
[Federal Register Volume 81, Number 250 (Thursday, December 29, 2016)]
[Rules and Regulations]
[Pages 95857-95860]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-30279]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-6898; Directorate Identifier 2016-NM-010-AD; 
Amendment 39-18752; AD 2016-25-26]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for all The 
Boeing Company Model MD-90-30 airplanes. This AD was prompted by 
reports of stick shaker activation at airspeeds that were above the 
stall protection system's stick shaker schedule. This AD requires 
installing angle-of-attack (AOA) sensor external case heaters on the 
existing AOA sensors, installing additional wires, and doing a 
functional test and applicable corrective actions. We are issuing this 
AD to address the unsafe condition on these products.

DATES: This AD is effective February 2, 2017.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of February 2, 
2017.

ADDRESSES: For service information identified in this final rule, 
contact Boeing Commercial Airplanes, Attention: Contractual & Data 
Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 
90740-5600; telephone 562-797-1717; Internet https://www.myboeingfleet.com. You may view this referenced service information 
at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., 
Renton, WA. For information on the availability of this material at the 
FAA, call 425-227-1221. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2016-
6898.

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-
6898; 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 AD, the regulatory evaluation, any comments received, and 
other information. The address for the Docket Office (phone: 800-647-
5527) is Docket Management Facility, U.S. Department of Transportation, 
Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 
New Jersey Avenue SE., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Eric Igama, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130L, FAA, Los Angeles Aircraft 
Certification Office (ACO), 3960 Paramount Boulevard, Lakewood, CA 
90712-4137; phone: 562-627-5388; fax: 562-627-5210; email: 
roderick.igama@faa.gov.

SUPPLEMENTARY INFORMATION: 

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 by adding an AD that would apply to all The Boeing Company 
Model MD-90-30 airplanes. The NPRM published in the Federal Register on 
June 13, 2016 (81 FR 38113) (``the NPRM''). The NPRM was prompted by 
reports of stick shaker activation at airspeeds that were above the 
stall protection system's stick shaker schedule. The NPRM proposed to 
require installing AOA sensor external case heaters on the existing AOA 
sensors, installing additional wires, and doing a functional test and 
applicable corrective actions. We are issuing this AD to prevent ice 
formation between the AOA sensor vane and face plate, which could cause 
both vanes to become immobilized. If both vanes become immobilized, the 
stall protection system could become unreliable or non-functional, 
which could result in loss of control of the airplane.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the NPRM and 
the FAA's response to each comment.

Support of the NPRM

    The Air Line Pilots Association, International provided comments 
that supported the intent of the NPRM.

Request To Change Boeing Address Identified in the NPRM

    Boeing asked that we change its mailing address for obtaining 
copies of service information as specified in the NPRM to the 
following: Boeing Commercial Airplanes, Attention: Contractual & Data 
Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 
90740-5600; telephone 562-797-1092; Internet https://www.myboeingfleet.com. Boeing stated that this address is valid for 
this and all future ADs affecting Boeing airplanes.
    We agree with the commenter's request. We have updated the contact 
information accordingly. However, we have corrected the telephone 
number; it should be 562-797-1717. We have changed this AD to include 
this new mailing address for Boeing service information.

Request To Clarify Certain Language in the NPRM

    Boeing asked that we clarify the language specifying what prompted 
the AD action, and the description of the unsafe condition, as 
specified in the SUMMARY section. Boeing stated that the reported 
incident occurred ``on Model 717-200 airplanes'' and included further 
description of what prompted the AD action. Boeing also stated that 
including this description clarifies the airplane model on which the 
safety issue was identified. Boeing also asked that we revise the 
description of the unsafe condition, which stated that ``the vane'' 
could become immobilized. Boeing noted that the safety issue is a 
common cause failure (both vanes could become immobilized) due to an 
external threat (i.e., weather).
    We agree to add ``both vanes'' to the Discussion section and 
paragraph (e) of this AD for clarification. Information concerning the 
origin of the safety issue on Model 717-200 airplanes was included in 
the Discussion section of the NPRM. Since the information in the 
Discussion section of the NPRM does not reappear in the final rule, we 
have not changed this AD in this regard. In addition, we do not agree 
that the requested changes are necessary in the SUMMARY section, which 
merely provides a high-level description of the relevant information. 
Details concerning the unsafe condition that appeared in the SUMMARY 
section of the NPRM have been removed from this final rule in response 
to new guidance from the Office of the Federal Register.
    Boeing also asked that we clarify the AD requirements by specifying 
``installing additional wires'' in lieu of ``changing wires'' and 
installing AOA sensor external case heaters ``on the AOA sensors'' in 
lieu of ``and AOA sensors.'' Delta Air Lines (Delta) asked that we 
change ``and AOA sensors'' to

