DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0830; Project Identifier AD-2020-00257-R]
Airworthiness Directives; Bell Textron Canada Limited Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: The FAA proposes to adopt a new airworthiness directive
for Bell Textron Canada Limited Model 206L-1, 206L-3, and 206L-4
helicopters with certain Air Comm Corporation (Air Comm) air
conditioning systems installed. This proposed AD would require 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 proposed AD would also require reinstalling certain
parts, applying torque, and aligning certain bolt holes. This proposed
AD was prompted by reports of damage to the drive ring spline teeth and
the mating spline teeth. The actions of this proposed AD are intended
to address an unsafe condition on these products.
DATES: The FAA must receive comments on this proposed AD by November
ADDRESSES: You may send comments by any of the following methods:
Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow
online instructions for sending your comments electronically.
Fax: (202) 493-2251.
Mail: Send comments to the U.S. Department of
Transportation, Docket Operations, M-30, West Building Ground Floor,
Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590-0001.
Hand Delivery: Deliver to Mail address between 9 a.m. and
5 p.m., Monday through Friday, except Federal holidays.
For service information identified in this proposed 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
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-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 NPRM, any referenced service information, any comments received,
and other information. The street address for Docket Operations is
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.
The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include "Docket No. FAA-2021-0830; Project Identifier
AD-2020-00257-R" at the beginning of your comments. The most helpful
comments reference a specific portion of the proposal, explain the
reason for any recommended change, and include supporting data. The FAA
will consider all comments received by the closing date and may amend
this proposal because of those comments.
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 agency will also post a report summarizing each
substantive verbal contact received about this NPRM.
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
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. Any commentary that the FAA receives
which is not specifically designated as CBI will be placed in the
public docket for this rulemaking.
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'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 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. Accordingly, the FAA proposes to adopt a new AD for
certain 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 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
206L-3+ designation are Model 206L-3 helicopters.
The FAA is issuing this NPRM after determining that the unsafe
condition described previously is likely to exist or develop on other
products of the same type design.
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.
Proposed AD Requirements in This NPRM
This proposed AD would 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. This proposed AD would also require reinstalling
certain parts, and if required, reinstalling the drive pulley by
torqueing and aligning the drive pulley bolt holes.
Differences Between This Proposed 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 proposed AD
would not. SB 206EC-091119 Rev B requires reporting any deformation or
fretting to Air Comm Service Department, whereas this proposed AD would
not. SB 206EC-091119 Rev B provides an option to deactivate the air
conditioning system if deformation of fretting is found on the drive
ring or the oil cooler blower shaft assembly, whereas this proposed AD
would require removing these parts from service instead.
Costs of Compliance
The FAA estimates that this proposed AD would affect up to 100
helicopters of U.S. Registry. The FAA estimates that operators may
incur the following costs in order to comply with this proposed AD.
Labor costs are estimated at $85 per work-hour.
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 would 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 would take about 3 work-hours and parts
would cost about $300 for an estimated cost of $555 per replacement.
Replacing the oil cooler blower assembly would take about 3 work-
hours and parts would cost about $2,720 for an estimated cost of $2,975
Aligning each bolt hole and re-torqueing the drive pulley would
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.
The FAA 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, I certify this proposed regulation:
1. Is not a "significant regulatory action" under Executive Order
2. Would not affect intrastate aviation in Alaska, and
3. Would 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
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
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