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1/27/15

RA-15-00349 C)

John A. Hamilton The Boeing Company Lead Administrator P.O. Box 3707 MC 03-56 RegulatoryAdministratiO}f

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U.S. DepartmentofTransportation 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: Special Instructions:

This lettersubmits: Petition toAmend Partial Time Limited Exemption No. 11070to include 14 CFR 25.939(a) at Amendment**25~40** in support ofCertification Plan 15053, Operation in Ice Crystal Icing for GEnx engines on 747-8/-8FAirplanes
747-8, 747-8F PS14-0053 a) Boeing letter RA-14-02210, 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 GEnx engines on 7 4 7-8/-8F airplanes, dated May 2, 2014. b) Time Limited Grant of Exemption No. 11070, Regulatory Docket No. FAA-2014-0299

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

(X)Amendmentto Exemption
The Boeing Company respectfully submits this petition fora partial time limited exemption from the requirements of 14 CFR 25.939(a} at Amendment 25-40 to be amended to the existing Reference (b) Exemption No. 11070, in support of Certification Plan 15053, Operation in Ice Crystal Icing for GEnx engines on 747- 8/-8F airplanes. Enclosed with this letter is the Exemption No. 11070 amendment petition.
Yourtimely cooperation in these matters is greatly appreciated.

# ~BEING

RA-15-00349 Page2

Boeing Respectfully Requests this petition for a time limited exemption be approved by January 28, 2015 forthe following reason:
If requested relief is not granted, continued adherence to the currentAFM limitation with the ICI accommodations provided in EEC C068 software (and later EEC software versions) will result in unnecessaryflight crew workload 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**cu~rent** AFM limitation is onerous on the airlines and flight crews. The AFM limitation requires newand 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 grantofexemption as it is in the best economic interest ofthe United States. Modification ofthe AFM to reflect the new GEnx-2B 

### I C068 (and later EEC software versions) engine ICIIimitation for avoidance of ICI conditions makesthe 747-8/-8F airplanes more operationally economical and provides a competitive advantage forfuture airplane sales; As many 747-8/-8F customers areforeign, further delays in the modification ofthe AFM limitation is not in the interest ofthe public due to the potential negative impactto export sales, the balance-of-trade, the gross domestic product, and the economic health ofthe United States.



### This letter is sent for:· (X) Review and FAA position on proposed amendment to Exemption No. 11070.

# rtL-.HDEINC

RA-15-00349 Page 3



### Please contactthis office orthe following individuals ifyou have further questions: (X) ProjectAdministrator (PA): John Grover at (425) 239-9001
BCA Regulatory Administration 747/767 Program Manager: JeremyTaylor

for Digitallysigned by JeremyJTaylor, 1802561 Date: 2015.01.26 20:07:26 -08'00' Douglas

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

Enclosure: Petition toAmend an Existing Time Limited Exemption No. 11070to include 14 CFR 25.939(a) atAmendment 25-40 for 747-8 and 747-8F Airplane Minor Models, ODA Project Number PS14-0053

cc:
Name R. Reed (747- J. Sutherland Share Yes Yes Comments (FAA) 6Y-01 (FAA) 6Y-01Enclosureto RA-15-00349 Page 1 of5


### Petition to Amend Exemption 11070to Include §25.939(a) Amendment 25-40 for 747-8 and 747-SF 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 of Federal 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 determine that no adverse characteristics (such as stall, surge, orflameout) are present, to a hazardous degree, during normal and emergencyoperation within the range ofoperating limitations ofthe airplane and ofthe engine.


# IC. The extent ofrelief being sought
Requlation Requires: Reliefis necessary because: §25.939(a) 747-8/-8F The GEnx-28 engines installed on 747-8/-8F Amendment airplanes airplanes have experienced engineflameout and 25-40 powered by engine mechanical damage in Ice Crystal Icing GEnx-2B (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) C068 Procedure to accountfor the GEnx-2B engine software (and limitation associated with GEnx-2B Electronic later EEC Engine Control (EEC) software version C068. software The ICI functionality in C068 was 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-28 Ice flameout/rollbackto a remote possibility, but is Crystal Icing insufficientto fully mitigate the mechanical (ICI) engine damage events, through the full airplane operating limitation envelope.Enclosure to RA-15-00349 Page 2 of5 envelope certified under ODA Project Number PS14- 0053, are required to complywith turbine engine operating characteristics requirements of§25.939(a). 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. The AFM revision associated with this interim solution raises the current ICI operating floor from 30,000 feet to 35,500 feet with use ofa flight crew procedure to maintain adequate engine power levels, implemented via minimum Mach numberand grossweight 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 relieffora limited period to allow sufficienttime to develop, validate, and certify an engine configuration that isfully 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 747-8F and 747-8 incorporating EEC C068 software (or later EEC software versions), and upon modification ofthe AFM to reflectthe applicable GEnx-2B 

### I C068 (and later EEC software versions) engine ICIIimitation. The relief sought is limited to 747-8/-8F airplanes priorto the incorporation ofan engine configuration compliant to §25.939(a). Certification ofa compliant design will be accomplished by 31 December2015, or the operation ofthe airplaneswould revert to the existing AFM Certificate Limitation and Operating Procedure certified under ODA Project Numbers PS12-0298 and PS13-0956.

