
[Federal Register Volume 81, Number 185 (Friday, September 23, 2016)]
[Proposed Rules]
[Pages 65579-65581]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-21397]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-9072; Directorate Identifier 2015-NM-110-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain Boeing Model 727 airplanes. This proposed AD was prompted by 
fuel system reviews conducted by the manufacturer. This proposed AD 
would require modifying the fuel quantity indicating system (FQIS) to 
prevent development of an ignition source inside the body-mounted 
auxiliary fuel tanks due to electrical fault conditions. As an 
alternative to the modification, this proposed AD would allow 
deactivating the body-mounted auxiliary fuel tanks. We are proposing 
this AD to prevent ignition sources inside the body-mounted auxiliary 
fuel tanks, which, in combination with flammable fuel vapors, could 
result in a fuel tank explosion and consequent loss of the airplane.

DATES: We must receive comments on this proposed AD by November 7, 
2016.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE., Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2016-
9072; or in person at the Docket Management Facility between 9 a.m. and 
5 p.m., Monday through Friday, except Federal holidays. The AD docket 
contains this proposed AD, the regulatory evaluation, any comments 
received, and other information. The street address for the Docket 
Office (phone: 800-647-5527) is in the ADDRESSES section. Comments will 
be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Jon Regimbal, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office 
(ACO), 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-
6506; fax: 425-917-6590; email: Jon.Regimbal@faa.gov.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2016-9072; 
Directorate Identifier 2015-NM-110-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    The FAA has examined the underlying safety issues involved in fuel 
tank explosions on several large transport airplanes, including the 
adequacy of existing regulations, the service history of airplanes 
subject to those regulations, and existing maintenance practices for 
fuel tank systems. As a result of those findings, we issued a final 
rule titled ``Transport Airplane Fuel Tank System Design Review, 
Flammability Reduction, and Maintenance and Inspection Requirements'' 
(66 FR 23086, May 7, 2001). In addition to new airworthiness standards 
for transport airplanes and new maintenance requirements, that rule 
included Amendment 21-78, which established Special Federal Aviation 
Regulation No. 88 (``SFAR 88'') at 14 CFR part 21. Subsequently, SFAR 
88 was amended by: Amendment 21-82 (67 FR 57490, September 10, 2002; 
corrected at 67 FR 70809, November 26, 2002) and Amendment 21-83 (67 FR 
72830, December 9, 2002; corrected at

[[Page 65580]]

68 FR 37735, June 25, 2003, to change ``21-82'' to ``21-83'').
    Among other actions, SFAR 88 requires certain type design (i.e., 
type certificate (TC) and supplemental type certificate (STC)) holders 
to substantiate that their fuel tank systems can prevent ignition 
sources in the fuel tanks. This requirement applies to type design 
holders for large turbine-powered transport airplanes and for 
subsequent modifications to those airplanes. It requires them to 
perform design reviews and to develop design changes and maintenance 
procedures if their designs do not meet the new fuel tank safety 
standards. As explained in the preamble to the rule, we intended to 
adopt airworthiness directives to mandate any changes found necessary 
to address unsafe conditions identified as a result of these reviews.
    In evaluating these design reviews, we have established four 
criteria intended to define the unsafe conditions associated with fuel 
tank systems that require corrective actions. The percentage of 
operating time during which fuel tanks are exposed to flammable 
conditions is one of these criteria. The other three criteria address 
the failure types under evaluation: Single failures, combination of 
failures, and unacceptable (failure) experience. For all three failure 
criteria, the evaluations included consideration of previous actions 
taken that may mitigate the need for further action.
    We have determined that the actions identified in this proposed AD 
are necessary to reduce the potential of ignition sources inside fuel 
tanks, which, in combination with flammable fuel vapors, could result 
in fuel tank explosions and consequent loss of the airplane.

Model 727 FQIS Design

    The design of the in-tank FQIS components and wiring has the 
potential for a latent FQIS electrical fault condition inside the fuel 
tank combined with an electrical hot short condition connecting a high 
power source to the FQIS wiring to cause an ignition source in a fuel 
tank.
    Under the policy contained in FAA Policy Memo PS-ANM100-2003-112-
15, SFAR 88--Mandatory Action Decision Criteria, dated February 25, 
2003 (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgPolicy.nsf/
0/dc94c3a46396950386256d5e006aed11/$FILE/Feb2503.pdf), the FAA 
determined that this ignition source risk combined with the fleet 
average flammability for the optional auxiliary fuel tanks on those 
Model 727 airplanes created an unsafe condition for those tanks. 
Applying that same policy, the FAA determined that due to a lower fleet 
average flammability, that same unsafe condition does not exist in the 
main tanks of Model 727 airplanes.

