# r{i-IIDEING

September 24, 2015 RA-15-03889 John A. Hamilton Lead Administrator Regulatory Administration Commercial Airplanes The Boeing Company P.O. Box 3707 MC 03-56 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.: References:

Special Instructions:

This lettersubmits: Petition toAmend Exemption 10767 A from 14 CFR 25.981(a)(3) Amendment 25-125 and 14 CFR 25.901(c) Amendment 25-126 pertaining to planned changes forthe 767-300ER and 767-300F Fuel Quantity Indication System (FQIS) 767-300, 767-300F PS15-0460 a) Limited Time Partial Exemption number 10767, issued May17, 2013 b) Limited Time Partial Exemption number 10767A, issued May4, 2015

The BCA Regulatory Administration PA recommends the prime TPM forthe subject be Tom Thorson.

(X) Petition forAmendmentto Exemption 10767 A The Boeing Company respectfully submitsthe enclosed Petition forAmendmentto Exemption 10767Afrom theTitle 14 Code of Federal Regulations §14 CFR 25.901(c) Amendment 25-126 and 14 CFR 25.981(a)(3) Amendment 25-125. Enclosed with this letter isthe exemption petition. Yourtimely cooperation in these matters is greatly appreciated.

# fi--BDEING

RA-15-03889 

### Page2
Boeing respectfully requests this petition for a time limited exemption be approved by December 18, 2015for the following reason: If requested relief is notgranted the result will be a shutdown ofthe 767 production line. Public Interest is enhanced by the proposed centerfuel tank FQIS wire separation, a 750 hour BITE check, and incorporation of NGS for all 767 production airplaneswill further improve fuel tank safety and reduce fleet safety risks. This will provide importantenhancements to airplane safety earlier, and on more production airplanes. The Boeing approach to incorporate design changes to add centerfuel tankwire separation, a 750 hour BITE check, and installation of NGS on all newly produced 767 airplaneswill provide for an improved safety margin overthe existing, approved in-servicefleet

This letter is sentfor: (X) Regulatory Review/Approval

Please contactthis office orthefollowing individuals ifyou havefurther questions: (X) Project Administrator (PA): John Grover at (425) 239-9001 (X) BCA RegulatoryAdministration Program Manager: Nicholas

### A. Smith, 

### 747n67 Production
Sincerely,

for Digitally signedby john.p.grover@boeing.com Date:2015.09.23 18:33:47 -07'00' Douglas M. Lane Director, Regulatory Administration (425) 237-1383, MC 03-56 FAX: (425) 294-9340 Enclosure: Petition for Exemption from 14 CFR 25.981(a)(3) Amendment 25-125 and 14 CFR 25.901(c) Amendment 25-126 pertaining to planned changes for the 767-300ER and 767-300F Fuel Quantity Indication System (FQIS) cc: Name K. Patel (767/777) V. Wicklund G. Roussos Sharepoint Yes Yes Yes Comments {FAA) 6Y-01 (FAA) 6Y-01 (FAA) 6Y-01Enclosure RA-15-03889

Petition for Exemption from 14 CFR 25.981(a)(3) Amendment 25-125 and 14 CFR 25.901(c) Amendment 25-126 pertaining to planned changes forthe 767-300ER and 767-300F Fuel Quantity Indication System (FQIS)



### Petitioner:

References: Douglas Lane, Director, Regulatory Administration The Boeing Company Boeing Commercial Airplanes PO Box 3707 Seattle, Washington, 98124
a) Limited Time Partial Exemption numb.er 10767, issued May17, 2013 b) Limited Time Partial Exemption number 10767A, issued May4, 2015

The Boeing Company respectfully submits the enclosed Petition for Exemption from the Title 14 Code of Federal Regulations §14 CFR 25.901(c) Amendment 25-126 and 14 CFR 25.981(a)(3) Amendment 25-125. 

### Section(s} ofthe Regulations from which Relief issought:
14 CFR 25.901(c) atAmendment 25-126 requires: (c) For each power plant and auxiliary power unit installation, it must be established that no single failure or malfunction or probable combination offailures will jeopardize the safe operation ofthe airplane exceptthatthefailure ofstructural elements need not be considered if the probability ofsuch failure is extremely remote.

