Petition for Exemption from 14 CFR 25.981(a)(3) Amendment 25-125 and 14 CFR 25.901(c) Amendment 25-126, Code of Federal Regulations

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)

Reference: Limited Time Pa rtial Exemption number 10767

Name and Address of the Petitioner

Douglas Lane, Director, Regulatory Administration The Boeing Company

PO Box 3707 Seattle, Washington, 98124

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 a uxiliary 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 Am endment 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 i gnition of fuel or vapors. This must be shown by:

(3) Demonstrating that an ignition so urce 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 manufact uring variability, aging, wear, corrosion, and likely damage must be considered.

The Extent of Relief Sought and Reason(s):

Regulation Compliance requires: Relief is Necessary because:

14 CFR 25.901(c)

Amendment 25-

126 No single failure or malfunction or probable

combination of failures will jeopardize safe operation Direct compliance would require excessive design changes to incorporate FQPU modifications and Remote

Electronic Units that result in investment not commensurate with level of safety improvement. Changes include the following:Petition for Exemption from 14 CFR 25.981(a)(3) Amendment 25-125 and 14 CFR 25.901(c) Amendment 25-126, Code of Federal Regulations

- 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 Remote Electronic Units (REU) on the E5 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).

14 CFR 25.981(a)(3)

Amendment 25-

125 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. Same as abovePetition for Exemption from 14 CFR 25.981(a)(3) Amendment 25-125 and 14 CFR 25.901(c) Amendment 25-126, Code of Federal Regulations

Description of Issue:

Background:

The 767 Fuel Quantity Processer Unit (FQPU) uses digital ARINC 429 busses to receive/transmit data to the flight dec k, EICAS and refueling panels through two redundant Input/Output Channel (IOC) circ uit cards. The current production IOC card utilizes many integrated electronic microc hips to transmit and receive the ARINC 429 data. One of the microchip components, wh ich is 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 a nd also on the BITE card would run out in late 2012 and that there were no sources for pr ocurement of the current chip. The supplier

initiated a contract with anot her chip manufacturer to deve lop a replacement chip to the unchanged requirements of the original chip as defined by the s upplier’s Specification Control Document. The new chip, by require ment, 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 po ssible extension into March 2013.

In the previous exemption applicatio n for this subject, The Boeing Company communicated that if showing full comp liance to 25.901(c) Amendment Level 25-126 and 25.981(a)(3) Amendment Level 25-125 for the FQIS at the system level was required due to replacing this obsolescent chip with an identical form-fit-f unction chip, then a significant number of changes would be requi red to the FQIS intr insically safe side wiring. The previous exemption was gran ted as a time-limited exemption (reference exemption number 10767), expiring in 2016, af ter which full compliance of the FQIS would be required. Since the issuance of the time limited exemption, The Boeing Company has been working on a FQIS that would meet the requirements and has quantified the design ch ange required and the cost of the new design. Based on these findings The Boeing Company is petitioning fo r a new time limited exemption to address the remaining production of the 767-300 and -300F.

Discussion:

This new petition for a time limited exemption is being made since full compliance to these rules for the 767 would require exte nsive system design changes which do not substantially improve the safety of the current airplane design, are economically prohibitive given the remaining production of the 767-300 and -300F and are not in the public’s interest. In conjunc tion with this petition The Boeing Company is proposing to incorporate significant improvements to newly produced 767 airplanes that will increase the level of safety by addressing both ignition sources and exposure time.Petition for Exemption from 14 CFR 25.981(a)(3) Amendment 25-125 and 14 CFR 25.901(c) Amendment 25-126, Code of Federal Regulations

Boeing proposes that all new production airpla nes incorporate design changes similar to

the center fuel tank wire separation being developed by SB 767-28-XXXX which will be required by AD for all 767 freighters that do not have NGS. These wire separation changes would be implemented on all new production airplanes one year after the exemption is granted. Boeing will further address ignition sources by requiring a three tank, 750 hour BITE check, similar to instructio ns for the center wing tank provided in a SB 767-28-0118 for freighters without NGS, a nd being required by AD. The proposed BITE instructions would apply to all tanks.

All newly produced 767 airplanes, sin ce line number 993 in July 2010, address flammability exposure time with the incorpora tion 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 ai rplanes since line number 993.

In the previously granted time limited exemp tion, the FAA stated that current fuel tank safety airworthiness standard s rely upon a balanced appr oach 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.

This time limited exemption is being sought fo r the no single plus la tent (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-environm ental aspects of §25.901(c) provided by FAA interpretation, a nd the explicit §25.981(a)(3) requirements of manufacturing variabilit y, aging, wear, corrosion, and likely damage, as these considerations are already covered by f actory manufacturing pro cesses, and airline maintenance of the type design of airplane. Exemption is requested to apply through the end of 2019 to provide coverage through the end of the currently committed 767-300 and -300F production activity and pot ential 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 petition, Boeing is propos ing to address both ignition sources and exposure time in the center tank (NGS on all newly produced airpla nes). In-service airplanes are currently require d to address either exposure time (passenger airplanes) or ignition sources (freighter airp lanes) but not both. This a pproach addresses both aspects, incorporating improvements to address bot h ignition sources and exposure time.

