Document ID: FAA-2021-0460-0004
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Airbus Helicopters
Posted Date: 2021-10-18T04:00Z

[Federal Register Volume 86, Number 198 (Monday, October 18, 2021)]
[Rules and Regulations]
[Pages 57569-57571]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-22466]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0460; Project Identifier MCAI-2020-01620-R; 
Amendment 39-21744; AD 2021-20-06]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
Airbus Helicopters Model AS355E, AS355F, AS355F1, and AS355F2 
helicopters. This AD was prompted by multiple fatigue cracks in power 
turbine (PT) 3rd stage wheels. This AD requires revising the existing 
Rotorcraft Flight Manual (RFM) for your helicopter and installing a 
placard. The FAA is issuing this AD to address the unsafe condition on 
these products.

DATES: This AD is effective November 22, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of a certain documents listed in this AD as of November 22, 
2021.

ADDRESSES: For Airbus Helicopters service information identified in 
this final rule, contact Airbus Helicopters, 2701 North Forum Drive, 
Grand Prairie, TX 75052; telephone (972) 641-0000 or (800) 232-0323; 
fax (972) 641-3775; or at https://www.airbus.com/helicopters/services/technical-support.html. For Rolls-Royce service information identified 
in this final rule, contact Rolls-Royce Corporation, 450 South Meridian 
Street, Mail Code NB-01-06, Indianapolis, IN 46225; telephone (317) 
230-1667; email: royce.com">[email protected]royce.com; or at royce.com">https://www.rolls-royce.com. You may view the referenced service information at the FAA, 
Office of the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., 
Room 6N-321, Fort Worth, TX 76177. For information on the availability 
of this material at the FAA, call (817) 222-5110. Service information 
that is incorporated by reference is also available at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-
0460.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0460; or in person at 
Docket

[[Page 57570]]

Operations between 9 a.m. and 5 p.m., Monday through Friday, except 
Federal holidays. The AD docket contains this final rule, the European 
Union Aviation Safety Agency (EASA) AD, any comments received, and 
other information. The street 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: Michael Hughlett, Aerospace Engineer, 
General Aviation & Rotorcraft Section, International Validation Branch, 
FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone (817) 222-
5110; email [email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to Airbus Helicopters 
Model AS355E, AS355F, AS355F1, and AS355F2 helicopters with a Rolls-
Royce Corporation (formerly Allison) engine Model 250-C20F installed. 
The NPRM published in the Federal Register on June 11, 2021 (86 FR 
31194). In the NPRM, the FAA proposed to require revising the existing 
RFM for your helicopter to replace a note with a caution to not allow 
rotor speed to stagnate between 279 and 374 revolutions per minute 
(RPM). The NPRM also proposed to require installing a placard to avoid 
71-95% N2 steady-state speed (avoid operation at 279-374 RPM). The 
owner/operator (pilot) may revise the existing RFM for your helicopter 
and the owner/operator must enter compliance with the applicable 
paragraphs of the AD into the aircraft records in accordance with 14 
CFR 43.9(a)(1) through (4) and 14 CFR 91.417(a)(2)(v). This is an 
exception to the FAA's standard maintenance regulations.
    The NPRM was prompted by EASA AD 2020-0266, dated December 8, 2020 
(EASA AD 2020-0266), issued by EASA, which is the Technical Agent for 
the Member States of the European Union, to correct an unsafe condition 
for Airbus Helicopters (AH), formerly Eurocopter, Eurocopter France, 
Aerospatiale Model AS 355 E, AS 355 F, AS 355 F1, and AS 355 F2 
helicopters, all serial numbers, if equipped with Rolls-Royce 
Corporation (formerly Allison) (RRC) engine Model 250-C20F. EASA 
advises of multiple fatigue cracks in PT 3rd stage wheels. 
Investigation has revealed that crack initiation at the hub trailing 
edge could occur in low-cycle fatigue and progress in high-cycle 
fatigue up to separation of the blade. According to EASA, RRC has 
determined that detrimental vibrations could occur within a particular 
range of turbine speeds, below the normal operating range of this 
helicopter, which are a potential contributing factor to these 
failures. This condition, if not addressed, could result in fatigue 
failure of a PT 3rd stage wheel, and subsequent loss of engine power, 
release of debris and damage to the helicopter, and loss of control of 
the helicopter.
    Accordingly, EASA AD 2020-0266 requires revising the Normal 
Procedures Section of the applicable RFM or RFM supplement, informing 
flight crews, and installing a placard in full view of both pilots.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from one commenter, Airbus Helicopters, 
who asked why the Special Flight Permits paragraph specifies a 
different Nr range (71-88%) from the avoidance rate of 71-95% described 
in a previous paragraph. The FAA has determined that the difference was 
in error and has corrected the avoidance rate in the Special Flights 
Permits paragraph of this AD. The correct avoidance rate is between 71-
95% N2.

Conclusion

    These helicopters have been approved by EASA and are approved for 
operation in the United States. Pursuant to the FAA's bilateral 
agreement with the European Union, EASA has notified the FAA about the 
unsafe condition described in its AD. The FAA reviewed the relevant 
data, considered the comments received, and determined that air safety 
requires adopting this AD as proposed. Accordingly, the FAA is issuing 
this AD to address the unsafe condition on these helicopters. Except 
for the correction to the avoidance rate specified in the Special 
Flight Permits paragraph, this AD is adopted as proposed in the NPRM. 
This change will not increase the economic burden on any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Airbus Helicopters Alert Service Bulletin No. 
AS355-71.00.21, Revision 1, dated November 10, 2020. This service 
information specifies replacing a note with a caution in the Flight 
Manual to not allow rotor speed to stagnate between 279 and 374 RPM 
during engine acceleration. This service information also specifies 
procedures for making and installing a label (placard) for the pilot 
and co-pilot to avoid 71-95% N2 steady-state speed (avoid operation at 
279-374 RPM).
    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.

