rti-BDEING 

1\i(lV 1 3 7015 

RA-15-04504 

The Boeing Company 

P.O. Box 3707 

Seattle, WA 98124-2207 

U.S. Department of Transportation 

Docket Operations, M-30 

1200 New Jersey Avenue, S.E. 

Room W12-140, West Bldg. Ground Floor 

Washington, DC 20590-0001 

Subject: 

Model: 

RA Project No.: 

References: 

AD Related: 

Petition for a Time Limited 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 767-300 and 767-300F Fuel Quantity Indication 

System (FQIS) in support of Certification Plan 15287, 

"Center Wing Tank Fuel Quantity Indicating System Wire 

Separation for 7 4 7 -400/400F /767 -300/-300F without 

Nitrogen Generating Systems and Production 767-300F 

with Nitrogen Generating Systems" 

767-300 and 767-300F 

PS15-0460 

a) Limited Time Partial Exemption number 10767, 

issued May17, 2013. 

b) Limited Time Partial Exemption number 10767A, 

issued May 4, 2015. 

c) Denied Petition for Exemption number 107678, 

issued Oct 30, 2015 

Yes: 04-AD-56 

Special Instructions: The BCA Regulatory Administration PA recommends the 

prime TPM for the subject be Mr. Tom Thorson. 

This letter submits: 

(X) Petition for Exemption 

The Boeing Company respectfully submits the enclosed Petition for Amendment to 

Exemption 107678 from the Title 14 Code of Federal Regulations Part 25.981(a)(3) 

Amendment 25-125 and 14 CFR 25.901 (c) Amendment 25-126 in support of 

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RA-15-04504 

Page 2 

Certification Plan 15287, "Center Wing Tank Fuel Quantity Indicating System Wire 

Separation for 747-400/400F/767-300/-300F without Nitrogen Generating Systems and 

Production 767-300F with Nitrogen Generating Systems." 

Your timely cooperation in these matters is greatly appreciated. 

Boeing respectfully requests this petition for a time limited exemption be approved by 

December 18, 2015 for the following reason: 

If requested relief is not granted the result will be a shutdown of the 767 production line 

on December 18,2015. 

This letter is sent for: 

(X) Regulatory Review/Approval 

Please contact this office or the following individuals if you have further 

questions: 

(X) Project Administrator (PA): John Grover at (425) 239-9001 

(X) BCA Regulatory Administration 747/767 Program Manager: Nicholas Smith 

ililif 

\O{ 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 767-300 and 767-300F Fuel Quantity Indication System (FQIS) 

cc: 

Name 

K. Patel 

A. Lam 

Sharepoint 

Yes 

Yes 

Comments 

6Y-01 

BASOO - LAACO 

Enclosure 

RA-15-04504 

Page 1 of 8 

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 767-300 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 number 10767, issued May17, 2013 

b) Limited Time Partial Exemption number 10767 A, issued May 4, 2015 

c) Denied Petition for Exemption number 1 0767B, issued Oct 30, 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) of the Regulations from which Relief is sought: 

14 CFR 25.901 (c) at Amendment 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 of failures will jeopardize the safe 

operation of the airplane except that the failure of structural elements need not be considered if 

the probability of such failure is extremely remote. 

14 CFR 25.981 (a)(3) at Amendment 25-125 requires: 

(a) No ignition source may be present at each point in the fuel tank or fuel tank system where 

catastrophic failure could occur due to ignition of fuel or vapors. This must be shown by: 

(3) Demonstrating that an ignition source could not result from each single failure, from 

each single failure in combination with each latent failure condition not shown to be 

extremely remote, and from all combinations of failures not shown to be extremely 

improbable. The effects of manufacturing variability, aging, wear, corrosion, and likely 

damage must be considered. 
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The Extent of Relief Sought and Reason(s): 

Regulation Compliance requires: 

14 CFR 25.901(c) No single failure or 

Amendment 25-126 malfunction or probable 

combination of failures will 

jeopardize safe operation 

Relief is Necessary because: 

Direct compliance would require excessive 

design changes to incorporate FQPU 

modifications and Line Replaceable Units 

(LRU) that result in investment not 

commensurate with level of safety 

improvement. 

Changes include the following: 

- Redesign of the Airplane Wiring 

System to ensure FQIS wire 

separation for numerous airplane 

configurations. 

- Modification of the 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 if shorter 

in-tank probes are required). 
Enclosure 

RA-15-04504 

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14 CFR An ignition source could not 

25.981 (a)(3) result from each single 

Amendment 25-125 failure, from each single 

failure in combination with 

each latent failure condition 

not shown to be extremely 

remote, and from all 

combinations of failures not 

shown to be extremely 

improbable. The effects of 

manufacturing variability, 

aging, wear, corrosion, and 

likely damage must be 

considered. 

