UNITED STATES OF AMERICA 

DEPARTMENT OF TRANSPORTATION 

FEDERAL AVIATION ADMINISTRATION 

RENTON, WASHINGTON 98057-3356 

In the matter of the petition of 

Exemption No. It 070 

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

for an exemption from§§ 25.1305(c)(5) of Title 

14, Code of Federal Regulations 

TIME-LIMITED GRANT OF EXEMPTION 

By letter no. RA-14-0221 0, 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 of Title 14, Code of Federal 

Regulations ( 14 CFR) 25.1305(c)(5). This exemption would permit temporary relief from 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 relief from 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 of the 

powerplant ice-protection system for each engine. 

The petitioner supports its request with 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-20 14-0299. 

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 of engine 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 Project Number PS13-1001 

incorporates logic that eliminates any effects of ICI on engine operation, within the 

engine limitation envelope certified under ODA Project Number PS 14-0053. EEC C065 

software detects the presence of ice 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 of ICI 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 indicator to 

indicate the functioning of the 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 of the ICI VBV system will be used to provide an EICAS [engine indication 

and crew alerting 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 if Boeing were required to incorporate an ICI VBV 

powerplant ice protection system indication for closure ofODA Project Number PS14-

0053. 

With this petition for exemption, Boeing is requesting relief for 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 of the 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 relief from 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 of the AFM to reflect the new GEnx-2B/C065 engine ICilimitation. 

The relief sought 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 7 4 7 -8F and 7 4 7-8 airplanes 

covered by this exemption can order parts 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 of the AFM limitation for avoidance of ICI conditions. This petition for 

time-limited exemption will apply to this future design. 

Effect on safety 

The activation of the 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 icing conditions based on visual cues and easily 

available information; this is not the case with ICI conditions. 

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TAT [total air temperature] less than 10 degrees C and the presence of visible moisture or 

the formation of ice 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 or verify 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 of the engine sensed parameters used in the ICI VBV logic is a dual channel sensor. 

Failure or loss of any 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 of a 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 prior to 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 of that flight. This type ofEEC 

fault detection logic is common to all GE EECs. The fault detection and accommodation 

of the 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 of public 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 of ICJ VBV system operation. Conversely, if the requested relief is not granted 

the addition of the subject flight deck indication would lead to delay in the modification 

of the 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, 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 of additional fuel , increased workload for 

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flight crews and in numerous instances has resulted in extensive diversions resulting in 

disruptions to the airline operations. Granting of this exemption will diminish the 

likelihood of future events of this nature. The public interest will be advanced by the 

grant of exemption as it is in the best economic interest of the United States. Modification 

of the AFM to reflect the new GEnx-2B/C065 engine ICI limitation 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 74 7-8/-8F customers are 

foreign, further delays in the modification of the 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 of the United States. 

Federal Register publication 

A summary notice of the 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 of the powerplant iceprotection system for each engine. 

The intent of this regulatory requirement is to provide feedback to the flight crew when the 

powerplant ice-protection system is functioning. Flight-crew awareness of the status of the iceprotection system is needed to assure the system has been activated and to annunciate failure of a 

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 crew regarding 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 of the 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 of operation of the 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 precursor to 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. 

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Specific 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 

of an 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 of the 

AFM limitation for avoidance of ICI 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 of VBV ice-protection 

system changes and AFM changes identified in the petition. If the petitioner plans design 

changes beyond these changes, they should re-petition identifying any further design changes 

and identify the impact these changes will have, if any, on meeting the conditions of the 

exemption. 

The FAA agrees with the petitioner's statement of public interest for the reasons the petitioner 

cites. 

The FAA's decision 

In consideration of the foregoing, I find that a time-limited grant of exemption 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 of an engine 

VBV ice-protection system for Boeing Model 747-8/-8F airplanes powered by General Electric 

GEnx-2B engines, or subsequent variants of the 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 of operation 

of the 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 must demonstrate Boeing's progressive performance and 

accomplishments indicating its projected success in meeting the schedule and conditions 

of the exemption. Boeing must also submit drafts of the service information required by 

condition 1 (above) to the FAA by May 31 , 2015 . 

3. For Model 74 7-8/8F airplanes granted a certificate of airworthiness 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 owner or operator. 

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4. If an application for an airworthiness certificate is made on or after March 31 , 2015, the 

affected airplanes must incorporate the indication of powerplant ice-protection system 

operation in compliance with§ 25.1305(c)(5). 

5. The FAA will not issue original airworthiness-certificate approvals for any Boeing Model 

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 of this exemption have been met. 

Issued in Renton, Washington, on SEP 2 6 2014 

Michael Kaszyc i 

Acting Manager, Transport Airplane Directorate 

Aircraft Certification Service 

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