Exemption No. 10193

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

Inthe mattcr ofthe petition of The Boeing Company foran exemption from § 25.1535 ofTitle 14,Code ofFederal Regulations, as specified inAppendix K, § K25.1.4(a)(3) Regulatory Docket No. FAA-2010-0496

GRANT OF EXEMPTION By letter BDCO-IO-03739, dated Seplember 7,2010, Mr. Jordan B. Zundell, Lead Project Administrator-Production and Retrofit Projects, The Boeing Company, P.O. Box 3707, MC 67-LR, Seattle, WA 98124-2207, petitioned the Federal Aviation Administration (FAA) for an exemption from the requirements of § 25.1535 ofTitle 14,Code ofFederal Regulations (14 CFR) for its Model 777-200, 777-200LR, 777-300ER, and 777F airplanes, as the regulation applies to low-fuel alelting for approval ofthese mode~s forextended operations (ETOPS) beyond 180 minutes. This exemption, ifgranted, would permit the Boeing Company aperiod of time to develop and incorporate design changes for their low-fuel-alerting system into the Model 777 ai.rplanes. The petitioner requests relief from the following regulation: Section 25.1535, as specified inAppendix K, § K25.1.4(a)(3)

- Low-fuel alerting. K25.1.4(a)(3)

- An alert must be displayed tothe flightcrew when the quantity offuel available tothe engines falls below the level required to flyto the destination. The alert must be given when there is enough fuel remaining to safely complete adiversion. This alert must account for abnormal fuel management ortransfer between tanks, andpossible loss offuel. This paragraph does not apply to airplanes with arequired flight engi.neer.The petitioner supports its request with the following information:

This section quotes therelevant infonnation from the petitioner's request. The complete petition is available atthe Department ofTransportation's Federal Docket Management System, on the Intemet athttp://regulations.gov, inDocket No. FAA-201O-0496.

Discussion Title 14CFR, Part 25, Appendix K, Section K25.1.4(a)(J) states that, "An alert must be displayed to the flight crew when the quantity offllel available tothe engines falls below the level required to flyto the destination. The alert must be given when there is enough fuel remaining to safely complete adiversion. This alert must account for abnormal fuelmanagement ortransfer between tanks, andpossible loss offuel. This paragraph does not apply to airplanes with arequired flight engineer." The above rule ostensibly grew out ofthe Airbus incident in the Azores where the crew was unaware ofa massive fuel leak andhad to glide the airplane tothe runway. Boeing and FAA SACO have conducted numerous meetings about how to demonstrate model 777 compliance with the above rule. Boeing believes that appropriate architectural changes to AIMS, with correspondingly revised check list operations, comply with the rule, and Boeing ison record to accede the incorporation afthe AIMS changes. Itis estimated that the incorporation ofthese changes will take approximately five years. These AI:MSchanges for low fuel alerting 'fill be implemented along with other AIMS changes not related ta extended ETOPS, and those other changes will take approximately two to three years tobe designed, tested and certified, plus an additional one year for in-service incorporation by airline operators. These discussions between Boeing and FAA precipitated the decision byF AA to clarify their position via Issue Paper. While these discussions and negotiations between Boeing and FAA have been proceeding, EASA has granted ETOPS certification far operation beyond 180 minutes. The EASA NPA 2008-01 forextended ETOPS contains adifferent standard with regards to low fuel alerting than FAA Jule K25.1.4(a)(3), and Boeing's current 

## , architecture is likely compliant with the EA,SA

## eRr without further changes. This puts Boeing FAA certified aircraft:at asigni:ficant disadvantage inthe marketplace. Granting ofthe exemption will allow FAA certified aircraft to operate beyond 180/207 minutes, thereby leveling the comp1etitiveness ofF AA-certified aircraft to that ofEASA-certified aircraft.