14 CFR 25.981(a)(3) atAmendment 25-125 requires: (a) No ignition source may be present at each point in thefuel tank orfuel tank system where catastrophicfailure could occurdueto ignition offuel orvapors. This must be shown by: (3) Demonstrating that an ignition source could not result from each singlefailure, from each single failure in combination with each latentfailure condition notshown to be extremely remote, and from all combinations offailures not shown to be extremely improbable. The effects ofmanufacturing variability, aging, wear, corrosion, and likely damage must be considered.Page 2 of 8

The Extent of Relief Sought and Reason(s): Regulation Compliance requires: Relief is Necessary because:
14 CFR 25.901(c) No single failure or Direct compliance would require excessive Amendment 25-126 malfunction or probable design changes to incorporate FQPU combination offailures will modifications and Line Replaceable Units jeopardize safe operation (LRU) that result in investment not commensurate with level of safety improvement. Changes include the following:



# - Redesign ofthe Airplane Wiring System to ensure FQIS wire separation for numerous airplane configurations.



### - Modification ofthe Fuel Quantity Processor Unit (FQPU) and associated connectors.



### - FQIS architecture change and to locate new LRUs on an EE shelf.



# - In-tank component changes (new brackets, potential need for shorter probes, revised in-tank wire harness and retention means).



### - Software changes related to Fuel Tank Gauging Function (to account for capacitance changes ifshorter in-tank probes are required).Page 3of 8

14CFR An ignition source could not Same as above 25.981(a)(3) result from each single Amendment 25-125 failure, from each single failure in combination with each latentfailure condition not shown to be extremely remote, and from all combinations offailures not shown to be extremely improbable. The effects of manufacturing variability, aging, wear, corrosion, and likely damage must be considered.



### Description of Issue: Background:
The 767 Fuel Quantity Processer Unit (FQPU) uses digital ARINC 429 busses to receive/transmit data to theflight deck, EICAS and refueling panels through two redundant Input/ Output Channel (IOC) circuit cards. The current production IOC card utilizes many integrated electronic microchips to transmit and receive the ARINC 429 data. One ofthe microchip components, which are involved with communication to theflight deck and refueling panel, has been out ofproduction for several years, and the supply has now become exhausted.
In February 2012 the FQPU supplier informed Boeing thatthe supply ofthis particularARINC 429 chip used on thetwo IOC cards and also on the Built in Test Equipment (BITE) card would run out in late 2012 and thatthere were no sources for procurement ofthe current chip. The supplier initiated a contract with another chip manufacturerto develop a replacement chip to the unchanged requirements ofthe original chip as defined bythe supplier's Specification Control Document. The new chip, by requirement, is an identical form-fit-function replacement to the current production chip. In August, 2012, Boeing and the supplier reviewed the existing stores of parts and determined the existing supplywould support production through January 2013 with a possible extension into March 2013.
In thefirst exemption (10767) application forthis subject, The Boeing Company (TBC) communicated that ifshowing full compliance to 25.901(c) Amendment Level25-126 and 25.981(a)(3) Amendment Level25-125forthe FQIS atthe system level was required dueto replacing this obsolescent chip with an identical form-fit-function chip, then a significant number ofchanges would be required to the FQIS intrinsically safe side wiring. Thefirst exemption (10767) was granted as a time-limited exemption (reference exemption number 10767), expiring in May 17, 2016, afterwhich full compliance ofthe FQIS would be required. In the second exemption (10767A) application forthis subject, The Boeing Company communicated that showing full compliance to 25.901(c) Amendment Level25-126 and 25.981(a)(3) Amendment Level25-125forthe FQIS atthe system level was not economical andPage 4 of8

