### 2a15


## JAN 172015

RA-15-00350 The Boeing Company P.O. Box3707 Seattle, WA 98124-2207

U.S. Department ofTransportation Docket Operations, M-30 1200 NewJerseyAvenue, S.E. Room W12-140, West Bldg. Ground Floor Washington, DC 20590-0001
Subject:

Model: RA Project No.:

Reference:

AD Related: Petition to Amend Partial Time Limited Exemption No. 11081 to include 14 CFR 25.939(a) atAmendment 25-40 in support ofCertification Plan 15053, Operation in Ice Crystal Icing for GEnxengines on 787-8 and 787-9 Airplanes
787-8, 787-9 PS14-0053
a) Boeing letter RA-14-02186, Petition for a Time Limited Exemption from 14 CFR 25.1305(c)(5) atAmendment 25-120 in support ofCertification Plan 15053, Operation in Ice Crystal Icing for GEnxengines on 787-8 and 787-9 airplanes, dated May 20, 2014. b) Time Limited Grant of Exemption No. 11081, Regulatory Docket No. FAA-2014-0330

Yes- AD 2013-24-01 Avoidance of Ice Crystal Icing Special Instructions: The BCA Regulatory Administration PA recommends the prime TPM forthe subject be Mr. Tom Thorson.

This lettersubmits: (X) Amendmentto Exemption

The Boeing Company respectfully submits this petition for a partial time limited exemption from the requirements of 14 CFR 25.939(a) atAmendment 25-40 to be amended to the existing Reference (b) Exemption No. 11081, in support of Certification Plan·15053, Operation in Ice Crystal Icing for GEnxengines on 787- 8/-9 airplanes. Enclosed with this letter is the Exemption No. 11081 amendment petition.

Yourtimely cooperation in these matters is greatly appreciated.

# ~DEING

RA-15-00350 Page2

Boeing Respectfully Requests this petition for a time limited exemption be approved by January 28, 2015 forthe following reason:
Ifthe requested relief is not granted, continued adherence to the currentAFM limitation with the ICI accommodations provided in EEC B178 software (and later EEC software versions) would result in unnecessary flight crewworkload and burdensome operational planning that can result in otherwise avoidable cancelled and diverted flights. Additionally, Boeing has received reports from the airlines that adherence with the currentAFM limitation is onerous on the airlines and flight crews. The AFM limitation requires new and unique flight operations planning, carrying of additional fuel, increased workload forflight crews and in numerous instances has resulted in extensive diversions resulting in disruptions to the airline operations. Granting ofthis amended exemption will diminish the likelihood of future events ofthis nature.

The public interestwill be advanced by the grant ofexemption as it is in the best economic interest ofthe United States. Modification ofthe AFM to reflect the new GEnx-1 B I B178 (and later EEC software versions) engine ICI limitation for avoidance of ICI conditions makesthe 787-8/-9 airplanes more operationally economical and provides a competitive advantage forfuture airplane sales. As many 787-8/-9 customers are foreign, further delays in the modification ofthe AFM limitation is not in the interest ofthe public dueto the potential negative impactto export sales, the balance-of-trade, the gross domestic product, and the economic health ofthe United States.

This letter is sentfor: (X) Review and FAA position on proposed amendmentto Exemption No. 11081.

# rtJ-aDEIND

RA-15-00350 Page3

Please contactthis office orthe following individuals ifyou havefurther questions: (X) ProjectAdministrator (PA): John Groverat (425) 239-9001
(X) BCA Regulatory Administration 787 Program Manager: Tim Dowling

Sincerely,

# ~~t2/ for

# ~ Douglas M. Lane Director, Regulatory Administration (425) 237-1383, MC 03-56 FAX: (425) 294-9340

Enclosure: Petition to Amend an Existing Time Limited Exemption No. 11081 to include 14 CFR 25.939(a) atAmendment 25-40 for 787-8 and 787-9 Airplane Minor Models, ODA Project Number PS14-0053

cc:
Name Sharepoint Comments J. Voytilla Yes (FAA) 6Y-01Enclosure to RA-15-00350 Page 1of5



### Petition to Amend Exemption 11081 to Include §25.939(a) Amendment 25-40 for787-8 and 787-9 Airplane Minor Models, ODA Project Number PS14-0053


# IA. Name and Address ofthe Petitioner

Doug Lane, Director Regulatory Administration The Boeing Company, PO Box 3707, Seattle, Washington, 98124 

# IB. Section ofthe Code ofFederal Regulations (CFRs) that are affected

As provided for in §11.61(b), Boeing hereby petitions for a partial time-limited exemption to the following CFR:
Regulation At Which Requires Amendment §25.939(a) 25-40 (a) Turbine engine operating characteristics must be investigated in flight to determinethat no adverse characteristics (such as stall, surge, orflameout) are present, to a hazardous degree, during normal and emergency operation within the range ofoperating limitations ofthe airplane and ofthe engine. 

