AD 2019-24-18
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 727-100 Series | Airworthiness Directives; the Boeing Company Airplanes |
| aircraft | The Boeing Company | 727-100C Series | Airworthiness Directives; the Boeing Company Airplanes |
| aircraft | The Boeing Company | 727-200 Series | Airworthiness Directives; the Boeing Company Airplanes |
| aircraft | The Boeing Company | 727-200F Series | Airworthiness Directives; the Boeing Company Airplanes |
| aircraft | The Boeing Company | 727 Series | Airworthiness Directives; the Boeing Company Airplanes |
| aircraft | The Boeing Company | 727C Series | Airworthiness Directives; the Boeing Company Airplanes |
| aircraft | The Boeing Company | 757-200 Series | Airworthiness Directives; the Boeing Company Airplanes |
| aircraft | The Boeing Company | 757-200CB Series | Airworthiness Directives; the Boeing Company Airplanes |
| aircraft | The Boeing Company | 757-200PF Series | Airworthiness Directives; the Boeing Company Airplanes |
| aircraft | The Boeing Company | 757-300 Series | Airworthiness Directives; the Boeing Company Airplanes |
| aircraft | The Boeing Company | 767-200 Series | Airworthiness Directives; the Boeing Company Airplanes |
| aircraft | The Boeing Company | 767-300 Series | Airworthiness Directives; the Boeing Company Airplanes |
| aircraft | The Boeing Company | 767-300F Series | Airworthiness Directives; the Boeing Company Airplanes |
| aircraft | The Boeing Company | 767-400ER Series | Airworthiness Directives; the Boeing Company Airplanes |
Unsafe Condition
ice build-up in the AOA sensor faceplate and vane, which may immobilize the AOA sensor vanes, and could result in inaccurate or unreliable AOA sensor data being transmitted to airplane systems and consequent loss of controllability of the airplane.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
a general visual inspection of the AOA sensors for certain AOA sensors, and replacement of affected AOA sensors.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within 36 months after the effective date of this AD, or within 36 months or 9,960 flight hours after the effective date of this AD, whichever occurs first.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
The Boeing Company Model 727 airplanes, Model 757 airplanes, and Model 767-200, -300, -300F, and -400ER series airplanes.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 727 airplanes, Model 757 airplanes, and Model 767-200, -300, -300F, and -400ER series airplanes. This AD was prompted by reports of nuisance stick shaker activation while the airplane accelerated to cruise speed at the top of climb. This AD was also prompted by an investigation of those reports that revealed that the angle of attack (AOA) (also known as angle of airflow) sensor vanes could not prevent the build-up of ice, causing the AOA sensor vanes to become immobilized, which resulted in nuisance stick shaker activation. This AD requires a general visual inspection of the AOA sensors for certain AOA sensors, and replacement of affected AOA sensors. The FAA is issuing this AD to address the unsafe condition on these products.
Applicability Source Text
Show captured applicability text from the source AD
(c) Applicability
This AD applies to The Boeing Company airplanes, identified in
paragraphs (c)(1) through (3) of this AD, certificated in any
category.
(1) Model 727, 727C, 727-100, 727-100C, 727-200, and 727-200F
series airplanes, as identified in Boeing Alert Service Bulletin
727-34A0247, Revision 1, dated October 1, 2019; except for airplanes
having variable numbers QB065, QD191, QD192, QD402, QD403, QD407,
and QD410.
(2) Model 757-200, -200PF, -200CB, and -300 series airplanes, as
identified in Boeing Alert Service Bulletin 757-34A0611, Revision 1,
dated March 22, 2019.
[[Page 71782]]
(3) Model 767-200, -300, -300F, and -400ER series airplanes, as
identified in Boeing Alert Service Bulletin 767-34A0828, dated
December 6, 2018.