[[Page 95858]]

``and existing AOA sensors'' since they are not new sensors.
    We agree to make the requested changes in the SUMMARY section, the 
Discussion and the Related Service Information under 1 CFR part 51 
sections of this final rule, and in paragraph (g) of this AD for 
clarification.
    Delta asked that we remove the references to ``water intrusion'' 
from the NPRM related to the description of the unsafe condition. Delta 
stated that the referenced service information does not address water 
intrusion. Delta added that the installation of the external case 
heater only prevents the existing water from freezing and rendering the 
vane immobilized. UTC Aerospace Systems (UTC) also asked that we remove 
the reference to moisture (water) intrusion since the referenced 
service information does nothing to reduce or eliminate the problem; it 
simply keeps the water from freezing. UTC also asked that we add to the 
description of the unsafe condition that the AD is intended to reduce 
or eliminate ice formation between the AOA sensor vane and face plate.
    We partially agree with the commenters' requests. Water intrusion 
is addressed in the referenced service information since it contributes 
to ice formation between the AOA sensor vane and face plate. However, 
water intrusion is not corrected by this AD. Therefore, we have revised 
the Discussion section and paragraph (e) of this AD to state ``We are 
issuing this AD to prevent ice formation between the angle-of-attack 
(AOA) sensor vane and face plate.''

Request To Clarify Corrective Actions

    UTC asked that we re-identify the corrective actions in the SUMMARY 
and Discussion sections of the NPRM as removing and replacing the 
existing AOA unit having part number (P/N) 0861EW1 with a certified 
AOA, or installing a new AOA in accordance with the instructions 
specified in Boeing Alert Service Bulletin MD90-30A029, dated November 
25, 2015. UTC stated that this would clarify the potential cause of the 
problem as related to the subject AOA and provide another choice for 
operators to comply with the proposed AD. UTC added that this would 
also define the AOA replacement as not including the existing AOA unit 
having P/N 0861EW1.
    We agree that clarification is necessary; however, we do not agree 
that this clarification should be included in the SUMMARY section and 
the Discussion section of this final rule. The purpose of the language 
in the SUMMARY section is to provide a high-level description of the 
relevant information, and the information in the Discussion section of 
the NPRM does not reappear in the final rule. Therefore, we have 
revised the description of the required actions in the Related Service 
Information under 1 CFR part 51 section of this final rule, as 
specified by the commenter, to provide clarification to operators. We 
have also included the correct part number for the existing AOA unit in 
paragraph (g) of this AD.

Request To Update Referenced Service Information To Include the Correct 
Part Number

    UTC asked that Boeing Alert Service Bulletin MD90-30A029, dated 
November 25, 2015, be updated to correct the part number for the AOA 
sensor identified therein. UTC stated that the service information 
identifies replacing any AOA sensor having P/N ``081EW1,'' but the 
correct part number is ``0861EW1.''
    We acknowledge the commenter's concern; however, Boeing Alert 
Service Bulletin MD90-30A029, dated November 25, 2015, has not yet been 
revised by the airplane manufacturer. We have confirmed that this part 
number does not exist, and have clarified the correct part number for 
the existing AOA sensor in paragraph (g) of this AD.

Request To Change the Costs of Compliance Section

    Boeing asked that we change the Costs of Compliance section of the 
NPRM to include the parts cost for the external case heaters, as 
provided by the supplier. Boeing stated that the supplier of these 
heaters has received FAA parts manufacturer approval (PMA), which 
allows operators to go directly to the supplier to procure the parts. 
Boeing noted that the parts cost for two heaters is $2,389 each, for a 
total of $4,778 (operators are required to purchase two external case 
heaters for installation).
    We agree with the commenter's request for the reason provided. We 
have changed the Costs of Compliance section in this final rule 
accordingly.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
this AD with the changes described previously and minor editorial 
changes. We have determined that these minor changes:
     Are consistent with the intent that was proposed in the 
NPRM for correcting the unsafe condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM.
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this AD.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Service Bulletin MD90-30A029, dated 
November 25, 2015. The service information describes procedures for 
installing AOA sensor external case heaters on the existing AOA 
sensors, installing additional wires, and doing a functional test and 
applicable corrective actions. The applicable corrective actions 
include removing and replacing the existing AOA unit (P/N 0861EW1) with 
a certified AOA, or installing a new AOA. This service information is 
reasonably available because the interested parties have access to it 
through their normal course of business or by the means identified in 
the ADDRESSES section.

