Leonardo S.p.A.

Via Giovanni Agusta, 520

21017 Cascina Costa di Samarate (VA) Italy
Tel.: +39 0331 229111 - Fax: +39 0331 229605/222595

SERVICE BULLETIN N° 169-178

DATE: August 4, 2020
EMERGENCY ALERT REV. : / - July 10, 2020

TITLE
ATA 64 - TR FLIGHT CONTROL PERIODICAL INSPECTION FOR IMPROVED DUPLEX
BEARING

REVISION LOG
First issue.

An appropriate entry should be made in the aircraft log book upon accomplishment.
If ownership of aircraft has changed, please, forward to new owner.

Page 1 of 27
 1. PLANNING INFORMATION

A. EFFECTIVITY
Part I: All AW 169 helicopters equipped with Tail Rotor Duplex Bearing
P/N MM6430V00151 and TRA P/N 6F6730V00331.
Part II: All AW 169 helicopters equipped with Tail Rotor Duplex Bearing
P/N MM6430V00151.
Part III: All AW 169 helicopters equipped with Tail Rotor Duplex Bearing
P/N MM6430V00151.
Part IV: All AW 169 helicopters equipped with Tail Rotor Duplex Bearing
P/N MM6430V00151.

B. COMPLIANCE

GENERAL NOTE
A non-cumulative tolerance of 10% may be applied to
the compliance times specified in this SB to allow
synchronization of the required inspections with other
required maintenance tasks for which a non-cumulative
tolerance is already granted in the applicable
Maintenance Manual.
Part I:
Within 10 FH from any installation of TR Duplex Bearing P/N MM6430V00151. Then
repeat the inspection every 10 FH.

NOTES
• Every time it is required to perform Part II,
accomplishment of Part I on the same
maintenance downtime must be performed as a
prerequisite.
• If Part III is required in the same maintenance
downtime of Part II, it shall be performed lastly.

Part II:
Within 50 FH from any installation of TR Duplex Bearing P/N MM6430V00151. Then
repeat the inspection every 50 FH.
Part III:
Upon any installation of TR Duplex Bearing P/N MM6430V00151. Then repeat the
inspection every 100 FH.

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 NOTES
• Perform in sequence Part I and Part II as a
prerequisite.
• If Part III is required in the same maintenance
downtime of Part IV, it shall be performed after
Part IV.
• The operations performed in accordance with
Part IV of this SB covers also the already
approved AMPI Maintenance Task (i.e. MT 64-
07, required every 400 FH).

Part IV:
Within 100 FH from any installation of TR Duplex Bearing P/N MM6430V00151. Then
repeat the inspection every 100 FH.

C. CONCURRENT REQUIREMENTS
N.A.

D. REASON
This Service Bulletin is issued in order to require the periodical inspection of the
slippage marking of the back-end castellated nut of the TR servo-actuator, the
introduction of a new Thermal strip and the periodical detailed inspection of the new
improved TR duplex bearing.

E. DESCRIPTION
Following the introduction on in-service fleet of the new improved TR Duplex Bearing
P/N MM6430V00151, this Service Bulletin provides the instructions for the new
inspection regime, partially requiring some of the checks already requested by SB
169-148 on previous TR Duplex Bearing P/N 4F6430V00551.
In details, Part I of this Service Bulletin provides the periodical detailed inspection of
the slippage marking of the castellated nut installed on the back end of the TRA
P/N 6F6730V00331, retaining the requirements of Part I of SB 169-148.
Part II partially retains the requirement of the Parts II, IV and V of the SB 169-148,
requiring the detailed inspection of TR duplex bearing, in addition to the verification of
particle presence in the grease and the recursive check of the Thermal strip.
Part III provides the instructions to install a new dedicated Thermal strip in the area of
the TR duplex bearing.

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DATE: August 4, 2020
REVISION: / Page 3 of 27
 Part IV partially retains the requirement of the Parts II and VI of the SB 169-148,
requiring a check for axial play and a roughness check of the duplex bearing to be
performed after removal of the spider assembly.
Incorrect installation of the TR servo-actuator back-end nut or seizure of the TR
Duplex bearing may lead to loss of Tail Rotor control which, depending on the flight
condition, could lead to loss of control of the aircraft.
Feedback on the compliance to this Service Bulletin is required.