# IC. The extent of relief being sought

Reaulation Reauires: Relief is necessarv because: §25.939(a) 787-8/-9 The GEnx-1B engines installed on 787-8/-9 Amendment airplanes airplanes have experienced engine flameout and 25-40 powered by engine mechanical damage in Ice Crystal Icing GEnx-1B (ICI) conditions in-service. The engine reaction in engines ICI conditions resulted in the issuance ofAD incorporating 2013-24-01, to address the unsafe condition. Electronic ODA Project Number PS14-0053, will certify a Engine Control revised AFM Certificate Limitation and Operating (EEC) B178 Procedure to account for the GEnx-1B engine software (and limitation associated with GEnx-1 B Electronic later EEC Engine Control (EEC) softwareversion B178. software The ICI functionality in B178was developed versions}, and through the use ofcomputational fluid dynamics operating (CFD) modeling validated by engine testing atthe within the GE Winnipeg Test, Research and Development associated Centre. The EEC software reduces the risk of GEnx-1B Ice flameout/rollback to a remote possibility, but is Crystal Icing insufficienttofully mitigatethe mechanical (ICI) engine damage events, through the full airplane operatingEnclosure to RA-15-00350 Page 2of5

limitation envelope certified under ODA Project Number PS14- 0053, are required to comply with turbine engine operating characteristics requirements of§25.939(a). envelope.

The revised AFM Certificate Limitation and Operating Procedure were developed to prohibit airplane operation at engine power levels that could result in ice crystal accretion leading to mechanical damage. TheAFM revision associated with this interim solution raises the current ICI operating floor from 30,000 feet to 37,500 feetwith use ofa flight crew procedure to maintain adequate engine power levels, implemented via minimum Mach number and gross weight operating limitations.

The FAA recently clarified that in-flight power setting restrictions under a crew procedure to avoid conditions thatwould result in unacceptable operating characteristics does not meetthe intent of§25.939(a).

With this petition for exemption, Boeing is requesting relieffor a limited period to allow sufficienttime to develop, validate, and certify an engine configuration that is fully compliantwith §25.939(a).

The requested time-limited partial exemption will provide relieffrom the turbine engine operating characteristics requirements of§25.939(a) for new production and in-service Boeing Models 787-8 and 787-9 incorporating EEC B178 software (or later EEC software versions), and upon modification oftheAFM to reflect the applicable GEnx-1B 

### I B178 (and later EEC software versions) engine ICI limitation. The reliefsought is limited to 787-8/-9 airplanes priorto the incorporation ofan engine configuration compliant to §25.939(a). Certification ofa compliant design will be accomplished by 31 December 2015, or the operation ofthe airplanes would revert to the existing AFM Certificate Limitation and Operating Procedure certified under ODA Project Numbers PS13-0746 and PS13-0956.

Certification ofthe Interim ICI Limitation has been
more complexthan initially estimated. In parallel, Boeing and GE have been working the development ofsoftware supporting the finalEnclosure to RA-15-00350 Page 3 of5



# ID. Description ofthe Issue compliant configuration, which has also taken
more time than anticipated. Evaluation and incorporation ofthe results ofthe extensive NASA Glenn Testing are anticipated to take several months.

Review ofdatawith regulatory agencies and finalization ofan agreed to certification approach will follow. Based on the previously mentioned items, the estimated completion date ofa design compliantto §25.939(a) is December 31, 2015.

This requested time-limited partial exemption will applyto future design changes requiring assessment of§25.939(a) while the AFM Certificate Limitation and Operating Procedure are necessary for safe operation in ICI conditions.

The GEnx-1 B engines installed on 787-8/-9 airplanes have been shown to be susceptible to flameout 

### I engine damage during operation in ICI conditions. Ingestion of ice crystals results in accretion in the propulsor atthe booster outlet guidevanes (BOGV), fan hub frame (FHF) outerflow path, and the HPC inlet guide vanes (IGV). ICIIogic included in GEnx-1 B EEC softwareversion B178 (and later EEC software versions) reduces the risk offlameout/rollback to a remote possibilitywithin the envelope associated with the ICI engine limitation. EEC B178 software certified under ODA Project Number PS14-0621, detects the presence ofice crystal icing and activates the cycling ofthe variable bleed valve (VBV) doors. TheAFM revision associated with this interim solution (ODA Project Number PS14-0053) raises the current ICI operating floorfrom 30,000 feet to 37,500 feetwith use ofa flight crew procedure to maintain adequate engine power levels, implemented via minimum Mach number and gross weight operating limitations. This ICIIogic in conjunction with the revised AFM limitation for avoidance of ICI conditions will be substantiated as effective in identifying ICI conditions and addressing the ICI threat, when operating in ICI conditions in-service. The FAA recently clarified that in-flight power setting restrictions under a crew procedure to avoid conditions that would result in unacceptable operating characteristics does not meetthe intent of§25.939(a). Therefore, Boeing is requesting this time-limited exemption in orderto implement an engine configuration compliantto §25.939(a) priorto the expiration ofthis time-limited exemption.