Related Rulemaking

    On March 21, 2016, we issued AD 2016-07-07, Amendment 39-18452 (81 
FR 19472, April 5, 2016), for certain Boeing Model 757-200, -200PF, -
200CB, and -300 series airplanes. AD 2016-07-07 requires similar 
actions to those proposed in this NPRM. AD 2016-07-07 addressed the 
numerous public comments that were submitted on the proposal.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

    This proposed AD would require modifying the fuel quantity 
indication system (FQIS) to prevent development of an ignition source 
inside the body-mounted auxiliary fuel tanks due to electrical fault 
conditions. As an alternative to the modification, this proposed AD 
would allow deactivating the body-mounted auxiliary fuel tanks.

Explanation of Compliance Time

    The compliance time for Model 727 airplanes is shorter than other 
FQIS AD actions because it is expected that the operators of the 
relatively small number of affected airplanes will choose to deactivate 
the body-mounted auxiliary tanks, either permanently or during an 
interim period prior to reactivating the tanks with approved corrective 
actions.

Costs of Compliance

    We cannot estimate the number of airplanes of U.S. registry that 
would be affected by this proposed AD. Boeing originally built about 
272 airplanes of the affected design, but cannot provide information on 
whether any are still in service. Boeing expects that most of the 
affected airplanes are out of service or have already had their 
auxiliary fuel tanks removed.
    For any affected airplane, we estimate the following costs to 
comply with this proposed AD:

                                        Estimated Costs: Required Actions
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                                                                                                     Cost per
                    Action                                Labor cost               Parts cost        product
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Modification.................................  300 work-hours x $85 per hour =        $100,000         $125,500
                                                $25,500.
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                                      Estimated Costs: Alternative Actions
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                                                                                                     Cost per
                    Action                                Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Tank deactivation............................  10 work-hours x $85 per hour =               $0             $850
                                                $850.
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Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII: Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on

[[Page 65581]]

products identified in this rulemaking action.

Regulatory Findings

    We determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would not 
have a substantial direct effect on the States, on the relationship 
between the national Government and the States, or on the distribution 
of power and responsibilities among the various levels of government.
    For the reasons discussed above, I certify this proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under the DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

The Boeing Company: Docket No. FAA-2015-9072; Directorate Identifier 
2015-NM-110-AD.

(a) Comments Due Date

    We must receive comments by November 7, 2016.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 727, 727-100, 727C, 
727-100C, 727-200, and 727-200F series airplanes; certificated in 
any category; equipped with Boeing body-mounted auxiliary fuel 
tanks.

(d) Subject

    Air Transport Association (ATA) of America Code 28, Fuel.

(e) Unsafe Condition

    This AD was prompted by fuel system reviews conducted by the 
manufacturer. We are issuing this AD to prevent ignition sources 
inside the body-mounted auxiliary fuel tanks, which, in combination 
with flammable fuel vapors, could result in a fuel tank explosion 
and consequent loss of the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Modification

    Within 12 months after the effective date of this AD, do the 
actions specified in either paragraph (g)(1) or (g)(2) of this AD, 
using a method approved in accordance with the procedures specified 
in paragraph (h) of this AD.
    (1) Modify the fuel quantity indicating system (FQIS) to prevent 
development of an ignition source inside the body-mounted auxiliary 
fuel tanks due to electrical fault conditions.
    (2) Deactivate the body-mounted auxiliary fuel tanks.

(h) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested 
using the procedures found in 14 CFR 39.19. In accordance with 14 
CFR 39.19, send your request to your principal inspector or local 
Flight Standards District Office, as appropriate. If sending 
information directly to the manager of the ACO, send it to the 
attention of the person identified in paragraph (i) of this AD. 
Information may be emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair, modification, or alteration required by this AD 
if it is approved by the Boeing Commercial Airplanes Organization 
Designation Authorization (ODA) that has been authorized by the 
Manager, Seattle ACO, to make those findings. To be approved, the 
repair method, modification deviation, or alteration deviation must 
meet the certification basis of the airplane and the approval must 
specifically refer to this AD.

(i) Related Information

    For more information about this AD, contact Jon Regimbal, 
Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle ACO, 
1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-6506; 
fax: 425-917-6590; email: Jon.Regimbal@faa.gov.

    Issued in Renton, Washington, on August 30, 2016.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-21397 Filed 9-22-16; 8:45 am]
 BILLING CODE 4910-13-P


