[Federal Register Volume 84, Number 181 (Wednesday, September 18, 2019)]
[Rules and Regulations]
[Pages 49005-49008]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-20184]



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 Rules and Regulations
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  Federal Register / Vol. 84, No. 181 / Wednesday, September 18, 2019 / 
Rules and Regulations  

[[Page 49005]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0696; Product Identifier 2019-NM-136-AD; Amendment 
39-19730; AD 2019-18-03]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
The Boeing Company Model 737 series airplanes, excluding Model 737-100, 
-200, -200C, -300, -400, and -500 series airplanes. This AD requires 
revising the existing maintenance or inspection program to remove text 
that allows the size of the thrust reverser upper locking actuator lock 
sensor target to be changed, and, for certain airplanes, performing 
repetitive integrity tests of the thrust reverser upper locking 
actuator. This AD was prompted by a report indicating that alteration 
of thrust reverser upper locking actuators in accordance with certain 
data in the Boeing aircraft maintenance manual (AMM) could delay or 
prevent detection of the failure of the locking mechanism of a thrust 
reverser upper locking actuator. The FAA is issuing this AD to address 
the unsafe condition on these products.

DATES: This AD is effective October 3, 2019.
    The FAA must receive comments on this AD by November 4, 2019.

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-2019-
0696; 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 final rule, the regulatory evaluation, 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: Christopher Baker, Aerospace Engineer, 
Propulsion Section, FAA, Seattle ACO Branch, 2200 South 216th St., Des 
Moines, WA 98198; phone and fax: 206-231-3552; email: 
Christopher.R.Baker@faa.gov.

SUPPLEMENTARY INFORMATION: 

Discussion

    In May 2019, Boeing informed the FAA that alteration of thrust 
reverser upper locking actuators, in accordance with unapproved data in 
the Boeing AMM, could cause a locking mechanism failure of a thrust 
reverser upper locking actuator to remain undetected for thousands of 
flights.
    Boeing informed the FAA of the risk that operators could use an 
existing AMM procedure that was intended for use in rigging a newly 
installed thrust reverser upper locking actuator to instead alter the 
functioning of a worn upper locking actuator's lock indication. That 
procedure removes material from the upper locking actuator's lock 
sensor target until the upper locking actuator's unlocked indication 
(the ``REVERSER'' light on the flight deck aft overhead panel, which is 
illuminated when the upper locking actuator is unlocked or when other 
system failures are detected) is no longer illuminated. However, that 
procedure does not require a check to verify that the thrust reverser 
upper locking actuator locking mechanism is operative or that the 
unlocked indication functions normally after removal of the material. 
As a result, it is possible that use of this procedure could prevent 
actuator unlocked indications to the flight crew if the thrust reverser 
upper locking actuator locking mechanism has already failed or 
subsequently fails.
    An undetected unlocked thrust reverser upper locking actuator in 
flight significantly increases the likelihood of an in-flight 
deployment of the thrust reverser. In-flight thrust reverser deployment 
in some phases of flight would likely result in loss of airplane 
control.

FAA's Determination

    The FAA is issuing 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.

AD Requirements

    This AD requires revising the existing maintenance or inspection 
program to remove certain text from all locations in the existing 
maintenance and inspection program that instructs the maintainers to 
remove material from or grind or trim the sensor target of the thrust 
reverser upper locking actuator. For Model 737-600, -700, -700C, -800, 
-900, and -900ER series (737 NG) airplanes, this AD also requires 
repetitive integrity tests of the thrust reverser upper locking 
actuator.
    The Model 737-8 and -9 (737 MAX) airplane fleet is a young fleet 
and those airplanes have not been subjected to enough wear to warrant 
the use by any operator of the sensor target trimming procedure that 
leads to the upper locking actuator lock indication failure that may 
exist on 737 NG airplanes. The FAA therefore has determined that the 
integrity test is not necessary for the 737 MAX fleet.

Interim Action

    The FAA considers this AD interim action. The manufacturer is 
currently developing a modification that will address the unsafe 
condition identified in this AD. Once this modification is developed, 
approved, and available, the

[[Page 49006]]

FAA might consider additional rulemaking.

