Airworthiness Directives; CFM International, S.A. Turbofan Engines
| Citation | 85 FR 3871 |
| Record Number | 2020-01158 |
| Published date | 23 January 2020 |
| Court | Federal Aviation Administration |
Federal Register, Volume 85 Issue 15 (Thursday, January 23, 2020)
[Federal Register Volume 85, Number 15 (Thursday, January 23, 2020)]
[Proposed Rules]
[Pages 3871-3874]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-01158]
[[Page 3871]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2019-1093; Product Identifier AD-2019-00144-E]
RIN 2120-AA64
Airworthiness Directives; CFM International, S.A. Turbofan
Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for all CFM International S.A. (CFM) LEAP-1B21, -1B23, -1B25, -1B27, -
1B28, -1B28B1, -1B28B2, -1B28B2C, -1B28B3, -1B28BBJ1, and -1B28BBJ2
model turbofan engines. This proposed AD was prompted by reports of two
new unsafe conditions and the need to supersede corrective actions for
two previously addressed unsafe conditions. The FAA proposes to
supersede AD 2018-25-09 and AD 2019-12-01, which apply to the affected
LEAP-1B model turbofan engines. Since the FAA issued the ADs, the FAA
received information and analysis indicating that supersedure of these
ADs is warranted.
DATES: The FAA must receive comments on this proposed AD by February
12, 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 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.
For service information identified in this NPRM, contact CFM
International Inc., Aviation Operations Center, 1 Neumann Way, M/D Room
285, Cincinnati, OH 45125; phone: 877-432-3272; fax: 877-432-3329;
email: [email protected]. You may view this service
information at the FAA, Engine and Propeller Standards Branch, 1200
District Avenue, Burlington, MA 01803. For information on the
availability of this material at the FAA, call 781-238-7759. It is also
available on the internet at https://www.regulations.gov by searching
for and locating Docket No. FAA-2019-1093.
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-2019-
1093; 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, 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 McGuire, Aerospace
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803;
phone: 781-238-7120; fax: 781-238-7199; email: [email protected].
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include ``Docket No. FAA-2019-1093;
Product Identifier AD-2019-00144-E'' at the beginning of your comments.
The FAA specifically invites comments on the overall regulatory,
economic, environmental, and energy aspects of this NPRM. The FAA will
consider all comments received by the closing date and may amend this
NPRM because of those comments.
The FAA understands that CFM has communicated with affected
operators regarding the proposed corrective actions for these unsafe
conditions. As a result, affected operators are already aware of the
proposed corrective actions and in some cases, have already begun
implementation. Therefore, the FAA has determined that a 20-day comment
period is appropriate given the particular circumstances related to the
proposed corrections of these unsafe conditions on the CFM LEAP-1B
model turbofan engines.
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
https://www.regulations.gov, including any personal information you
provide. The FAA will also post a report summarizing each substantive
verbal contact received about this proposed AD.
Confidential Business Information
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 Christopher McGuire, Aerospace Engineer, ECO
Branch, FAA, 1200 District Avenue, Burlington, MA 01803. 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 reports of two new unsafe conditions affecting
CFM LEAP-1B model turbofan engines: (1) Increased fuel flow through
certain fuel nozzles due to fuel nozzle coking, potentially causing
distress to the static structures of the high-pressure turbine (HPT)
and in-flight shutdown (IFSD) of one or more engines; and (2) the
potential for undetected subsurface anomalies formed during the
manufacturing process that could result in uncontained failure of the
HPT stage 2 disk. To address the newly identified unsafe conditions,
the FAA is proposing this AD.
Further, the FAA received additional information related to the
unsafe conditions addressed by AD 2018-25-09 and AD 2019-12-01
regarding: (1) Icing in the pressure sensor lines, potentially causing
inaccurate pressure sensor readings and loss of thrust control; and (2)
inadequate oil flow to the radial drive shaft (RDS) bearing, which can
cause failure of the bearing and IFSD of one or more engines.
Thus, this AD would also supersede the two previously issued ADs
addressing icing in the pressure sensor lines and inadequate oil flow
to the RDS bearing.
