Document ID: FAA-2021-0185-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: Bell Textron Canada Limited (Type Certificate Previously Held by Bell Helicopter Textron Canada Limited) Helicopters
Posted Date: 2021-03-22T04:00Z

[Federal Register Volume 86, Number 53 (Monday, March 22, 2021)]
[Proposed Rules]
[Pages 15146-15149]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-05433]

[[Page 15146]]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0185; Project Identifier MCAI-2020-00265-R]
RIN 2120-AA64

Airworthiness Directives; Bell Textron Canada Limited (Type 
Certificate Previously Held by Bell Helicopter 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 (AD) 
for Bell Textron Canada Limited (type certificate previously held by 
Bell Helicopter Textron Canada Limited) (Bell) Model 505 helicopters. 
This proposed AD was prompted by the discovery of a gap between the 
transmission restraint assembly aft attachment hardware lower washer 
and mating airframe truss assembly (truss assembly) clevis lower lug. 
This proposed AD would require inspecting the transmission restraint 
aft attachment hardware installation for a gap and corrective action 
depending on the inspection results. The FAA is proposing this AD to 
address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by May 6, 
2021.

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 https://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 between 9 a.m. and 
5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this NPRM, contact Bell 
Textron Canada Limited, 12,800 Rue de l'Avenir, Mirabel, Quebec J7J1R4; 
telephone (450) 437-2862 or (800) 363-8023; fax (450) 433-0272; or at 
https://www.bellcustomer.com. You may view this 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.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0185; 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 
Transport Canada AD, any comments received, and other information. The 
street address for Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Matt Fuller, AD Program Manager, 
General Aviation & Rotorcraft Unit, Airworthiness Products Section, 
Operational Safety Branch, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 
76177; telephone (817) 222-5110; email matthew.fuller@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    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-2021-0185; Project Identifier 
MCAI-2020-00265-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 Matt 
Fuller, AD Program Manager, General Aviation & Rotorcraft Unit, 
Airworthiness Products Section, Operational Safety Branch, FAA, 10101 
Hillwood Pkwy., Fort Worth, TX 76177; telephone (817) 222-5110; email 
matthew.fuller@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.

Background

    Transport Canada, which is the aviation authority for Canada, has 
issued Canadian AD CF-2019-35, dated October 2, 2019, to correct an 
unsafe condition for Bell Model 505 helicopters, serial numbers (S/Ns) 
65011 and subsequent. Transport Canada advises of a gap between the 
transmission restraint assembly aft attachment hardware lower washer 
and the lower lug of the truss assembly clevis identified during 
quality control activity of a helicopter in final assembly. This gap 
can occur on the right-hand (RH) and left-hand (LH) sides of the truss 
assembly clevis. Subsequent investigation revealed that this condition 
may exist on in-service helicopters. Transport Canada advises that 
excessive gapping at either of these locations will result in increased 
stress when fasteners are installed and that the increased stress may 
result in cracking on the clevis lower lug and subsequent failure of 
one or both clevis lower lugs. Transport Canada further advises that 
this condition, if not corrected, could lead to loss of pylon pitch 
stiffness, excessive pylon pitch motions leading to unknown cyclic 
inputs to the main rotor, and consequent loss of control of the 
helicopter.
    Accordingly, the Transport Canada AD requires identifying the S/N 
of the installed truss assembly, and for a helicopter with an affected 
truss assembly installed, performing an initial inspection of the 
transmission restraint aft attachment hardware installations for a gap. 
Depending on the inspection results, the Transport Canada AD requires 
reducing the torque to the attachment hardware, updating records, and 
repetitive inspections of the attachment hardware for wear and fretting 
because of the reduced friction between the mating surfaces; reporting 
findings to Bell and accomplishing corrective actions specified by 
Bell; or completing the installation of the

[[Page 15147]]

attachment hardware and updating records.