Document Text
Show stored source text (verify against official source)
[Federal Register Volume 84, Number 249 (Monday, December 30, 2019)]
[Rules and Regulations]
[Pages 71778-71782]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2019-27887]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2019-0252; Product Identifier 2019-NM-048-AD; Amendment
39-21007; AD 2019-24-18]
RIN 2120-AA64
Airworthiness Directives; the Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain The Boeing Company Model 727 airplanes, Model 757 airplanes,
and Model 767-200, -300, -300F, and -400ER series airplanes. This AD
was prompted by reports of nuisance stick shaker activation while the
airplane accelerated to cruise speed at the top of climb. This AD was
also prompted by an investigation of those reports that revealed that
the angle of attack (AOA) (also known as angle of airflow) sensor vanes
could not prevent the build-up of ice, causing the AOA sensor vanes to
become immobilized, which resulted in nuisance stick shaker activation.
This AD requires a general visual inspection of the AOA sensors for
certain AOA sensors, and replacement of affected AOA sensors. The FAA
is issuing this AD to address the unsafe condition on these products.
DATES: This AD is effective February 3, 2020.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of February 3,
2020.
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 <a href="https://www.myboeingfleet.com">https://www.myboeingfleet.com</a>. You may view this service information at the
FAA, Transport Standards Branch, 2200 South 216th St., Des Moines, WA.
For information on the availability of this material at the FAA, call
206-231-3195. It is also available on the internet at <a href="https://www.regulations.gov">https://www.regulations.gov</a> by searching for and locating Docket No. FAA-2019-
0252.
Examining the AD Docket
You may examine the AD docket on the internet at <a href="https://www.regulations.gov">https://www.regulations.gov</a> by searching for
[[Page 71779]]
and locating Docket No. FAA-2019-0252; 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 address for Docket Operations is 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: Jeffrey W. Palmer, Aerospace Engineer,
Systems and Equipment Section, FAA, Los Angeles ACO Branch, 3960
Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5351; fax:
562-627-5210; email: <a href="/cdn-cgi/l/email-protection#d79db2b1b1a5b2aef980f987b6bbbab2a597b1b6b6f9b0b8a1"><span class="__cf_email__" data-cfemail="94def1f2f2e6f1edbac3bac4f5f8f9f1e6d4f2f5f5baf3fbe2">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Discussion
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to certain The Boeing
Company Model 727 airplanes, Model 757 airplanes, and Model 767-200, -
300, -300F, and -400ER series airplanes. The NPRM published in the
Federal Register on July 9, 2019 (84 FR 32667). The NPRM was prompted
by reports of nuisance stick shaker activation while the airplane
accelerated to cruise speed at the top of climb. The NPRM was also
prompted by an investigation of those reports that revealed that the
AOA sensor vanes could not prevent the build-up of ice, causing the AOA
sensor vanes to become immobilized, which resulted in nuisance stick
shaker activation. The NPRM proposed to require a general visual
inspection of the AOA sensors for certain AOA sensors, and replacement
of affected AOA sensors.
The FAA is issuing this AD to address ice build-up in the AOA
sensor faceplate and vane, which may immobilize the AOA sensor vanes,
and could result in inaccurate or unreliable AOA sensor data being
transmitted to airplane systems and consequent loss of controllability
of the airplane.
Changes Since the NPRM Was Issued
The FAA has reviewed Boeing Alert Service Bulletin 727-34A0247,
Revision 1, dated October 1, 2019 (the FAA referred to Boeing Alert
Service Bulletin 727-34A0247, dated January 2, 2019, as an appropriate
source of service information for accomplishing the actions specified
in the NPRM) and have revised this AD to refer to Boeing Alert Service
Bulletin 727-34A0247, Revision 1, dated October 1, 2019. This service
information adds airplanes to the effectivity, but specifies that no
additional work is needed if the actions in Boeing Alert Service
Bulletin 727-34A0247, dated January 2, 2019, have been accomplished.