Justification for Immediate Adoption and Determination of the Effective 
Date

    Section 553(b)(3)(B) of the Administrative Procedure Act (APA) (5 
U.S.C.) authorizes agencies to dispense with notice and comment 
procedures for rules when the agency, for ``good cause,'' finds that 
those procedures are ``impracticable, unnecessary, or contrary to the 
public interest.'' Under this section, an agency, upon finding good 
cause, may issue a final rule without seeking comment prior to the 
rulemaking. Similarly, Section 553(d) of the APA authorizes agencies to 
make rules effective in less than thirty days, upon a finding of good 
cause.
    An unsafe condition exists that requires the immediate adoption of 
this AD without providing an opportunity for public comments prior to 
adoption. The FAA has found that the risk to the flying public 
justifies forgoing notice and comment prior to adoption of this rule 
because alteration of thrust reverser upper locking actuators in 
accordance with certain unapproved AMM data could cause a thrust 
reverser upper locking actuator that is unlocked in flight to remain 
undetected, which could significantly increase the likelihood of an in-
flight deployment of the thrust reverser and consequent loss of 
airplane control. The compliance time for the required action is 
shorter than the time necessary for the public to comment and for 
publication of the final rule.
    Accordingly, notice and opportunity for prior public comment are 
impracticable and contrary to the public interest pursuant to 5 U.S.C. 
553(b)(3)(B). In addition, for the reasons stated above, the FAA finds 
that good cause exists pursuant to 5 U.S.C. 553(d) for making this 
amendment effective in less than 30 days.

Comments Invited

    This AD is a final rule that involves requirements affecting flight 
safety and was not preceded by notice and an opportunity for public 
comment. However, the FAA invites you to send any written data, views, 
or arguments about this final rule. Send your comments to an address 
listed under the ADDRESSES section. Include the docket number FAA-2019-
0696 and Product Identifier 2019-NM-136-AD at the beginning of your 
comments. The FAA specifically invites comments on the overall 
regulatory, economic, environmental, and energy aspects of this final 
rule. The FAA will consider all comments received by the closing date 
and may amend this final rule because of those 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, to 
http://www.regulations.gov, including any personal information you 
provide. The FAA will also post a report summarizing each substantive 
verbal contact received about this final rule.

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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to 
Christopher Baker, Aerospace Engineer, Propulsion Section, FAA, Seattle 
ACO Branch, 2200 South 216th St., Des Moines, WA 98198; phone and fax: 
206-231-3552; email: Christopher.R.Baker@faa.gov. Any commentary that 
the FAA receives which is not specifically designated as CBI will be 
placed in the public docket for this rulemaking.

Regulatory Flexibility Act

    The requirements of the Regulatory Flexibility Act (RFA) do not 
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt 
a rule without prior notice and comment. Because the FAA has determined 
that it has good cause to adopt this rule without notice and comment, 
RFA analysis is not required.

Costs of Compliance

    The FAA estimates that this AD affects 2,149 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
              Action                    Labor cost        Parts cost      Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Integrity test (2,039 airplanes).  8 work-hours x $85               $0  $680 per test cycle  $1,386,520 per test
                                    per hour = $680                                           cycle.
                                    per test cycle.
----------------------------------------------------------------------------------------------------------------

    The FAA has determined that revising the existing maintenance or 
inspection program takes an average of 90 work-hours per operator, 
although the agency recognizes that this number may vary from operator 
to operator. In the past, the FAA has estimated that this action takes 
1 work-hour per airplane. Since operators incorporate maintenance or 
inspection program 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 total cost per 
operator to be $7,650 (90 work-hours x $85 per work-hour).
    The FAA estimates the following costs to do any necessary 
replacement that would be required based on the results of the 
integrity test. The FAA has no way of determining the number of 
aircraft that might need this replacement:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Actuator replacement..........................  8 work-hours x $85 per hour =            $38,908         $39,588
                                                 $680.
----------------------------------------------------------------------------------------------------------------


[[Page 49007]]

    According to the manufacturer, some or all of the costs of this AD 
may be covered under warranty, thereby reducing the cost impact on 
affected individuals. The FAA does not control warranty coverage for 
affected individuals. As a result, the FAA has included all known costs 
in the cost estimate.

