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Federal Register / Vol. 86, No. 170 / Tuesday, September 7, 2021 / Rules and Regulations
PART 39AIRWORTHINESS
DIRECTIVES

c Applicability This AD applies to Bell Textron Canada Limited Model 429 helicopters, certificated in any category, serial numbers 57001 and subsequent.

1. The authority citation for part 39
continues to read as follows:

d Subject Joint Aircraft Service Component JASC
Code: 6720, Tail Rotor Control System.

the FAA amends 14 CFR part 39 as follows:

Authority: 49 U.S.C. 106g, 40113, 44701.
39.13

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

20211810 Bell Textron Canada Limited:
Amendment 3921711; Docket No.
FAA20210497; Project Identifier 2019SW043AD.
a Effective Date This airworthiness directive AD is effective October 12, 2021.

e Unsafe Condition This AD was prompted by three reports of unexpected forces or uncommanded inputs to the directional yaw control system. The FAA is issuing this AD to prevent yaw trim runaway. The unsafe condition, if not addressed, could result in loss of control of the helicopter.
f Compliance Comply with this AD within the compliance times specified, unless already done.
g Required Actions 1 Within 30 days after the effective date of this AD, revise the existing Rotorcraft Flight Manual for your helicopter as follows:

b Affected ADs None.

49911

i In Section 2, Normal Procedures, under 24. INTERIOR AND PRESTART CHECK, add the following as item 25: 25. Depress the cyclic force TRIM REL button and collective FORCE REL button 4-axis only to center actuators and extinguish any active out of detent indications.
ii In Section 2, Normal Procedures, under 25. ENGINE START and under 28.
TAKEOFF, add the following above item 1:
CAUTION: WHEN MANIPULATING
FLIGHT CONTROLS WITH FORCE TRIM
SELECTED ON, DO NOT RELEASE
AFFECTED FLIGHT CONTROL UNTIL THE
OUT OF DETENT INDICATION
EXTINGUISHES. THE FLIGHT CONTROLS
MAY BE RESET BY DEPRESSING THE
CYCLIC FORCE TRIM REL BUTTON AND
COLLECTIVE FORCE REL BUTTON 4AXIS
ONLY UNTIL THE OUT OF DETENT
INDICATION EXTINGUISHES.
iii In Section 3, Emergency and Malfunction Procedures, under 39.
AUTOMATIC FLIGHT CONTROL SYSTEM, add the information in Figure 1 to paragraph g1iii of this AD as item 39D:

3-9-D. TRIM RUNAWAY
INDICATIONS:
Flight controls -

Uncommanded movement.

Flight control forces - High in axis of uncommanded movement, normal in other axes.
Out of detent indication for affected axis PROCEDURE:
1. Cyclic force TRIM REL and/or collective FORCE REL button 4-axis only - Depress until the out of detent indication extinguishes.
2. Flight controls - Do not release flight control if out of detent indication is present.
3. Force TRIM switchOFF; check TRM OFF illuminates on PFD.
4. IfIMC, land as soon as practical. IfVMC, continue flight in SCAS.

iv In Section 4, Performance, under 42.
POWER ASSURANCE CHECK, add the following above the instructions for performing a power assurance check:
CAUTION: WHEN MANIPULATING
FLIGHT CONTROLS WITH FORCE TRIM

VerDate Sep<11>2014

16:15 Sep 03, 2021

Jkt 253001

SELECTED ON, DO NOT RELEASE
AFFECTED FLIGHT CONTROL UNTIL THE
OUT OF DETENT INDICATION
EXTINGUISHES. THE FLIGHT CONTROLS
MAY BE RESET BY DEPRESSING THE
CYCLIC FORCE TRIM REL BUTTON AND

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COLLECTIVE FORCE REL BUTTON 4AXIS
ONLY UNTIL THE OUT OF DETENT
INDICATION EXTINGUISHES.
2 Using a document with information identical to the information in paragraph g1 of this AD is acceptable for compliance
E:FRFM07SER1.SGM

07SER1

ER07SE21.000

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Figure 1 to paragraph gl iii