Certification ofthe Interim ICI Limitation has been
more complex than initially estimated. In parallel, Boeing and GE have been working the development ofsoftware supporting the final compliant configuration, which has also taken
more time than anticipated. Evaluation and incorporation ofthe results ofthe extensive NASAEnclosureto RA-15-00349 Page 3 of5



## I D. Description ofthe Issue Glenn Testing are anticipated to take several months.

Review ofdata with regulatory agencies and finalization ofan agreed to cert approach will follow. Based on the previously mentioned items, the estimated completion date ofa design compliant to §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 necessaryfor safe operation in ICI conditions.

The GEnx-2B engines installed on 74 7-8/-BF airplanes have been shown to be susceptible to flameout 

### I engine damage during operation in ICI conditions. Ingestion ofice crystals results in accretion in the propulsor at the boosteroutlet guide vanes (BOGV), fan hubframe (FHF) outerflow path, and the HPC inletguidevanes (IGV). ICI logic included in GEnx-28 EEC software version C068 (and later EEC software versions) reduces the risk offlameouUrollback to a remote possibility within the envelope associated with the ICI engine limitation. EEC C068 software certified under ODA Project Number PS14-0545, detects the presence ofice crystal icing and activates the cycling ofthe variable bleed valve (VBV) doors. The AFM revision associated with this interim solution (ODA Project Number PS14-0053) raises the current ICI operating floorfrom 30,000 feet to 35,500 feet with use ofa flight crew procedure to maintain adequate engine power levels, implemented via minimum Mach numberand grossweight operating limitations. This ICI logic 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 powersetting 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. Statement of No Adverse Effecton Safety

The proposed AFM Certificate Limitation and Operating Procedure for operating nearor in ICI conditions require the flight crew to 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 Engine Anti Ice System, Weight Limitations and Center ofGravity Limits, and Ground Operations in Icing Conditions. Boeing has determined thatthis AFM limitation is acceptable from aworkload and complexity standpoint, and is operationally feasible. The revised AFM Certificate Limitation and associated Operating Procedure will be extensively communicated tothe operators and theirEnclosureto RA-15-00349 Page4of5 flight crews via Flight Crew Operations Manual, FleetTeam Digest, Multi-Operator Message and otheroperatorforums. 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 propulsoratthe booster outlet guide vanes (BOGV), fan hub frame (FHF) outerflow path, and the HPC inlet guide
vanes (IGV). Analysis, validated by engine testing, substantiates that the ICI detection (delta T3) and mitigation logic (cycling VBV doors) in EEC software C068, reduces the risk of flameout/rollback to a remote possibility when operating in ice crystal icing. While the threat of engine mechanical damage is notfully abated by the EEC C068 software, the application of the AFM Certificate Limitation and Operating Procedure between 30,000 feet and 35,500feet does prevent mechanical damage events. 

# IF. Statement of Public Interest

Ifthe requested relief is not granted, continued adherence to the currentAFM limitation with the ICI accommodations provided in EEC C068 software (and later EEC software versions) will 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 AFM limitation is onerous on the airlines and flight crews. The AFM limitation requires new and unique flight 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 by the grant ofexemption as it is in the best economic interest ofthe United States. Modification ofthe AFM to reflect the new GEnx-28 

### I C068 (and later EEC software versions) engine ICIIimitation for avoidance of ICI conditions makes the ' 747-8/-8F airplanes more operationally economical and provides a competitive advantage for future airplane sales. As many 747-8/-8F customers are foreign, further delays in the modification ofthe AFM limitation is not in the interest ofthe public due to the potential negative impactto export sales, the balance-of-trade, the gross domestic product, and the economic health ofthe United States.


# IG. Request for Waiver of Publication

The petitioner requests thatthe public comment period forthis petition for amended exemption 11070 be waived, as this is considered a minor addition to the existing exemption. A delay in processing ofthe exemption could delaythe modification ofthe AFM to reflect the new GEnx28 

### I C068 (and later EEC software versions) engine ICIIimitation for avoidance of ICI conditions. The scheduled closure ofODA Project Number PS14-0053 is January2015. 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 operationalEnclosure to RA-15-00349 Page 5 of5 envelopewill 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 necessaryfor operations based within foreign countries having bilateral agreementswith 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 7 4 7-8/-8F airplanes relieffrom the turbine engine operating characteristics requirement of §25.939(a) for the ICI VBVsystem.
Boeing petitionsfor amended exemption from §25.939(a) at amendment 25-40 for the GEnx2B ICI VBV ice protection system based on the proposed AFM Certificate Limitation and Operating Procedure, in conjunction with adequate operatorand 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 747-8F and 747-8, to allow modification ofthe AFM to reflect the new GEnx-2B 

### I C068 (and later EEC software versions) engine ICIIimitation for avoidance of ICI conditions. The relief sought.is limited until 31 December 2015, at which time production 747-8F and 747-8 airplanes will incorporate a compliantdesign, orthe operation ofthe airplanes would revert to the· existing AFM Certificate Limitation and Operating Procedure certified under ODA Project Numbers PS12-0298 and PS13-0956. 

# I