Description of Issue: 

Background: 

Same as above 

The 767 Fuel Quantity Processer Unit (FQPU) uses digital ARINC 429 busses to 

receive/transmit data to the flight 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 of the 

microchip components, which are involved with communication to the flight deck and refueling 

panel, has been out of production for several years, and the supply has now become 

exhausted. 

In February 2012 the FQPU supplier informed Boeing that the supply of this particular ARINC 

429 chip used on the two IOC cards and also on the Built in Test Equipment (BITE) card would 

run out in late 2012 and that there were no sources for procurement of the current chip. The 

supplier initiated a contract with another chip manufacturer to develop a replacement chip to the 

unchanged requirements of the original chip as defined by the 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 supply would support production through January 2013 with a 

possible extension into March 2013. 

In the first exemption (1 0767) application for this subject, The Boeing Company (TBC) 

communicated that if showing full compliance to 25.901(c) Amendment Level25-126 and 

25.981(a)(3) Amendment Level25-125 for the FQIS at the system level was required due to 

replacing this obsolescent chip with an identical form-fit-function chip, then a significant number 

of changes would be required to the FQIS intrinsically safe side wiring. The first exemption 

(10767) was granted as a time-limited exemption (reference exemption number 10767), expiring 

in May 17, 2016, after which full compliance of the FQIS would be required. 

In the second exemption ( 1 0767 A) application for this subject, The Boeing Company 

communicated that showing full compliance to 25.901(c) Amendment Level25-126 and 

25.981(a)(3) Amendment Level25-125 for the FQIS at the system level was not economical and 
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had no substantial effect on the safety of the fleet since production was going to end in 2019. 

The second exemption (10767A) was granted as a time-limited exemption, expiring in 2019, 

after which full compliance of the FQIS would be required. But there were several conditions, 

one of which was that for the exemption, for production to not expire, TBC must submit for FAA 

approval the service instructions modifying the 767 FQIS as requested by the FAA in 

accordance with §§ 21.99 and 183.69 by December 18, 2015. 

Since the issuance of the second time limited exemption, The Boeing Company has been 

working on the service instructions, the production changes required by May 4, 2016, and a fully 

compliant FQIS in production prior to December 31, 2019. 

After receiving Exemption 10767A in mid May 2015, TBC has been working rapidly to meet the 

most difficult of the conditions, that being condition 2 which reads "Boeing must submit for FAA 

approval the service instructions modifying the 767 FQIS as requested by the FAA in 

accordance with§§ 21.99 and 183.69 by December 18, 2015. This exemption will expire on that 

date unless Boeing has submitted approvable service instructions. In addition, the FAA requires 

the service instructions be certified through showing compliance by inspection on a candidate 

(in-service) airplane. TBC put forth the effort to meet this schedule, but it became apparent as 

the days passed, that no in-service airplanes would be available during the time before the 

Exemption 1 0767 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 the wiring on an in-service airplane initially appeared to support the 

Exemption 1 0767 A timeline, however no freighter airplanes are available due to the heavy 

delivery usage months prior to year end. 

In light of these difficulties, The Boeing Company petitioned for a change to Exemption 10767 A 

to change the commitment dates to July 29, 2016, and 767 production not be made dependent 

on the SB for the fleet, but rather the SB would be issued following production incorporation. 

This petition was denied in reference c) Exemption No. 1 0767B issued on Oct 30, 2015. The 

FAA communicated in that letter that the Boeing Company was not providing sufficiently 

committed schedules to grant the extension. 

Discussion: 

This new petition for a revised time limited exemption is to request a change to the conditions 

identified in Exemption 10767A. According to the guidance provided by the FAA in the recently 

denied Exemption 1 0767B, a committed schedule for the accomplishment of a remote 

certification and the submittal of the compliance deliverables is required. TBC proposes that 

10767 A condition 2 be revised to be May 31, 2016 which will also allow the production 

installation to precede the retrofit installation. Boeing will provide evidence (such as contracts 

with an airline and schedules approved by the Chief Project Engineers and ODA Administrator) 

of the commitment to meet this date by December 2, 2015. The FAA has agreed to support this 

commitment by also communicating to the airlines the urgency of completing the CWT FQIS 

wire separation project. The purpose of the retrofit project is to address freighters without NGS 

per the direction of the FAA. The production project is TBC initiated to enhance safety while 

providing for [previously] the production line to end in 2019 with acceptable safety and 

economics, and now for the production line to install a new FQIS starting by 2019, as the 

production life has been significantly extended since petitioning for Exemption 1 0767 A. 

