U

.S. Department of Transportation Federal Aviation Administration



# JUN 1

# 9

**Z01~** Exemption No. II070BTransport Airplane Directorate 1601 Lind Avenue, S.W

. Renton ,Washington 98057-3356

Regulatory Docket No. FAA-2014-0299

Mr. Jeremy Taylor Regulatory Administration 747/767 Program Manager The Boeing Company P.O. Box 3707 MC 03-56 Seattle, WA 98124-2207

Dear Mr. Taylor: This letter is to inform you that we have again amended exemption no
. 11070. Itexplains the basis for ourdecision and describes its effect. 

### The Basis for Our Decision By letter no. RA-15-01262, dated March 24,2015, you petitioned the Federal Aviation Administration (FAA), on behalfofThe Boeing Company, to permit extended time-limited relieffrom the regulations to allow time for Boeing to upgrade ice-crystal icing (ICI) indicator software, per Title 14, Code ofFederal Regulations (14 CFR) 25.939(a), on Boeing Model 747-8 and -8F airplanes equipped with GEnx-2B engines. Exemption no
. 11070 was issued in support ofCertification Plan 16286 and provides temporary relieffrom the requirements of§ 25.1305(c)(5). Exemption no
. 11 070 was modified by exemption no. 11070A, which granted relieffrom§ 25.939(a). The extension now requested would allow relieffor the Model 747-8 and -8F airplanes for which an application for an airworthiness certificate was made prior to December 31, 2015, for a limited time, to allow sufficient time for Boeing to develop, validate, and certify an engine configuration that is fully compliant with§ 25.939(a). Your petition states, in pertinent part, that: Boeing's goal is to certify an engine configuration capable offull ICI limitation removal as quickly as possible. Recent experience ofrealistic progress for all the necessary pieces supporting certification strongly influences a requested [timelimited grant ofextended exemption] end date ofDec 31, 2015.

Certification ofthe Interim ICI Limitation has been more complex than initially estimated. In parallel, Boeing and [General Electric] have been working the development ofsoftware supportingthe final compliant configuration, which has2

also taken more time than anticipated. Evaluation and incorporation ofthe results of the extensive NASA Glenn Testing are anticipated to take several months. Review ofdata with regulatory agencies and finalization ofan agreed-to [type certification] 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 apply to future design changes requiring assessment of§ 25.939(a) while the [Airplane Flight Manual] Certificate Limitation and Operating Procedure are necessary for safe operation in ICI conditions. Otherthan requesting an extended time-limit deadline, the FAA finds that your petition includes no request for substantive change in the conditions, and reasons relative to public interest and safety, that were the basis for granting the original time-limited exemption

. We now tind that extendingthe expiration for this time-limited exemption to December 31, 2015, is in the public interest. In the previous amendment to the exemption, we granted your request for certain relieffrom§ 25.939(a). We did not extend the expiration, as requested, to December 31,2015, due to Boeing·s request for expedited review and immediate FAA decision on granting relieffrom§ 25.939(a). We have subsequently reviewed the data Boeing provided and have determined that the requested 6 additional months will allow Boeingto complete testing, compile and analyze extensive test data, and complete a thorough showing ofcompliance. Additionally, other measures, including operating limitations, will continue to ensure that operators, during the duration ofthis extension, avoid the environments that are likely to cause engine icing. Therefore, we find that this extension is in the public interest. 

### FederalRegister Publication The FAA has determined that good cause exists for not publishing a summary ofthe petition in the 

### FederalRegister for public comment because the requested amendment to the exemption would not set a precedent, and any delay in acting on this petition would be detrimental to Boeing airplane deliverables. Our Decision The FAA has determined that thejustification for the issuance ofexemption no. 11070 remains valid with respect to this amendment and is in the public interest, for the reasons Boeing stated in their petition and as discussed above. The Effect ofOur Decision Our decision extends a time-limited exemption from § 25.939(a), at Amendment 25-40, for Model 747-8 and 747-SF airplanes that have incorporated engine-ice-protection system modifications and associated AFM limitations. This grant ofamended exemption provides a revised expiration date to exemption no. 11070. The Grant ofAmended Exemption In consideration ofthe foregoing, I find that a time-limited grant ofexemption is in the public interest regarding§ 25.939(a) at Amendment25-40. Therefore, pursuant to the authority contained in 49 U.S.C

. 40113 and 44701 , delegated to me by the Administrator, I3
grant The Boeing Company an exemptionuntil December 31 , 2015, from the requirements of§ 25.939(a), as amended by Amendment 25-40. Specifically, this amendment approves substituting laboratory and ground tests for the requirement to investigate engine operating characteristics in flight and permitting use ofairplane speed as a means to set minimum engine power needed to maintain engine operability in ice crystal icing environments. This amendment to the exemption is applicable to newproduction and in-service BoeingModel 747-8 and 747-8F airplanes incorporating modified EEC software with engine-ice-protection system changes and associated AFM limitations. Boeingmust showfull compliance to§ 25.939(a), at Amendment 25-40, for newly produced Model 747-8 and 747-8F airplanes in order to receive a certificate ofairworthiness after December 31,2015. Design changes and modifications to in-service Model 747-8 and 747- 8F airplanes involving engine-ice-protection systems and associated AFM limitations made after December 31 , 2015, must also fully comply with§ 25.939(a) at Amendment 25-40. All conditions and limitations ofexemption no. II070 remain the same
. This letter must be attached to, and is a part of, exemption no. II070. Sincerely,

Jeffrey E. Duven Manager, Transport Airplane Directorate Aircraft Certification Service