Document ID: FAA-2020-0785-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: The Boeing Company Airplanes
Posted Date: 2020-09-09T04:00Z

[Federal Register Volume 85, Number 175 (Wednesday, September 9, 2020)]
[Proposed Rules]
[Pages 55622-55624]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-19583]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0785; Product Identifier 2020-NM-063-AD]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for all The Boeing Company Model 747 airplanes and Model 767 airplanes. 
This proposed AD was prompted by a report of an un-commanded fuel 
transfer between the main and center fuel tanks. This proposed AD would 
prohibit operation of an airplane with any inoperative refuel valve 
(fueling shut-off valve) secured in the open position. The FAA is 
proposing this AD to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by October 26, 
2020.

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 https://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 https://www.regulations.gov by searching for and locating Docket No. FAA-2020-
0785; or in person at Docket Operations between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays. The AD docket contains 
this NPRM, any comments received, and other information. The street 
address for Docket Operations is listed above. Comments will be 
available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Jeffrey Rothman, Aerospace Engineer, 
Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98190; phone and fax: 206-231-3558; jeffrey.rothman@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to participate in this rulemaking by submitting 
written comments, data, or views about this proposal. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. To 
ensure the docket does not contain duplicate comments, commenters 
should submit only one copy of the comments. Send your comments to an 
address listed under the ADDRESSES section. Include ``Docket No. FAA-
2020-0785; Product Identifier 2020-NM-063-AD'' at the beginning of your 
comments.
    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in 14 CFR 
11.35, the FAA will post all comments received, without change, as well 
as a report summarizing each substantive public contact with FAA 
personnel concerning this proposed rulemaking. Before acting on this 
proposal, the FAA will consider all comments received by the closing 
date for comments. The FAA will consider comments filed after the 
comment period has closed if it is possible to do so without incurring 
expense or delay. The FAA may change this NPRM because of those 
comments.

Confidential Business Information

    CBI is commercial or financial information that is both customarily 
and actually treated as private by its owner. Under the Freedom of 
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public 
disclosure. If your comments responsive to this NPRM contain commercial 
or financial information that is customarily treated as private, that 
you actually treat as private, and that is relevant or responsive to 
this NPRM, it is important that you clearly designate the submitted 
comments as CBI. Please mark each page of your submission containing 
CBI as ``PROPIN.'' The FAA will treat such marked submissions as 
confidential under the FOIA, and they will not be placed in the public 
docket of this NPRM. Submissions containing CBI should be sent to the 
person identified in the FOR FURTHER INFORMATION CONTACT section. Any 
commentary that the FAA receives which is not specifically designated 
as CBI will be placed in the public docket for this rulemaking.

Discussion

    The FAA has received a report of a flight diversion due to an un-
commanded fuel transfer between the main and center fuel tanks. 
Following the flight, the operator discovered that a significant amount 
of fuel had migrated from the left main tank to the center tank. This 
condition was determined to be created by applying the Master Minimum 
Equipment List (MMEL)/Dispatch Deviation Guide (DDG) relief for 
inoperative refuel valves (fueling shut-off valves) secured in the 
``open'' position in the main and center fuel tanks.
    During investigation of the event, the operator's maintenance 
personnel restored all fueling shut-off valves to their normal 
configuration (closed). The system was tested, and it was confirmed 
that the fuel migration stopped.
    Multiple refuel valves secured in the ``open'' position can result 
in un-commanded fuel transfer between tanks, which adversely affects 
the airplane's center of gravity, aerodynamic drag, and fuel economy. 
Fuel exhaustion may occur due to a combination of increased trim drag 
(due to unmitigated fuel imbalance) and the unavailability of trapped 
fuel due to a fully depleted main tank defeating the center tank fuel 
scavenge system.
    The FAA is proposing this AD to address multiple refuel valves 
secured in the ``open'' position via MMEL dispatch allowance, which 
allows un-commanded fuel transfer between fuel tanks. This condition, 
if not addressed, could result in a fuel exhaustion event.

FAA's Determination

    The FAA is proposing this AD because the agency 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 prohibit operation of an airplane with 
multiple refuel valves secured in the ``open'' position.

[[Page 55623]]

MMEL Revisions

    This proposed AD refers to items in Sections 28-20 and 28-21 of the 
MMEL \1\; those items may also be included in an operator's FAA-
approved minimum equipment list (MEL). This proposed AD would prohibit 
operation of the airplane under conditions currently allowed by those 
items in the MMEL. The FAA plans to revise the MMEL to remove those 
items in a future revision; operators would then be required to also 
remove those items from their existing FAA-approved MEL.
---------------------------------------------------------------------------

    \1\ The MMEL items can be found in the applicable FAA-approved 
MMEL: Boeing 747 B-747-100/200/300/SP SERIES MMEL, Revision 35, 
dated April 25, 2014; Boeing 747 B-747-400 LCF MMEL, Revision 3, 
November 7, 2014; Boeing 747 B-747-400, B-747-400D, B-747-400F MMEL, 
Revision 32, dated December 27, 2018; Boeing 747-8 MMEL, Revision 7, 
dated August 25, 2017; and Boeing 767 MMEL, Revision 39, dated 
October 26, 2018; which can be found on the Flight Standards 
Information Management System (FSIMS) website, https://fsims.faa.gov/PICResults.aspx?mode=Publication&doctype=MMELByModel.
---------------------------------------------------------------------------

Costs of Compliance

    The FAA estimates that this proposed AD would affect 750 airplanes 
of U.S. registry.
    The FAA has determined that revising the operator's existing FAA-
approved MEL takes an average of 90 work-hours per operator, although 
the agency recognizes that this number may vary from operator to 
operator. Since operators typically incorporate MEL changes for their 
affected fleet(s), the FAA has determined that a per-operator estimate 
is more accurate than a per-airplane estimate. Therefore, the FAA 
estimates the average total cost per operator to be $7,650 (90 work-
hours x $85 per work-hour).

