fuels is a function ofthe vaporpressure ofthe fuel, which increases with temperature. The vapor pressure ofwide cut fuels such as JP-4 and Jet B is considerably higherthan narrow cut fuels such as Jet A. Undernormal conditions, the aircraft fuel boostpumps maintain the pressure in the fuel feed system above the vaporpressure ofthe fuel.
Ifall aircraft boostpumps are inoperative, the engine fuel pumps will continue to draw fuel out ofthe tanks to maintain engine operation. This is termed suction feed operation. At high fuel temperatures and high altitudes, the pressure in the fuel feed system can decrease to, orreach a value near the vaporpressure ofthe fuel allowing some fuel to vaporize and potentially causing engine flameout. Regulation 14 CFR25.961(a)(5) addresses this condition, among others, and is intended to insure that airplane operation will not be adversely impacted by fuel temperature. Boeing seeks to establish appropriate temperature and altitude limitations to ensure the intent of the regulation is met. 

### StatementofPublic Interest It is in the public interest that the 767-2C be able to operate with JP-4 and Jet B fuels. These fuels are used in some parts ofthe world, particularly in cold weather areas due to their low freezing point. Occasionallythey are the only fuels available at military ordiversion airfields. Use ofJP-4 and JetB fuels will allowthe 767-2C greater utilization and flexibility.
The 767-2C will provide industry-leading operating economics and environmental improvements. The 767-2C will be replacing older aircraft with poorer fuel economy and higher maintenance costs. Granting this petition will reduce operational costs byreducing the amount offuel consumed and reducing aircraft maintenance costs. The reduction in fuel consumed willEnclosure RA-13-03942 Page 3 of4

also result in reduced engine emissions into the atmosphere. These benefits will accrue with no decrease in safety.


### StatementofNo Adverse Effecton Safety Boeing believes that incorporating a temperature limitation of85°F for JP-4 and Jet B fuels provides a level ofsafety equal to that intended bythe regulation. This position is based on the following: (1) Suction feed performance flight testing with JP-4 at the maximum allowed temperature will be demonstrated for certification. (2) Ifrequired, altitude restrictions based on fuel temperature will be incorporated to keep fuel pressure and V/L (vapor/liquid) ratio within the engine manufacturers limitations at the engine pump inlet. The need for such restrictions will be

### determin~d during certification flight testing. (3) The fuel tanks must be defueled to sump level (i.e. level at which fuel pump low-pressure lights illuminate) following operations with JP-4 orJet B fuel. Ifthe fuel tanks are not defueled, the JP-4 fuel usage limitations shall continueto apply. (4).The maximum fuel temperature ofthe left main tank, centerwing tank, forward body tank, and aft middle bodytank is indicated in the flight deck which allows the Flight Crewto operate withinthe limitation.
It should be noted thatthere is an inherent margin ofsafety associated with limitingJP-4 orJetB fuel usage based on suction fuel feed capability. Under normal conditions, the airplane fuel boost pumps will be functioning. There are two AC powered boost pumps in each ofthe main fuel tanks, and two AC powered boost pumps in the center fuel tank. Under pressure feed conditions, the airplane can operate normally with JP-4 fuel at a temperature of 110°F up to maximum altitude. Suction feed operation is required onlywhen all AC power is lost on the airplane. The probability ofthis occurrence is extremely low due to redundancies incorporated in the airplane electrical system. 

### Requestto 'WaivePublication and Comment' Not requested. 

### Privileges oftheExemption OutsidetheUnited States Not requested. 

### Summaryto be Published in theFederalRegister Boeing is requesting relieffrom the requirements of 14 CFR25.961(a)(5), Amendment 57, for JP-4 and Jet B fuel usage on 767-2C program. The regulation requires that the airplane and engines perform satisfactorily with the critical fuel at a temperature ofat least 110°F. Boeing requests thatthe FAA approve limitations for JP-4 and Jet B fuels on 767-2C in lieu of compliance to the specified temperature of 110°F. The limitations would consist ofrestricting the fuel temperatureto 85°F' and altitude restrictions ifrequired. The altitude restrictions will beEnclosure RA-13-03942 Page 4 of4

based on fuel temperature to keep fuel pressure and V/L (vapor/liquid) ratio withinthe engine manufacturers limitations at the engine pump inlet.
Similarexemptions have been approved on 757-300 and 747-400/-400F model airplanes. Boeing asserts that an exemption to 14 CFR 25.961(a)(5) subject to the limitations presented herein is in the public interest and maintains a level ofsafety equal to that intended bythe regulation.