FAA's Determination

    These helicopters have been approved by the aviation authority of 
Canada and are approved for operation in the United States. Pursuant to 
the FAA's bilateral agreement with Canada, Transport Canada, its 
technical representative, has notified the FAA of the unsafe condition 
described in its AD. The FAA is proposing this AD after evaluating all 
known relevant information and determining that an unsafe condition is 
likely to exist or develop in other helicopters of the same type 
design.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Bell Alert Service Bulletin (ASB) 505-19-12, 
Revision A, dated July 11, 2019 (505-19-12 Rev A). This service 
information specifies procedures for an inspection of the restraint 
hardware installation for the presence of a gap and if needed, reducing 
the torque to the affected attachment hardware, a repetitive 100-hour 
inspection of the pitch restraint attachment hardware, and repair of 
fretting damage on the truss assembly clevis lower lug.
    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 Bell ASB 505-19-12, dated June 27, 2019. This 
revision of the service information contains the same procedures as 
505-19-12 Rev A, except 505-19-12 Rev A corrects a torque value.

Proposed AD Requirements in This NPRM

    This proposed AD would require within 100 hours time-in-service 
(TIS):
     Accessing and cleaning the lower attachment hardware 
securing the restraint to the truss assembly, loosening the torque on 
each lower nut to measure the tare, and adding a torque value of 20 
inch-lbs to the measured tare of each nut and torqueing each nut to 
this new total value.
     Inspecting for a gap around the circumference between the 
nut and the washer and between the washer and the truss assembly clevis 
lower lug mounting surface of the RH and LH sides, and if there is a 
gap, measuring the gap.
     If there is a gap that is less than 0.003 inch (0.076 mm), 
installing the hardware using the original torque value of 40 to 58 
foot-pounds (55 to 78 Nm) plus tare and completing the installation of 
the attachment point.
     If there is a gap that is 0.003 inch (0.076 mm) to 0.020 
inch (0.508 mm) inclusive, installing the hardware with a decreased 
torque value limit of 20 to 60 inch-pounds (2.3 to 6.8 Nm) plus tare 
and completing the installation of the attachment point. This proposed 
AD would also require updating records for your helicopter to indicate 
the new torque limits on one or both sides. Thereafter, within 100 
hours TIS, and thereafter at intervals not to exceed 100 hours TIS, 
this proposed AD would require inspecting the assembly for fretting 
between washer and truss lower lug mounting surface, the security of 
the pitch restraint attachment hardware to make sure it does not turn 
freely, and the torque seal lacquer between the nut and the washer to 
make sure the torque seal is intact on the RH and LH sides. Depending 
on the inspection results, this proposed AD would require removing the 
cotter pin from service and removing the nut, washer, and bolt, and 
inspecting the bolt and the lower surface of the truss assembly clevis 
lower lug. Depending on these inspection results, this proposed AD 
would require removing the bolt from service; reworking and cleaning 
the lower surface of the clevis lower lug and inspecting for any 
cracks; removing the clevis lower lug from service; or applying primer 
and final paint. This proposed AD would then require installing the 
hardware with a decreased torque value limit of 20 to 60 inch-pounds 
(2.3 to 6.8 Nm Nm) plus tare and completing the installation of the 
attachment point.
     If there is a gap that is more than more than 0.020 inch 
(0.508 mm), removing the nut, washer, and bolt from service and 
repairing or replacing the truss assembly clevis lower lug in 
accordance with FAA-approved procedures.

Differences Between This Proposed AD and the Transport Canada AD

    The applicability of the Transport Canada AD is by helicopter S/N 
and requires identifying the S/N of the installed truss assembly P/N 
SLS-030-056-015 to determine if the helicopter is affected by the 
unsafe condition, whereas the applicability of this proposed AD is by 
helicopters with certain serial-numbered truss assembly P/N SLS-030-
056-015 installed instead. The compliance time of the initial 
inspections required by the Transport Canada AD is within 100 hours air 
time or 6 months, whichever occurs first, whereas this compliance time 
in this proposed AD is within 100 hours TIS instead. The Transport 
Canada AD requires reporting information to Bell to obtain certain 
corrective action, while this AD requires repairing or removing 
affected parts from service instead.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 87 helicopters of U.S. registry. Labor costs are estimated at 
$85 per work-hour. Based on these numbers, the FAA estimates the 
following costs to comply with this proposed AD.
    Measuring tare and inspecting for a gap between the transmission 
restraint assembly aft attachment hardware lower washer and the truss 
assembly would take about 1 work-hour for an estimated cost of $85 per 
helicopter and $7,395 for the U.S. fleet. If required, inspecting a 
pitch restraint attachment point would take about 1 work-hour for an 
estimated cost of $85 per attachment point per inspection cycle.
    The FAA estimates the following costs to do any necessary repairs 
or replacements based on the results of the inspections:
     Updating records to indicate the new torque limits would 
take about 0.25 work-hour for an estimated cost of $21.
     Replacing a bolt would take a minimal additional amount of 
time after inspecting and the part would cost about $50.
     Reworking the lower surface of the clevis lower lug would 
take about 1 work-hour for an estimated cost of $85.