The FAA has added paragraph (i) to this AD to provide credit for
actions done prior to the effective date of this AD using Boeing Alert
Service Bulletin 727-34A0247, dated January 2, 2019. Subsequent
paragraphs have been redesignated accordingly.
Although Boeing Alert Service Bulletin 727-34A0247, Revision 1,
dated October 1, 2019, adds airplanes to the effectivity, the FAA has
not added those airplanes to the applicability of this AD. In paragraph
(c) of this AD, the FAA refers to the airplanes identified in Boeing
Alert Service Bulletin 727-34A0247, Revision 1, dated October 1, 2019,
except for the additional airplanes (variable numbers QB065, QD191,
QD192, QD402, QD403, QD407, and QD410). Adding airplanes to the
applicability of this AD would necessitate (under the provisions of the
Administrative Procedure Act) reissuing the notice, reopening the
comment period, considering additional comments subsequently received,
and eventually issuing a final rule. In consideration of the urgency of
the unsafe condition identified in this final rule, the FAA has
determined that delay of this final rule is not appropriate. However,
the FAA might consider further rulemaking on this issue to address the
additional airplanes.
Comments
The FAA gave the public the opportunity to participate in
developing this final rule. The following presents the comments
received on the NPRM and the FAA's response to each comment.
Effect of Winglets on Accomplishment of the Proposed Actions
Aviation Partners Boeing (APB) stated that they have reviewed the
NPRM and have determined that the installation of winglets per
Supplemental Type Certificate (STC) ST01518SE (for Model 757 airplanes)
and STC ST01920SE (for Model 767 airplanes) do not affect the
accomplishment of the manufacturer's service instructions.
The FAA agrees with the commenter that STC ST01518SE and STC
ST01920SE do not affect the accomplishment of the manufacturer's
service instructions. Therefore, the installation of STC ST01518SE or
STC ST01920SE does not affect the ability to accomplish the actions
required by this AD. The FAA has not changed this AD in this regard.
Request To Reduce Compliance Time
The Air Line Pilots Association, International (ALPA) requested the
compliance time in the proposed AD be shortened from within 36 months
after the effective date of this AD to within 24 months after the
effective date of this AD for all airplanes. The ALPA stated that it
agrees with the intent of the proposed AD, but does not agree that a
36-month compliance time is sufficient when considering the publication
dates of the service information, the low estimated time to complete
the repairs, and the high risk associated with inaccurate AOA readings
and nuisance stick shaker indications.
The FAA does not agree with the request. The FAA has determined
that the compliance time specified in this AD for each airplane model
will accommodate the time necessary to accomplish the actions required
by this AD and maintain an adequate level of safety. In addition, the
commenter did not provide adequate data to justify a shortened
compliance time. Lastly, the suggested compliance time change would
alter the requirements of this AD to be more restrictive, so additional
rulemaking would be required, ultimately delaying issuance of the AD.
The FAA finds that delaying this action is inappropriate in light of
the identified unsafe condition. However, if additional data are
presented that would justify a shorter compliance time, the FAA may
consider further rulemaking on this issue. The FAA has not changed this
AD in this regard.
Request To Extend Compliance Time
American Airlines (AAL) and United Airlines (UAL) requested that
the FAA extend the compliance time for the Boeing Model 767 fleet from
within 36 months or 3,470 flight hours (FH) after the effective date of
this AD, whichever occurs first, to match the compliance time of the
Boeing Model 757 fleet, which is within 36 months or 9,960 FH after the
effective date of this AD, whichever occurs first. AAL reasoned that
the Boeing Model 757 and 767 fleets share the same parts for both the
AOA sensors and air data computers and operate similar missions with
similar cold-soak times on the AOA vanes, and argued that the risk
should be the same. AAL asserted that matching the FH compliance times
will ensure that accomplishing this proposed AD can be effectively and
economically planned, while allowing for the components to be handled
the same regardless of fleet. AAL concluded this
[[Page 71780]]
method would maintain an equivalent level of safety.
