# rzJ- BDEING

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EP 30 20 16
RA-16-01977
U.S. Department of Transportation Docket Operations West Bldg. Ground Floor, Room W12-140 1200 New Jersey Avenue, SE. Washington, DC 20590 Dear Sir or Madam,

Subject :

Model : Response Due : Reference : Petition for an Extension to Time-Limited Partial G r ant of Exemption 10905- Exemption from 1 4 CFR 25.901(c) Amendment 25-126 and 25.98 1(a)(3) Amendment 102 or late r Pertaining to Planned Changes to the 737-600/-700/-700C/-800/-900/-900ER Fuel Quantity Indication System (FQIS) 737-600/-700/-700C/-800/-900/-900ER December 31,2016 Boeing Letter RA-16-01978 , " Submittal of Petition for an Extension to Time-Limited Partial Grant of Exemption 10905- Exemption from 1 4 CFR 25
.901(c) Amendment 25-126 and 25.981(a)(3) Amendment 102 or later Pertaining to Planned Changes to the 737-600/700/-700C/- 800/-900/-900ER Fuel Quantity Indication System (FQIS) and Additional Supporting Data ", dated September 30, 2016 This letter is to submit : Petition for an Extension to Time-Limited Partial Grant of Exemption The Boeing Company respectfully submits the petition for an extension to time-limited partial grant of Exemption 10905- exemption from 14 CFR 25.901(c) Amendment 25-126 and 25
. 981(a)(3) Amendment 102 or later pertaining to planned changes to the 737-600/-700/- 700C/-800/-900/-900ER Fuel Quantity Indication System (FQIS). Additional proprietary information and data has been submitted directly to the cognizant FAA directorate i n support of this petition via Boeing Letter RA-16-0 1 978 dated September 30, 2016. Please contact th is office or the followi ng individuals if you have furth er qu estions : Certification Engineer: Matthew 

### A. Henriksen at 425-234-5818 Program Manager: Guillermo 

### J . (Bill) Campisteguy at 425-237-1377

# ~OEING

Page 2 RA-16-01977

Your timely cooperation in these matters is greatly appreciated. Sincerely ,



# ~~ G. J. Campisteauv 

## 2016.09.30 14:41 :22 -07'00' (for) Douglas M. Lane Director, Commercial Airplanes (425) 237-1383 , MC 03-56 FAX: (425) 294-9340 MAH
Enclosure: Petition for an Extension to Time-Limited Partial Grant of Exemption 10905
cc



# ---

Name Encl EDT Comments Mr. Jeff Duven 

### X X Mgr. , FAA TAD



# -- Mr. Victor Wicklund 

### X X Mgr. , FAA TAD- Propulsion Mr. John Piccola 

### X X Mgr., FAA BASOO Mr
. Patrice Adjibly 

### X X FAA Program Mgr., 6Y-01 Mr. J. Sutherland 

### X X FAA Program Mgr., 6Y-01 Mr. Tom Thorson 

### X X FAA Propulsion TPMRA-16-01977 Enclosure. page 1 of5
Pet ition for an Ex tension to Time- Lim ited Partia l Grant of Exe m pti on 10905 Name a nd Address of the Petitioner Douglas M. Lane , Director Commercial Airplanes The Boeing Company PO Box 3707 MC 03-56 Seattle, Washington , 98124-2207 Secti o n(s) of th e Regulations f rom which Relief is sought: 14 CFR 25.901(c) amendment 25-126 and 25
.981 (a)(3) amendment 25-102 or later §25.901(c) Amendment 25-126: (c) For each powerplant and auxiliarypower unit installation, it must be established that no single failure or malfunction orprobable combination of failures willjeopardize the safe operation ofthe airplane except that the failure of structural elements need not be considered if the probability ofsuch failure is extremely remote. §25.981(a)(3) Amendment 25-102 and 125: (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 offuel 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 offailures not shown to be extremely improbable. The effects ofmanufacturing variability , aging , wear , corrosion, and likely damage must be considered. Th e Original E xtent of Relief Sought and Reas o n(s)