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.
    The FAA is 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 products identified in this rulemaking action.

Regulatory Findings

    The FAA 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) Will not affect intrastate aviation in Alaska, and
    (3) 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-2020-0785; Product Identifier 
2020-NM-063-AD.

(a) Comments Due Date

    The FAA must receive comments by October 26, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company airplanes, 
certificated in any category, identified in paragraphs (c)(1) and 
(2) of this AD.
    (1) Model 747-100, -100B, -100B SUD, -200B, -200C, -200F, -300, 
-400, -400D, -400F, 747SR, 747SP, -8F, and -8 series airplanes.
    (2) Model 767-200, -300, -300F, -400ER, and -2C series 
airplanes.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by a report of an un-commanded fuel 
transfer between the main and center fuel tanks. The FAA is issuing 
this AD to address multiple refuel valves secured in the ``open'' 
position via Master Minimum Equipment List (MMEL) dispatch 
allowance, which allows un-commanded fuel transfer between fuel 
tanks. This condition could result in a fuel exhaustion event.

(f) Compliance

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

(g) Conditions for Prohibited Operation

    No later than 60 days after the effective date of this AD: 
Operation of an airplane with any inoperative refuel valve (fueling 
shut-off valve) secured in the open position is prohibited.

(h) MMEL Items

    The MMEL items specified in paragraphs (h)(1) through (6) of 
this AD are affected by this prohibition.
    (1) For Model 747-100, -200, and -300 series airplanes: The 
following ``Pressure Fueling System'' items.
    (i) MMEL Item 28-20 2), ``Main Tank 1 and 4 Refueling Valves.''
    (ii) MMEL Item 28-20 3), ``Main Tank 2 and 3 Refueling Valves.''
    (iii) MMEL Item 28-20 4), ``Center Tank Refueling Valves.
    (iv) MMEL Item 28-20 5), ``Reserve Tank 1 and 4 Refueling 
Valves.''
    (v) MMEL Item 28-20 6), ``Reserve Tank 2 and 3 Refueling 
Valves.''
    (2) For Model 747-400LCF series airplanes: MMEL Item 28-21-1 1), 
``Refuel Valves,'' second dispatch case with refueling valves 
inoperative open.
    (3) For Model 747-400 series airplanes: MMEL Item 28-21-1 1), 
``Refuel Valves,'' first dispatch case with refueling valves 
inoperative open.
    (4) For Model 747-8 series airplanes: MMEL Item 28-21-01-01-01A, 
``Refuel Valves,''
    (5) For Model 767 series airplanes: MMEL Item 28-21-01-01B, 
``Fuel Shutoff Valves.''
    (6) For Model 767-2C/KC-46 airplanes: The following ``Pressure 
Fueling System'' items.
    (i) MMEL Item 28-21-01-01E, ``Main Tank Shutoff Valve 
Inoperative Open.''
    (ii) MMEL Item 28-21-01-01F, ``Center Tank Shutoff Valve 
Inoperative Open.''

    Note 1 to paragraph (h): The MMEL items specified in paragraph 
(h) of this AD can be found in the applicable FAA-approved MMEL: 
Boeing 747 B-747-100/200/300/SP SERIES MMEL, Revision 35, dated 
April 25, 2014; Boeing 747 B-747-400 LCF MMEL, Revision 3, November 
7, 2014; Boeing 747 B-747-400, B-747-400D, B-747-400F MMEL, Revision 
32, dated December 27, 2018; Boeing 747-8 MMEL, Revision 7, dated 
August 25, 2017; and Boeing 767 MMEL,

[[Page 55624]]

Revision 39, dated October 26, 2018; which can be found on the 
Flight Standards Information Management System (FSIMS) website, 
https://fsims.faa.gov/PICResults.aspx?mode=Publication&doctype=MMELByModel.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle ACO Branch, 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 certification office, send it to the attention of the 
person identified in paragraph (j) 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 Company Organization Designation 
Authorization (ODA) that has been authorized by the Manager, Seattle 
ACO Branch, FAA, 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.

(j) Related Information

    For more information about this AD, contact Jeffrey Rothman, 
Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 
2200 South 216th St., Des Moines, WA 98190; phone and fax: 206-231-
3558; jeffrey.rothman@faa.gov.

    Issued on August 21, 2020.
Gaetano A. Sciortino,
Deputy Director for Strategic Initiatives, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2020-19583 Filed 9-8-20; 8:45 am]
BILLING CODE 4910-13-P