UAL also pointed out that UAL's Boeing Model 757 and 767 fleets are
equipped with equivalent AOA sensors and air data computers, and the
operation and cold-soak times of the AOA sensors are the same. UAL
argued that changing the FH compliance time for Model 767 airplanes to
match the FH compliance time for Model 757 airplanes would provide an
equivalent level of safety, stating that the AOA sensors of both
airplane models are exposed to the same adverse conditions in the air
and on the ground.
The FAA does not agree with the request. The FAA has determined
that the flight-hour compliance times identified in the service
information, without a time threshold, will not ensure that the
identified unsafe condition is addressed in a timely manner. In
developing an appropriate compliance time for this AD, the FAA
considered the degree of urgency associated with addressing the subject
unsafe condition, the average utilization of the affected fleet, and
the time necessary to perform the modifications. In light of all of
these factors, the FAA finds the compliance times specified in the
applicable service information, or within 36 months after the effective
date of this AD, whichever occurs first, represents an appropriate
interval of time for affected airplanes to continue to operate without
compromising safety. However, under the provisions of paragraph (j) of
this AD, the FAA will consider requests for approval of an extension of
the compliance time if sufficient data are submitted to substantiate
that the new compliance time would provide an acceptable level of
safety. The FAA has not changed the AD in this regard.
Request To Include Records Review
All Nippon Airways (ANA) requested that the FAA add a statement to
the proposed AD that allows a review of the airplane maintenance
records for the part number (P/N) of the AOA sensor, if the P/N of the
AOA sensor can be conclusively determined from that review. ANA stated
that they have installed AOA sensor P/N 0861FL1 (new Boeing P/N
S233T913-5) on their Boeing Model 767 fleet because it began
accomplishing Boeing Alert Service Bulletin 767-34A0828, dated December
6, 2018, since the issue date of the service information. ANA argued
that the proposed AD would require them to repeat accomplishment of
Boeing Alert Service Bulletin 767-34A0828, dated December 6, 2018. ANA
stated that it manages the P/N of the AOA sensor within its airplane
maintenance records, and the installation of the new AOA sensor P/N
0861FL1 (new Boeing P/N S233T913-5) on each airplane can be traced by
reviewing its airplane maintenance records.
The FAA agrees with the commenter's request to add a records
review. The FAA has added paragraph (h)(2) to this AD to allow a review
of airplane maintenance records in lieu of the inspections for the AOA
sensor P/Ns. The FAA also notes that paragraph (f) of this AD states to
accomplish the required actions within the compliance times specified,
``unless already done.'' Therefore, if operators have accomplished the
actions required for compliance with this AD before the effective date
of this AD and have records that show the actions were done as
specified in the AD, no further action is necessary.
Request To Reference Later Revisions of Service Information
AAL requested that the applicability, required actions, and
exceptions to service information in the proposed AD be revised to
include any future FAA approved revisions of service information. AAL
requested that the FAA add the phrase ``or later FAA approved
revisions'' to Boeing Alert Service Bulletin 757-34A0611, Revision 1,
dated March 22, 2019; and Boeing Alert Service Bulletin 767-34A0828,
dated December 6, 2018. AAL suggested that any requirement that
references service information would state, for example, ``Boeing Alert
Service Bulletin 757-34A0611, Revision 1, dated March 22, 2019, or
later FAA approved revisions.'' AAL argued that allowing later FAA
approved revisions of service information would avoid extra work and
delays in implementation required for an alternative method of
compliance (AMOC) approval should either service information require a
revision due to an error or omission of data.
The FAA does not agree with the request. The FAA may not refer to
any document that does not yet exist. In general terms, the FAA is
required by Office of the Federal Register (OFR) regulations for
approval of materials incorporated by reference, as specified in 1 CFR
51.1(f), to either publish the service document contents as part of the
actual AD language; or submit the service document to the OFR for
approval as referenced material, in which case the FAA may only refer
to such material in the text of an AD. The AD may refer to the service
document only if the OFR approved it for incorporation by reference.