2Justification Existing ETOPS CeTtificatioD Basis ETOPS certification ofcurrent 777 models is based on 777 ETOPS special conditions (25-ANM-84/84A) and ETOPS Policy Letter no. 20-1 (EPL-20-1). Effect on Safety Dunng the exemption period, Boeing will make changes to the existing 777 "Low Fuel Alerting" architecture tobecome fully compliant with K25.1.4(a)(3). While this change activity isproceeding, it is important to take the following factors into consideration:
The current 777 "Low Fuel Alerting" architecture contains aFuel Imbalance and Fuel Disagree EICAS Advisory message. Both Fuel Disagree and Fuel Imbalance have associated crew-checklist items for leak determination. Also, the FMC provides an alert forInsufficient Fuel. These messages, in addition to the crew fuel-monitoring procedures, listed in AC 120-42B, Section 304, provide significant crew awareness. Boeing has already made achange tothe Fuel Disagree Message as aresult ofan internal cross model safety assessment based on the A330 Azores incident. AJthough no deficiencies were noted inthe Boeing designs, it was decided to elevate the Fuel Disagree to an EICAS Advisory message from an FMC scratch pad message as a safety enhancement.
The operational approval for330 minutes will be limited to areas south ofthe equator, including the Indian Ocean, South Pacific, South Atlantic, and South Pole region where operations are expected to be thin and grow slowly. Therefore, exposure to beyond 180minutes will be very small compared to the historical database and continuing operations at 180minutes. Boeing will study the planned enhancements to comply with K25.1.4(a)(3), in conjunction with existing guidelines and crew procedures, to determine ifBoeing can supplement existing guidelines and crew procedures so as to mitigate the impacts due tothe enhancements notbeing available during the exemption period.
In light ofthe abovejustifications, Boeing seeks atime-limited exemption from § K15.1.4(a)(3). Public Interest This exemption isessential for Boeing's airline customers flying FAAvcertified aircraft to compete with airline customers flying EASA-certified aircraft and to

3reduce operational costs on longer-range flights. One airline stated that the success of its long-term business plan is dependent on ETOPS beyond 180/207 minutes.
This reduction inoperational costs will also benefit the flying public economically and environmentally. The economic benefit~ are derived fTomreduced ticket prices and reduced personal travel times due to the more direct flight routes. The reduction intravel times isespecially important to the business traveler segment ofthe flying public. The enviromnental benefit isderived from the operator's ability to shorten flight tracks around many regions around the world or natural disasters like volcanic eruptions. The longer flight tracks required for 180-minutes ETOPS result in large increases in fuel bum and/or large reductions in revenue payload. The number of airlines requesting the extended ETOPS certification is significant, which only exacerbates the overall environmental impact. One airline stated that ETOPS beyond 180/207 is an important and significant enabler forthe airline to reach its environmental goal to reduce CO2 emissions. This exemption would represent a significant step toward reducing costs to the operators and thereby its customers, as well as serving to protect the environment from unnecessary fuel consumption. Request Boeing hereby petitions for an exemption from 14CFR K25.1.4(a)(3) as itrelates to low fuel alerting on Boeing Model 777-200, 777-200LR, 777-300ER, and 777F airplanes. This exemption isrequested to al~owBoeing to certify the 777 models for FAA operators wishing to operate ETOPS missions beyond 180/207 minutes per the mles outlined inAppendix K ofTitle 14CFR Part 25. Boeing Response toFAA Letter dated June 10, 2010. FAA Question 1: What specific design changes will yoube making to comply with section K25.1.4(a)(3)? Boeing reply: Boeing will answer this question inresponse to Issue Paper EE-1.

4Supplemental Boeing reply: Boeing transmitted adescription ofthe specific changes itwill make to the Model 777 design to comply with 

### §K25.1.4(a)(3) inletter number BDCO-1O-04796 dated November 12, 2010. These changes are identified inthe following table.
Current 777 Functionality Design Changes for Compliance to K25.1.4(a)(3) Insufficient Fuel Message FMC Scratch Pad Message Add EICAS Advisory Message INSUFFICIENT FUEL on Active INSUFFICIENT FUEL Route. Retain FMC Scratch Pad Message INSUFFICIENT FUEL on Mod Route. No associated checklist Add QRH Checklist for INSUFFICIENT FUEL. None Add a color change to the Total Fuel Quantity indication on the prima'Y EICAS and the expanded fuel indications synoptic page: Turn "amber" while the message is active. Fuel Disgree Message FUEL DISAGREE EICAS Revise the trigger threshold for FUEL DISAGREE EICAS Advisory Advisory Message Message to a lower value. QRH Checklist No change to QRH Checklist. FMC fuel predictions use Revise FMC logic to allow the Flight Crew to switch between FQIS Calculated Fuel as the default. Totalizer Fuel and Calculated Fuel, at any time, regardless of the A one-time selection to FQIS status of FUEL DISAGREE message. Totalizer Fuel is available to the Flight Crew after the FUEL DISAGREE is issued. A manual fuel entry at engine Remove inhibit of FUEL DISAGREE due 10a manuallvel entry start inhibits FUEL DISAGREE before engine start. Add functionality to delete the manual entry total message. fuel quantity and synchronize the CALC fuel with the FQIS totalizer fuel quantity value, at engine start. Imbalance Message No change. Fuel Qty Low No change. Fuel Flow Eng l,R None Add EICASAdvisory Message FUEL FLOW ENG L,Rfordetection offuel flow anomaliesdownstream oftheflowmeters. None Add FUEL FLOW ENG L.R QRHChecklist. None Add functionalitytoautomatically displaythesecondaryengineindications when the message FUEL FLOW ENG L,Ris active. None Add functionalitytoautomatically displaythe expandedfuel indications when !he message FUEL FLOW ENG L,Ris active. FAA Question 2: How many operators (and airplanes) want to enter such operations immediately after greater-than-180-minutes ETOPS approval isgranted? How many ofthose are U.S. operators?