[[Page 3872]]
Unsafe Conditions--Fuel Nozzle Coking and Subsurface Material Anomalies
The FAA has received reports of unsafe conditions on the CFM LEAP-
1B model turbofan engine related to fuel nozzle coking and to
subsurface anomalies that can be present in the HPT stage 2 disk. The
FAA has not previously issued an AD on these unsafe conditions on the
CFM LEAP-1B model turbofan engine.
Fuel Nozzle Coking
Two LEAP-1B model turbofan engines have experienced fuel nozzle
coking which led to distress of HPT static structures. On one of these
engines, fuel nozzle coking and subsequent HPT static structure
distress led to turbine center frame (TCF) burn-through, and an engine
IFSD while the aircraft was engaged in a ferry flight. Fuel nozzle
coking can lead to failure of the HPT static structures, TCF case burn-
through, and in-flight shutdown of one or more engines, loss of thrust
control, and damage to the airplane.
Subsurface Material Anomalies
During a broad investigation by CFM into melt-related material
anomalies, a subsurface anomaly was found in a part manufactured from
the same material as the LEAP-1B HPT stage 2 disk. This type of
subsurface anomaly has the potential to cause failure of the LEAP-1B
HPT stage 2 disk. CFM introduced enhanced inspections to prevent
failure of the HPT stage 2 disk which can lead to uncontained engine
failure, loss of thrust control, and damage to the airplane.
The FAA reviewed CFM's assessment of the unsafe conditions and the
proposed corrective actions and agrees with its conclusions. Updating
the Airworthiness Limitations Section (ALS) of the Engine Shop Manual
and the continuous airworthiness maintenance program for the affected
LEAP-1B model turbofan engines would be the most effective way to
address these unsafe conditions pertaining to fuel nozzle coking and
subsurface material anomalies. These ALS updates would require a one-
time inspection of the HPT stage 2 disk for subsurface anomalies and
engine condition monitoring or repetitive inspections of the HPT static
structures for fuel nozzle coking.
ADs Being Superseded: AD 2018-25-09 and AD 2019-12-01
The FAA is proposing to supersede AD 2018-25-09 and AD 2019-12-01.
The FAA issued AD 2018-25-09, Amendment 39-19520 (83 FR 63559, December
11, 2018), (``AD 2018-25-09''), for all CFM LEAP-1B21, -1B23, -1B25, -
1B27, -1B28, -1B28B1, -1B28B2, -1B28B2C, -1B28B3, -1B28BBJ1, and -
1B28BBJ2 turbofan engines. The FAA issued AD 2019-12-01, Amendment 39-
19656 (84 FR 28202, June 18, 2019), (``AD 2019-12-01''), for certain
CFM LEAP-1B21, -1B23, -1B25, -1B27, -1B28, -1B28B1, -1B28B2, -1B28B3,-
1B28B2C, -1B28BBJ1, and -1B28BBJ2 model turbofan engines.
AD 2018-25-09--Icing in Pressure Sensor Lines
The FAA issued AD 2018-25-09 to prevent icing in the pressure
sensor lines and inaccurate pressure sensor readings that could result
in failure of one or more engines, loss of thrust control, and loss of
the airplane. AD 2018-25-09 required removing certain electronic engine
control (EEC) systems operation (OPS) and engine health monitoring
(EHM) software and installing versions eligible for installation. AD
2018-25-09 resulted from six aborted takeoffs on the similarly-designed
CFM LEAP-1A model turbofan engine after those engines did not advance
to the desired takeoff fan speed due to icing in the pressure sensor
line.
Since the FAA issued AD 2018-25-09, the FAA received reports of two
temporary loss of thrust control events caused by icing in the pressure
sensor lines. Both events occurred on affected CFM turbofan engines
with the EEC OPS and EHM software installed per AD 2018-25-09. After
further investigation, the operators found water and ice in the
pressure sensor lines, which prevented the pressure sensor from
accurately measuring the pressure. As a result, the previous CFM EEC
OPS and EHM software update mandated by AD 2018-25-09 would be further
modified by this AD to detect and accommodate a frozen pressure sensor
and to prevent loss of thrust control from occurring.
AD 2019-12-01--RDS Bearing Failure
The FAA issued AD 2019-12-01 to prevent failure of the RDS bearing,
which could result in failure of one or more engines, loss of thrust
control, and loss of the airplane. AD 2019-12-01 required initial and
repetitive inspections of the TGB scavenge screens and, depending on
the results of the inspection, possible removal of the engine from
service. AD 2019-12-01 resulted from multiple reports of IFSDs due to
RDS bearing failure.
Since the FAA issued AD 2019-12-01, further investigation by CFM
identified an additional contributing factor to the cause of the RDS
failures. Insufficient oil supply to the radial shaft bearing and rivet
fatigue of the cage assembly are the primary contributing factors to
these bearing failures. The inspections that would be mandated by this
proposed update to the ALS have a time-based limit and include in-
service limits for the affected bearings. Even though the ALS changes
would be applicable to all LEAP-1B engines, the requirements in the ALS
for the RDS inspections would apply only to the engines affected by AD
2019-12-01.
Related Service Information Under 1 CFR Part 51
The FAA reviewed ALS data module, CFM LEAP-1B-05-21-03-01A-281B-C,
Issue 002, dated January 9, 2020; and ALS data module, CFM LEAP-1B-05-
29-00-01A-281B-C, Issue 001, dated January 9, 2020. CFM LEAP-1B-05-21-
03-01A-281B-C describes procedures for an ultrasonic inspection of the
HPT stage 2 disk. CFM LEAP-1B-05-29-00-01A-281B-C, describes procedures
for inspection of the RDS bearing; monitoring and inspections of the
fuel nozzle; and the required version of EEC system software. 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.
FAA's Determination
The FAA is proposing this AD because the agency evaluated all the
relevant information and determined the unsafe conditions described
previously are likely to exist or develop in other products of the same
type design.
Proposed AD Requirements
This proposed AD would require revising the ALS of the applicable
CFM LEAP-1B Engine Shop Manual and the operator's approved continuous
airworthiness maintenance program.
Costs of Compliance
The FAA estimates that this proposed AD affects 162 engines
installed on airplanes of U.S. registry.
The FAA estimates the following costs to comply with this proposed
AD:
[[Page 3873]]
Estimated Costs
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Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Update ALS......................... 4 work-hours x $85 per hour $0 $340 $55,080
= $340.
TGB Screen Inspection.............. 1 work-hour x $85 per hour 0 85 13,770
= $85.
HPT stage 2 Disk Inspection........ 6 work-hours x $85 per hour 0 510 82,620
= $510.
Fuel Nozzle Inspection............. 6 work-hours x $85 per hour 0 510 82,620
= $510.
Pressure Sub-system Software 0.5 work-hours x $85 per 0 42.50 6,885
Upgrade. hour = $42.50.
RDS Borescope Inspection........... 2 work-hours x $85 per hour 0 170 27,540
= $170.
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The FAA estimates the following costs to do any necessary
replacements that would be required based on the results of the
inspection. The FAA has no way of determining the number of aircraft
that might need these replacements:
On-Condition Costs
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Cost per
Action Labor cost Parts cost product
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RDS Replacement............................ 200 work-hours x $85 per hour = $30,500 $47,500
$17,000.
HPT stage 2 Disk Replacement............... 1 work-hour x $85 per hour = $85... 225,000 225,085
Replace Set of Fuel Nozzles................ 40 work-hours x $85 per hour = 120,000 123,400
$3,400.
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Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, Section 106, describes the
authority of the FAA Administrator. Subtitle VII, Aviation Programs,
describes in more detail the scope of the Agency's authority.
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 engines, propellers, and
associated appliances to the Manager, Engine and Propeller Standards
Branch, Policy and Innovation Division.