# IE. Statementof No Adverse Effecton Safety

The proposed AFM Certificate Limitation and Operating Procedure for operating nearor in ICI conditions require the flight crewto maintain a minimum Mach, which maintains an adequate level ofsafetyforthe time period ofthis Exemption. The use ofthis AFM Certificate Limitation is consistentwith otherAFM Certificate Limitations such as EngineAnti Ice System, Weight Limitations and Center ofGravity Limits, and Ground Operations in Icing Conditions. Boeing has determined thatthis AFM limitation is acceptable from a workload and complexityEnclosure to RA-15-00350 Page 4 of5
standpoint, and is operationallyfeasible. The revised AFM Certificate Limitation and associated Operating Procedure will be extensively communicated to the operators and their flight crews via Flight Crew Operations Manual, Fleet Team Digest, Multi-Operator Message and other operatorforums.
Investigation ofthe in-service ICI events in conjunction with CFD modeling and engine ice crystal ingestion testing has identified that ice crystals accrete in the propulsor atthe booster outlet guidevanes (BOGV), fan hub frame (FHF) outerflow path, and the HPC inlet guide
vanes (IGV). Analysis, validated by engine testing, substantiates thatthe ICI detection (delta T3) and mitigation logic (cycling VBVdoors) in EEC software 8178, reduces the risk of flameout/rollback to a remote possibilitywhen operating in ice crystal icing. While the threat of engine mechanical damage is notfully abated by the EEC 8178 software, the application of the AFM Certificate Limitation andOperating Procedure between 30,000 feet and 37,500 feet does prevent mechanical damage events.


# IF. Statement ofPublic Interest

Ifthe requested relief is not granted, continued adherence to the currentAFM limitation with the ICI accommodations provided in EEC 8178 software (and later EEC software versions) will result in unnecessaryflight crewworkload and burdensome operational planning that can result in otherwise avoidable cancelled and diverted flights.
Additionally, Boeing has received reports from the airlines that adherence with the AFM limitation is onerous on the airlines and flight crews. The AFM limitation requires new and uniqueflight operations planning, carrying ofadditional fuel, increased workload forflight crews and in numerous instances has resulted in extensive diversions resulting in disruptions to the airline operations. Granting ofthis amended exemption will diminish the likelihood offuture events ofthis nature.

The public interestwill be advanced bythe grant ofexemption as it is in the best economic interest ofthe United States. Modification oftheAFM to reflect the new GEnx-1B I 8178 (and later EEC software versions) engine ICIIimitation for avoidance of ICI conditions makes the · 787-81-9 airplanes more operationally economical and provides a competitive advantage for future airplane sales. As many 787-81-9 customers are foreign, further delays in the modification ofthe AFM limitation is not in the interest ofthe public dueto the potential negative impactto export sales, the balance-of-trade, the gross domestic product, and the economic health ofthe United States.


# IG. Request forWaiver ofPublication

The petitioner requests thatthe public comment period forthis petition for amended exemption 11081 be waived, as this is considered a minor addition to the existing exemption. A delay in processing ofthe exemption could delaythe modification oftheAFM to reflect the new GEnx1 8 

### I 8178 (and later EEC software versions) engine ICI limitation for avoidance of ICI conditions. The scheduled closure ofODA Project Number PS14-0053 is January 2015.Enclosure to RA-15-00350 Page 5 of5 Granting ofthe exemption is critical to the operators as the seasonal conditions associated with weatherfronts containing ICI is approaching. Currently, the limitations require diversion from standardjetwayswhen encountering ICI conditions; the granting ofthis exemption will result in less diversions and more standard airline operations. The revised operational envelope will expand the options to flight crews when confronted with weatherfronts associated with ICI conditions.


# IH. Privileges ofthis Exemption Outside the United States

Per §11.81(h), Boeing requests that the privileges ofthis exemption be extended outside the United States. This extension ofprivileges is necessary for operations based within foreign countries having bilateral agreements with the United States accepting FAA 14 CFR Part 25 as their airworthiness standards fortransport category aircraft.


# It Conclusion

The requested partial time-limited exemption will allow 787-8/-9 airplanes relieffrom the turbine engine operating characteristics requirement of§25.939(a) forthe ICI VBVsystem.
Boeing petitions for amended exemption from §25.939(a) at amendment 25-40 forthe GEnx1 B ICI VBV ice protection system based on the proposed AFM Certificate Limitation and Operating Procedure, in conjunction with adequate operator and flight crew communication.

The Boeing petition for exemption applies specifically to the turbine engine operating characteristics requirement of§25.939(a), for new production and in-service Boeing Models 787-8 and 787-9 to allow modification ofthe AFM to reflect the new GEnx-1B 

### I B178 (and later

· EEC software versions) engine ICIIimitationfor avoidance of ICI conditions. The reliefsought

is limited until 31 December2015, at which time production 787-8 and 787-9 airplanes will incorporate a compliant design, orthe operation ofthe airplanes would revert to the existing AFM Certificate Limitation and Operating Procedure certified under ODA Project Numbers PS13-0746 and PS13-0956.