5Boeing reply: The number ofoperators, to date, that have expressed interest inentering the 180- minutes-plus ETOPS operations, immediately after approval is granted, is eight. Of those eight, three are U.S. operators. The estimated number of airplanes involved is behveen thirty and thirty-five.
J?AA Question 3: How many operators would be operating in.greater-than-I80-minute ETOPS during the exemption period?
FAA Question 4:
How many airplanes would be operating ingreater-than-180-minute ETOPS during the exemption period? Boeing reply: Our current analysis sunnises that the 777 will generate historic growth in the Southern- and mid.Pacific~region routes over the next five years. The extrapolation assumes that the trends seen inthe North Atlantic and North Pacific will continue in the Southern Oceans once the 777 iscertified forbeyond 180/207. The analysis assumes atotal of780 flights in2009 ramping up to 6,500 B777 flights in2015 for the Southern and mid-Pacific oceans. It is assumed that these flights will utilize greater than 180/207 asitbecomes available. The estimated fleet size that corresponds to 6,500 flights peryear is appr:oximately 70to 100airplanes by 2015. That translates mto afleet increase of62-plus airplanes. Furthermore, other regions, like the polar region, are expected to need greater-than1801207 ETOPS capability for increased flexibility, depending on the availability of alternates. Itis expected that aU.S. carrier operating in the polar region would utilize 240-minute ETOPS approximately 50 times ayear. A separate marketing analysis has projected afleet size of 13 airplanes for operations that provide increased flexibility with 240-minute ETOPS. Consideration must also be given to whether the Western and Southern Pacific routes are saturated. Approval ofgreater-than-180

## Jminute ETOPS and its attendant increased profit potential iscertain to attract additional carriers into that market sector. The above dissertation translates into the following numbers for the 5-year exemption period:

6Additional airplanes: 70

- 100 Additional operators: 12

- 15 Boeing is unable topredict atthis time how many ofthose would be U.S. earners. FAA Question 5: What will be the schedule for incorporating the design changes, particularly forthe operators who will he operating ingreater-than-180-minute ETOPS during an exemption period? Boeing reply: Boeing requests a 5-year exemption period based on the following timeline for events: a) 1year fOfIssue Paper EE-l Closure and Finn Design on software change b) 2-3 years for software development and certification (standard flow) c) 1year foroperator incorporation after software change iscertified Federal Register publication Although the petitioner initially requested that action on its petition not be delayed for publication inthe Federal Register, theFAA found that the petition, ifgranted, would set a precedent. Therefore, to allow an opportunity forthe public to comment on the petition, a summary ofitwas published inthe Federal Register on September 23,2010 (75 FR 184). The FAA received comments from three sources. Comments from V Australia Airline and Air New Zealand fully support Boeing's exemption request. The Air Line Pilots Association, International (ALPA) suggests both a shorter timeframe than that which Boeing requests forcomplying with low-fuel-messaging regulations, and that"

...the petition should be more derinite inoutlining [Boeing's] plan to ultimately comply with the cited FAR." This commcnter feels that five years to implement asoftware change isunrealistically long and exposes aircraft, passengers, and crews to avoidable risk during that time. The FAA's analysis Boeing states intheir petition forexemption that appropriate architectural changes to the Airplane Infonnation Management System (A.llvfS),with correspondingly revised check list operations, would comply with the ETOPS low fuel alert requirement, and that Boeing is on record to accede to the incorporatlon ofthe AlMS changes. Boeing provides no explanation in its petition why the company would not be able to comply with this requirement before type certification. This implies that acommitment to making acompliant design change inthe future is allthejustification necessary to obtain anexemption. To counter this implication, additional conlext isnecessary.