See 1 CFR part 51.
To allow operators to use later revisions of the referenced
document (issued after publication of the AD), either the FAA must
revise the AD to reference specific later revisions, or operators must
request approval to use later revisions as an AMOC with this AD under
the provisions of paragraph (j) of this AD.
Request To Clarify the Impact of Case Heaters on Unsafe Condition
The commenter, Alan Peterson, FedEx, stated that the proposed AD
does not address the possibility that the case heaters within the AOA
sensor may be contributing to the unsafe condition, noting specifically
that the proposed AD does not address the case heaters within the AOA
sensors for Captain and First officer positions on FedEx's large fleet
of Boeing Model 757 and 767 airplanes. The commenter pointed out that
the case heaters keep the dampening fluid inside the body of the AOA
sensor from getting cold-soaked in flight and on the ground. The
commenter explained that the wiring of the case heater is in parallel
with the AOA vane heater, so in a scenario where the case heater fails,
the AOA sensor vane would continue working, but the AOA sensor would
become slow to move once it becomes cold-soaked due to the lack of heat
from the case heater within the AOA sensor. The commenter described
this as a critical oversight in the proposed AD because both the case
heater and the AOA vane heater must work correctly for the AOA vanes to
function properly.
The commenter stated that, in his experience, an operator may check
the resistance of the case heater wiring on both AOA sensor vanes to
verify that it is within the tolerance specified by the component
maintenance manual (CMM) and verify the wiring is not burnt due to an
open circuit. The commenter stated that this check was accomplished on
the Boeing Model 757 and 767 fleet, and, if a discrepancy was
discovered during the resistance check or revealed evidence of an open
circuit in the case heater, the AOA vane would then be replaced. The
commenter noted that a malfunction with the case heater would not be
registered by the engine-indicating and crew-alerting system (EICAS)
because the system only monitors the AOA vane heaters, and suggested
that a malfunctioning case heater could affect reactive windshear,
reduced vertical separation minimum (RVSM), and stall warning. The FAA
infers that the commenter is requesting that the FAA clarify the impact
of case heaters within the AOA sensors on the unsafe condition.
[[Page 71781]]
The FAA agrees to clarify. One of the specific mitigating design
changes in this AD is the position of the case heater. Although the
case heaters in the AOA vane assembly are not specifically mentioned in
the preamble of the proposed AD, the new AOA sensors with supplier P/N
0861FL1 (new Boeing P/N S233T913-5) have a repositioned case heater
specifically designed to mitigate the unsafe condition of moisture
build-up and freezing. AOA sensors with supplier P/N 2566A-21 (new
Boeing P/N 10-60878-3), 2566A-30 (new Boeing P/N 10-60878-4), and
0861FL (new Boeing P/N S233T913-4), mitigate the unsafe condition using
an improved vane design. The FAA has not changed the AD in this regard.
Conclusion
The FAA reviewed the relevant data, considered the comments
received, and determined that air safety and the public interest
require adopting this final rule with the changes described previously
and minor editorial changes. The FAA has determined that these minor
changes:
<bullet> Are consistent with the intent that was proposed in the
NPRM for addressing the unsafe condition; and
<bullet> Do not add any additional burden upon the public than was
already proposed in the NPRM.
The FAA also determined that these changes will not increase the
economic burden on any operator or increase the scope of this final
rule.
Related Service Information Under 1 CFR Part 51
The FAA reviewed Boeing Alert Service Bulletin 727-34A0247,
Revision 1, dated October 1, 2019; Boeing Alert Service Bulletin 757-
34A0611, Revision 1, dated March 22, 2019; and Boeing Alert Service
Bulletin 767-34A0828, dated December 6, 2018. The service information
describes procedures for a general visual inspection of the AOA sensors
for certain AOA sensors, and replacement of affected AOA sensors. These
documents are distinct since they apply to different airplane models.
