AUG 2 6 2013 

RA-13-03942 

U.S. Department of Transportation 

Docket Operations 

John A. Hamilton 

Lead Administrator 

Regulatory Administration 

Commercial Airplanes 

West Building Ground Floor, Room W12-140 

1200 New Jersey 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: December 23, 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 hereby petitions for an exemption for relief from 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 Company respectfully 

requests that the enclosed information be processed by December 23, 2013. 

Furthermore, The Boeing Company requests to be notified when the encloses 

petition processing has been completed_ 
rtJ--_BDE,NG 

Page 2 

Mr. A:Xidias 

RA-13-03942 

Please contact this office or the following individuals if you have further 

questions: · 

Project Administrator (PA): 

Program Manager . 

Certification Lead/Specialist: 

S. Gordon 

T.Howorth 

M. Darnen 

425-237-:6068 

425-717.,9847 

425-717-8775 

The information being forwarded to the FAA by or with this correspondence is 

for the exclusive purpose of support of applications for or amendments to Type 

Certificates. 

Sincerely, · 

· Douglas M. Lane 

Dire.ctor 

Commercial Airplanes 

(425) 237;.1383, MC 03~56 

FAX: (425) 294~9340 

Enclosure: Petition for Exemption from 14 CFR25~961(a)(5) 

cc 

Name· 

• Jim Cashdollar 

Angelos Xidias 

Letter 

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EDT 

Enclosures 

EDT 

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Comments 

. ANM-:lOOB 

ANM-IOOB 
Enclosure 

RA-13-03942 

Page 1 of4 

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

Name and Address of the Petitioner 

Douglas M. Lane, Director 

The Boeing Company 

PO Box 3707 

Seattle, Washington, 98124 

(a) Section(s) of the Regulations from which Relief is sought: 

§25.961(a)(5) Fuel System Hot Weather Operation.: 

"(a) The fuel system must perform satisfactorily in hot weather operation. This must be shown 

by showing that the fuel system from the tank outlets to each engine is pressurized, under all 

intended operations, so as to prevent vapor formation, or must be shown by climbing from the 

altitude of the airport elected by the applicant to the maximum altitude established as an 

operating limitation under Sec. 25.1527. If a climb test is elected, there may be no evidence of 

vapor lock or other malfunctioning during the climb test conducted under the following 

conditions: 

(5) The fuel temperature must be at least 110° F." 

(b) Extent of Relief and Reason 

Boeing is requesting relieffrom the requirements of 14 CFR 25.961(a)(5), Amendment [25-57], 

for the Pratt & Whitney-powered 767-2C. The regulation requires that the airplane and engines 

perform satisfactorily with the critical fuel at a temperature of at least 11 0°F. Boeing requests 

that the FAA approve a set oflimitations for JP-4** and Jet B fuels on the Pratt & Whitneypowered 767-2C in lieu of compliance to the specified temperature of 110°F. The limitations 

consist of restricting the fuel temperature to 85°F, restricting the initial cruise altitude vs. fuel 

temperature if required, and making use of fuel tank temperature indication to allow JP-4 usage 

in any tank. Similar limitations were approved for the Rolls Royce-powered 757-300 and 747-

400/-400F. This exemption from the 11 OoF requirement is required because the properties of JP4 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 Jet B fuels. A maximum temperature of 85°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 under this exemption. 

(3) The 767-2C will demonstrate fuel feed performance under normal and abnormal conditions 

to cover all other approved fuels to temperatures in excess of 11 0°F. 

(4) The proposed limitations on fuel temperature and maximum altitude for initial cruise (if 

required) provide a level of safety equal to that intended by 14 CFR 25.961(a)(5). 

(5) The FAA has granted similar exemptions 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 Exemption No. 7496, issued 

4/12/2001) 

(d) the Rolls Royce-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 of Issue 

Boeing is introducing a 767-2C airplane model powered by Pratt & Whitney PW4062 engines. 

The 767 with Pratt & Whitney PW4000 series engines was introduced in 1986, and has 

accumulated over 15.1 million flight hours of revenue service. The 767-2C will offer only the 

PW 4062 engine at this time. The customer has 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 

limitation that does not allow it for revenue flights. 

With regard to 14 CFR 25.961(a)(5), the ability of an airplane to operate with JP-4 and Jet B 

fuels is a function of the vapor pressure of the fuel, which increases with temperature. The vapor 

pressure of wide cut fuels such as JP-4 and Jet B is considerably higher than narrow cut fuels 

such as Jet A. Under normal conditions, the aircraft fuel boost pumps maintain the pressure in 

the fuel feed system above the vapor pressure of the fuel. 

If all aircraft boost pumps are inoperative, the engine fuel pumps will continue to draw fuel out 

of the 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, or reach a 

value near the vapor pressure of the fuel allowing some fuel to vaporize and potentially causing 

engine flameout. Regulation 14 CFR 25.961(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. 

Statement of Public 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 of the world, particularly in cold weather areas due to their low 

freezing point. Occasionally they are the only fuels available at military or diversion airfields. 

Use of JP-4 and Jet B fuels will allow the 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 by reducing the amount 

of fuel consumed and reducing aircraft maintenance costs. The reduction in fuel consumed will 
Enclosure 

RA-13-03942 

Page 3 of4 

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

decrease in safety. 

Statement of No Adverse Effect on Safety 

Boeing believes that incorporating a temperature limitation of 85°F for JP-4 and Jet B fuels 

provides a level of safety equal to that intended by the 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) If required, 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 or Jet B fuel. If the fuel tanks are not 

defueled, the JP-4 fuel usage limitations shall continue to apply. 

(4).The maximum fuel temperature ofthe left main tank, center wing tank, forward body 

tank, and aft middle body tank is indicated in the flight deck which allows the Flight Crew to 

operate within the limitation. 

It should be noted that there is an inherent margin of safety associated with limiting JP-4 or Jet B 

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 of the 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 11 0°F up to maximum 

altitude. Suction feed operation is required only when all AC power is lost on the airplane. The 

probability of this occurrence is extremely low due to redundancies incorporated in the airplane 

electrical system. 

Request to 'Waive Publication and Comment' 

Not requested. 

Privileges of the Exemption Outside the United States 

Not requested. 

Summary to be Published in the Federal Register 

Boeing is requesting relief from the requirements of 14 CFR 25.961(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 of at least 11 0°F. Boeing 

requests that the 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 of restricting 

the fuel temperature to 85°F' and altitude restrictions if required. The altitude restrictions will be 
Enclosure 

RA-13-03942 

Page 4 of4 

based on fuel temperature to keep fuel pressure and V/L (vapor/liquid) ratio within the engine 

manufacturers limitations at the engine pump inlet. 

Similar exemptions 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 of safety equal to that intended by the regulation.