7The ETOPS low fuel alert requirement came into existence in amendment 25-120 topart 25,

which became effective onFebruary IS, 2007. This requirement was not apart ofthe previous ETOPS policy orpractice that was codified inthis amendment to part 25, but came about as a result ofservice experience that indicated such arequirement was necessary to ensure continued safe long-range operations. At the time the FAA deliberated on this requirement~ we and Boeing believed the Model 777 desih'l1would comply without further change. Itwas not until after several engine fuel leaks occurred on the Model 777 in late 2008 and early 2009 that the FAA came to realize that the existing 777 alerting system was not sufficient to confmn the existence ofa fuel leak so that the flight crew could take appropriate corrective action. Therefore, itwould not comply with the new low fuel alert requirement after all.
Intwo ofthese events, the flight crew detected afuel imbalance and diverted, but did not shut down the leaking engine. In each case, the airplane continued to lose fuel overboard during the diversion and the fuel leak was not confirmed until after the airplane landed safely. By the time Boeing committed tomaking design changes to the Model 777 airplane to comply with the ETOPSlow fuel alert requirement, they were within six months ofthe time when the company sought type design approval forgreater than l8D-minute ETOPS. Since the identification ofthe non-compliance with the low fuel alert requirement camc relatively late inthe 777 certification program for greater than ISO-minute ETOPS and Boeing had committed to making appropriate design changes, the FAA felt that an exemption for an appropriate period oftime for Boeing to design and develop acompliant design could be found tobe inthe public interest. The FAA has evaluated Boeing's petition for exemption from the low-fuel alert required by 14CFR § 25.1535, as specified inAppendix K, §K.25.1.4(a)(3). We considered whether ornot granting such atinle-limited exemption would be inthe public interest, and ifdoing sowould not adversely affect safety orprovide alevel ofsafety atleast equal to that provided bythe rule from which Boeing seeks exemption. Ifthose 1\voconditions could be met, we also looked into what would be an appropriate period oftime forBoeing to design, test, and incorporate design changes into the 777 fleet that will comply with this airworthiness requirement, taking the resulting level ofsafety into consideration.
ALPA stated that the petition should bemore definite inoutlining the plan to ultimately comply with the cited regulation. The FAA received more defulitive information about Boeing's plan to comply with the low-fuel alert requirement inletter number BDCO-IO-04796, dated November 12, 2010. We have placed this letter inthe public docket forthis exemption petition. While we have not yet found that the specific setofchanges to the Model 777 design proposed by Boeing will comply with the rule, we accept that such changes will be apart ofa showing ofcompliance.
Public Interest: The FAA agrees that areduction inoperational costs associated with being able to operate on more direct airline routes will also benefit the flying public both economically and environmentally. We agree that the economic benefits are derived from reduced ticket prices and reduced personal travel times due to the more direct flight routes. We also agree that the

8reduction intravel times is especially important to business travelers for whom time is avaluable

