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

In the matter ofthe petition of Exemption No. It070

The Boeing Company Regulatory Docket No. FAA-2014-0299

for an exemption from§§ 25.1305(c)(5) ofTitle 14, Code ofFederal Regulations

TIME-LIMITED GRANT OF EXEMPTION By letter no. RA-14-02210, dated May 9, 2014, Mr. Douglas M. Lane, Regulatory Administration Director, The Boeing Company, P.O. Box 3707, Seattle, WA 98124-2207, petitioned for a time-limited exemption from the requirements ofTitle 14, Code ofFederal Regulations (14 CFR) 25.1305(c)(5)

.This exemption would permit temporary relieffrom the regulations to allow time for Boeing to upgrade ice-crystal icing indicator software on Boeing Model 747-8 and -8F airplanes equipped with GEnx-2B engines. The petitioner requests relieffrom the following regulation(s): Section 25.1305(c)(5) at Amendment 25-120 requires that, for turbine-engine powered airplanes, an indicator for the tlight crew is required to indicate the functioning ofthe powerplant ice-protection system for each engine. The petitioner supports its requestwith the following information: The following quotes, in pertinent part, the petitioner's information. The complete petition is available on-line in the Federal Docket Management System at http://ww\\.rc!.!,ulations.gov, docket number F AA-2014-0299. The GEnx-2B engines installed on 747-8/-8F airplanes have been shown to be susceptible to operation in Ice Crystal Icing (ICI) conditions in-service. These lCI conditions have resulted in a range ofengine responses. ODA Project Number PS 14-0053, will certify a new GEnx-2B engine limitation associated with GEnx-2B Electronic Engine Control (EEC) software version C065 to address the in-service ICI operational issues. GEnx-2B EEC software version C065 certified under ODA ProjectNumber PS13-1001 incorporates logic that eliminates any effects ofICI on engine operation, within the engine limitation envelope certified under ODA Project Number PS14-0053. EEC C065 software detects the presence ofice crystals and cycles the Variable Bleed Valve (VBV)doors, minimizing ice crystal ingestion into the engine core. The ICI VBV system will be substantiated as effective in identifying ICI conditions and eliminating the ICI threat, within the associated GEnx-2B/C065 ICI engine limitation envelope. The Airplane Flight Manual (AFM) limitation for avoidance ofICI conditions will be modified to reflect the new GEnx-2B/C065 engine limitation. The FAA recently clarified that the ICI VBV system used in this capacity constitutes a "powerplant ice protection system," thus invoking the indication requirements of§25.1305(c)(5). Section 25.1305(c)(5) is a prescriptive regulation that requires a flight deck indicatorto indicate the functioning ofthe powerplant ice protection system for each engine. The 747-8/-8F does not provide a specific flight deck indicator for the functioning ofthe ICI VBV system. In a future Integrated Display System (IDS) software roll, the EEC monitoring ofthe ICI VBV system will be used to provide an EICAS [engine indication and crewalerting system] indication to the flight crew, when the ICI VBV system logic is active. However, the ICI VBV EICAS indications will not be active at the time the AFM limitation is modified to reflect the new GEnx-2B/C065 engine ICI limitation. There would be a significant burden ifBoeing were required to incorporate an ICI VBV powerplant ice protection system indication for closure ofODA Project NumberPS14- 0053. With this petition for exemption, Boeing is requesting relieffor a limited period to allow sufficient time to develop, validate, and certify an IDS software incorporating an ICI VBV indication compliant to §25.1305(c)(5). Following incorporation ofthe compliant indication in IDS software, Boeing will issue a service bulletin that recommends all affected airplanes covered by this time limited exemption be retrofitted. The requested time-limited exemption will provide relieffrom the ICI VBV powerplant ice protection system indication requirement of§25.1305(c)(5), for new production and in-service Boeing Models 747-8F and 747-8, incorporating EEC C065 software, and upon modification ofthe AFM to reflect the new GEnx-2B/C065 engine ICilimitation. The reliefsought is limited to 747-8/-8F airplanes prior to the incorporation ofthe IDS software incorporating an ICI VBV indication compliant to §25.1305(c)(5). Certification ofthe ICI VBV indication will be accomplished by 31 March 2015. A service bulletin will be available no later than 30 June 2015 such that all 74 7-8F and 7 47-8 airplanes covered by this exemption can orderparts and install a compliant configuration. The Boeing service bulletin will recommend that all airplanes be retrofitted by 31 March 2016. Note that Boeing and GE continue to work on a design that will ultimately allow complete lifting ofthe AFM limitation for avoidance ofICI conditions. This petition for time-limited exemption will apply to this future design. 