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.
    This AD is issued in accordance with authority delegated by the 
Executive Director, Aircraft Certification Service, as authorized by 
FAA Order 8000.51C. In accordance with that order, issuance of ADs is 
normally a function of the Compliance and Airworthiness Division, but 
during this transition period, the Executive Director has delegated the 
authority to issue ADs applicable to transport category airplanes and 
associated appliances to the Director of the System Oversight Division.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD will 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 that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866, and
    (2) Will not affect intrastate aviation in Alaska.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 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):

2019-18-03 The Boeing Company: Amendment 39-19730; Docket No. FAA-
2019-0696; Product Identifier 2019-NM-136-AD.

(a) Effective Date

    This AD is effective October 3, 2019.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 737 series 
airplanes, certificated in any category, excluding Model 737-100, -
200, -200C, -300, -400, and -500 series airplanes.

(d) Subject

    Air Transport Association (ATA) of America Code 78, Exhaust.

(e) Unsafe Condition

    This AD was prompted by a report indicating that alteration of 
thrust reverser upper locking actuators in accordance with certain 
data contained in the Boeing aircraft maintenance manual (AMM) could 
delay or prevent detection of the failure of the locking mechanism 
of a thrust reverser upper locking actuator. The FAA is issuing this 
AD to address the potential for an undetected unlocked condition of 
the thrust reverser upper locking actuator locking mechanism in 
flight, which could significantly increase the likelihood of an in-
flight deployment of the thrust reverser and consequent loss of 
airplane control.

(f) Compliance

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

(g) Maintenance/Inspection Program Revision

    For all airplanes: Within 30 days after the effective date of 
this AD, revise the existing maintenance or inspection program, as 
applicable, by removing any steps that change the size of the thrust 
reverser upper locking actuator lock sensor target.

(h) Prohibition From Altering Locking Actuator Target

    For all airplanes: As of the effective date of this AD, no 
person may alter the thrust reverser upper locking actuator lock 
sensor target by grinding or trimming or otherwise removing material 
from the lock sensor target.

(i) Actuator Integrity Test

    For Model 737-600, -700, -700C, -800, -900, and -900ER series 
airplanes: Within 90 days after the effective date of this AD, 
conduct an integrity test of the thrust reverser upper locking 
actuator on all 4 locking actuators on the airplane. The integrity 
test must include at least the steps specified in figure 1 to 
paragraphs (i) and (k) of this AD. The integrity test is not 
required to be completed for all 4 actuators in one maintenance 
visit, provided all 4 actuators are tested within the compliance 
times specified in this paragraph. During the test, a slight 
movement from fully stowed on the lower portion of the thrust 
reverser is acceptable due to the wind up in the flexible shafts 
between the synchronization lock and the upper actuator lock.

[[Page 49008]]

[GRAPHIC] [TIFF OMITTED] TR18SE19.000


    Note 1 to paragraph (i):  Additional guidance for the integrity 
test can be found in Boeing 737 AMM Task 78-31-03.

(j) Repetitive Test Interval

    After the initial integrity test required by paragraph (i) of 
this AD, repeat the test thereafter at intervals not to exceed 750 
flight hours.

(k) Corrective Action for Failed Integrity Test

    If, during any integrity test required by paragraph (i) or (j) 
of this AD, the movement of the thrust reverser exceeds the 
acceptable ``slight movement'' described in paragraph (i) of this 
AD, replace the locking actuator before further flight.

(l) Parts Installation Prohibition

    For airplanes identified in paragraph (c) of this AD, excluding 
Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes: 
As of the effective date of this AD, no person may install a thrust 
reverser upper locking actuator part number 315A2801-1, -2, -3, -4, 
or -5.

(m) 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 (n) 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.

(n) Related Information

    For more information about this AD, contact Christopher Baker, 
Aerospace Engineer, Propulsion Section, FAA, Seattle ACO Branch, 
2200 South 216th St., Des Moines, WA 98198; phone and fax: 206-231-
3552; email: Christopher.R.Baker@faa.gov.

(o) Material Incorporated by Reference

    None.

    Issued in Des Moines, Washington, on September 11, 2019.
Dionne Palermo,
Acting Director, System Oversight Division, Aircraft Certification 
Service.
[FR Doc. 2019-20184 Filed 9-17-19; 8:45 am]
 BILLING CODE 4910-13-P