Regulation Requires: Relief is Necessary because: §25.901(c) For each powerplant and Direct compliance would require Amendment 25-126 auxiliary power unit extensive airplane design changes for installation, it must be both new production and retrofit for inestablished that no single service airplanes
. Changes include: failure or malfunction or probable combination of Redesign of the Airplane Wiring System failures will jeopardize the safe to ensure Fuel Quantity Indication System operation of the airplane (FQIS) wire separation for more than 100 except that the failure of unique customer driven airplane structural elements need not configurations
. be considered if the probability of such failure is extremely Make new main tank penetrations inremote. board of the struts and procure new intank wiring harnesses. Modify the Fuel Quantity Processor Unit (FQPU) mother board and associatedRA- 16-0 1977 En closure , page 2 of 5 Regulation Requires : Relief is Necessary because : connectors
. The solution would likely require the FQPU to grow in size. Relocate the FQPU from the forward equipment center to the forward cargo compartment to allow for a larger FQPU and enable a clear path for wire separation. In-tank Component Changes (new brackets , shorter probe , revised in-tank wire harness and retention means)
. Software changes related to Fuel Tank Gauging Function (to account for capacitance change due to in-tank component changes)
. §25.981 (a)(3) An ignition source could not Same as above. Amendment 25-102 result from each single failure, and 25-125 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. Des c ri ptio n of Iss u e Exist ing Grant of Exempti o n On December 18, 2013 , Federal Aviation Administration (FAA) Time Limited Partial Grant of Exemption 10905 was published granting Boeing relief for up to 48 months after the effective date from §§25
.901 (c) , Amendment 25-126 and 25
.981(a)(3) , Amendment 25-102 or later, as they pertain to fuel tank ignition prevention associated with the following FQIS changes on inservice and newly-produced 737-600/-700/-700C/-800/-900/-900ER airplanes: • Replacement of the Signal Conditioner Circuit Cards (SCCC) and the Aeronautical Radio Incorporated (ARINC) display card within the FQPU ; and • Changed areas for the re-routing and separation of FQIS wires where the changed areas of the FQIS wire routing meet the installation requirements for separation and fault tolerance required to comply with § 25
.981 (a)(3) as associated with the : o Semi-monolithic side-of-body change , and o Forward bulkhead relocation
.RA-16-01977 E nclosure
. page 3 of 5
After expiration of this time-lim ited exemption , the FQIS on all newly-produced airplanes will need to be shown to comply with§§ 25
.901(c) , Amendment 25-46 , and 25
.981 (a)(3) , Amendment 25-102, or later amendments
. Note: For simplification, the 737-600/-700/-700C/-800/-900/-900ER airplane models will henceforth be referred to as 737NG
. Likewise , the 737-7/-8/-9 airplane models will henceforth be referred to as 737MAX
. Proposed Revision of Limitation Boeing is requesting that the original time limit of 48 months as approved in Exemption 10905 be extended through December 17, 2025
. The reasons that this extension is needed are summarized here : • Exemption 10905 will expi re on December 18 , 2017 which does not provide coverage for the production of the remaining commercial 737NG ai rp lanes prior to transitioning fully to the 737MAX
. The estimated number aircraft utilizing relief provided by Exemption 10905 , if the extension is granted , would be 4.4% greater than the projected number of airplanes requiring relief at the time of the issuance of Exemption 10905
. Final production of 737NG airplanes for commerc ial customers will come to an end by December 18 , 2019
. • In order to support a United States military customer, Boe ing will continue producing the 737-7001GW military platform at a very low rate through December 17, 2025. • An improvement to the 737NG FQIS wire sleeving is planned which will improve the current level of protection. Additionally, producibility enhancements to the FQPU are planned
. The proprietary data to describe these changes has been sent to the cognizant FAA Directorate via RA-16-01978
. Statement of No Adverse Effect on Safety Accounting for the Extension of the Existing Exemption for the 737NG airplanes Boeing proposes that the safety position provided in the original request for an exemption is not compromised by this extension
. Additional factors that will ma intain or improve the safety position prov ided in the original request are listed below : • The extension does not significantly increase the quantity of aircraft that would be exempt under the grant of the exemption
. The proprietary fleet data to support this petition has been sent to the cognizant FAA Directorate via RA- 16- 1978
. • As a component , the redesigned FQPU was found to be fully compliant with §25
.981(a)(3) , Amendment 25-125 which represents an incremental improvement in system safety
. • An additional sleevi ng improvement is planned to be i mplemented on the FQIS wiring pend i ng acceptance of the pet ition for extension .RA-16-01977 Enclosure , page 4 of 5

