Enclosure to RA

- 13

- 00338

Petition for Exemption from § 25.901(c) Amendment 25

- 126 and 25.981(a)(3) Amendment 25

- 125 , Title 14, Code of Federal Regulations

Page 1 Name and Address of the Petitioner

Doug Lane, Director, Regulatory Administration Deputy Lead Administrator 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 Amendme nt 25

- 126 requires:

(c) For each powerplant 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
catastr ophic 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
t o 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.

The Extent of Relief Sought and Reason(s) : Regula tion Compliance r equires: Relief is Necessary because: 14 CFR 25.901(c) Amendment 25

- 126 N o single failure or malfunction or probable combination of failures will jeopardize safe operation Direct compliance would require
unnecessary redesign of the Airplane Wiring System to ensure Fuel Quantity Indication System ( FQIS ) tank circuit wire separation for retrofit of 777

- 200/

- 300 model series aircraft using the changed Fuel Quantity Processing Unit ( FQPU ) for replacement or repair.

14 CFR 25.981(a)(3) A mendment 25

- 125 An ignition source could not result from each single failure, from each single failure in Same as aboveEnclosure to RA

- 13

- 00338

Petition for Exemption from § 25.901(c) Amendment 25

- 126 and 25.981(a)(3) Amendment 25

- 125 , Title 14, Code of Federal Regulations

Page 2 combination with each latent failure condition not shown to be extremely remote, and from all combinations of failures not shown to be extremely impro bable. The effects of manufacturing variability, aging, wear, corrosion, and likely damage must be considered

.

Description of Issue :

The Fuel Quantity Processor Unit ( FQPU ) manufacturer informed Boeing that their supply of particular com ponents within the FQPU would be exhausted in late 2013 and that they had unsuccessfully attempted to find alternate sources for the procurement of these components , leading
to component changes within the FQPU

. The FQPU component changes included the fol lowing hardware changes to the FQPU C ircuit Card Assemblies (C CA s) , which contain the following airborne electronic hardware (AEH) devices that are complex per RTCA/DO

- 254:

- ARINC 429 receiver Application Specific Integrated Circuit ( ASIC ) device

- ARINC 629 ASIC device

- Three unique FPGAs (Field Programmable Gate Array)

- Commercial Off The Shelf (COTS) microprocessors

It is the position of The Boeing Company that system level full compliance to 25.901(c) Amendment 25

- 126 and 25.981(a)(3) Amendment 25

- 125 for Fuel Quantity Indicating Systems ( FQIS ) for retrofit of previously delivered 777

- 200 and 777

- 300 model series airplanes prior to line number 562 should not be required for this proposed change

. The objective of this exemption is to allow airline operators to install the changed FQPU on earlier airplane models that are no longer in production. The basis for this exemption request is that w ithout exemption relief, significant airplane changes would be required for these earlier airplanes

. These changes invo lve n ew system architecture and extensive airplane wiring installation changes to ensure adequate wire separation throughout the fuel quantity indication system.

This level of retrofit change for the existing fleet would be a significant burden as the cha nges are costly and time consuming and would not provide a proportional benefit or increased level of safety that is comparable to the level of effort required to incorporate them

.Enclosure to RA

- 13

- 00338

Petition for Exemption from § 25.901(c) Amendment 25

- 126 and 25.981(a)(3) Amendment 25

- 125 , Title 14, Code of Federal Regulations

Page 3 Statement of Public Interest :
Granting this exemption is in the pu blic interest because denial of this petition for exemption would result in the airlines having to perform extraordinary work which would result in disruption of operations and would pose significant burden on the airlines to make the airplane changes outl ined for installation of a 25.901(c) and 25.981(a)(3) compliant FQIS whenever an in

- service FQPU fails within their fleet

. Statement of No Adverse Effect on Safety :
The current FQIS system on the 777

- 200 and 777

- 300 model series has been thoroughly evalu ated for safety aspects in such forums as Boeing’s safety assessment that was required per 14 CFR Special Federal Aviation Regulation No. 88 (SFAR88) for the FQIS and no safety issues were identified by Boeing

. Since then there have been safety improvemen ts to address issues identified by the FAA. The replacement FQPU will be certified and thoroughly tested to the current regulations during qualification testing. Allowing the changed FQPU to be retrofitted and installed as a part of the existing FQIS wil l not adversely affect the existing level of safety

.
Request for Reduction of Publication Comment Period:

In view of the anticipated obsolescence of parts by late 2013, Boeing requests that the Public comment period be kept to a minimum

. Privileges of t he 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 bilat eral agreements with the United States accepting FAA 14 CFR P art 25 as their airworthiness standards for transport category aircraft.

Conclusion :
Boeing is petitioning for an exemption from the provisions of 14 CFR 25.901(c)[ Amdt. 25

- 126] and 25.981(a) (3)[ Amdt. 25

- 125] at the system level as they apply to the FQIS installed on the 777

- 200 and 777

- 300 airplanes prior to line number 562 for the FQPU parts obsolescence change described

. The following component changes are necessary due to part obsolesce nce:

- ARINC 429 receiver ASIC device ( Applicat ion Specific Integrated Circuit)

- ARINC 629 ASIC device

- Three unique FPGAs (Field Programmable Gate Array) The changed FQPU with these components will not impact the FQIS safety and the part itself will be shown to meet the requirements of 14 CFR 25.901(c) and 25.981(a)(3)

.Enclosure to RA

- 13

- 00338

Petition for Exemption from § 25.901(c) Amendment 25

- 126 and 25.981(a)(3) Amendment 25

- 125 , Title 14, Code of Federal Regulations

Page 4 Granting this exemption will allow use of the type certified production FQPU line replaceable unit ( LRU ) on previously delivered 777

- 200 and 777

- 300 model series without extensive rework to an in

service aircraft.

Summary to be Published in the Federal Register :

PETITIONER : Boeing Commercial Airplanes

SECTION OF 14 CFR AFFECTED : 14 CFR 25.901(c) Amdt. 25

- 126 , 14 CFR 25.981(a)(3) Amdt. 25

- 125

DESCRIPTION OF RELIEF SOUGHT :
Boeing is pet itioning for an exemption from the provisions of 14 CFR 25.901(c)[ Amdt. 25

- 126] and 25.981(a)(3)[ Amdt. 25

- 125] at the system level as they apply to the FQIS installed on the 777

- 200 and 777

- 300 airplanes prior to line number 562 for an FQPU parts obsolesce nce retrofit modification, without extensive rework to the in

- service aircraft

.