F. APPROVAL
The technical content of this Service Bulletin is approved under the authority of DOA
nr. EASA.21.J.005. For helicopters registered under other Aviation Authorities, before
applying the Service Bulletin, applicable Aviation Authority approval must be checked
within Leonardo Helicopters customer portal.
E.A.S.A. states mandatory compliance with inspections, modifications or technical
directives and related time of compliance by means of relevant Airworthiness
Directives.
If an aircraft listed in the effectivity embodies a modification or repair not LHD certified
and affecting the content of this Service Bulletin, it is responsibility of the
Owner/Operator to obtain a formal approval by Aviation Authority having jurisdiction on
the aircraft, for any adaptation necessary before incorporation of the present Service
Bulletin.

G. MANPOWER
To comply with this Service Bulletin the following MMH are deemed necessary:
Part I: approximately half (0.5);
Part II: approximately two (2);
Part III: approximately one (1);
Part IV: approximately three (3);
MMH are based on hands-on time and can change with personnel and facilities
available.

H. WEIGHT AND BALANCE

N.A.

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 I. REFERENCES

1) PUBLICATIONS
DATA MODULE DESCRIPTION PART
DM01 69-A-00-20-00-00A-120A-A Helicopter on ground for a safe I, II, III,
maintenance. IV, V, VI
DM02 69-A-06-40-00-00A-010A-A Access door provision I, II
DM03 69-A-64-31-01-00A-520A-A Pitch link - Remove procedure II
DM04 69-A-64-21-05-00A-520A-A Lightning conductor jumper – II
Remove procedure
DM05 69-A-64-31-03-00A-520A-A Spider plug - Remove procedure II, III, IV,
V, VI
DM06 69-A-64-31-03-00A-720A-A Spider plug - Install procedure II, III, IV,
V, VI
DM07 69-A-64-31-02-00A-520A-A Scissors group – Remove II
procedure
DM08 69-A-64-31-07-00A-520A-A Boot - Remove procedure II
DM09 69-A-64-31-04-00A-520A-A Sliding control assy – Remove II, VI
procedure
DM10 69-A-64-31-04-00A-720A-A Sliding control assy – Install II, VI
procedure
DM11 69-A-64-31-05-00A-520A-B Duplex bearing - Remove II, IV, V,
procedure VI
DM12 69-A-64-31-05-00A-720A-B Duplex bearing - Install procedure II, IV, V,
VI

2) ACRONYMS
SB Service Bulletin
DM Data Module
DOA Design Organization Approval
EASA European Aviation Safety Agency
LHD Leonardo Spa Helicopters
MMH Maintenance Man Hours
SB Service Bulletin
FH Flight Hours
TR Tail Rotor
TRA Tail Rotor Actuator

3) ANNEX
N.A.

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DATE: August 4, 2020
REVISION: / Page 5 of 27
 J. PUBLICATIONS AFFECTED
N.A.

K. SOFTWARE ACCOMPLISHMENT SUMMARY

N.A.

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 2. MATERIAL INFORMATION

A. REQUIRED MATERIALS

1) PARTS
ALTERNATIVE
# P/N DESCRIPTION Q.TY LVL NOTE LOG P/N
P/N
1 M06SHA094D01R1 Thermal Strip 1 . (1)(2) -
2 LAMHALPATCH01R1 Protective layer 1 . (1) -

Refer also to AW169 IPD for the spares materials required to comply with the AMP
DMs referenced in the accomplishment instructions.

2) CONSUMABLES
The following consumable materials, or equivalent, are necessary to accomplish this
Service Bulletin:
# Spec./LHD code number DESCRIPTION Q.TY NOTE PART
TT-N-95-B / Aliphatic Naphtha
3 AR (3) II,III
Code No. 531055030 (C059)

Refer to AW169 AMDI for the consumables required to comply with the AMP DMs
referenced in the accomplishment instructions.

3) LOGISTIC MATRIX
N.A.