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
The FAA estimates that this AD affects 1,287 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:
Estimated Costs for Required Actions
----------------------------------------------------------------------------------------------------------------
Cost on U.S.
Action Labor cost Parts cost Cost per product operators
----------------------------------------------------------------------------------------------------------------
Inspection................... 1 work-hour x $0.................... $85................... $109,395.
$85 per hour =
$85.
Replacement.................. Up to 3 work- Up to $54,000......... Up to $54,255......... Up to
hours x $85 per $69,826,185.
hour = Up to
$255.
----------------------------------------------------------------------------------------------------------------
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,
(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.
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):
2019-24-18 The Boeing Company: Amendment 39-21007; Docket No. FAA-
2019-0252; Product Identifier 2019-NM-048-AD.
(a) Effective Date
This AD is effective February 3, 2020.
(b) Affected ADs
None.
(c) Applicability
This AD applies to The Boeing Company airplanes, identified in
paragraphs (c)(1) through (3) of this AD, certificated in any
category.
(1) Model 727, 727C, 727-100, 727-100C, 727-200, and 727-200F
series airplanes, as identified in Boeing Alert Service Bulletin
727-34A0247, Revision 1, dated October 1, 2019; except for airplanes
having variable numbers QB065, QD191, QD192, QD402, QD403, QD407,
and QD410.
(2) Model 757-200, -200PF, -200CB, and -300 series airplanes, as
identified in Boeing Alert Service Bulletin 757-34A0611, Revision 1,
dated March 22, 2019.
[[Page 71782]]
(3) Model 767-200, -300, -300F, and -400ER series airplanes, as
identified in Boeing Alert Service Bulletin 767-34A0828, dated
December 6, 2018.
(d) Subject
Air Transport Association (ATA) of America Code 34, Navigation.
(e) Unsafe Condition
This AD was prompted by reports of nuisance stick shaker
activation while the airplane accelerated to cruise speed at the top
of climb. This AD was also prompted by an investigation of those
reports that revealed that the angle of attack (AOA) (also known as
angle of airflow) sensor vanes could not prevent the build-up of
ice, causing the AOA sensor vanes to become immobilized, which
resulted in nuisance stick shaker activation. The FAA is issuing
this AD to address ice build-up in the AOA sensor faceplate and
vane, which may immobilize the AOA sensor vanes, and could result in
inaccurate or unreliable AOA sensor data being transmitted to
airplane systems and consequent loss of controllability of the
airplane.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Required Actions
Except as specified in paragraph (h) of this AD: Within 36
months after the effective date of this AD or at the applicable
times specified in paragraph 1.E., ``Compliance,'' of Boeing Alert
Service Bulletin 727-34A0247, Revision 1, dated October 1, 2019;
Boeing Alert Service Bulletin 757-34A0611, Revision 1, dated March
22, 2019; or Boeing Alert Service Bulletin 767-34A0828, dated
December 6, 2018; as applicable, whichever occurs first, do all
applicable actions identified as ``RC'' (required for compliance)
in, and in accordance with, the Accomplishment Instructions of
Boeing Alert Service Bulletin 727-34A0247, Revision 1, dated October
1, 2019; Boeing Alert Service Bulletin 757-34A0611, Revision 1,
dated March 22, 2019; or Boeing Alert Service Bulletin 767-34A0828,
dated December 6, 2018; as applicable. All replacements of the
affected AOA sensors must be done before further flight.
(h) Exceptions to Service Information Specifications
(1) Where Boeing Alert Service Bulletin 727-34A0247, Revision 1,
dated October 1, 2019; Boeing Alert Service Bulletin 757-34A0611,
Revision 1, dated March 22, 2019; or Boeing Alert Service Bulletin
767-34A0828, dated December 6, 2018; as applicable, uses the phrase
``the original issue date of this service bulletin,'' this AD
requires using ``the effective date of this AD.''