commodity. Boeing points out that more direct flights would also be asignificant factor in reaching airline environmental goals for reducing CO2 emissions. Any benefit ofatime-limited exemption on CO2 emissions would be dependent onthe period oftime that an airplane could be operated on shorter ETOPS routes before compliant design changes are incorporated. We don't share Boeing's view that this would be asignificant benefit because any reduction in CO2 emissions during cruise compared to flying alonger route forthe same citypair, to stay within existing 180- minute ETOPS authority, is small compared tothe emi~sions during takeoff and climb, which would notbe affected by an exemption. Also, these public benefits would be realized eventually after acompliant design is incorporated iDtothe 777 fleet even without an exemption. Therefore, the remaining question then iswhether itis inthe public interest that these benefits occur now, rather than after Boeing incorporates a compliant design into the 777 fleet atthe end ofan exemption period. Boeing states that this exemption would be essential forBoeing's airline customers flying FAA-certified aircraft to compete with airline customers flying aircraft that have already received approval rromother authorities forETOPS beyond 180minutes. We agree that delaying approval ofthe 777 for ETOPS beyond 180minutes, while waIting for acomphant low-fuel alert design, could create a real economic disadvantage to those operators ofthe 777 airplane who are in direct competition with aircraft serving the same citypairs. This could result inthose operators choosing tobuy those other aIrcraft to remain competitive. Boeing mentions in its petition that the European Aviatlon Safety Agency (EASA) has approved other aircraft for ETOPS beyond 180minutes based on adifferent European safety standard than the FAA has adopted. While the FAA has not yetmade aspecific finding on these aircraft for compliance with § K25.1.4(a)(3), we have reason tobelieve that they would not comply with the marc stringent FAA standard. As such, itwould not be in the public interest to create a competitive environment that could result in alargcr population ofnon-compliant airplanes in service than would occur ifanexemption were granted. Any non~compliant 777 airplanes that enter greater than 180-minute ETOPS during an exemption period would have to bemodified with acompliant design when itbecomes available as acondition for the exemption. Level ofSafety During the Exemption Peliod: We agree with ALPA that operating passenger aircraft with anon-compliant design would expose passengers and crews to increased risk during the exemption period. We believe that such risk could be mitigated with compensating factors during the exemption period and that the effectiveness ofsuch compensating factors should be indirect proportion with the length oftime that they would be ineffect. However, this risk is also mitigated byexisting features inthe 777 design that will be apart ofthe complete set oftligbt-deck alerts Boeing will use to comply with the low-fuel alert requirement. So, the additional risk to bemitigated by compensating ractors is limited to the specific conditions that the Boeing proposed design changes will address.

9Service experience has shown that that the current 777 design and operational procedures have

not adequately confirmed the existence ofsome fuel leaks. Even though the airplane landed safely following each occurrence, the flightcrews did not take specific action to stop the loss of fuel because of alack ofsuch confmnation, Delays in confirming and taking corrective action for fuel leaks would have amuch more significant effect on safety the farther away an airplane is from aplace to land. While existing 777 design features provide flightRdeckinformation that a flightcrew could useto discover and take corrective action for fuel loss, diversion times beyond 180minutes result in less margin fordelays in such discovery before the loss offuel becomes critical. The design features Boeing is proposing forcompliance with the low-fuel alert requirement include several flightcrew alerts with associated operating procedures that are intended to improve flightcrcw a\vareness and identifIcation ofthe source offuel loss, orhigher-thanplanned fuel consumption. The most significant changes to the 777 design and flightcrew operating procedures are intended to detect fuel leaks downstream ofthe engine-fuel now meters. Such leaks have been a significant source offuel loss in service and are currently only detectable with aFlight Management Computer (FMC) INSUFFICIENT FUEL scratch-pad message. It is displayed when the predicted quantity offuel on board the airplane, upon arrival atthe destination, is less than the planned reserves. The current FMC message isnot inthe flightcrew's nonnal field ofview. Boeing is proposing toraise flightcrew awareness ofthe INSUFFICIENT FUEL alert bydisplaying itas anEICAS advisory message. Anew alert that will more directly detect fuel leaks downstream ofthe engine-fuel flow meter will be aFUEL FLOW ENG L,R Engine Indicating and Crew Alerting System (EICAS) advisory message. Boeing did not indicate what logic would trigger this message, only that itwould detect anomalies downstream ofthe flow meters. Other design changes Boeing proposes primarily address improvements in the current FUEL DISAGREE EICAS message. Tllis message is displayed when the fuel quantity indicating system (FQIS)Rmeasured totalizer fuel quantity and the FMC calculated-total-fuel quantity differsby more than athreshold amount. One ofthese improvements isto reduce the triggering threshold to alower value so that fue1leaks upstream ofthe engine-fuel flow meter will be detected earlier in the flight. The FAA evaluated several options for compensating factors that could be applied until a compliant low-fuel alert design is incorporated into the 777 fleet. These options focused primarily 011 reducing the risk offuel leaks downstream ofthe engine-fuel flow meter, which are not adequately addressed inthe current 777 design. Although the proposed changes inthe FUEL DJSAGREE EICAS message will improve detection of fuelleaks upstream ofthe engine-fuel flow meters, the cUlTentdesign will detect these types offuel loss. Also, after fuel inthe center fuel tank is consumed, afuel leak for any cause would result in amain fuel-tank imbalance EICAS message. The flightcrew procedure forthis message asks the crew to detennine ifthe imbalance is caused by afuel leakbefore opening the fuel-crossfeed valve to balance the tanks. The FAA-evaluated options are: Option I: Carry fivepercent additional fuel reserves above the ETOPS fuel reserves determined under 14CFR 121.646(b). The additional fuel reserves would allow more time for aflightcrew to detect and take corrective action for fuelloss before itbecomes critical. The downside ofoption

