Exemption No. 10199

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

In the matter ofthe petition of

The Boeing Company

for anexemption from § 25.1309(c) ofTitle 14, Code ofFederal 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 atime-limited exemption from the requirements ofTitle 14, Code of Federal Regulations (14 CFR) 25.1309(c). The exemption would provide relief from the requirement to provide indication ofanticipated fuel system contamination to the flightcrew of Boeing Model 787-8 airplanes powered byRolls-Royce Trent 1000 engines. This exemption would expire June 30, 20I4, for new airplane deliveries and December 31, 2018, for retrofitted airplanes.

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

Section 25.1309(c), atAmendment 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 bedesigned 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 isFAA~20I0-1017.The Rolls-Royce (RR) Trent 1000isthe first engine to incorporate abypass inthe fuel oil

heat exchanger (FOHE). The bypass was added to address the condition ofatransient high concentration ofice infuel which could potentially block the FOHE and result in significant loss ofthrust. The FOHE bypass isnot presently designed to provide flightcrew alerting to indicate an impending or actual bypass condition. The FAA recently provided Boeing guidance regarding what isneeded to show compliance with §25.1309(c) for flightcrew alerting ofimpending 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 787

w8 isnot 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 alimited number of787-8 airplanes to allow sufficient time to develop, validate, certify and incorporate into production acompliant FOHE bypass indication and alerting scheme and additional alerting for dual engine impending fuel filter bypass. Following incorporation ofthe compliant design into production, Boeing will issue aservice bulletin recommending that all airplanes delivered during the effective dates ofthe time-limited exemption beretrofitted 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 acompliant configuration. The relief sought is limited to 787-8 airplanes delivered prior to incorporation ofthe compliant message inproduction. The production incorporation ofthe compliant message will be accomplished no later than June 30, 2014.

Effect on Safety

The fuel system architecture ofthe RR Trent 1000 engine is similar indesign to other RR engines. These engines have accumulated millions ofin-service hours, including over 50 million hours on Boeing airplanes. There have not been any in-flight engine shutdowns
orin-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 inthe design ofthe RR Trent 1000 engine isan improvement that provides an alternate path for fuel, reducing the likelihood ofa sudden engine shutdo\Vlldue to fuel starvation.

The main fuel filter inthe RR Trent 1000 engine complies with the requirements of §§ 25.997(d) and 25.1305(c)(6). When the filter isexposed to contaminated fuel and debris accumulates to the point that itreaches impending bypass, the flightcrew is alerted via anengine indicating and crew alerting system [EICAS] advisory alert (ENG FUEL FILTER LorENG FUEL FILTER R). The advisory alert is presented well before the pressure drop (delta P) across the fuel filter reaches alevel that would result in bypassing the fuel filter. This alerting scheme provides an adequate level ofsafety for the airplanes affected by this exemption. This is the same fuel filter alerting on all Boeing production airplanes.
The RR Trent 100FOHE unit itself m.eetsthe qualification requirements in EASA AMC E 670, Contaminated Fuel Testing. The level ofcontamination inthe fuel used to meet

2these requirements is greater than the industry standard used to determine the

acceptability ofjet fuel.

The service history ofthe 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 ofsafety for the airplanes affected by this exemption. Approximately 100airplanes v.rillbe affected by this exemption and Boeing will recommend that these airplanes be retrofitted into afully compliant configuration by December 31, 2018.

The petitioner's statement ofpublic interest: Granting this petition isinthe public interest because itwould allow adequate time for Boeing and Rolls Royce to develop aneffective and robust design solution for the flight deck indication ofthe dual fuel filter impending bypass requirement and FOI-IE impending and/or bypass requirement. Conversely, ifthe requested relief is not granted, the addition ofaflight deck indication that both engines on the same flight are subjected to afuel filter impending bypass condition and FOHE impending and/or bypass atthis late stage ofthe airplane development program would lead to delays inthe deliveries of Model 787-8 airplanes. Availability of787·8 airplanes with the RR Trent 1000engines will reduce fuel bum and hence reduce emissions ofcarbon dioxide, reduce global emissions ofNOx, and reduce operating costs ofairlines from current in-service airplanes.