NOTE
(1) This item, strictly required for Part III embodiment, may be required on condition
also within the embodiment of other Parts of this SB.
(2) Identification on label M06SHAL094D01R1 is printed on the thermal strip.
(3) Item to be furnished as local supply.

B. SPECIAL TOOLS
Refer to ITEP for the special tools required to comply with the AMP DMs referenced in
the accomplishment instructions.

C. INDUSTRY SUPPORT INFORMATION

Owners/Operators who comply with the instructions of this Service Bulletin no later
than the applicable date in the “Compliance” section will be eligible to receive
REQUIRED MATERIALS on free of charge basis, except for Consumable Materials
and Special Tools.

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DATE: August 4, 2020
REVISION: / Page 7 of 27
 NOTE: Customers who fail to comply with the instructions in this Service Bulletin
before the compliance date are not eligible for the aforementioned special policy.
Please Issue relevant MMIR form to your Warranty Administration Dpt.
NOTE: WRM will include RETURN MATERIAL AUTHORIZATION (RMA) number; the
unit disembarked from the aircraft has to be returned to LHD within thirty (30) calendar
days after the shipment of the replacement part. In case of missing return within thirty
(30) calendar days, Customer will be invoiced for the price of the replacement part.

S.B. N°169-178 EMERGENCY ALERT

DATE: August 4, 2020
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 3. ACCOMPLISHMENT INSTRUCTIONS

GENERAL NOTES
a) Place an identification tag on all components that
are re-usable, including the attaching hardware that
has been removed to gain access to the
modification area and adequately protect them until
their later re-use.

PART I
1. In accordance with AMP DM 69-A-00-20-00-00A-120A-A, prepare the helicopter on
ground for a safe maintenance. Disconnect the battery, all electrical power sources
and/or the external power supply.

NOTE
Removal of access panels 470AT and 470BT can be
avoided if visual access to the inspection area is
available by other means. A suitable borescope can be
used for this purpose.
2. In accordance with AMP DM 69-A-06-40-00-00A-010A-A remove the access panels
470AT and 470BT.
3. Take a picture of the back-end area of the TRA clearly showing the slippage mark, and
keep a record in a local archive to be made available if required.
4. With reference to Figure 1, check the slippage mark on the castellated nut for absence
of evidence of rotation between the parts. Record the result on Table I on Figure 5.
5. If any evidence of rotation is found, contact the Product Support Engineering
(engineering.support.lhd@leonardocompany.com) to receive further instructions before
performing the following checks:
5.1 Send the picture taken at step 3 to Product Support Engineering
(engineering.support.lhd@leonardocompany.com).
5.2 If the helicopter is already compliant with the SB 169-140, perform HUMS data
download from AMMC to DTD. Upload the HUMS data to Heliwise.
5.3 Perform Thermal strip and TR Duplex bearing detailed inspection as per Part II of
this SB;
5.4 In case replacement of Duplex Bearing is confirmed as necessary, perform step
6.3 of Part II of this SB.
6. If no evidence of rotation is found in step 4, return the helicopter to a ready to flight
condition and record for compliance with Part I of this Service Bulletin on the helicopter

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DATE: August 4, 2020
REVISION: / Page 9 of 27
 logbook.
7. Send the attached compliance form and the compiled Table I to the following mail box:
engineering.support.lhd@leonardocompany.com
As an alternative, gain access to My Communications section on Leonardo WebPortal
and compile the “Service Bulletin Application Communication”.

S.B. N°169-178 EMERGENCY ALERT

DATE: August 4, 2020
Page 10 of 27 REVISION: /
 PART II
1. In accordance with AMP DM 69-A-00-20-00-00A-120A-A, prepare the helicopter on
ground for a safe maintenance. Disconnect the battery, all electrical power sources
and/or the external power supply.