had no substantial effecton the safety ofthe fleet since production was going to end in 2019. The second exemption (10767A) was granted as a time-limited exemption, expiring in 2019, afterwhich full compliance ofthe FQIS would be required. Buttherewere several conditions, one ofwhich was thatforthe exemption, for production to not expire, TBC must submitfor FAA approval the service instructions modifying the 767 FQIS as requested bythe FAA in accordancewith§§ 21.99 and 183.69 by December 18,2015. Since the issuance ofthe second time limited exemption, The Boeing Company has been working on the service instructions, the production changes required by May4, 2016, and a fully compliant FQIS in production priorto December31, 2019. After receiving Exemption 10767A in mid May 2015, TBC has been working rapidly to meetthe mostdifficult ofthe conditions, that being condition 2 which reads "Boeing mustsubmitforFAA approval the seNice instructions modifying the 767FQIS as requestedbythe FAA in accordance with§§ 21.99 and 183.69byDecember 18, 2015. This exemption will expire on that date unless Boeing has submittedapprovable seNice instructions. In addition, the FAA requires the service instructions be certified through showing compliance by inspection on a candidate (in-service) airplane. TBC putforth the effortto meetthis schedule, but it became apparent as the days passed, that no in-service airplanes would be available during the time before the Exemption 10767 A Condition 2 date. TBC developed the certification compliance plans and conformity plans needed to carry out a remote cert demonstration. The plan to do a remote certification to retrofit thewiring on an in-service airplane initially appeared would supportthe Exemption 10767 A timeline, however no freighter airplanes are available dueto the heavy delivery usage months priorto year end.
Discussion:
This new petition for a revised time limited exemption is to request a change to the conditions identified in Exemption 10767 A to a schedule that allows sufficienttimeforthe identification of an in-service airplane, and forthe accomplishment ofa remote certification, and the submittal of the compliance deliverables. TBC proposes that 10767 A condition 2 be revised to be July 29, 2016, which will also allowthe production installation to precede the retrofit installation. In addition, TBC proposesthatthe expiration ofthe exemption not be dependent on a retrofit project asthis presents an excessive hardship for both production and retrofit. In any case, the purpose ofthe retrofit project is to address freighters without NGS perthe direction ofthe FAA. The production project isTBC initiated to enhance safetywhile providing for [previously] the production line to end in 2019 with acceptable safety and economics, and nowforthe production lineto install a new FQIS starting by 2019, asthe production life has been significantly extended since petitioning for Exemption 10767 A.
The previous petitionsfor a time limited exemption (10767 

### & 10767A)were made since full compliance to these rules for the 767 would require extensive system design changes which do not substantially improvethe safety ofthe current airplane design, are economically prohibitive given the remaining production ofthe 767-300ER and -300F and are not in the public's interest, which was applicable forthe known production upto 2019. Based on the granting of Exemption 10767A onlyforthe 767-300F (and does not apply to the 767-300ER), The Boeing Company is incorporating significant improvementsto newly produced 767 airplanes starting in May 2016 thatwill increase the level of safety by addressing both ignition sources and exposure time as was proposed. All new production airplanes from May 2016 to 2019will incorporate design changes similarto the centerfuel tankwire separation being developed by SB 767-28-0122 which will be required byAD for all 767 freighters that do not have NGS. These wire separationPage 5of 8

changes are scheduled to be implemented on all new production airplanes one year afterthe exemption 10767Awas granted. This also includes the CenterWing Tank, 750 hour BITE check, similarto instructionsfor the center wing tank provided in a SB 767-28-0118 for freighters without NGS, and being required byAD.
All newly produced 767 airplanes, since line number 993 in July 2010, address flammability exposure time with the incorporation ofa centertankfuel tankflammability reduction system, the Nitrogen Generation System (NGS). This addresses exposure time as required for all 767 in-service passenger airplanes and addsflammability reduction systemsfor all freighter airplanes since line number 993.
In the first granted time limited exemption (10767), the FAA stated that "currentfuel tank safety airworthiness standards rely upon a balanced approach of precluding ignition sources that could form in thefuel tanks and limiting fuel tankflammability exposure time. The aforementioned fuel tank wire separation, BITE check and flammability reduction system will address both exposure time and ignition sourcesfor all newly produced 767 airplanes, both passenger and freighter. Also, starting in production in 2019, which may include the 767 -300ER, a newand fully compliant FQISwill become a production installation, and so there will be no further exemption petitions for 767 FQIS. This time limited exemption (TLE) is being soughtforthe no single plus latent (greaterthan extremely remote) as is stated in §25.981(a)(3) and interpreted by the FAAfor §25.901(c). Exemption is also being soughtfor the non-environmental aspects of§25.901(c) provided by FAA interpretation, and the explicit §25.981 (a)(3) requirements of manufacturing variability, aging, wear, corrosion, and likely damage, as these considerations are already covered by factory manufacturing processes, and airline maintenance ofthetype design ofairplane. Exemption is requested to continue to apply through the end of2019 to provide coverage -300F production activity and potential incremental sales. The 767-2C, which will be produced beyond 2019, will be fully compliantto these requirements. Statement of Public Interest:
In support ofthis third petition, Boeing is proposing to continue to address both ignition sources and exposure time in the center tank (NGS on all newly produced airplanes), but differently before and after 2019. In-service airplanes are currently required to address either exposure time (passenger airplanes) or ignition sources (freighter airplanes) but not both. This approach addresses both aspects, incorporating improvements to address both ignition sources and exposure time. Beforethe petitioned TLE expiration in 2019, all new production airplanes will incorporate design changes similarto the centerfuel tank wire separation being developed by SB 767-28- 0122 which will be required byADfor all 767 freighters that do not have NGS. These wire separation changes will be implemented on all new production airplanes one year afterthe exemption (10767A) was granted and will be madewith the guidance of28-AWL-09. In addition, as identified in 10767A, the CWTtank, the 750 hour BITE check, similarto instructions forthe centertank provided in SB 767-28-0118 forfreighters without NGS, and being required by AD. These changes will address ignition sources on all newly produced 767 airplanes. All newly produced 767 airplanes, since line number 993 in July 2010, address flammability exposure timewith the incorporation ofa centertankfuel tankflammability reduction system, the Nitrogen Generation System (NGS). This addresses exposure time as required for all 767Page 6 of 8