Inaddition, without adequate time to develop arobust solution, nuisance flight deck alerts in-service have the potential to reduce operational safety when flightcrews are tasked torespond 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 ofExemption as itis inthe best economic interest ofthe United States. Many 787-8 customers are overseas. Further delivery delays ofthe 787-8 are not inthe interest ofthe public due tothe potential negative impact to export sales, the balance~of·trade, the gross domestic product, and economic health ofthe United States.

Federal Register publication

A summary notice ofthe petition was published inthe Federal Register on November 8, 2010 (75 FR 68666). No comments were received.



### 3Tbe FAA's analysis

The Boeing Model 787-8 airplane isequipped with Rolls-Royce Trent 1000engines that include
amain fuel filter upstream ofthe gear stage ofthe engine driven fuel pump. The design includes indication to the flightcrew inthe event the fuel filter has collected contaminants that could cause the filter to bypass debris to critical downstream engine components. This indication allows annunciation tothe flightcrew so that appropriate action, such as landing at the nearest suitable airport, can betaken. We agree with the petitioner that this design complies with the engine installation requirements of §§ 25.997(d) and 25.I305(c)(6). Incombination, these regulations rcquire that the engine fuel feed system has afilter with acapacity that meets the engine endurance requirements of 14CFR part 33 upstream ofthe positive displacement pump on the engine, andthat the filter used to show compliance with 

### §25.997 includes indication tothe flightcrew ofimpending exceedance ofthe filter capacity.

Service experience shows that severe fuel contamination can leadto fuel filter bypass, engine power loss, and diversions. Most importantly, fuel contamination is acommon 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 befeeding multiple engines. In addition, there isno specific requirement to provide flightcrew indication ofimpending bypass on multiple engine fuel filters orthe 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 ageneral requirement to provide indication tothe flightcrew under certain conditions.

Forthe Model 787-8, Boeing has elected to comply with §25.1309(c) by using tbe guidance in the current draft ofAdvisory Circular (Ae) 25.1309-1X, System Design andAnalysis, referred to
as the "Arsenal" version. The Arsenal version ofAC 25.1309-1X states that "information concerning unsafe system operating conditions must be provided to the crew to enable them to take appropriate action." Inaddition, the Arsenal version ofAC 25.1309-1X states that "systems and controls, including indications and annunciations, must bedesigned to minimize crew errors, which could create additional hazards." Boeing has incorporated an indication for single engine fuel filter impending bypass condition forcrew awareness. Boeing has also added acollector 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 formultiple engines and the procedure will allow the flightcrew to take appropriate corrective action. This is
asignificant improvement from previously approved designs. Boeing has also incorporated afuel bypass feature intended toprevent atemporary interruption offuel supply to the engines resulting from ice build up inthe FOHE ofthe Rolls-Royce Trent 1000engine used on the Boeing 787-8 airplanes. This additional feature would prevent the temporary fuel flow intenuption due to icethat caused the loss ofthrust on the Boeing 777 at Heathrow airport. However, the FAA has determined that the lack ofany fIightcrew indication ofimpending bypass on the FOHE and associated flightcrew procedures is non-compliant with the requirements of § 25.1309. Inaddition to ice, contaminants could also cause blockages inthe

4FOHE. Under certain operating conditions, this could lead tothe engine oil overheating and

subsequent shutdown ofthe engines. Review ofthe design ofthe 787 airplane with Rolls-Royce Trent 1000 series engines showed this contamination would not be annunciated by any flight deck indications to the flightcrew ormaintenance messages. Boeing is working with Rolls-Royce to develop ameans toprovide flightcrew indication of impending bypass ofthe FORE, as well as changes to the airplane indication system, toprovide specific annunciation ofimpending fuel filter bypass forboth engines. These changes will take significant time to develop and incorporate into the design. The need for these indications was identified late inthe certification program, during flight testing, when manufacturing debris partially clogged the FORE. Therefore, it isimpractical to make significant modifications to the airplane and engine prior tothe scheduled 787~8certification date. Boeing stated in itspetition that previous Rolls-Royce engines without indication ofclogging ofthe FOHE have accumulated
over 50 million operating hours on Boeing airplanes without any reported engine in~flight shutdovms orpower loss events associated with blockage due to solid contaminants. We agree with the petitioner that the introduction ofthe FORE bypass inthe Trent 1000 engine is adesign improvement overthat ofearlier FAA~approved Rolls~Royce engine designs by providing an alternate bypass path for fuel around the FORE, thereby reducing the likelihood ofasudden engine shutdovm due to fuel starvation caused by ice orcontaminants. The 787 also incorporates enhanced annunciation ofcommon cause fuel contamination ofthe main engine fuel filters affecting multiple engines.