NOTE
If not damaged, the O-ring removed in the following
step can be retained for later reinstallation.
2. In accordance with AMP DM 69-A-64-31-03-00A-520A-A, remove the spider plug.
3. Perform the inspection of the Thermal Strip as detailed below:
3.1 With reference to Figure 2, check the thermal strip and the protective layer for
good adhesion and general condition, and the thermal strip only for readability;
then proceed as follows:
3.1.1 If the strip and/or the protective layer are detached, partially detached,
damaged or unreadable, perform steps 3.1.2 thru 3.1.6, otherwise skip
to step 3.2:
3.1.2 perform the TR duplex bearing inspection in accordance with step 4;
3.1.3 If helicopter is already compliant with the SB 169-140, perform HUMS
data download from AMMC to DTD. Upload the HUMS data to Heliwise
3.1.4 Contact the Product Support Engineering
(engineering.support.lhd@leonardocompany.com) to receive further
instructions;
3.1.5 Replace the thermal strip in accordance with the instructions reported
in Part III of this SB;
3.1.6 Skip to step 7.
3.2 If any of the Thermal Strip cells appears coloured, provide a picture of the
Thermal Strip to Product Support Engineering
(engineering.support.lhd@leonardocompany.com), then proceed with the
following step.
3.3 With reference to Figure 5, check the temperature reached by the thermal strip
installed on spacer P/N MM6430A00151.
3.4 Record the check result on Table II (refer to Figure 6) and provide the Table and
the Compliance Form to Product Support Engineering, as required by step 8.
3.5 If temperature has reached a value equal to or above 104°C, proceed with steps
3.5.1 thru 3.5.4, otherwise skip to step 4:
3.5.1 perform the TR duplex bearing inspection in accordance with step 4
thru step 5.

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DATE: August 4, 2020
REVISION: / Page 11 of 27
 3.5.2 If the helicopter is already compliant with the SB 169-140, perform
HUMS data download from AMMC to DTD. Upload the HUMS data to
Heliwise.
3.5.3 Contact immediately the Product Support Engineering
(engineering.support.lhd@leonardocompany.com) to receive further
instruction before thermal strip and duplex bearing removal and
replacement.
3.5.4 In case replacement of Duplex Bearing is confirmed as necessary,
perform steps 6.3 of Part II of this SB.
4. Perform the inspection of the TR duplex bearing in accordance with the following
procedure:
4.1 Inspect the visible parts of the TR duplex bearing (including the seals) for
absence of wear, damages and security of attachment. Record the results on
Table II (refer to Figure 6).
4.2 Check the visible part of the TR duplex bearing for particles absence.

CAUTION
Pay attention not to damage the thermal strip and the
protective layer during the grease sampling from the
bearing housing.
4.3 If any grease leakage is present on the visible part of the TR Duplex Bearing
and/or on the spider plug, confirm absence of any particles by finger touch.
4.4 Perform grease inspection for magnetic/metallic particles as detailed below:
4.4.1 Put a small quantity of grease using a small spatula in a transparent
container and add a solvent (aliphatic naphtha). Then use a magnet on
the bottom out side of the container to confirm absence of magnetic
particles in the solution.
4.4.2 Record the result on Table II (refer to Figure 6) and collect the grease
leaked from the visible surface in a proper container.
5. If none of the checks performed in steps 4.1 thru 4.4.1 fails, proceed as follows,
otherwise skip to step 6:
5.1 If helicopter is already compliant with the SB 169-140, perform HUMS data
download from AMMC to DTD. Upload the HUMS data to Heliwise.
5.2 Skip to step 7.
6. If any of the checks performed in steps 4.1 thru 4.4.1 fails, perform the following
operations:
6.1 If helicopter is already compliant with the SB 169-140, perform HUMS data

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DATE: August 4, 2020
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 download from AMMC to DTD. Upload the HUMS data to Heliwise.
6.2 Contact immediately the Product Support Engineering
(engineering.support.lhd@leonardocompany.com) to receive further instructions.
6.3 In case replacement of Duplex Bearing is confirmed as necessary, refer to the
following procedure:
6.3.1 In accordance with applicable steps of AMP DM 69-A-64-31-01-00A-
520A-A, temporarily detach the upper attachment of all the pitch links
from the TR.
6.3.2 In accordance with applicable steps of AMP DM 69-A-64-31-02-00A-
520A-A, disconnect the upper half scissors from the spider.
6.3.3 In accordance with applicable steps of AMP DM 69-A-64-31-07-00A-
520A-A, disconnect and lower the boot from the spider.
6.3.4 In accordance with AMP DM 69-A-64-21-05-00A-520A-A, disconnect
the TR lightning conductor jumper.

