Exemption No. 10199

UNITED STATES OF AMERICA

DEPARTMENT OF TRANSPORTATION

FEDERAL AVIATION ADMINISTRATION

RENTON, WASHINGTON 98057-3356

In the matter of the petition of

The Boeing Company

for an exemption from § 25.1309(c) of Title 14,

Code of Federal Regulations

Regulatory Docket No. FAA-2010-1017

GRANT OF EXEMPTION

By letter dated October I, 2010 (BDCO-IO-04186», C. M. Thompson, Lead Project

Administrator, Development Projects, The Boeing Company, P.O. Box 3707, Seattle, WA

98124~2207, petitioned for a time-limited exemption from the requirements of Title 14, Code of

Federal Regulations (14 CFR) 25.1309(c). The exemption would provide relief from the

requirement to provide indication of anticipated fuel system contamination to the flightcrew of

Boeing Model 787-8 airplanes powered by Rolls-Royce Trent 1000 engines. This exemption

would expire June 30, 20 I4, for new airplane deliveries and December 31, 2018, for retrofitted

airplanes.

The petitioner requests relief from the following regulation(s):

Section 25.1309(c), at Amendment 25-116, requires "Warning information must be

provided to alert the crew to unsafe system operating conditions, and to enable them to

take appropriate corrective action. Systems, controls, and associated monitoring and

warning means must be designed to minimize crew errors which could create additional

hazards. "

The petitioner supports its request with the following information:

The following information summarizes the petition submitted by The Boeing Company. The

complete petition is available on-line in the Federal Docket Management System at

http://www.regulations.gov. The docket number is FAA~20 I0-1017.
The Rolls-Royce (RR) Trent 1000 is the first engine to incorporate a bypass in the fuel oil

heat exchanger (FOHE). The bypass was added to address the condition of a transient

high concentration of ice in fuel which could potentially block the FOHE and result in

significant loss of thrust. The FOHE bypass is not presently designed to provide

flightcrew alerting to indicate an impending or actual bypass condition. The FAA

recently provided Boeing guidance regarding what is needed to show compliance with

§ 25.1309(c) for flightcrew alerting of impending FOHE bypass or actual bypass. The

FAA has also provided additional guidance regarding FOHE and fuel filter flightcrew

alerting for dual engine impending or actual bypass. The 787w8 is not designed to

provide the FAA-required dual impending bypass indication for the filter and does not

currently provide impending and/or bypass indication for the FOHE. Boeing is

requesting relief for a limited number of787-8 airplanes to allow sufficient time to

develop, validate, certify and incorporate into production a compliant FOHE bypass

indication and alerting scheme and additional alerting for dual engine impending fuel

filter bypass. Following incorporation of the compliant design into production, Boeing

will issue a service bulletin recommending that all airplanes delivered during the

effective dates of the time-limited exemption be retrofitted by December 31, 2018. The

service bulletin will be available no later than June 30, 2014, such that all 787-8 airplanes

delivered under this exemption can order parts and install a compliant configuration. The

relief sought is limited to 787-8 airplanes delivered prior to incorporation of the

compliant message in production. The production incorporation of the compliant

message will be accomplished no later than June 30, 2014.

Effect on Safety

The fuel system architecture of the RR Trent 1000 engine is similar in design to other RR

engines. These engines have accumulated millions of in-service hours, including over 50

million hours on Boeing airplanes. There have not been any in-flight engine shutdowns

or in-flight power loss events associated with FOHE blockage cause by solid

contaminants being introduced in the worldwide fuel supply or solid contaminants left in

airplane fuel tanks. Incorporating the FOHE bypass in the design of the RR Trent 1000

engine is an improvement that provides an alternate path for fuel, reducing the likelihood

of a sudden engine shutdo\Vll due to fuel starvation.

The main fuel filter in the RR Trent 1000 engine complies with the requirements of

§§ 25.997(d) and 25.1305(c)(6). When the filter is exposed to contaminated fuel and

debris accumulates to the point that it reaches impending bypass, the flightcrew is alerted

via an engine indicating and crew alerting system [EICAS] advisory alert (ENG FUEL

FILTER L or ENG FUEL FILTER R). The advisory alert is presented well before the

pressure drop (delta P) across the fuel filter reaches a level that would result in bypassing

the fuel filter. This alerting scheme provides an adequate level of safety for the airplanes

affected by this exemption. This is the same fuel filter alerting on all Boeing production

airplanes.

The RR Trent 100 FOHE unit itself m.eetsthe qualification requirements in EASA AMC

E 670, Contaminated Fuel Testing. The level of contamination in the fuel used to meet

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these requirements is greater than the industry standard used to determine the

acceptability of jet fuel.

The service history of the RR fuel system architecture, the maintenance actions in place

to prevent solid contamination from entering the fuel tank, and the existing flightcrew

alert messages and associated flightcrew procedures provide an adequate level of safety

for the airplanes affected by this exemption. Approximately 100 airplanes v.rillbe

affected by this exemption and Boeing will recommend that these airplanes be retrofitted

into a fully compliant configuration by December 31, 2018.

The petitioner's statement of public interest:

Granting this petition is in the public interest because it would allow adequate time for

Boeing and Rolls Royce to develop an effective and robust design solution for the flight

deck indication of the dual fuel filter impending bypass requirement and FOI-IE

impending and/or bypass requirement. Conversely, if the requested relief is not granted,

the addition of a flight deck indication that both engines on the same flight are subjected

to a fuel filter impending bypass condition and FOHE impending and/or bypass at this

late stage of the airplane development program would lead to delays in the deliveries of

Model 787-8 airplanes.

Availability of787·8 airplanes with the RR Trent 1000 engines will reduce fuel bum

and hence reduce emissions of carbon dioxide, reduce global emissions of NOx, and

reduce operating costs of airlines from current in-service airplanes.

In addition, without adequate time to develop a robust solution, nuisance flight deck

alerts in-service have the potential to reduce operational safety when flightcrews are

tasked to respond to false indications potentially resulting in unnecessary flight

diversions, landing at airports that they are not familiar with, and conceivably, shutting

down an engine urmecessarily.

The public interest will be advanced by the grant of Exemption as it is in the best

economic interest of the United States. Many 787-8 customers are overseas. Further

delivery delays of the 787-8 are not in the interest of the public due to the potential

negative impact to export sales, the balance~of·trade, the gross domestic product, and

economic health of the United States.

Federal Register publication

A summary notice of the petition was published in the Federal Register on November 8, 2010

(75 FR 68666). No comments were received.

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Tbe FAA's analysis

The Boeing Model 787-8 airplane is equipped with Rolls-Royce Trent 1000 engines that include

a main fuel filter upstream of the gear stage of the engine driven fuel pump. The design includes

indication to the flightcrew in the event the fuel filter has collected contaminants that could cause

the filter to bypass debris to critical downstream engine components. This indication allows

annunciation to the flightcrew so that appropriate action, such as landing at the nearest suitable

airport, can be taken. We agree with the petitioner that this design complies with the engine

installation requirements of §§ 25.997(d) and 25. I305(c)(6). In combination, these regulations

rcquire that the engine fuel feed system has a filter with a capacity that meets the engine

endurance requirements of 14 CFR part 33 upstream of the positive displacement pump on the

engine, and that the filter used to show compliance with § 25.997 includes indication to the

flightcrew of impending exceedance of the filter capacity.

Service experience shows that severe fuel contamination can lead to fuel filter bypass, engine

power loss, and diversions. Most importantly, fuel contamination is a common cause threat that

may affect multiple engines due to general fuel contamination across the entire fuel system or

because a single contaminated fuel tank may be feeding multiple engines. In addition, there is no

specific requirement to provide flightcrew indication of impending bypass on multiple engine

fuel filters or the FOHE. Previously approved airplane rely on pilot skill to interpret impending

fuel bypass indications from each engine to make the determination that contamination may be

affecting more than one engine. However, § 25.1309(c) contains a general requirement to

provide indication to the flightcrew under certain conditions.

For the Model 787-8, Boeing has elected to comply with § 25.1309(c) by using tbe guidance in

the current draft of Advisory Circular (Ae) 25.1309-1X, System Design and Analysis, referred to

as the "Arsenal" version. The Arsenal version of AC 25.1309-1X states that "information

concerning unsafe system operating conditions must be provided to the crew to enable them to

take appropriate action." In addition, the Arsenal version of AC 25.1309-1X states that "systems

and controls, including indications and annunciations, must be designed to minimize crew errors,

which could create additional hazards."

Boeing has incorporated an indication for single engine fuel filter impending bypass condition

for crew awareness. Boeing has also added a collector message that includes both visual and

aural indication for multiple engine fuel filter impending bypass conditions, with associated

flightcrew procedures. This indication will annunciate impending fuel filter bypass for multiple

engines and the procedure will allow the flightcrew to take appropriate corrective action. This is

a significant improvement from previously approved designs.

Boeing has also incorporated a fuel bypass feature intended to prevent a temporary interruption

of fuel supply to the engines resulting from ice build up in the FOHE of the Rolls-Royce Trent

1000 engine used on the Boeing 787-8 airplanes. This additional feature would prevent the

temporary fuel flow intenuption due to ice that caused the loss of thrust on the Boeing 777 at

Heathrow airport. However, the FAA has determined that the lack of any fIightcrew indication

of impending bypass on the FOHE and associated flightcrew procedures is non-compliant with

the requirements of § 25.1309. In addition to ice, contaminants could also cause blockages in the

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FOHE. Under certain operating conditions, this could lead to the engine oil overheating and

subsequent shutdown of the engines. Review of the design of the 787 airplane with Rolls-Royce

Trent 1000 series engines showed this contamination would not be annunciated by any flight

deck indications to the flightcrew or maintenance messages.

Boeing is working with Rolls-Royce to develop a means to provide flightcrew indication of

impending bypass of the FORE, as well as changes to the airplane indication system, to provide

specific annunciation of impending fuel filter bypass for both engines. These changes will take

significant time to develop and incorporate into the design. The need for these indications was

identified late in the certification program, during flight testing, when manufacturing debris

partially clogged the FORE. Therefore, it is impractical to make significant modifications to the

airplane and engine prior to the scheduled 787~8 certification date. Boeing stated in its petition

that previous Rolls-Royce engines without indication of clogging of the FOHE have accumulated

over 50 million operating hours on Boeing airplanes without any reported engine in~flight

shutdovms or power loss events associated with blockage due to solid contaminants. We agree

with the petitioner that the introduction of the FORE bypass in the Trent 1000 engine is a design

improvement over that of earlier FAA~approved Rolls~Royce engine designs by providing an

alternate bypass path for fuel around the FORE, thereby reducing the likelihood of a sudden

engine shutdovm due to fuel starvation caused by ice or contaminants. The 787 also incorporates

enhanced annunciation of common cause fuel contamination of the main engine fuel filters

affecting multiple engines.

While Boeing has recommended retrofitting the airplanes delivered under the provisions of this

exemption to full compliance by December 31, 2018, they have not provided a reason why

retrofit should take 4 years to complete after the service information is provided in 2014.

Without information indicating otherwise, we believe that bringing the aircraft into full

compliance sooner is in the public interest and that a 2-year retrofit program is reasonable. We

are limiting operation of aircraft delivered under the provisions ofthis exemption to

December 31, 2016, unless they have been retrofitted to full compliance.

The 787-8 is designed to limit maintenance actions that require entry into the fuel tanks. The

first tank entry is scheduled for 10' years after the airplane enters service. The reduced number of

fuel tank entries minimizes the potential for maintenance errors resulting in debris inside the fuel

tanks. This exemption is time limited for 5-6 years after the first 787-8 enters service, so few out

of sequence maintenance actions are expected that would increase the exposure for large

quantities of fuel contaminants inside the fuel tanks. The exemption also includes a provision

that requires special inspections of the FORE prior to airplane delivery, and after any out of

sequence maintenance actions that result in entry into the center wing fuel tank after the airplane

enters service.

The FAA considers the petitioner's request to be in the public interest because the Boeing Model

787-8 airplane design provides improved flightcrew awareness of common cause fuel

contamination of the main engine filters, and a fuel bypass of the FORE to prevent loss of thrust

due to ice accwnulations. We have also included special maintenance requirements as condition

of this exemption that will minimize the potential for contamination in the fuel tanks. These

compensating features provide an acceptable level of safety, and due to the late discovery of this

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deficiency, full compliance to § 25.1309(c) prior to delivery is impractical. Full compliance

would require significant modifications to the airplane and engine and delay the airplane's

delivery. The 787-8 meets later safety standards that provide improved safety and reduced costs

and emissions, when compared to the airplane fleet it is replacing. In addition, the 787~8

airplane has significant improvements in fuel efficiency and will typically be replacing older,

less~fuel~efficient models. Introduction of the 787-8 will reduce the public expense for fuel

consumed in air travel and freight delivery as well as reduce greenhouse gas emissions. In

addition, the Boeing Model 787-8 airplane type-certification program is near completion.