The previous petitions for 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 
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not substantially improve the safety of the current airplane design, are economically prohibitive 

given the remaining production of the 767-300 and -300F and are not in the public's interest, 

which was applicable for the known production up to 2019. Based on the granting of Exemption 

1 0767 A only for the 767 -300F (and does not apply to the 767 -300), The Boeing Company is 

incorporating significant improvements to newly produced 767 airplanes starting in February 

2016 that will increase the level of safety by addressing both ignition sources and exposure time 

as was proposed. All new production airplanes from February 2016 to 2019 will incorporate 

design changes similar to the center fuel tank wire separation being developed by SB 767-28-

0122 which will be required by AD for all 767 freighters that do not have NGS. These wire 

separation changes have been and are on schedule to be implemented on all new production 

airplanes one year after the exemption 1 0767 A was granted. This also includes the Center 

Wing Tank 750 hour BITE check, similar to instructions for the center wing tank provided in a 

SB 767-28-0118 for freighters without NGS, and being required by AD. 

All newly produced 767 airplanes, since line number 993 in July 2010, address flammability 

exposure time with the incorporation of a center tank fuel tank flammability reduction system, 

the Nitrogen Generation System (NGS). This addresses exposure time as required for all 767 

in-service passenger airplanes and adds flammability reduction systems for all freighter 

airplanes since line number 993. 

In the first granted time limited exemption (10767), the FAA stated that "current fuel tank safety 

airworthiness standards rely upon a balanced approach of precluding ignition sources that could 

form in the fuel tanks and limiting fuel tank flammability exposure time. The aforementioned fuel 

tank wire separation, BITE check and flammability reduction system will address both exposure 

time and ignition sources for all newly produced 767 airplanes, both passenger and freighter. 

Also, starting in production in 2019, which may include the 767-300, a new and fully compliant 

FQIS will become a production installation, and so there will be no further exemption petitions 

for 767 FQIS. 

This time limited exemption (TLE) is being sought for the no single plus latent (greater than 

extremely remote) as is stated in §25.981(a)(3) and interpreted by the FAA for §25.901(c). 

Exemption is also being sought for 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 of the type design of airplane. 

Exemption is requested to continue to apply through the end of 2019 to provide coverage for 

300F production activity and potential incremental sales. The 767-2C, which will be produced 

beyond 2019, will be fully compliant to these requirements. 

Statement of Public Interest: 

In support of this fourth 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. 

Before the petitioned TLE expiration in 2019, all new production airplanes will incorporate 

design changes similar to the center fuel tank wire separation being developed by SB 767-28-

0122 which will be required by AD for all767 freighters that do not have NGS. These wire 
Enclosure 

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separation changes will be implemented on all new production airplanes one year after the 

exemption (1 0767 A) was granted and will be made with the guidance of 28-AWL-09. In addition, 

as identified in 10767 A, the Cwr tank, the 750 hour BITE check, similar to instructions for the 

center tank provided in SB 767-28-0118 for freighters 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 201 0, address flammability 

exposure time with the incorporation of a center tank fuel tank flammability reduction system, 

the Nitrogen Generation System (NGS). This addresses exposure time as required for all 767 

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 of safety than any in-service 767 

airplanes. Design changes that would be required to be fully compliant would not provide a 

significant benefit or increased level of safety for new production airplanes that incorporate the 

proposed wire separation, BITE check, and have the Nitrogen Generation System (NGS) 

installed. Although this is so, Boeing will be providing a new FQIS that is fully compliant as it is 

now economically justifiable due to 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 of safety and would be economically prohibitive given 

the relatively small number of additional production aircraft that would be burdened with these 

costs. These changes would include the following: 

• New system architecture and extensive airplane wiring changes to ensure adequate wire 

separation throughout the 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 Safety function if shorter 

probes are required. 

Finally, the associated design proposal in support of this petition for exemption will implement 

center tank FQIS and FLSS limited wire separation and FQIS BITE check earlier than other 

alternatives, on line number 1094 for FQIS wire separation (factory rollout on 2/1/16) and on 

line number 1096 (factory rollout on 3/10/16) for FLSS wire separation. TBC will brief the FAA 

on a monthly basis until this project is complete. This will provide important enhancements to 

airplane safety earlier, and on more production airplanes. Please note, relief is not being sought 

for 767-300F or 300 production after 2019, or for the 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. 

A fully compliant FQIS will be incorporated into production prior to the expiration of the TLE in 

2019. 