Regulatory Findings
The FAA has 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 that the 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:
0
a. Removing airworthiness directive (AD) 2018-25-09, Amendment 39-19520
(83 FR 63559, December 11, 2018), and AD 2019-12-01, Amendment 39-19656
(84 FR 28202, June 18, 2019); and
0
b. Adding the following new AD:
CFM International S.A.: Docket No. FAA-2019-1093; Product Identifier
AD-2019-00144-E.
(a) Comments Due Date
The FAA must receive comments on this AD action by February 12,
2020.
(b) Affected ADs
This AD replaces AD 2018-25-09, Amendment 39-19520 (83 FR 63559,
December 11, 2018), and AD 2019-12-01, Amendment 39-19656 (84 FR
28202, June 18, 2019).
(c) Applicability
This AD applies to all CFM International S.A. (CFM) LEAP-1B21, -
1B23, -1B25, -1B27, -1B28, -1B28B1, -1B28B2, -1B28B3, -1B28B2C, -
1B28BBJ1, and -1B28BBJ2 model turbofan engines.
(d) Subject
Joint Aircraft System Component (JASC) Code, 7200 (Turbine/
Turboprop).
(e) Unsafe Condition
(1) This AD was prompted by multiple reports of engine in-flight
shutdowns (IFSDs) and defects in the related applicable systems and
one report of a melt-related defect of the high-pressure turbine
(HPT) stage 2 disk material. The FAA is issuing this AD to prevent:
(i) Increased fuel flow through certain fuel nozzles leading to
distress of the HPT static structures and IFSD of one or more
engines;
(ii) undetected subsurface anomalies formed during the
manufacturing process that could lead to uncontained HPT disk
failure;
(iii) icing in the pressure sensor lines, inaccurate pressure
sensor readings and loss of thrust control; and
[[Page 3874]]
(iv) inadequate oil flow to the radial drive shaft (RDS)
bearing, failure of the bearing, and IFSD of one or more engines.
(2) These unsafe conditions, if not addressed, could result in
IFSD or failure of one or more engines, loss of thrust control and
loss of the airplane.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Required Actions
Within 15 days after the effective date of this AD, revise the
Airworthiness Limitations Section (ALS) of the applicable CFM LEAP-
1B Engine Shop Manual and the operator's existing approved
continuous airworthiness maintenance program by inserting the
following changes:
(1) Paragraph 6.B.(2) of the CFM Engine Shop Manual (ESM) Data
Module LEAP-1B-05-21-03-01A-281B-C, Issue 002, dated January 9,
2020; and
(2) paragraphs 6.B.(1), 6.B.(2), and 6.C.(1) of the CFM ESM Data
Module LEAP-1B-05-29-00-01A-281B-C, Issue 001, dated January 9,
2020.
(h) No Alternative Procedures or Intervals
After the revisions required by paragraph (g) of this AD have
been made, no alternative inspections, procedures, or intervals may
be used unless approved as an alternative method of compliance in
accordance with the procedures specified in paragraph (i) of this
AD.
(i) Alternative Methods of Compliance (AMOCs)
(1) The Manager, ECO 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)(1) of this AD. You may email your
request to: [email protected].
(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.
(j) Related Information
(1) For more information about this AD, contact Christopher
McGuire, Aerospace Engineer, ECO Branch, FAA, 1200 District Avenue,
Burlington, MA 01803; phone: 781-238-7120; fax: 781-238-7199; email:
[email protected].
(2) For service information identified in this AD, contact CFM
International Inc., Aviation Operations Center, 1 Neumann Way, M/D
Room 285, Cincinnati, OH 45125; phone: 877-432-3272; fax: 877-432-
3329; email: [email protected]. You may view this
referenced service information at the FAA, Engine & Propeller
Standards Branch, 1200 District Avenue, Burlington, MA 01803. For
information on the availability of this material at the FAA, call
781-238-7759.
Issued in Burlington, Massachusetts, on January 15, 2020.
Robert J. Ganley,
Manager, Engine & Propeller Standards Branch, Aircraft Certification
Service.
[FR Doc. 2020-01158 Filed 1-21-20; 11:15 am]
BILLING CODE 4910-13-P