Without this exemption, Boeing would not receive design approval for the airplane in a timely

manner, delaying the fleet safety~and~efficiency improvements. Delay would also cause

disruption to several major domestic and international corporations that are anticipating the

imminent delivery of the Boeing Model 787-8 airplane to meet their business needs.

The FAA has considered the information provided by the petitioner and has determined that it

has sufficient merit to warrant a grant of exemption.

The FAA's decision

In consideration of the foregoing, I find that a time-limited grant of exemption is in the public

interest regarding 14 CFR 25.1309(c), as amended by Amendment 25-116. Therefore, pursuant

to the authority contained in 49 U.S.c. §§ 40113 and 44701, delegated to me by the

Administrator, The Boeing Company is granted an exemption Wltil December 31, 2016, from the

requirements of § 25.1309( c), as amended by Amendment 25-116, as they pertain to indication

of impending bypass of the fuel oil heat exchanger and indication of impending bypass on the

main fuel filters of multiple engines, for the Boeing Model 787-8 airplanes powered by RollsRoyce Trent 1000 engines with the following provisions:

1. For Model 787-8 airplanes granted a certificate of airworthiness before June 30, 2014, the

Airworthiness Limitations section of the Instructions for Continued Airworthiness must

include a limitation that requires operators to verify contaminants have not accumulated

on the fuel oil heat exchangers (FaREs) in service. The procedures must be

accomplished after the first flight following any maintenance actions that result in

personnel entry into the center wing fuel tank and before the next flight. The limitation

must also require an inspection of the FOHE following a main fuel filter replacement due

to an approaching bypass or impending bypass maintenance message.

2. Boeing must develop and implement procedures that include appropriate pass/fail criteria

acceptable for inspection of the face of each FORE following completion of production

flight tests, and prior to issuance of the standard certificate of airworthiness or export

certificate of airworthiness (as applicable in support of customer delivery). The

inspection must verify there is no evidence of unacceptable contamination of the FORE.

3. Prior to June 30, 2014, Boeing must complete the design and show compliance to

§ 25.1309(c), as amended by Amendment 25~116, for design improvements and

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flightcrew procedures to allow timely flightcrew awareness and response to hazardous

fuel contamination.

4. Prior to July 31, 2014, Boeing will develop and submit for FAA approval service

information to incorporate any design changes and/or operating and maintenance

limitations developed to meet the provision of § 25.1309(c), as identified in provision 3

(above).

5. By July I, 2011, Boeing must present to the FAA's Seattle Aircraft Certification Office a

comprehensive compliance plan and schedule, supporting the deliverables outlined in

conditions 3 and 4 (above). 111ereafter, Boeing must submit a status report every three

months to the Seattle Aircraft Certification Office identifying aU actions completed to

date as well as those that remain outstanding. The report must demonstrate Boeing's

progressive performance and accomplishments indicating its projected success in meeting

the schedule and conditions of the exemption. Boeing must also submit drafts of the

service information required by condition 4 (above) to the Seattle Aircraft Certification

Office by April 30, 2014.

6. For Model 787-8 airplanes granted a certificate of airworthiness prior to June 30, 2014,

the "Airworthiness Limitation" section of the Model 787-8 airplane "Instructions for

Continued Airworthiness" must state that delivered airplanes cannot be operated after

December 31, 2016, unless the design changes submitted in accordance with provision 4

(above) are incorporated by the owner or operator.

7. If an application for an airworthiness certificate is made on or after June 30, 2014, the

affected airplanes must incorporate the indication of impending bypass of the fuel oil heat

exchanger in compliance with § 25.1309(c).

8. The FAA will not issue original airworthiness approvals for Boeing Model 787-8

airplanes on or after June 30, 2014, unless Boeing has shown rull compliance with the

provisions of this exemption by that date.

Issued in Renton, Washington, on JAN 28 1011

Ali Bahrami

Manager, Transport Airplane Directorate

Aircraft Certification Service

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