Granting this time limited exemption is in the public interest for the aforementioned reasons and 

will: 

1. Promote continued production of the 767 airplane after May 17, 2016, and to end in 

2019, when an exemption will no longer be needed. All production airplanes will 

address fuel tank safety with incorporation of wire separation, scheduled health checks, 

and a fuel tank inerting system (NGS). A grant of exemption will also provide significant 
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economic benefit to the public in the form of continued 767 production and support 

efficient, safe operation by our customers by providing a consistent fleet configuration. 

2. The proposal for this exemption request of implementing the center tank FQIS limited 

wire separation and FQIS BITE check can be accomplished on the earlier granted 

schedule, (scheduled May 4, 2016,one year after the exemption 10767 A was granted) 

enhancing safety earlier on more airplanes. 

3. Enable the new FQIS project (wire separation) to continue undisrupted by the possibility 

of Exemption 10767A expiration, which would disrupt 767 production. 

Statement of No Adverse Effect on Safety: 

The replacement of the existing ARINC 429 chip with the new replacement chip does not 

adversely affect the safety of the current system. There is no threat to fuel tank ignition from the 

lOGs within the FQPU because there is no electrical conductor connection between the boards 

with the obsolete chip and the fuel tank. Hence, the change has no relation to fuel tank ignition 

prevention, does not impact line replaceable unit (LRU) or system level failure modes, effects, 

or probabilities relative to fuel tank ignition and therefore has no effect on the safety of the 

system and has no impact to airplane safety. 

The 767 FQIS was found to be compliant to §25.901 (c) during airplane type certification for the 

FQIS change in 1992 and since then Boeing has completed the SFAR88 safety assessment 

and has increased the airplane fuel system safety with installation of a hot short protector for the 

densitometer and with installation of a NGS for the center fuel tanks. The proposed change to 

address the previous time limited exemption has no impact on any of the SFAR88 related 

assessments. 

Even prior to the implementation of NGS which further reduces any risk, the Boeing assessment 

was that the risks for the 767 FQIS installation were extremely improbable, which is the typical 

industry and CFR §25.1309 standard for an acceptable safety for systems. 

The Boeing approach to incorporate design changes to add center fuel tank fuel wire 

separation, a 750 hour BITE check, and installation of NGS on all newly produced 767 airplanes 

will provide for an improved safety margin over the existing, approved in-service fleet. These 

changes are scheduled to be done one year after grant of 10767 A exemption, thereby 

incorporating changes to more airplanes than possible under the existing time limited 

exemption. After 2019, the proposal is to incorporate a new FQIS into production, which will be 

compliant to the present interpretation of the 25.901(c), and 25.981(a)(3) [A125] 

Request to Waive Publication and Comment: 

Given the time-sensitive nature of this request for exemption, Boeing respectfully requests that 

the FAA waive the "publication and comment" step in the process for making a final decision on 

this exemption. In addition to the timeliness concern, it is the Boeing position that the 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 10767 A). Expedited treatment is necessary to prevent interruption to 767 

production deliveries. 
Enclosure 

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Privileges of the Exemption Outside the United States: 

Per 14 CFR 11.81(h), Boeing requests that the privileges of this exemption be extended outside 

the United States. This extension of privileges is necessary for operations based within foreign 

countries having bilateral agreements with the United States accepting FAA 14 CFR part 25 as 

their airworthiness standards for transport category aircraft. 

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] at the system level as they apply to the FQIS installed on 

the 767-300 and 767-300F airplanes for the FQPU parts obsolescence change described 

above. We are also requesting that the service instructions submittal date be extended to May 

31, 2016. The FAA has also agreed to support this commitment by also communicating to the 

airlines the urgency of completing the CWT FQIS wire separation project. TBC will report on the 

progress of the 767 improvements on a monthly basis until the projects are complete. The 

proposed center fuel tank FQIS wire separation, a 750 hour BITE check, and incorporation of 

NGS for all 767 production airplanes will further improve fuel tank safety and reduce fleet safety 

risks. Exemption is continued to be requested to apply through the end of 2019, as the FQIS in 

767 production will be compliant to these regulations after that time. The 767-2C, which will be 

produced beyond 2019, will be fully compliant to these requirements. 

Summary to be published in the Federal Register: 

PETITIONER: 

SECTION OF 14 CFR AFFECTED: 

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] and exemption 10767A at the system level 

as they apply to the FQIS and FLSS installed on the 767-300 and 767-300F airplanes through 

the end of 2019, thereby providing relief until the end of 2019 for the current 767-300F 

production and anticipated 767-300 production. TBC is also petitioning for an extension of 

condition 2 of 10767A from December 18, 2015 to May 31, 2016.