All new production airplanes will incorporat e design changes similar to the center fuel tank wire separation being developed by SB 767-28-XXXX which will be required by AD for all 767 freighters that do not have NGS. These wire separation changes will bePetition for Exemption from 14 CFR 25.981(a)(3) Amendment 25-125 and 14 CFR 25.901(c) Amendment 25-126, Code of Federal Regulations

implemented on all new production airplanes one year after the exemption is granted and will be made with the guidance of 28-AWL -09. In addition, Boeing is proposing a three tank, 750 hour BITE check, similar to instruct ions for the center tank provided in SB 767-28-0118 for freighters without NGS, and be ing required by AD. These changes will address ignition sources on all newl y produced 767 airplanes.

All newly produced 767 airplanes, sin ce line number 993 in July 2010, address flammability exposure time with the incorpora tion 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 ai rplanes since line number 993.

By addressing both exposure time and i gnition sources, newly produced 767 airplanes will use a balanced approach and achieve a high er level of safety than any in-service 767 airplane. Design changes that would be requi red 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, BI TE check, and have the Nitrogen Generation System (NGS) installed. Additionally, the cost s associated with these changes would not

be commensurate with the increased leve l of safety and would be economically prohibitive given the relatively small number of additional production ai rcraft that would

be burdened with these costs. Thes e changes would include the following:

 New system architecture and extensiv e airplane wiring changes to ensure adequate wire separation throughout th e fuel quantity indication system.

 In-tank component changes (new brackets , potential need fo r shorter probes,

revised in-tank wire harn ess and retention means).

 Software changes related to Fuel Tank Gauging Function and Safety function if shorter probes are required.

Release of new Boeing design architecture requirements, supplier development and qualification of new software and hardware to be fully compliant would negatively affect offerability of the 767-300 and 300F airplanes. These design changes would also affect only one customer and result in an undesira ble configuration mix for that customer, driving maintenance complexity and increased operational costs.

Finally, the associated design proposal in support of this petition for exemption will implement center tank FQIS limited wire se paration and a three tank FQIS BITE check earlier than other alternatives, approximately one year after grant of the petition. This will provide important enhancements to airp lane safety earlier, and on more production airplanes. Please note, relief is not being sought for the 767-2C, which will be fully compliant with a new FQIS, and is anticipat ed to be the only minor model produced for

the next several decades.Petition for Exemption from 14 CFR 25.981(a)(3) Amendment 25-125 and 14 CFR 25.901(c) Amendment 25-126, Code of Federal Regulations

Granting this time limited exemption is in th e public interest for the aforementioned

reasons and will:

1. Promote continued production of the 767 airplane after Ma y 17, 2016, currently forecasted to end in 2019. 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 th e form of continued 767 production and support efficient, safe operation by our cu stomers by providing a consistent fleet configuration.

2. The proposal for this exemption reques t of implementing the center tank FQIS limited wire separation and three tank FQ IS BITE check can be accomplished on an earlier schedule, (p roposed to be one year afte r the exemption is granted) enhancing safety earlie r on more airplanes.

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 sy stem. 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 obs olete chip and the fuel ta nk. Hence, the change has no relation to fuel tank ignition prevention, does not impact lin e replaceable unit (LRU) or system level failure modes, effects, or proba bilities relative to fuel tank ignition and therefore has no affect on the safety of the sy stem 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 pr evious 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 ch anges to add center fuel tank fuel wire separation, a three tank 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 ar e also proposed to be done one year after grant of exemption, thereby incorporating cha nges to more airplanes than possible under the existing time limited exemption.Petition for Exemption from 14 CFR 25.981(a)(3) Amendment 25-125 and 14 CFR 25.901(c) Amendment 25-126, Code of Federal Regulations

Request to Waive Publication and Comment:

Given the time-sensitive nature of this request for exemption, Boeing respectfully requests that the FAA waive the “publicati on 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 safety-a ssociated aspects related to th is system have been fully vetted in the public forum as part of the SFAR88 project and the previous time-limited partial exemption (reference exemption numb er 10767). Expedited treatment is necessary to prevent interru ption 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 n ecessary for operations based within foreign countries having bilateral agreements with the United States accepting FAA 14 CFR part 25 as their airworthiness st andards for transport category aircraft.

Conclusion:

Boeing is petitioning for a time-limited ex emption 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. Th e proposed center fuel tank wire separation, FQIS three tank, 750 hour BITE check, and in corporation of NGS for all 767 production airplanes will further improve fuel tank safety and reduce fleet safety risks. Exemption is requested to apply through th e end of 2019 to provide cove rage through the end of the currently committed 767-300 and -300F producti on activity. 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: Boeing Commercial Airplanes

SECTION OF 14 CFR AFFECTED: 14 CFR 25.981(a)(3) Amendment 25-125 and 14 CFR 25.901(c) Amendment 25-126

DESCRIPTION OF RELIEF SOUGHT:

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 767-300 and 767-300F airplanes through the end of 2019, thereby providing relief through the e nd of the currently anticipated 767-300 and 767-300F production.