### Effect on safety The activation ofthe ice protection feature ofthe ICI VBV system logic is completely automated with no flight crew input or control. In contrast, ice protection systems for Engine Anti-Ice (EAI) can be manually operated and can include latent faults; hence a functionality indicator provides necessary pilot feedback. Traditionally flight crews have been trained to independently verify icingconditions based on visual cues and easily available information; this is not the case with ICI conditions.

2TAT [total air temperature] less than10 degrees C and the presence ofvisible moisture or the formation ofice on the windscreen wipers are being used to indicate airplane operation in 14 CFR Pm1 25 Appendix C icing conditions. Reacting to these visual cues, the flight crew can either manually turn on the EAI system orverify its activation by an automatic ice detection system. The EEC automatically determines when ICI conditions exist and automatically provides engine ice protection when required. Accurately detecting the conditions that require engine protection for IC1 encounters is not possible for the flight crew, as it involves internal engine measurements not available to the flight crew and complicated computations. Visible detection cues associated with ICl are not as consistent as they are with natural icing. The EEC ICI VBV fault detection and accommodation logic is robust. All logic inputs for the ICI VBV control are monitored continuously to ensure proper engine operation. Each ofthe engine sensed parameters used in the ICI VBV logic is a dual channel sensor. Failure or loss ofany single channel's input is detected and accommodated by the EEC, does not affect ICI VBV system functionality and results in a 10 day time-limited dispatch condition (ENG Cl EICAS latched status message). Detection ofa dual failure by the automatic health checks for any ofthe critical control signals will result in a non-dispatchable ENGINE CONTROL EICAS latched Status message, requiring resolution priorto the next flight. Hence, there is protection against latent faults to the TCI VBV ice protection feature for each individual engine and the airplane's exposure to that failure would be the remainder ofthat flight. This type ofEEC fault detection logic is common to all GE EECs. The fault detection and accommodation ofthe sensors used in the ICl VBV logic has not changed, as these parameters were already considered critical parameters required to control the engine. The AFM was revised in April 2014 to provide information regarding engine parameter effect when the JCI VBV logic is active. Since the ICI VBV system is automatic with no pilot input, and operational information is provided to the flight crews regarding engine parameter fluctuations when the ICI VBV logic is active, there is no adverse effect on airplane safety awaiting installation of the ICI VBV system EICAS indicator. 

### Statement ofpublic interest Granting this petition is in the public's interest because it would allow adequate time for Boeing and its supplier to develop an effective design solution to add a flight deck indication ofICJ VBV system operation. Conversely, ifthe requested reliefis not granted the addition ofthe subject flight deck indication would lead to delay in the modification ofthe AFM to reflect the new GEnx-2B/C065 engine ICI limitation. Continued adherence to the current AFM limitation with the ICI accommodations provided in EEC C065 software results in unnecessary flight crew workload and burdensome operational planning that can result in otherwise avoidable cancelled and diverted flights. Additionally, Boeinghas 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 for

3flight crews and in numerous instances has resulted in extensive diversions resulting in disruptions to the airline operations. Granting ofthis exemption will diminish the likelihood offuture events ofthis nature

. The public interest will 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-2B/C065 engine ICI limitation for avoidance ofICI 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 of the public due to the potential negative impact to export sales, the balance-of-trade, the gross domestic product, and the economic health ofthe United States. 

### Federal Register publication A summary notice ofthe petition was published in the Federal Register on June 17, 2014 (79 FR 34561)

.No comments were received. 

### The FAA's analysis Section 25.1305(c)(5) at Amendment 25-120 requires that, for turbine-engine powered airplanes, an indicator for the flight crew is required to indicate the functioning ofthe powerplant iceprotection system for each engine. The intent ofthis regulatory requirement is to provide feedback to the flight crew when the powerplant ice-protection system is functioning. Flight-crew awareness ofthe status ofthe iceprotection system is needed to assure the system has been activated and to annunciate failure ofa manual or automated system. Engine-power fluctuations have occurred during flight testing with modified GEnx engine software. These fluctuations occurred randomly on each engine as the VBV ice-protection system automatically activated. Boeing revised the AFM in April 2014 to provide information to the flight crewregarding engine parameter effects when the ICI VBV logic is active. The applicant has stated, Since the ICI VBV system is automatic with no pilot input, and operational information is provided to the flight crews regarding engine parameter fluctuations when the ICI VBV logic is active, there is no adverse effect on airplane safety awaiting installation of the ICI VBV system EICAS indicator. The FAA has determined that indication to the flight crew ofthe GEnx-2B ice-protection activation would be in compliance with section 25.1305(c)(5) and provides a tangible safety benefit. The flight crew needs to be aware ofoperation ofthe ICI VBV system so they will understand why engine-power fluctuations are occurring, and that these fluctuations are normal when the system is activated. Without this indication, flight crews might disregard engine-power fluctuations that may be a precursorto an engine power-loss event, thinking that the ICI VBV system has activated when it has not, or flight crews might take inappropriate action when the ICI VBV system is active and the engines and ice-protection system are functioning normally