in-service passenger airplanes and adds flammability reduction systems for all freighter airplanes since line number 993. By addressing both exposure time and ignition sources, newly produced 767 airplanes until 2019 will use a balanced approach and achieved a higher level ofsafety than any in-service 767 airplanes. Design changes thatwould be required to be fully compliant would not provide a significant benefit or increased level ofsafetyfor new production airplanes that incorporate the proposed wire separation, BITE check, and havethe Nitrogen Generation System (NGS) installed. Although this is so, Boeing will be providing a new FQIS that is fully compliant as it is now economicallyjustifiable dueto increased production airplanes beyond 2019. Until and if production ended in 2019, the costs associated with these changes would not be commensurate with the increased level ofsafety and would be economically prohibitive given the relatively small number ofadditional production aircraftthatwould be burdened with these costs. These changes would include the following:

• Newsystem architecture and extensive airplane wiring changesto ensure adequatewire separation throughoutthe fuel quantity indication system. • In-tank component changes (new brackets, potential need for shorter probes, revised intank wire harness and retention means). • Software changes related to Fuel Tank Gauging Function and Safetyfunction ifshorter probes are required.
Finally, the associated design proposal in support ofthis petition for exemption will implement centertank FQIS limited wire separation and FQIS BITE check earlierthan other alternatives, approximately one year after grant ofthe 10767A petition. This will provide important enhancements to airplane safety earlier, and on more production airplanes. Please note, relief is not being soughtfor 767-300F or 300ER production after 2019, orforthe 767-2C, which will be fully compliant with a new FQIS, and is anticipated to be the only minor model produced for the next several decades. Following the expiration ofthe TLE in 2019, the 767 will incorporate a fully compliant FQIS. Granting thistime limited exemption is in the public interestforthe aforementioned reasons and will:
1. Promote continued production ofthe 767 airplane after May 17, 2016, and to end in 2019, when an exemption will no longer be needed. All production airplanes will addressfuel tank safetywith incorporation ofwire separation, scheduled health checks, and a fuel tank inerting system (NGS). A grant ofexemption will also provide significant economic benefitto the public in the form ofcontinued 767 production and support efficient, safe operation by our customers by providing a consistentfleet configuration.
2. The proposal for this exemption request ofimplementing the centertank FQIS limited wire separation and FQIS BITE check can be accomplished on the earlier granted schedule, (scheduled May 4, 2016,one year afterthe exemption 10767 A was granted) enhancing safety earlier on more airplanes.
3. Disconnect production and in-service design solutions so thatthe 2 projects can be resolved independently, and have the retrofit problems only affectthe retrofit solution.Page 7of 8

4. Enable the new FQIS project (wire separation) 

### to'continue undisrupted by the possibility of Exemption 10767A expiration, which would disrupt 767 production on May 4, 2016.