Costs of Compliance

    We estimate that this AD affects 95 airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
             Action                   Labor cost          Parts cost       Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Installation of AOA sensor        Up to 44 work-      Up to $5,998        Up to $9,738        Up to $925,110
 external case heaters on the      hours (depending    (depending on the   (depending on the   (depending on the
 AOA sensors, installation of      on the group        group number).      group number).      group number).
 additional wires, and a           number) x $85 per
 functional test.                  hour = $3,740.
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[[Page 95859]]

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 products identified in this 
rulemaking action.

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,
    (2) Is not a ``significant rule'' under 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.

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):

2016-25-26 The Boeing Company: Amendment 39-18752; Docket No. FAA-
2016-6898; Directorate Identifier 2016-NM-010-AD.

(a) Effective Date

    This AD is effective February 2, 2017.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model MD-90-30 
airplanes, certificated in any category.

(d) Subject

    Air Transport Association (ATA) of America Code 34, Navigation.

(e) Unsafe Condition

    This AD was prompted by reports of stick shaker activation at 
airspeeds that were above the stall protection system's stick shaker 
schedule. We are issuing this AD to prevent ice formation between 
the angle-of-attack (AOA) sensor vane and face plate, which could 
cause both vanes to become immobilized. If both vanes become 
immobilized, the stall protection system could become unreliable or 
non-functional, which could result in loss of control of the 
airplane.

(f) Compliance

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

(g) Installation of AOA Sensor External Case Heater

    Within 6 years after the effective date of this AD, install AOA 
sensor external case heaters on the existing AOA sensors, install 
additional wires, and do a functional test and applicable corrective 
actions, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin MD90-30A029, dated November 25, 2015. 
All applicable corrective actions must be done before further 
flight. The correct part number for the existing AOA sensor is P/N 
0861EW1.

(h) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles 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-LAACO-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 required by this AD if it is approved by the 
Boeing Commercial Airplanes Organization Designation Authorization 
(ODA) that has been authorized by the Manager, Los Angeles ACO, to 
make those findings. For a repair method to be approved, the repair 
must meet the certification basis of the airplane, and the approval 
must specifically refer to this AD.
    (4) For service information that contains steps that are labeled 
as Required for Compliance (RC), the provisions of paragraphs 
(h)(4)(i) and (h)(4)(ii) of this AD apply.
    (i) The steps labeled as RC, including substeps under an RC step 
and any figures identified in an RC step, must be done to comply 
with the AD. If a step or substep is labeled ``RC Exempt,'' then the 
RC requirement is removed from that step or substep. An AMOC is 
required for any deviations to RC steps, including substeps and 
identified figures.
    (ii) Steps not labeled as RC may be deviated from using accepted 
methods in accordance with the operator's maintenance or inspection 
program without obtaining approval of an AMOC, provided the RC 
steps, including substeps and identified figures, can still be done 
as specified, and the airplane can be put back in an airworthy 
condition.

(i) Related Information

    For more information about this AD, contact Eric Igama, 
Aerospace Engineer, Systems and Equipment Branch, ANM-130L, FAA, Los 
Angeles ACO, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; 
phone: 562-627-5388; fax: 562-627-5210; email: 
roderick.igama@faa.gov.

(j) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Boeing Alert Service Bulletin MD90-30A029, dated November 
25, 2015.
    (ii) Reserved.
    (3) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Contractual & Data Services 
(C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-
5600; telephone 562-797-1717; Internet https://www.myboeingfleet.com.
    (4) You may view this service information at the FAA, Transport 
Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For 
information on the availability of this material at the FAA, call 
425-227-1221.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.


[[Page 95860]]


    Issued in Renton, Washington, on December 7, 2016.
Dionne Palermo,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-30279 Filed 12-28-16; 8:45 am]
 BILLING CODE 4910-13-P