CAUTION
Pay attention to prevent rod rotation, when screwing /
un-screwing the castellated nut, holding the rod square
end.

NOTE
Before removal of the TR duplex bearing, take note of
its installation orientation marking “OUT” on the
outboard visible face. After removal mark “IN” on the
inboard opposite face of the TR duplex bearing. Use
an indelible pen.
6.3.5 In accordance with AMP DM 69-A-64-31-05-00A-520A-B, remove the
TR duplex bearing.
6.3.6 Collect the grease leaked from the TR duplex bearing “IN” marked side
in a container different from the one used before.
6.3.7 Take a picture of both faces of the removed TR duplex bearing and
send them to PSE (engineering.support.lhd@leonardocompany.com)
before returning the bearing.
6.3.8 Clean by means of a soft lint-free cloth the housing of the TR duplex
bearing, the rod visible part and the internal side of the spider plug.
6.3.9 Immediately return (within 2 days) the removed TR duplex bearing and
the collecting containers of the grease to Leonardo Helicopters.
Contact the Product Support Engineering

S.B. N°169-178 EMERGENCY ALERT

DATE: August 4, 2020
REVISION: / Page 13 of 27
 (engineering.support.lhd@leonardocompany.com) to receive the
proper instructions to return the removed component.

CAUTION
Duplex Bearing must be installed with a controlled
orientation.
6.3.10 In accordance with AMP DM 69-A-64-31-05-00A-720A-B, install a new
TR duplex bearing, keeping the outer race outside marking properly
readable while letting down in the slider/spider seat. Refer to Figure 4

NOTE
Spacer P/N MM6430A00151 already installed on
helicopter can be kept in service, provided that no
damage or wear is present on the component.
6.3.11 In accordance with the instructions reported on Part III of SB 169-178,
replace Thermal Strip and Adhesive Protective Layer currently installed
on Spacer P/N MM6430A00151

CAUTION
Pay attention to prevent rod rotation, when screwing /
un-screwing the castellated nut, holding the rod square
end.

NOTE
In case during the installation of control rod nut, after
several attempts with different nuts, the minimum
required breakaway torque (as required by AMP DM
69-A-64-31-04-00A-720A-A) is not reached, please
contact the Product Support Engineering
(engineering.support.lhd@leonardocompany.com) to
receive dedicated instructions.
6.3.12 In accordance with AMP DM 69-A-64-31-04-00A-720A-A, restore
Sliding Control Assy installation on the helicopter.
6.3.13 With reference to Figure 1, restore the slippage marking on the
castellated nut from the hinge bracket element to the rod.
6.3.14 In accordance with AMP DM 69-A-64-31-01-00A-720A-A, restore the
correct installation of TR pitch links.

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DATE: August 4, 2020
Page 14 of 27 REVISION: /
 NOTE
When performing the following step allow the sealant
to cure for at least 2 hours before the next flight.
7. In accordance with AMP DM 69-A-64-31-03-00A-720A-A, install the spider plug.

NOTE
In case of any findings, report within 2 days the
inspection results along with the available records of
the previous checks.
8. Send the attached compliance form and the compiled Table II to the following mail box:
engineering.support.lhd@leonardocompany.com
As an alternative, gain access to My Communications section on Leonardo WebPortal
and compile the “Service Bulletin Application Communication”.
9. Return the helicopter to a ready to flight condition and record for compliance with Part II
of this Service Bulletin on the helicopter logbook.

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DATE: August 4, 2020
REVISION: / Page 15 of 27
 PART III
1. In accordance with AMP DM 69-A-00-20-00-00A-120A-A, prepare the helicopter on
ground for a safe maintenance. Disconnect the battery, all electrical power sources
and/or the external power supply.
2. In accordance with AMP DM 69-A-64-31-03-00A-520A-A, remove the spider plug.

CAUTION
Pay attention to prevent rod rotation, when screwing /
un-screwing the castellated nut, holding the rod square
end.
3. In accordance with applicable steps of AMP DM 69-A-64-31-04-00A-520A-A, temporarily
remove the spacer control rod P/N MM6430A00151 and the control rod nut.
4. With reference to Figure 2, perform on an applicable workbench the installation of
Thermal Strip and Adhesive protective layer as follows:
4.1 With the use of a non-metallic spatula, remove the layer P/N
LAMHALPATCH01R1 (if present) from the spacer.
4.2 With the use of a non-metallic spatula, remove the installed thermal strip from the
spacer
4.3 Clean the spacer surface with a soft lint-free cloth soaked with a small quantity of
aliphatic naphtha; then dry the surface with a clean cloth; make sure that no
traces of grease / oil / dirt remained;

CAUTION
When installing the thermal strip pay attention to:
• ensure a good adhesion with the spacer control
rod P/N MM6430A00151;
• Thermal Strip Celsius scale shall be kept on the
outer side to ensure good readability when the
spacer is installed.
4.4 Install the thermal strip P/N M06SHA094D01R1 on the control rod spacer P/N
MM6430A00151, paying particular attention to minimize formation of wrinkles;
ensure a good adhesion with the spacer;
4.5 Protect the thermal strip with the layer P/N LAMHALPATCH01R1, paying
particular attention to minimize formation of wrinkles;

CAUTION
Pay attention to prevent rod rotation, when screwing /
un-screwing the castellated nut, holding the rod square
end.

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DATE: August 4, 2020
Page 16 of 27 REVISION: /
 NOTE
In case during the installation of control rod nut, after
several attempts with different nuts, the minimum
required breakaway torque (as required by AMP DM
69-A-64-31-04-00A-720A-A) is not reached, please
contact the Product Support Engineering
(engineering.support.lhd@leonardocompany.com) to
receive dedicated instructions..
5. In accordance with applicable steps of AMP DM 69-A-64-31-04-00A-720A-A, reinstall
the spacer control rod P/N MM6430A00151 and the control rod nut.

NOTE
When performing the following step allow the sealant
to cure for at least 2 hours before the next flight.
6. In accordance with AMP DM 69-A-64-31-03-00A-720A-A, install the spider plug.
7. Return the helicopter to a ready to flight condition and record for compliance with Part III
of this Service Bulletin on the helicopter logbook.
8. Send the attached compliance form to the following mail box:
engineering.support.lhd@leonardocompany.com
As an alternative, gain access to My Communications section on Leonardo WebPortal
and compile the “Service Bulletin Application Communication”.

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DATE: August 4, 2020
REVISION: / Page 17 of 27
 PART IV
1. In accordance with AMP DM 69-A-00-20-00-00A-120A-A, prepare the helicopter on
ground for a safe maintenance. Disconnect the battery, all electrical power sources
and/or the external power supply.
2. In accordance with AMP DM 69-A-64-31-03-00A-520A-A, remove the spider plug.
3. In accordance with applicable steps of AMP DM 69-A-64-31-01-00A-520A-A, temporarily
detach the upper attachment of all the pitch links from the TR.
4. In accordance with applicable steps of AMP DM 69-A-64-31-02-00A-520A-A, disconnect
the upper half scissors from the spider.
5. In accordance with applicable steps of AMP DM 69-A-64-31-07-00A-520A-A, disconnect
and lower the boot from the spider.
6. In accordance with AMP DM 69-A-64-21-05-00A-520A-A, disconnect the TR lightning
conductor jumper.
7. Check for absence of axial play when trying to move the spider along the control rod
axis. Record the result on Table III (refer to Figure 7).
8. If axial play is detected, perform the following instructions, otherwise skip to step 9:
8.1 If the helicopter is already compliant with the SB 169-140, perform HUMS data
download from AMMC to DTD. Upload the HUMS data to Heliwise.
8.2 Contact immediately the Product Support Engineering
(engineering.support.lhd@leonardocompany.com) to receive further instruction
before thermal strip and duplex bearing removal and replacement.
8.3 In case replacement of Duplex Bearing is confirmed as necessary, perform step
6.3 of Part II of this SB.