Other Related Service Information

    The FAA also reviewed Rolls-Royce Alert Commercial Engine Bulletin 
A-1400, Revision 7, dated January 10, 2019. This service information 
specifies the speed avoidance range and operating procedures depending 
on the PT wheel part number installed.

Differences Between This AD and the EASA AD

    EASA AD 2020-0266 requires compliance within 50 flight hours or 30 
days, whichever occurs first after the effective date of its AD, 
whereas this AD requires compliance within 50 hours time-in-service 
after the effective date of this AD instead.

Costs of Compliance

    The FAA estimates that this AD affects 29 helicopters of U.S. 
Registry. Labor rates are estimated at $85 per work-hour. Based on 
these numbers, the FAA estimates the following costs to comply with 
this AD.
    Revising the existing RFM for your helicopter will take about 0.25 
work-hour for an estimated cost of $21 per helicopter and $609 for the 
U.S. fleet. Installing a placard will take about 0.25 work-hour and 
parts cost are a nominal amount, for an estimated cost of $21 per 
helicopter and $609 for the U.S. fleet.

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 helicopters identified in this rulemaking action.

[[Page 57571]]

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.

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:

2021-20-06 Airbus Helicopters: Amendment 39-21744; Docket No. FAA-
2021-0460; Project Identifier MCAI-2020-01620-R.

(a) Effective Date

    This airworthiness directive (AD) is effective November 22, 
2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Airbus Helicopters Model AS355E, AS355F, 
AS355F1, and AS355F2 helicopters, certificated in any category, with 
a Rolls-Royce Corporation (formerly Allison) engine Model 250-C20F 
installed.

(d) Subject

    Joint Aircraft Service Component (JASC) Code: 7250, Turbine 
section.

(e) Unsafe Condition

    This AD was prompted by multiple fatigue cracks in power turbine 
(PT) 3rd stage wheels. The FAA is issuing this AD to prevent fatigue 
failure of a PT 3rd stage wheel. The unsafe condition, if not 
addressed, could result in loss of engine power, release of debris 
and damage to the helicopter, and loss of control of the helicopter.

(f) Compliance

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

(g) Required Actions

    Within 50 hours time-in-service after the effective date of this 
AD:
    (1) Revise the existing Rotorcraft Flight Manual (RFM) for your 
helicopter by inserting the page applicable to your helicopter model 
and version from Appendix 4.A. through D., of Airbus Helicopters 
Alert Service Bulletin No. AS355-71.00.21, Revision 1, dated 
November 10, 2020 (ASB AS355-71.00.21 Rev 1). Inserting a different 
document with information identical to that in Appendix 4.A. through 
D., of ASB AS355-71.00.21 Rev 1, as applicable to your helicopter 
model and version, is acceptable for compliance with the requirement 
of this paragraph. The action required by this paragraph may be 
performed by the owner/operator (pilot) holding at least a private 
pilot certificate and must be entered into the aircraft records 
showing compliance with this AD in accordance with Sec.  43.9(a)(1) 
through (4) and Sec.  91.417(a)(2)(v). The record must be maintained 
as required by Sec.  91.417, Sec.  121.380, or Sec.  135.439.
    (2) Install a placard in full view of the pilot and co-pilot by 
following the Accomplishment Instructions, paragraph 3.B., of ASB 
AS355-71.00.21 Rev 1.

    Note 1 to paragraph (g)(2): Airbus Helicopters service 
information refers to a placard as a label.

(h) Special Flight Permits

    Special flight permits are permitted so long as continuous 
engine operation between 71 and 95% N2 is avoided.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, International Validation 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 International Validation Branch, send 
it to the attention of the person identified in paragraph (j)(1) of 
this AD. Information may be emailed 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 Michael 
Hughlett, Aerospace Engineer, General Aviation & Rotorcraft Section, 
International Validation Branch, FAA, 10101 Hillwood Pkwy., Fort 
Worth, TX 76177; telephone (817) 222-5110; email 
[email protected].
    (2) The subject of this AD is addressed in European Union 
Aviation Safety Agency (EASA) AD 2020-0266, dated December 8, 2020. 
You may view the EASA AD on the internet at https://www.regulations.gov in Docket No. FAA-2021-0460.

(k) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference 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) Airbus Helicopters Alert Service Bulletin No. AS355-
71.00.21, Revision 1, dated November 10, 2020.
    (ii) [Reserved]
    (3) For service information identified in this AD, contact 
Airbus Helicopters, 2701 North Forum Drive, Grand Prairie, TX 75052; 
telephone (972) 641-0000 or (800) 232-0323; fax (972) 641-3775; or 
at https://www.airbus.com/helicopters/services/technical-support.html.
    (4) You may view this service information at the FAA, Office of 
the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 
6N-321, Fort Worth, TX 76177. For information on the availability of 
this material at the FAA, call (817) 222-5110.
    (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: [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on September 15, 2021.
Ross Landes,
Deputy Director for Regulatory Operations, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2021-22466 Filed 10-15-21; 8:45 am]
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