(2) Where Boeing Alert Service Bulletin 727-34A0247, Revision 1,
dated October 1, 2019; Boeing Alert Service Bulletin 757-34A0611,
Revision 1, dated March 22, 2019; or Boeing Alert Service Bulletin
767-34A0828, dated December 6, 2018; specify to accomplish a general
visual inspection of the AOA sensors and to replace affected AOA
sensors, a review of the airplane maintenance records is acceptable
in lieu of those actions if the part number of the installed AOA
sensors can be conclusively determined during that review to have a
new or serviceable AOA sensor part number identified in Boeing Alert
Service Bulletin 727-34A0247, Revision 1, dated October 1, 2019;
Boeing Alert Service Bulletin 757-34A0611, Revision 1, dated March
22, 2019; or Boeing Alert Service Bulletin 767-34A0828, dated
December 6, 2018; as applicable.
(i) Credit for Previous Actions
This paragraph provides credit for actions specified in
paragraph (g) of this AD, if those actions were performed before the
effective date of this AD using Boeing Alert Service Bulletin 727-
34A0247, dated January 2, 2019.
(j) Alternative Methods of Compliance (AMOCs)
(1) The Manager, Los Angeles 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 (k) of this AD. Information may
be emailed to: <a href="/cdn-cgi/l/email-protection#90a9bdd1deddbddcd1d1d3dfbdd1dddfd3bdc2f5e1e5f5e3e4e3d0f6f1f1bef7ffe6"><span class="__cf_email__" data-cfemail="a79e8ae6e9ea8aebe6e6e4e88ae6eae8e48af5c2d6d2c2d4d3d4e7c1c6c689c0c8d1">[email protected]</span></a>.
(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, Los
Angeles 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.
(4) For service information that contains steps that are labeled
as Required for Compliance (RC), the provisions of paragraphs
(j)(4)(i) and (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.
(k) Related Information
For more information about this AD, contact Jeffrey W. Palmer,
Aerospace Engineer, Systems and Equipment Section, FAA, Los Angeles
ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137;
phone: 562-627-5351; fax: 562-627-5210; email:
<a href="/cdn-cgi/l/email-protection#f1bb949797839488dfa6dfa1909d9c9483b1979090df969e87"><span class="__cf_email__" data-cfemail="105a7576766275693e473e40717c7d7562507671713e777f66">[email protected]</span></a>.
(l) 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 727-34A0247, Revision 1, dated
October 1, 2019.
(ii) Boeing Alert Service Bulletin 757-34A0611, Revision 1,
dated March 22, 2019.
(iii) Boeing Alert Service Bulletin 767-34A0828, dated December
6, 2018.
(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 <a href="https://www.myboeingfleet.com">https://www.myboeingfleet.com</a>.
(4) You may view this service information at the FAA, Transport
Standards Branch, 2200 South 216th St., Des Moines, WA. For
information on the availability of this material at the FAA, call
206-231-3195.
(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, email <a href="/cdn-cgi/l/email-protection#caacafaeb8afade4a6afadaba68aa4abb8abe4ada5bc"><span class="__cf_email__" data-cfemail="e98f8c8d9b8c8ec7858c8e8885a987889b88c78e869f">[email protected]</span></a>, or go to: <a href="https://www.archives.gov/federal-register/cfr/ibr-locations.html">https://www.archives.gov/federal-register/cfr/ibr-locations.html</a>.
Issued in Des Moines, Washington, on December 9, 2019.
Michael Kaszycki,
Acting Director, System Oversight Division, Aircraft Certification
Service.
[FR Doc. 2019-27887 Filed 12-27-19; 8:45 am]
BILLING CODE 4910-13-P
Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
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