. The information Boeing has provided to the flight crew in the AFM,regarding engine-parameter effects when the ICI VBV logic is active, effectively precludes any adverse effect on safety in the interim while Boeing develops and incorporates the compliant flight-deck indication

.

4Specific indication to the flight crew is not provided for JCJ conditions. The airworthiness directive in place today relies upon flight crews to monitor weather radar, determine the presence ofan ICI environment, and to maintain a minimum distance from ICI conditions. The introduction ofthe ICI VBV system design improves airplane safety in ICI conditions because the system will automatically activate when icing conditions are present. The petitioner is continuing to work on a design that will ultimately allow complete lifting ofthe AFM limitation for avoidance ofICI conditions. They requested that this petition for timelimited exemption apply to any such future design. However, the FAA cannot grant the request to apply this exemption to a future design configuration beyond the scope ofVBV ice-protection system changes and AFM changes identified in the petition. Ifthe petitioner plans design changes beyond these changes, they should re-petition identifying any further design changes and identify the impact these changes will have, ifany, on meeting the conditions ofthe exemption. The FAA agrees with the petitioner's statement ofpublic interest for the reasons the petitioner cites. 

### The 

### FAA's decision In consideration ofthe foregoing, I find that a time-limited grant ofexemption is in the public interest regarding 14 CFR 25.1305(c)(5) at Amendment 25-120. Therefore, pursuant to the authority contained in 49 U.S.C. 40113 and 44701 , delegated to me by the Administrator, The Boeing Company is granted an exemption until June 30, 2015, from the requirements of § 25.1305(c)(5), as amended by Amendment 25-120, as it pertains to indication ofan engine VBV ice-protection system for Boeing Model 747-8/-8F airplanes powered by General Electric GEnx-2B engines, or subsequent variants ofthe engine with the following conditions: 1. By March 31 , 2015, Boeing must complete the design and show compliance to § 25.1305(c)(5), at Amendment 25-120, providing flight-deck annunciation ofoperation ofthe engine VBV ice-protection system

. On or before June 30, 2015, Boeing must develop and submit for FAA-approval service information to incorporate any design changes developed to meet the provision of§ 25.1305(c)(5)

. 2. By November 1, 2014, Boeing must present to the FAA a comprehensive compliance plan and schedule, supporting the deliverables outlined in condition 1(above). Thereafter, Boeing must submit a status report every three months to the Seattle Aircraft Ce11ification Office identifying all actions completed to date, as well as those that remain outstanding. The report mustdemonstrate Boeing's progressive performance and accomplishments indicating its projected success in meeting the schedule and conditions ofthe exemption

. Boeing must also submit drafts ofthe service information required by condition 1 (above) to the FAAby May 31 , 2015

. 3

. For Model 747-8/8F airplanes granted a certificate ofairworthiness based on this exemption and that do not have the design changes incorporated as identified by condition 1(above), the '·Airworthiness Limitation'' section ofthe Model 747-8/8F airplane "Instructions for Continued Airworthiness" must state that delivered airplanes cannot be operated after March 31 , 2016, unless the design changes submitted in accordance with condition 1 (above) are incorporated by the owneroroperator.



### 54. Ifan application for an airworthiness certificate is made on or after March 31 , 2015, the affected airplanes must incorporate the indication ofpowerplant ice-protection system operation in compliance with§ 25.1305(c)(5). 5

. The FAA will not issue original airworthiness-certificate approvals for any BoeingModel 747-8/8F airplane after March 31 , 2015, unless that airplane has incorporated the design changes that Boeing has shown to be fully compliant with§ 25

.1305(c)(5) and the conditions ofthis exemption have been met.

Issued in Renton, Washington, on 

## SEP 262014

Michael Kaszyc i Acting Manager, Transport Airplane Directorate Aircraft Certification Service



### 6