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.

[[Page 15148]]

Regulatory Findings

    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 above, I certify this proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (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 
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 adding the following new airworthiness 
directive:

Bell Textron Canada Limited (Type Certificate Previously Held by 
Bell Helicopter Textron Canada Limited): Docket No. FAA-2021-0185; 
Project Identifier MCAI-2020-00265-R.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by May 6, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Bell Textron Canada Limited (type certificate 
previously held by Bell Helicopter Textron Canada Limited) Model 505 
helicopters, certificated in any category, with a truss assembly 
part number (P/N) SLS-030-056-015 with a serial number listed in 
Attachment A of Bell Alert Service Bulletin (ASB) 505-19-12, 
Revision A, dated July 11, 2019 (ASB 505-19-12 Rev A).

(d) Subject

    Joint Aircraft System Component (JASC) Code 5310, Fuselage Main, 
Structure.

(e) Unsafe Condition

    The FAA is issuing this AD to address a gap between the 
transmission restraint assembly aft attachment hardware lower washer 
and the right-hand (RH) and left-hand (LH) mating airframe truss 
assembly (truss assembly) clevis lower lug. The unsafe condition, if 
not addressed, could result in increased stress, cracking and 
failure of one or both of the clevis lower lugs, and subsequent loss 
of pylon pitch stiffness, excessive pylon pitch motions leading to 
unknown cyclic inputs to the main rotor, 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 100 hours time-in-service (TIS) after the effective date 
of this AD, access the transmission restraint assembly and:
    (1) Remove the safety pin at each lower nut location of the aft 
bolts securing the restraint to the truss assembly. Use solvent (C-
304) to remove the corrosion preventive compound on each nut and 
washer located under the RH and LH truss assembly clevis lower lug.
    (2) Loosen the torque on each lower nut while holding the bolt 
with a wrench until the washer turns freely while sitting on top of 
the nut.
    (3) Measure and record the tare of each nut. For purposes of 
this AD, tare is the torque required to overcome the internal 
friction between a self-locking nut and bolt as the nut is being 
turned on the bolt, but before the nut contacts the washer. Add a 
torque value of 20 inch-lbs to the measured tare of each nut and 
torque each nut to this new total value.
    (4) Inspect for a gap around the circumference between the nut 
and the washer and between the washer and the truss assembly clevis 
lower lug mounting surface of the RH and LH sides as illustrated in 
Figure 1 of ASB 505-19-12 Rev A (2 sheets). If there is a gap, 
measure the gap.
    (i) If there is a gap that is less than 0.003 inch (0.076 mm), 
before further flight, install the hardware using the original 
torque value of 40 to 58 foot-pounds (55 to 78 Nm) plus tare. Do not 
exceed the limit specified in this paragraph plus tare. Install a 
cotter pin and apply corrosion preventive compound (C-101) and 
torque seal lacquer (C-049) between the nut, washer, and lower 
surface of the truss assembly clevis.
    (ii) If there is a gap that is 0.003 inch (0.076 mm) to 0.020 
inch (0.508 mm) inclusive, before further flight, install the 
hardware with a decreased torque value limit of 20 to 60 inch-pounds 
(2.3 to 6.8 Nm) plus tare. Do not exceed the limit specified in this 
paragraph plus tare. Install a cotter pin. You may install an 
additional washer P/N NAS1149E0863P before torqueing and installing 
the cotter pin while not exceeding the maximum limit of 60 inch-lbs 
plus tare. Apply corrosion preventive compound (C-101) and torque 
seal lacquer (C-049) between the nut, washer, and lower surface of 
the truss assembly clevis. Update records for your helicopter to 
indicate the new torque limits on one or both sides.
    (A) Within 100 hours TIS after performing paragraph (g)(4)(ii) 