Statement of No Adverse Effect on Safety:
The replacement ofthe existing ARINC 429 chip with the new replacement chip does not adversely affectthe safety ofthe current system. There is no threatto fuel tank ignition from the IOCs within the FQPU because there is no electrical conductor connection between the boards with the obsolete chip and thefuel tank. Hence, the change has no relation to fuel tank ignition prevention, does not impact line replaceable unit (LRU) orsystem level failure modes, effects, or probabilities relative to fuel tank ignition and therefore has no effect on the safety ofthe system and has no impactto airplane safety.
The 767 FQIS was found to be compliant to §25.901(c) during airplanetype certification forthe FQIS change in 1992 and since then Boeing has completed the SFAR88 safety assessment and has increased the airplane fuel system safetywith installation ofa hot short protectorforthe densitometer and with installation ofa NGS forthe centerfuel tanks. The proposed change to address the previous time limited exemption has no impact on any ofthe SFAR88 related assessments. Even priorto the implementation of NGS which further reduces any risk, the Boeing assessment was thatthe risks forthe 767 FQIS installation were extremely improbable, which is the typical industry and CFR §25.1309 standard for an acceptable safetyfor systems. The Boeing approach to incorporate design changes to add centerfuel tankfuel wire separation, a 750 hour BITE check, and installation of NGS on all newly produced 767 airplanes will provide for an improved safety margin overthe existing, approved in-service fleet. These changes are scheduled to be done one year after grant of 10767A exemption, thereby incorporating changes to more airplanesthan possible underthe existing time limited exemption. After2019, the proposal is to incorporate a new FQIS into production, which will be compliantto the present interpretation ofthe 25.901 (c), and 25.981(a)(3) [A125] Requestto Waive Publication and Comment: Given the time-sensitive nature ofthis request for exemption, Boeing respectfully requests that the FAAwaive the "publication and comment" step in the process for making a final decision on this exemption. In addition to thetimeliness concern, it is the Boeing position thatthe safetyassociated aspects related to this system have been fully vetted in the public forum as part of the SFAR88 project and the two previous time-limited partial exemptions (reference exemption number 10767 and 10767A). Expedited treatment is necessaryto prevent interruption to 767 production deliveries. Privileges ofthe Exemption Outside the United States:
Per 14 CFR 11.81(h), Boeing requests thatthe privileges ofthis exemption be extended outside the United States. This extension of privileges is necessaryfor operations based within foreign countries having bilateral agreementswith the United States accepting FAA 14 CFR part 25 as theirairworthiness standards fortransport category aircraft.Page 8 of 8



### Conclusion: Boeing is petitioning for a time-limited exemption from the provisions of 14 CFR 25.901(c)[25- 126] and 14 CFR 25.981(a)(3)[25-125] atthe system level as they apply to the FQIS installed on the 767-300ER and 767-300F airplanes forthe FQPU parts obsolescence change described above. Also requested is a revision to remove the linkage ofthe exemption expiring if Service Instructions are not submitted by a certain date and thatthis date in condition 2 be extended to July 29, 2016 for Service Instructionsto be submitted to the FAA. The proposed centerfuel tank FQIS wire separation, a 750 hour BITE check, and incorporation of NGSfor all767 production airplanes wiH further improve fuel tank safety and reduce fleet safety risks. Exemption is continued to be requested to apply through the end of2019, as the FQIS in 767 production will be compliantto these regulations afterthattime. The 767-2C, which will be produced beyond 2019, will befully compliantto these requirements.


### Summaryto be published in the Federal Register: PETITIONER: SECTION OF 14CFRAFFECTED:

DESCRIPTION OF RELIEF SOUGHT: Boeing Commercial Airplanes
14 CFR 25.901(c) Amendment 25-126 and 14 CFR 25.981(a)(3) Amendment 25-125

The Boeing Company is petitioning for a time limited exemption from the provisions of 14 CFR 25.901(c)[25-126] and 14 CFR 25.981(a)(3)[25-125] atthe system level as they applyto the FQIS installed on the 767-300ER and 767-300F airplanes through the end of2019, thereby providing relief until the end of2019forthe current 767-300F production and anticipated 767- 300ER production.