While Boeing has recommended retrofitting the airplanes delivered under the provisions ofthis exemption to full compliance by December 31, 2018, they have not provided areason why retrofit should take 4years 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 inthe public interest andthat a2-year retrofit program is reasonable. We
are limiting operation ofaircraft 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 5-6years after the first 787-8 enters service, so few out of sequence maintenance actions are expected that would increase the exposure for large quantities offuel contaminants inside the fuel tanks. The exemption also includes aprovision that requires special inspections ofthe 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 inthe public interest because the Boeing Model 787-8 airplane design provides improved flightcrew awareness ofcommon cause fuel contamination ofthe main engine filters, and afuel bypass ofthe FORE to prevent loss ofthrust due to ice accwnulations. We have also included special maintenance requirements as condition ofthis exemption that will minimize the potential for contamination inthe fuel tanks. These compensating features provide an acceptable level ofsafety, and due to the late discovery ofthis



### 5deficiency, 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 itis replacing. Inaddition, the 787~8 airplane has significant improvements infuel efficiency and will typically be replacing older, less~fuel~efficient models. Introduction ofthe 787-8 will reduce the public expense for fuel consumed inair travel and freight delivery aswell as reduce greenhouse gas emissions. In addition, the Boeing Model 787-8 airplane type-certification program isnear completion. Without this exemption, Boeing would not receive design approval for the airplane inatimely 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 ofthe Boeing Model 787-8 airplane to meet their business needs.

The FAA has considered the information provided bythe petitioner and has determined that it has sufficient merit towarrant agrant ofexemption.

The FAA's decision

Inconsideration ofthe foregoing, Ifind that atime-limited grant ofexemption is inthe public interest regarding 14CFR 25.1309(c), as amended by Amendment 25-116. Therefore, pursuant to the authority contained in49 U.S.c. §§ 40113 and 44701, delegated to me bythe Administrator, The Boeing Company is granted an exemption WltilDecember 31, 2016, from the requirements of § 25.1309(c), as amended by Amendment 25-116, asthey pertain to indication ofimpending bypass ofthe fuel oil heat exchanger and indication ofimpending bypass on the main fuel filters ofmultiple engines, forthe Boeing Model 787-8 airplanes powered byRollsRoyce Trent 1000 engines with the following provisions:

1. For Model 787-8 airplanes granted acertificate ofairworthiness before June 30, 2014, the Airworthiness Limitations section ofthe Instructions for Continued Airworthiness must include alimitation that requires operators to verify contaminants have not accumulated
on the fuel oilheat 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 andbefore the next flight. The limitation must also require an inspection ofthe FOHE following amain 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 ofthe face ofeach FORE following completion ofproduction flight tests, and prior to issuance ofthe standard certificate ofairworthiness orexport certificate ofairworthiness (as applicable in support ofcustomer delivery). The inspection must verify there is no evidence ofunacceptable contamination ofthe 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

6flightcrew procedures to allow timely flightcrew awareness and response to hazardous

fuel contamination.

4. Prior to July 31, 2014, Boeing will develop and submit forFAA 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 inprovision 3 (above).

5. By July I, 2011, Boeing must present tothe 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 astatus report every three months to the Seattle Aircraft Certification Office identifying aUactions completed to date aswell asthose that remain outstanding. The report must demonstrate Boeing's progressive performance and accomplishments indicating itsprojected success in meeting the schedule and conditions ofthe exemption. Boeing must also submit drafts ofthe service information required by condition 4 (above) to the Seattle Aircraft Certification Office by April 30, 2014.

6. For Model 787-8 airplanes granted acertificate ofairworthiness prior to June 30, 2014, the "Airworthiness Limitation" section ofthe 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 inaccordance with provision 4 (above) are incorporated by the owner oroperator.

7. Ifan application for an airworthiness certificate ismade on or after June 30, 2014, the affected airplanes must incorporate the indication ofimpending bypass ofthe fuel oil heat exchanger incompliance 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 ofthis exemption by that date.

Issued inRenton, Washington, on 

### JAN 28 1011

Ali Bahrami Manager, Transport Airplane Directorate Aircraft Certification Service

7