CAUTION
Pay attention to prevent rod rotation, when screwing /
un-screwing the castellated nut, holding the rod square
end.
9. In accordance with AMP DM 69-A-64-31-04-00A-520A-A, remove the sliding control
assembly.
10. With reference to Figure 3 lock the slider of the sliding control assembly in a bench vice
with padded jaws.
11. Examine the duplex bearing to find roughness in accordance with the following
procedure:

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DATE: August 4, 2020
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 NOTE
• To initiate rotation of the duplex bearing, a
break-out force could be necessary. The break-
out force is not an indication of roughness.
• Relative axial movement between the inner
races is acceptable and shall not be considered
as a finding.

11.1 Use your fingers to push down on the upper face of the inner race of the duplex
bearing.

NOTE
Do not release pressure, continue to apply pressure
with your fingers during the subsequent step.
11.2 With reference to Figure 3 section A-A Step 1, push the top inner race down and
at the same time turn it to feel if there is roughness.
11.3 Put your finger into the duplex bearing until you can pull up the lower face of the
inner race.

NOTE
Do not release pressure, continue to apply pressure
with your finger during the subsequent step.
11.4 With reference to Figure 3 section A-A Step 2, pull the bottom inner race in the
up direction and at the same time turn it to feel if there is roughness.
11.5 Repeat the Step 11.1 thru Step 11.4 at least one time to confirm the results.
11.6 Record the results of the previous steps on Table III (refer to Figure 7).
12. If any of the checks performed in steps 11 thru 11.6 fails, perform the following
operations, otherwise skip to step 13
12.1 If helicopter is already compliant with the SB 169-140, perform HUMS data
download from AMMC to DTD. Upload the HUMS data to Heliwise.
12.2 Contact immediately the Product Support Engineering
(engineering.support.lhd@leonardocompany.com) to receive further instructions.
12.3 In case replacement of Duplex Bearing is confirmed as necessary, perform step
6.3 of Part II of this SB.

CAUTION
Pay attention to prevent rod rotation, when screwing /
un-screwing the castellated nut, holding the rod square
end.

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DATE: August 4, 2020
REVISION: / Page 19 of 27
 NOTE
In case during the installation of control rod nut, after
several attempts with different nuts, the minimum
required breakaway torque (as required by AMP DM
69-A-64-31-04-00A-720A-A) is not reached, please
contact the Product Support Engineering
(engineering.support.lhd@leonardocompany.com) to
receive dedicated instructions.
13. In accordance with AMP DM 69-A-64-31-04-00A-720A-A, restore Sliding Control Assy
installation on the helicopter.
14. With reference to Figure 1, restore the slippage marking on the castellated nut from the
hinge bracket element to the rod.
15. In accordance with AMP DM 69-A-64-31-01-00A-720A-A, restore the correct installation
of TR pitch links.

NOTE
When performing the following step allow the sealant
to cure for at least 2 hours before the next flight.
16. In accordance with AMP DM 69-A-64-31-03-00A-720A-A, install the spider plug.
17. Return the helicopter to a ready to flight condition and record for compliance with Part IV
of this Service Bulletin on the helicopter logbook.

NOTE
In case of any findings, report within 2 days the
inspection results along with the available records of
the previous checks.
18. Send the attached compliance form and the compiled Table III to the following mail box:
engineering.support.lhd@leonardocompany.com
As an alternative, gain access to My Communications section on Leonardo WebPortal
and compile the “Service Bulletin Application Communication”.

S.B. N°169-178 EMERGENCY ALERT

DATE: August 4, 2020
Page 20 of 27 REVISION: /
 Figure 1
S.B. N°169-178 EMERGENCY ALERT
DATE: August 4, 2020
REVISION: /July 10, 2020 Page 21 of 27
 INSTALL:
THERMAL STRIP ON
INDICATED SPACER

Page 22 of 27
THERMAL STRIP
(FOR REFERENCE ONLY)

