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 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: 

Special Instructions: 

This letter submits: 

Petition to Amend Exemption 1 0767 A 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) 

767-300, 767-300F 

PS15-0460 

a) Limited Time Partial Exemption number 1 0767, issued 

May17, 2013 

b) Limited Time Partial Exemption number 10767A, issued 

May4, 2015 

The BCA Regulatory Administration PA recommends the 

prime TPM for the subject be Tom Thorson. 

(X) Petition for Amendment to Exemption 1 0767 A 

The Boeing Company respectfully submits the enclosed Petition for Amendment to Exemption 

10767A 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. Enclosed with this letter is the exemption 

petition. 

Your timely 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, 2015 for the following reason: 

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

Public Interest is enhanced by 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. This will provide important enhancements to airplane 

safety earlier, and on more production airplanes. 

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

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 Program Manager: Nicholas A. Smith, 747n67 Production 

Sincerely, 

for 

Digitally signed by 

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-01 
Enclosure 

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 for the 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 May 4, 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. 
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 of failures 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 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). 
Page 3 of 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 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: 

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 (10767) 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 
Page 4 of 8 

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 seNice 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 seNice 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 would support the 

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

delivery usage months prior to 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 sufficient time for the identification of 

an in-service airplane, and for the accomplishment of a 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 allow the production installation to precede the retrofit installation. In 

addition, TBC proposes that the expiration of the exemption not be dependent on a retrofit 

project as this presents an excessive hardship for both production and retrofit. In any case, 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 

not substantially improve the safety of the current airplane design, are economically prohibitive 

given the remaining production of the 767-300ER 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 

10767A only for the 767-300F (and does not apply to the 767-300ER), The Boeing Company is 

incorporating significant improvements to newly produced 767 airplanes starting in May 2016 

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

was proposed. All new production airplanes from May 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 
Page 5 of 8 

changes are scheduled to be implemented on all new production airplanes one year after the 

exemption 10767A 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 -300ER, 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 -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 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. 

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 all 767 freighters that do not have NGS. These wire 

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

exemption (10767A) was granted and will be made with the guidance of 28-AWL-09. In addition, 

as identified in 1 0767 A, the CWT 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 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 
Page 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 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 limited wire separation and FQIS BITE check earlier than other alternatives, 

approximately one year after grant of the 10767A petition. 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 300ER 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. 

Following the expiration of the TLE in 2019, the 767 will incorporate a fully compliant FQIS. 

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 

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. Disconnect production and in-service design solutions so that the 2 projects can be 

resolved independently, and have the retrofit problems only affect the retrofit solution. 
Page 7 of 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 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 

IOCs 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 10767A 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 10767A). Expedited treatment is necessary to prevent interruption to 767 

production deliveries. 

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

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

above. Also requested is a revision to remove the linkage of the exemption expiring if Service 

Instructions are not submitted by a certain date and that this date in condition 2 be extended to 

July 29, 2016 for Service Instructions to be submitted to the FAA. The proposed center fuel 

tank FQIS wire separation, a 750 hour BITE check, and incorporation of NGS for 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 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] at the system level as they apply to the 

FQIS installed on the 767-300ER 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-

300ER production.