The proprietary data to describe these changes has been sent to the cognizant FAA Directorate via RA-16-01978
. Statemen t of P u bl ic Interest Acc ou nting fo r th e Exte nsio n of the Ex isting Exempti on for th e 737NG airpl anes Co mm e rci a l Customers Boeing proposes that the public interest statement upon which the grant of exemption was based remains applicable as written in the original petition
. This petition for extension of the time to comply does not alter the previously submitted statement of public interest. Mil itary Cu stomers (737-7001GW only) In addition to the rationale supporting the statement of public interest in the original petition , a variant of the 737-7001GW is anticipated to be produced and delivered in limited quantities through December 17, 2025 to support unique US military operations
. The US government is expected to replace aging military aircraft with commercial aircraft platforms that allow the US government more cost effective acquisition and operations to support military mission requirements. Approval of this extension would enable continued limited production of the 737- 7001GW specifically to support these US Military requirements and therefore supports the public interest. The projected increase in the 737-7001GW fleet size due to this requirement is minimal at less than 30 aircraft. Additional proprietary data has been provided to the cognizant FAA Directorate via RA-16-1978 to support the petition for extension of the time limit on the existing exemption for the 737-7001GW. The associated design proposal in support of this petition for exemption will include a fully compliant FQPU (at the component level) further providing enhancements to airplane safety. Design changes that would be required for full compliance would not provide a significant benefit or increased level of safety for new production airplanes which have the Nitrogen Generation System (NGS) installed. Additionally , 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. Extending the time limit of the existing exemption for the 737-7001GW is in the public interest for the aforementioned reasons and will promote continued production of the 737-7001GW military airplane variants through December 17 , 2025. Request to 'Wa ive Publi cat ion and Comm ent' The relief sought by this exemption does not result in any reduction in level of safety for a previously type certified product with a highly reliable system ; rather, it allows for an additional incremental enhancement to the level of safety ofthe product. Boeing respectfully requests that , in order to expedite the exemption process , the FAA waive the requirement for publication and comment.RA-16-01977 Enclosure. page 5 of 5
Privi leges of the Exem pti o n Outs i d e the Un ited States Because the 737NG is used by customers around the world , Boeing requests that the privileges of this exemption be extended outside the United States , per 14 CFR 11
.81 (h). 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
.

Co nclusio n Boeing is seeking an exemption time limit extension to the original 48 month grant of Exemption 10905 from§§ 25
.901(c) , Amendment 25-126 , and 25
.981(a)(3) , Amendment 25-102 , or later
. The time extension requested is through December 17, 2025
. This extension is sought to allow for the full production transition from the commercial 737NG to the 737MAX airplanes by the end of 2019 and to enable Boeing to support a U
.S
. Military customer through the end of 2025 with a small number of 737-7001GW airplanes
. This request will also enable the implementation of planned FQIS wiring improvements and other potential system modifications
. The request is justifiable because the quantity of affected airplanes will not significantly increase, additional enhancements are being incorporated that increase the overall safety ofthe FQIS , and full compliance is not practical due to the timing of the transition to the 737MAX. These requests are justified based on the rationale provided in the original exemption petition , additional details provided in this petition and the additional proprietary data provided to the cognizant FAA Directorate via RA-16-1978
. S ummary to be Publ is hed in th e Fed eral Reg ist e r PETITIONER: Boeing Commercial Airplanes SE CTION OF 14 CFR AFFECTED : 14 CFR 25
.981(a)(3) Amendment 25-125 and 25
.901(c) Amendment 25-126 DESCR I PTION OF RELIEF SOUGHT : The Boeing Company , has requested a 96 month extension to the existing Time-Lim ited Partial Grant of Exemption 10905 to 14 CFR 25
.901 (c) , Amendment 25-126 , and 25
.981 (a)(3), Amendment 25-102 , or later amendments for the FQIS on 737NG commercial airplanes, through 2019 ,and a small number of 737-7001GW military platforms for through 2025
.