of this AD, and thereafter at intervals not to exceed 100 hours TIS, 
inspect the assembly for fretting between the washer and truss lower 
lug mounting surface, inspect the security of the pitch restraint 
attachment hardware to make sure it does not turn freely, and 
inspect the torque seal lacquer between the nut and the washer to 
make sure the torque seal is intact on the RH and LH sides.
    (B) If there is any fretting, the pitch restraint attachment 
hardware turns freely, or a torque seal is broken, remove the cotter 
pin from service and remove the nut, washer, and bolt. Inspect the 
bolt for damage and the lower surface of the truss assembly clevis 
lower lug for fretting damage.
    (1) If the bolt has damage, remove the bolt from service.
    (2) If the lower surface of the truss assembly clevis lower lug 
has fretting damage within allowable repair limits, use 400 grit 
sandpaper (C-423) and rework fretting damage smooth with adjacent 
surfaces, while removing minimum material. Do not exceed .010 inch 
(0.254 mm) deep total cumulative amount of material to be removed 
from the clevis's lower lugs compared to adjacent original surfaces 
after rework. Clean with acetone (C-316) and let dry. With the 
acetone dry, visually inspect the clevis lower lug for any cracks.
    (i) If there is a crack within allowable repair limits, repair 
in accordance with FAA-approved procedures. If there is a crack that 
meets or exceeds allowable repair limits, remove the truss assembly 
clevis lower lug from service.
    (ii) If there is not a crack, apply primer (C-204) to the 
reworked surface and let dry. With the primer dry, apply final paint 
(polyurethane topcoat color No. 16492) to the reworked surface.
    (3) If the lower surface of the truss assembly clevis lower lug 
has fretting damage that exceeds allowable repair limits, before 
further flight, remove the truss assembly clevis lower lug from 
service.
    (C) Install a nut, washer, and bolt with a decreased torque 
value limit of 20 to 60 inch-pounds (2.3 to 6.8 Nm) plus tare. Do 
not exceed the limit specified in this paragraph plus tare. Install 
a cotter pin. You may install an additional washer P/N NAS1149E0863P 
before torqueing and installing the cotter pin while not exceeding 
the maximum limit of 60 inch-lbs plus tare. Apply corrosion 
preventive compound (C-101) and torque seal lacquer (C-049) between 
the nut, washer, and lower surface of the truss assembly clevis.
    (iii) If there is a gap that is more than 0.020 inch (0.508 mm), 
before further flight, remove the nut, washer, and bolt from service 
and repair or replace the truss assembly clevis lower lug in 
accordance with FAA-approved procedures.

(h) Credit for Previous Actions

    You may take credit for the first instance of the actions that 
are required by paragraphs (g)(1) through (4), except not paragraphs 
(g)(4)(i), (g)(4)(ii)(A) through (C), or (g)(4)(iii), of this AD if 
you completed the Accomplishment Instructions, Part I of Bell

[[Page 15149]]

ASB 505-19-12, dated June 27, 2019, before the effective date of 
this AD.

(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: 9-AVS-AIR-730-AMOC@faa.gov.
    (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 Matt Fuller, AD 
Program Manager, General Aviation & Rotorcraft Unit, Airworthiness 
Products Section, Operational Safety Branch, FAA, 10101 Hillwood 
Pkwy., Fort Worth, TX 76177; telephone (817) 222-5110; email 
matthew.fuller@faa.gov.
    (2) For service information identified in this AD, contact Bell 
Textron Canada Limited, 12,800 Rue de l'Avenir, Mirabel, Quebec 
J7J1R4; telephone (450) 437-2862 or (800) 363-8023; fax (450) 433-
0272; or at https://www.bellcustomer.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.
    (3) The subject of this AD is addressed in Transport Canada AD 
CF-2019-35, dated October 2, 2019. You may examine the Transport 
Canada AD on the internet at https://www.regulations.gov in the AD 
Docket.

    Issued on March 11, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-05433 Filed 3-19-21; 8:45 am]
BILLING CODE 4910-13-P