101 isthat carrying the additional fuel reserves increases takeoff weight for agiven flight, which

requires higher engine fuel consumption to carry that weight, and negates some ofthe economic benefit ofbeing able to operate on the more direct, greater~than-180-minute ETOPS routes between city pairs. Also, carrying additional fuel does not provide adirect means ofdetecting fuel loss. Option 2: Require flightcrew recording ofengine-fuel flow rate for each engine once every 30 minutes during ETOPS flights, including recording the difference inthe engine-fuel flow rate between the two engines. Ifthe recorded difference in engine-fuel flow rate rate between the two engines changes by 500pounds per hour ormarc between two recording checkpoints, initiate the fuel-leak checklist procedure. This procedure would provide adirect means ofdetecting afuel leak downstream ofthe engine-fuel flow meter. The SOO-pound-per-hour, engine-fuel-flow-rate difference threshold, forgoing to the fuel-leak checklist procedure, would allow crews to catch most slow fuel leaks before they have achance to grow into large leaks. A 3D-minute recording interval limits the amount offuel that could be lostbefore aflightcrew becomes aware ofalarge leak. Option 3: Require periodic flightcrew recording ofthe FQIS-measured totalizer fuel quantity, the calculated total fuel quantity from the flight-management computer, and the difference from the planned-mission fuel quantity atthat point inthe flight. The existing FUEL DISAGREE EICAS message would detect large differences between totalizer and calculated fuel quantities due to fuel loss upstream ofthe engine-fuel flow meters, which may occur before such aleak would be detected by periodic fuel-quantity checks. So such acomparison would be useful to detect slower-rate leaks earlier in the flight. For leaks downstream ofthe engine-fuel flow meter, only the comparison ofthe measured fuel quantity with planned-mission fuel atthat point in the flight would detect sucb aleak. Itis astandard operating procedure, on oceanic flights, for airline flightcrews tomonitor total fuel onboard and compare itwith planned-mission fuel quantity. We do not see that this option really provides acompensating factor for the design features Boeing proposes forcompliance with the ETOPS low-fuel alert requirement unless these checks are done more frequently than current practice. The 2001 Air Transat A330 flightcrew monitored fuel quantity using such aprocedure. The onJyfuel check n::quiredby the standard procedure Air Transit used, during the tirneframe that resulted inthe A330 fuel exhaustion, occurred atapoint where the difference between measured and plamled total fuel quantity was within 1%. Conducting fuel-quantity checks atthe same frequency as recording engine-fuel £lowrates in option 2could identify fuel loss upstream ofthe engine-fuel flow meters before itbecomes critical. In addition, conducting the engine-fuel flow-rate check ofoption 2, inconjunction with a comparison oftotalizer and calculated fuel, would make acomparison oftotal fuel quantity and plalll1cd-missJOnfuel unnecessary because there could be no difference in these values that would not also be detected bythe two other comparisons. Boeing estimates that between 30 and 35 airplanes would be used ingreater-than-180-minute ETOPS initially growing tobetween 70 and 100airplanes after five years. Although the FAA does not accept operational procedures alone in lieu o['a flight-deck alert for showing compliance with the ETOPS low-fuel alert requirement, the FAA considers that the combination ofoptions 2 and 3 procedures accomplished at 3D-minute intervals during the ETOPS portion ofeach flight

11would lower the risk offuel exhaustion to an acceptable level for this limited number ofairplanes

during the exemption period. Exemption Period: The FAA is concerned, as is ALPA, about the 5years Boeing states are required to design, test, and incorporate compliant design changes into the 777 fleet. Boeing states, intheir response to our request foradditional information in support oftheir petition for exemption, that they need one year to complete firm design ofthe softv..'arechange, two to 

### three years for software development and certification using the standard flow times, and one year for incorporation. Boeing's response letter to the FAA was dated June 10,2010. Six months have elapsed since the date ofthe letter and Boeing has now proposed specific design changes for showing compliance with the low fuel alert requirement. So, we do notbelieve itwill take afull year from the date of the issuance of anexemption to complete firm design. Since theproposed design changes are necessary t.obring the 777 airplane into compl1ance witb the minimum airworthiness standard. [or ETOPS beyond 180minutes, we believe that the time to develop and certify the software should be closer tothe shorter two-year stahdard flow time from Boeing's development timeline. Also, after the software is certified, loading it into each airplane should require only ashort time and could be accomplished during an ovemight stop at an airport where the operator has a maintenance facility. Itshould notbe amajor burden for an operator to schedule incorporation of the software change into those airplanes oftheir fleet used on greater-than-180-minute routes. Therefore, the FAA believes that the entire projected fleet of70to 100 airplanes could getthe software updates within one month after final certification. Shortening Boeing's requested exemption period bythe six months that have passed since their original design completion estimate, using the shorter two~year span for software development and certification, plus the 11 months we do notbelieve are necessary for incorporation ofthe final~design change, results in areduction in the total flow time bytwo years and five months; from the five years inBoeing's petition. The Model 777 airplane has been in service for over fifteen years without afuel exhaustion accident, even inlight ofthe recent iil~servicehistory. Boeing and the engine manufacturer have taken corrective actions to address the cause ofthe fuel leaks inthose earlier occurrences and nomore fuel leaks have occurred since those actions were taken. The compensating factors identified above will reduce the risk ofWldetected fuel loss during anexemption period byproviding amanual me~ns forperforming the functions ofthe intended design changes. Therefore, rounding up tothe nearest whole year, wehave determined that atime-limited exemption oftlrree years would allow sufficient time forBoeing to design and implement acompliant low~fuel alert design into the affected 777 ETOPS fleet while maintaining an acceptable low risk offuel exhaustion. The FAA's decision
In consideration ofthe foregoing, 1find that agrant ofexemption is inthe public interest. Therefore, pursuant to the authority contained in49 U.S.c. 40113 and 44701, delegated tome by the Administrator, Boeing ishereby granted an exemption from 14CFR 25.1535, as specified in Appendix K, K25.1.4(a)(3), for alow fuel alert. The exemption is granted tothe extent necessary

12to allow Boeing to design, test, and incorporate design changes into the 777 fleet that will comply

with this airworthiness requirement.
This exemption is subject tothe following condition(s);
1. At the time oftype-design approval ofthe Model 777 for ETOPS beyond ISO-minutes, the Configuration, Maintenance, and Procedures (eMP) docwnent, required by § K25.1.6 of Appendix Kto 14 CFR part 25, must contain aconfiguration item requiring incorporation of

, alow-fuel alert that complies with § K25.1.4(a)(3) by adate no latcr than January 11, 2014. lfthe date oftype-design approval occurs after this date, the CMP must require the compliant low-fuel alert design as acondition for ETOPS beyond 180minutes.
2. The airplane flight manual must contain required flightcrew operating procedures tobe in effect during the exemption period for each ETOPS flight on routes that extend beyond 180- minutc diversion times, or 207-minute diversion times onNorth Pacific routes ifapproved on acase-by-case basis. These proccdures must contain the following elements:

a. Record the following once every 30 minutes during the ETOPS portion of each flight.

1. Engine-fuel flow rate foreach engine

11. Totalizer fuel quantity (from FQlS)

111. Calculated fuel quantity (from FMC) b. Record the difference inengine-fuel flow rate between the left and right engines at each recording intervaL Ifthe recorded difference inengine-fuel flow rate between engines changes by 500pounds per hour between recording intervals, initiate the fuelleak checklist procedure.

c. Compare totalizer and calculated fuel quantities. Iftotalizer fuel quantity is less than calculated fuel quantity, initiate the fuel-leak checklist procedure.

133. Boeing must develop acomprehensive compliance plan and schedule, supporting full

compliance with the low-fuel-alert requirements of 14CFR 25.1535, as specificd in Appendix K, K25.1.4(a)(3), tobe presented to the

### IfAA Boeing Aviation Safety Oversight Office (BASOO) byMarch 31,2011. Tbereafter, Boeing must submit, to tbe BASOO, a status report every three months identifying all actions completed to date as well as those that remain outstanding. The report must demonstrate Boeing's progressive performance and accomplishments indicating their projected success inmeeting both the schedule and conditions ofthe exemption. Issued in Renlon Washington, on 

## JAN11 

## 2011 

# ?~E.~

Jeffrey Duvcn Acting Manager, Transport Airplane Directorate Aircraft Certification Service

14