94 99 104 110 115 120 ˚C

MM6430A00151
SPACER

Figure 2
201 210 219 230 239 248 ˚F

SB189-272-002-01
MM6430A00151
SPACER

INSTALL:
THERMAL STRIP

SB169-178-001-01

S.B. N°169-178 EMERGENCY ALERT

REVISION: /
DATE: August 4, 2020
 A MM6430V00151
TAIL ROTOR DUPLEX BEARING
6F6430A01232
SLIDING CONTROL ASSEMBLY

DATE: August 4, 2020

REVISION: /July 10, 2020
A

S.B. N°169-178 EMERGENCY ALERT

SECTION A-A
STEP 1

Figure 3
MM6430V00151
TAIL ROTOR DUPLEX BEARING

SECTION A-A
STEP 2

SB169-178-002-01

Page 23 of 27
 6F6430A01232 SLIDING CONTROL ASSEMBLY

MM6430V00151 TAIL ROTOR DUPLEX BEARING

SB169-178-003-01

Figure 4
S.B. N°169-178 EMERGENCY ALERT
DATE: August 4, 2020
Page 24 of 27 REVISION: /
 TABLE I

SB COMPLIANCE
AIRCRAFT S/N
DATE:

P/N 6F6730V00331 A/C FH at SB

TRA S/N COMPLIANCE DATE:

TRA FH at SB A/C LANDINGS at SB

COMPLIANCE DATE COMPLIANCE DATE:

ACTION Required Obtained

PART I

CASTELLATED NUT NO ROTATION BETWEEN

paint mark check PARTS

Figure 5
S.B. N°169-178 EMERGENCY ALERT
DATE: August 4, 2020
REVISION: /July 10, 2020 Page 25 of 27
 TABLE II

SB COMPLIANCE
AIRCRAFT S/N
DATE:

P/N MM6430V00151
A/C FH at SB
TR DUPLEX
COMPLIANCE DATE:
BEARING S/N

TR DUPLEX
A/C LANDINGS at SB
BEARING FH at SB
COMPLIANCE DATE:
COMPLIANCE DATE

ACTION Required Obtained

PART II

THERMAL STRIP GOOD ADHESION AND

General condition check READABILITY. NO DAMAGE.

THERMAL STRIP
RECORDED TEMPERATURE
Temperature check

TEMPERATURE SHALL NOT

THERMAL STRIP
REACH A VALUE EQUAL TO OR
Temperature check
ABOVE 104°C.

TR DUPLEX BEARING
NO FINDINGS
wear and damages check

TR DUPLEX BEARING ABSENCE of ANY

Particles check PARTICLES

TR DUPLEX BEARING ABSENCE of METALLIC

Grease leakage check PARTICLES

Figure 6
S.B. N°169-178 EMERGENCY ALERT
DATE: August 4, 2020
Page 26 of 27 REVISION: /
 TABLE III

SB COMPLIANCE
AIRCRAFT S/N
DATE:

P/N MM6430V00151
A/C FH at SB
TR DUPLEX
COMPLIANCE DATE:
BEARING S/N

TR DUPLEX
A/C LANDINGS at SB
BEARING FH at SB
COMPLIANCE DATE:
COMPLIANCE DATE

ACTION Required Obtained

PART IV

TR SPIDER ABSENCE of
axial play check AXIAL PLAY

TR DUPLEX BEARING
FREE AND EASY ROTATION
Roughness check by fingers

Figure 7
S.B. N°169-178 EMERGENCY ALERT
DATE: August 4, 2020
REVISION: /July 10, 2020 Page 27 of 27
 Please send to the following address:
SERVICE BULLETIN COMPLIANCE FORM Date:

LEONARDO S.p.A.
CUSTOMER SUPPORT & SERVICES - ITALY Number:

PRODUCT SUPPORT ENGINEERING & LICENSES DEPT.

Via Giovanni Agusta, 520
21017 Cascina Costa di Samarate (VA) - ITALY Revision:
Tel.: +39 0331 225036 Fax: +39 0331 225988

Customer Name and Address: Telephone:

Fax:

B.T. Compliance Date:

Helicopter Model S/N Total Number Total Hours T.S.O.

Remarks:

Information:

We request your cooperation in filling this form, in order to keep out statistical data relevant to aircraft configuration up-to-date. The form should be filled in all
its parts and sent to the above address or you can communicate the application also via Technical Bulletin Application Communication Section placed in
Leonardo AW Customer Portal - MyCommunications Area. We thank you beforehand for the information given.