DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0830; Project Identifier AD-2020-00257-R;
Amendment 39-21836; AD 2021-24-15]
RIN 2120-AA64

Airworthiness Directives; Bell Textron Canada Limited 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
Bell Textron Canada Limited Model 206L-1, 206L-3, and 206L-4
helicopters with certain Air Comm Corporation air conditioning systems
installed. This AD was prompted by reports of damage to the drive ring
spline teeth and the mating spline teeth. This AD requires visually
inspecting the drive ring spline teeth and the mating area spline teeth
on the oil cooler blower shaft for signs of deformation and fretting
and depending on the results of the inspection, removing certain parts
from service. This AD also requires reinstalling certain parts,
applying torque, and aligning certain bolt holes. The FAA is issuing
this AD to address the unsafe condition on these products.

DATES: This AD is effective January 18, 2022.
The Director of the Federal Register approved the incorporation by
reference of a certain document listed in this AD as of January 18,
2022.

ADDRESSES: For service information identified in this final rule,
contact Air Comm Corporation, 1575 Westminster, CO 80234; telephone
(303) 440-4075; or at https://www.aircommcorp.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. It is also available at https://www.
regulations.gov by searching for and locating Docket No. FAA-2021-0830.

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0830; 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, any
referenced service information, 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: Matthew Bryant, Aerospace Engineer,
Denver ACO Branch, FAA, 26805 East 68th Avenue, Denver, CO 80249;
telephone (303) 342-1080; email 9-Denver-Aircraft-Cert@faa.gov.

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 Bell Textron Canada
Limited Model 206L-1, Model 206L-3, and Model 206L-4 helicopters with
certain Air Comm Corporation air conditioning systems installed. The
NPRM published in the Federal Register on September 24, 2021 (86 FR
53015). In the NPRM, the FAA proposed to require within 300 hours time-
in-service (TIS), and thereafter at intervals not to exceed 300 hours
TIS, gaining access to the drive ring spline teeth and the mating area
spline teeth on the oil cooler blower shaft, repetitively inspecting
the drive ring spline teeth and the mating spline teeth on the tail
rotor drive's oil cooler blower shaft for deformation and fretting, and
depending on the results of each inspection, removing certain parts
from service before further flight. The NPRM also proposed to require
reinstalling certain parts, and if required, reinstalling the drive
pulley by torqueing and aligning the drive pulley bolt holes.
The FAA issued Special Airworthiness Information Bulletin SW-19-05
on April 4, 2019 (SAIB SW-19-05), to alert owners and operators of Bell
Textron Canada Limited Model 206L-1, 206L-3, and 206L-4 helicopters
with Air Comm Corporation's Supplemental Type Certificate (STC)
SH2750NM installed. SAIB SW-19-05 was prompted by reports of the air
conditioner pulley's locking system, which is installed on the oil
cooler drive shaft's splined quill, causing excessive spline tooth wear
to the drive ring spline teeth and the mating spline teeth on the oil
cooler blower shaft. SAIB SW-19-05 recommends following the inspection
instructions of certain Air Comm Corporation service information and
routinely inspecting the air conditioner pulley lock ring.
At the time SAIB SW-19-05 was issued, the airworthiness concern was
not determined to be an unsafe condition that would warrant AD action
under 14 CFR part 39. However, subsequent investigations were not able
to determine whether the limited damaged observed on several oil cooler
blower shafts would remain localized or progress to a point where the
shaft is no longer safe for continued use. The FAA also later
determined that operators may have difficulty aligning the air
conditioning system's drive ring holes with the air conditioning
condenser drive pulley without leaving the condenser drive pulley
under-torqued. This condition, if not addressed, could result in a
failure of the oil cooler blower shaft, which could lead to loss of
tail rotor authority and subsequent loss of helicopter control.
Accordingly, the FAA is issuing this AD for Bell Textron Canada
Limited Model 206L-1 and 206L-3 helicopters with Bell Model 206L1/L3
Service Instruction for Increased Gross Weight Upgrade Kit BHT-206-SI-
2052, Revision 1, dated October 14, 2010, installed and Bell Model
206L-4 helicopters equipped with one of the following Air Comm
Corporation STC SH2750NM air conditioning systems part number; 206EC-
204-1, 206EC-204-2, 206EC-208-1, 206EC-208-2, 206EC-210-1, 206EC-210-2,
206EC-210-3, 206EC-212-3 or 206EC-212-4. Helicopters with a 206L-1+
designation are Model 206L-1 helicopters and helicopters with a 206L-3+
designation are Model 206L-3 helicopters.

Discussion of Final Airworthiness Directive

Comments

The FAA received no comments on the NPRM or on the determination of
the costs.

Conclusion

The FAA reviewed the relevant data and determined that air safety
requires adopting this AD as proposed except for minor editorial
changes. Accordingly, the FAA is issuing this AD to address the unsafe
condition on these helicopters.

Related Service Information Under 1 CFR Part 51

The FAA reviewed ACC Air Comm Corporation Service Bulletin SB
206EC-091119, Rev B, dated May 26, 2021 (SB 206EC-091119 Rev B), which
specifies procedures for visually inspecting the drive ring spline
teeth and the mating spline teeth on the tail rotor drive's oil cooler
blower shaft for deformation or fretting.
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.

Differences Between This AD and the Service Bulletin

SB 206EC-091119 Rev B requires inspecting the air conditioning
compressor drive belt tension and the general condition of the drive
belt, drive pulley, and surrounding components, whereas this AD does
not. SB 206EC-091119 Rev B requires reporting any deformation or
fretting to Air Comm Corporation Service Department, whereas this AD
does not. SB 206EC-091119 Rev B provides an option to deactivate the
air conditioning system if deformation or fretting is found on the
drive ring or the oil cooler blower shaft assembly, whereas this AD
requires removing these parts from service instead.

Costs of Compliance

The FAA estimates that this AD affects up to 100 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.
Removing the tail rotor drive system's forward short shaft, spline
adaptor, and drive ring and visually inspecting the drive ring spline
teeth and the mating area spline teeth take about 1 work-hour for an
estimated cost of $85 per helicopter and $8,500 for the U.S. fleet per
inspection cycle.
Replacing the drive ring takes about 3 work-hours and parts cost
about $300 for an estimated cost of $555 per replacement.
Replacing the oil cooler blower assembly takes about 3 work-hours
and parts cost about $2,720 for an estimated cost of $2,975 per
replacement.
Aligning each bolt hole and re-torqueing the drive pulley take
about 0.5 work-hours for an estimated cost of $43 per helicopter.

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.

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

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]

2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive: