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° 139-450

DATE: April 20, 2016
ALERT REV. : D - May 28, 2019

TITLE
ATA 62 - MAIN ROTOR DAMPER INSPECTIONS

REVISION LOG
Present revision D is issued to add, as last page of Annex B, the figure B4 showing the
setup parameters for the eddy current inspection instrument. This figure, missing in revision
C of the Service Bulletin, was already present in the previous issues.
No other changes are made to the accomplishment instructions and to the compliance time
scheduling already introduced with the previous revisions.
Revision A introduced an Eddy current inspection as valid alternative to the ones already
prescribed with the first issue and limited the checks on the body end up to 1200 FH while
for body ends having logged more than 1200 FH since new a more stringent inspection
program was provided in Service Bulletin 139-452.
Revision B was issued to introduce new MR damper P/N 3G6220V01353, fitting the new
body end P/N M006-01H046-041.
Revision C was issued to remove from the effectivity of this Service Bulletin MR damper
P/N 3G6220V01353, because it is no more subject to the inspections herein described. The
maintenance program applicable to MR damper P/N 3G6220V01353 has been reported in
AMPI Chapter 5 Issue 15.
Revision bars in the outer margin identify changes.

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 58
 1. PLANNING INFORMATION

A. EFFECTIVITY

NOTE
This Service Bulletin cancels and supersedes BT 139-
410 Rev. A and BT 139-446.

Part I: all MR dampers P/N 3G6220V01351 and P/N 3G6220V01352 installed on

AB139 / AW139 helicopters (except S/N 31004, S/N 31007 and S/N 41237).
all MR dampers P/N 3G6220V01351, P/N 3G6220V01352 kept in stock that
have logged three hundred (300) FH or more since new.
Part II: all MR dampers that have been already inspected according to Part I and that
have replaced the rod end assy with a component P/N M006-01H004-041 or
P/N M006-01H004-045 or P/N M006-01H004-053 not marked as per Service
Bulletin 139-450 figure 7.
Part III: all body ends P/N M006-01H002-041 or P/N M006-01H002-047 and rod ends
P/N M006-01H004-041 or P/N M006-01H004-045 or P/N M006-01H004-053,
part of MR dampers P/N 3G6220V01351 and P/N 3G6220V01352 installed on
AB139 / AW139 helicopters (except S/N 31004, S/N 31007 and S/N 41237).
Part IV: all body ends P/N M006-01H002-041 or P/N M006-01H002-047 and rod ends
P/N M006-01H004-041 or P/N M006-01H004-045 or P/N M006-01H004-053,
part of MR dampers P/N 3G6220V01351 and P/N 3G6220V01352 installed on
AB139 / AW139 helicopters (except S/N 31004, S/N 31007 and S/N 41237).
Part V: all MR dampers P/N 3G6220V01351 and P/N 3G6220V01352 up to S/N
MCR8086 included, that are installed on AB139 / AW139 helicopters (except
S/N 31004, S/N 31007 and S/N 41237) and have accumulated less than 600
FH since new.
Part VI: all AB139 / AW139 helicopters (except S/N 31004, S/N 31007 and S/N 41237)
equipped with MR dampers P/N 3G6220V01351 and P/N 3G6220V01352.
Part VII: all MR dampers P/N 3G6220V01351 and all MR dampers P/N 3G6220V01352
up to S/N MCR8764 (included) having rod end P/N M006-01H004-041 or -045
or -053, except MR dampers listed in table 1 of Annex A and MR dampers
marked with “BT 139-446 Part II” or “BT 139-446 Part III” on the logcard,
installed on AB139 / AW139 helicopters (except S/N 31004, S/N 31007 and
S/N 41237).
all MR dampers P/N 3G6220V01351 and P/N 3G6220V01352 that have
removed the damper rod end assy in accordance with AMP procedure before

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 2 of 58 REVISION: D - May 28, 2019
 the issuance of BT 139-446, even if they have S/N higher than MCR8764 or
they are listed in table 1 of Annex A.
Part VIII: all MR dampers P/N 3G6220V01351 and all MR dampers P/N 3G6220V01352
up to S/N MCR8764 (included) having rod end assy P/N M006-01H004-041 or
-045 or -053, except MR dampers listed in table 1 of Annex A and MR
dampers marked with “BT 139-446 Part II” or “BT 139-446 Part III” on the
logcard, kept in stock.

NOTE
MR damper ends marked as per figure 7 are not
affected by part I and part II of this Service Bulletin.

NOTE
The MR damper exact S/N may be composed of either
four or five digits, possibly preceded by letters MCR
and/or followed by letters A and/or B. For the purpose
of the present instructions, only valid numerical
characters are considered, neglecting “MCR”, “A”, “B”
and initial zeros.
Possible examples follow:
 S/N 0272 will be referred to as S/N 272;
 S/N 00344AB will be referred to as S/N 344;
 S/N MCR1848A will be referred to as S/N 1848;
 S/N MCR07568 will be referred to as S/N 7568;
 S/N MCR10755 will be referred to as S/N 10755;

MAG confirms that no duplicates exist in the valid

numerical digits of item serialization (that means that
only one among S/N 715, S/N MCR0715, S/N
MCR00715 or S/N MCR0715AB exists).

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 3 of 58
 B. COMPLIANCE

NOTE
Rod end and body end time since new or since
overhaul can be computed based on
removal/installation data recorded on MR damper
logcard Section 2.

Part I:
 within thirty (30) FH since receipt of this Service Bulletin or at first MR damper
removal, whichever comes first, on MR dampers that have logged three
hundred (300) FH or more since new.
 within thirty (30) FH since receipt of this Service Bulletin or when they reach
three hundred (300) FH since new, whichever occurs later, on MR dampers that
have not already logged three hundred (300) FH.
 before next installation on the helicopter for MR dampers kept in stock that have
logged three hundred (300) FH or more since new.
Part II: three hundred (300) FH after the replacement of the rod end assy.
Part III:
 for rod end, after the last flight of each day or before the first flight of each day
since the rod end has logged three hundred (300) FH or more since new or
since overhaul.
 for body end, after the last flight of each day or before the first flight of each day
since the body end has logged three hundred (300) FH or more since new and
until it has logged twelve hundred (1200) FH since new.
Part IV:
 for rod end
 within thirthy (30) FH since receipt of this Service Bulletin and then every ten
(10) FH for rod ends that have logged less than three hundred (300) FH since
new or since overhaul.
 after the last flight of each day or before the first flight of each day since the
rod end has logged three hundred (300) FH or more since new or since
overhaul.
 for body end
 within thirthy (30) FH since receipt of this Service Bulletin and then every ten
(10) FH for body ends that have logged less than three hundred (300) FH
since new.

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 4 of 58 REVISION: D - May 28, 2019
  after the last flight of each day or before the first flight of each day since the
body end has logged three hundred (300) FH or more since new and until it
has logged twelve hundred (1200) FH since new.
Part V: within thirthy (30) FH since receipt of this Service Bulletin and then every
twenty (20) FH until the affected damper reaches six hundred (600) FH Time
Since New.
Part VI: within fifty (50) FH since receipt of this Service Bulletin and then every one
hundred (100) FH.
Part VII: within fifty (50) FH since receipt of this Service Bulletin.
Part VIII: within three (3) months since receipt of this Service Bulletin or before the first
installation on the helicopter, whichever is first.

NOTE
For part IV and part V the compliance time must be
scheduled starting from the date of the last inspection
performed according to BT 139-410, if this has been
already accomplished at least one time.
For part VI the compliance time must be scheduled
starting from the date of the last inspection performed
according to BT 139-446 part I, if this has been already
accomplished at least one time.
Compliance with part VII and VIII is not required for
helicopters / parts that have already accomplished BT
139-446 part II or part III respectively.

C. CONCURRENT REQUIREMENTS
N.A.

D. REASON
This Service Bulletin is issued in order to introduce a new one off and a new periodic
inspection and to collect the existing periodic inspections of MR damper.

E. DESCRIPTION
Some failures of MR damper in the inboard spherical bearing area were experienced
by AW139 fleet; in addition, cases of rod end loosening were reported. This Service
Bulletin introduces the inspections to be performed on the MR damper, until
replacement with P/N 3G6220V01353 when the body end reaches twelve hundred
(1200) FH.

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 5 of 58
 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.

EASA 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: six (6) MMH;
Part II: four (4) MMH;
Part III: half (0.5) MMH
Part IV: half (0.5) MMH;
Part V: half (0.5) MMH;
Part VI: two (2) MMH;
Part VII:five (5) MMH;
Part VIII:half (0.5) MMH for each MR damper.
MMH are based on hands-on time and can change with personnel and facilities
available.

H. WEIGHT AND BALANCE

N.A.

I. REFERENCES

1) PUBLICATIONS
DATA MODULE DESCRIPTION PART
DM01 39-A-00-20-00-00A-120A-A Helicopter on ground for a safe I thru VII
maintenance
DM02 39-A-GG-02-00-00A-066A-A Platform, left (GG-01-00) I thru VII

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 6 of 58 REVISION: D - May 28, 2019
 DATA MODULE DESCRIPTION PART
DM03 39-A-62-22-02-00A-520A-A Main rotor damper – Remove I, II, IV,
procedures VI, VII
DM04 39-A-62-22-02-00A-720A-A Main rotor damper – Install I, II, IV,
procedures VI, VII
DM05 39-A-62-22-02-01A-921A-B Rod end (lag damper) - IV, VI, VII
Replacement (remove and install
a new item)
DM06 39-A-62-22-07-00A-520A-A Anti-rotation block - Remove VI
procedure
DM07 39-A-62-22-07-00A-720A-A Anti-rotation block - Install VI
procedure

2) ACRONYMS
AMDI Aircraft Material Data Information
AMP Aircraft Maintenance Publication
AMPI Aircraft Maintenance Planning information
AR As Required
BT Bollettino Tecnico
DM Data Module
FH Flight Hours
ITEP Illustrated Tools and Equipment Publication
LHD Leonardo Helicopter Division
LS Local Supply
MMH Maintenance-Man-Hours
MMIR Maintenance Malfunction Information Report
MR Main Rotor

3) ANNEX
Annex A MAG In Service Query Record n° ISQR-16-002
Annex B MR damper eddy current inspection

J. PUBLICATIONS AFFECTED
N.A.

K. SOFTWARE ACCOMPLISHMENT SUMMARY

N.A.

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 7 of 58
 2. MATERIAL INFORMATION

A. REQUIRED MATERIALS

1) PARTS
A MR damper or a rod end assy, as applicable, can be ordered to LHD only in case
replacement is requested by this Service Bulletin.

NOTE
MR damper P/N 3G6220V01353 is fully
interchangeable and mixable on the same MR Hub
with a damper with different P/N.
If a MR damper P/N 3G6220V01353 is furnished to
replace a damper with different P/N, also a new
antirotation block P/N 3G6220A05353 must be
supplied to replace the existing one.
The new anti-rotation block P/N 3G6220A05353 can
be used also with damper with different P/N.

2) CONSUMABLES
The following consumable materials, or equivalent, are necessary to accomplish this
Service Bulletin:
# Spec./LHD code number DESCRIPTION Q.TY NOTE PART
1 Commercial Masking tape, adhesive AR LS (1) I, II
Clean, lint-free, dry cloth (C011) or
2 Commercial AR LS (1) I, II
absorbent toweling
Penetrant, Type II, Method C, in aerosol
3 QPL-AMS2644 AR LS (1) I, II
container
Solvent remover, class 2, in aerosol
4 QPL-AMS2644 AR LS (1) I, II
container
VII,
5 MS20995C41 Safety wire (C241) AR LS
VIII
PERMACEL P422 Cod. No.
VII,
6 900002514 or 900002515 or Tape, antifretting AR LS
VIII
900002516 or 900002517
MIL-PRF-85285, Ty. I
7 Polyurethane paint, black AR LS (1) I, II
Color N° 37038
8 TT-N-95 Aliphatic naphtha (C059) AR LS III
9 Commercial Strap, tiedown 2 LS

Refer also to AMDI for the consumable materials required to comply with the AMP DM
referenced in the compliance instructions.

3) LOGISTIC MATRIX
N.A.

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 8 of 58 REVISION: D - May 28, 2019
 NOTE
(1) Required to perform the dye penetrant inspection. Refer to Annex B for
consumable materials required for the Eddy Current inspection.

B. SPECIAL TOOLS
The following special tools, or equivalent, are necessary to accomplish this Service
Bulletin:
# P/N DESCRIPTION Q.TY NOTE PART
RMGE-DS-06-2010-LH or
10 Platform left (GG-01-00) AR LS I thru VII
approved alternative
11 / Magnifying glass (5 power) 1 LS (B1) I, II, III
12 / Brush, fine tipped 1 LS (B1) I, II
13 Commercial Luxmeter 1 LS (B1) I, II
Small, clean, dry, not contamined recipient
14 / 1 LS (B1) I, II
(beaker or equivalent)
15 Commercial Mirror 1 LS III, V
Commercial Torque wrench (capability up to 100 Nm -
16 1 LS VI, VII, VIII
885 lb in)
17 Commercial Spanner 1-5/16” 1 LS VII, VIII
18 Commercial Spanner 5/8” 1 LS VI, VII, VIII
19 Commercial Digital centesimal caliper 1 LS VI

Refer also to ITEP for the special tools required to comply with the AMP DM
referenced in the compliance instructions.

SPECIAL TOOLS NOTE

(B1) Required to perform the dye penetrant inspection. Refer to Annex B for special
tools required for the Eddy Current inspection.

C. INDUSTRY SUPPORT INFORMATION

WARRANTY: 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 Main Rotor Damper or a Rod End Assy, as applicable, on a free of charge
basis, except for Consumable Materials & Special Tools.
Please Issue relevant MMIR form to your Warranty Administration Dpt.

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 9 of 58
 3. ACCOMPLISHMENT INSTRUCTIONS
PART I

NOTE
Skip steps 1 thru 3 when performing the inspection on
the MR dampers kept in stock.
1. In accordance with DM 39-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. Put the platform (GG-01-00), or an approved alternative, adjacent to the left side of the
fuselage.
3. Remove the MR dampers. Refer to AMP, see DM n° 39-A-62-22-02-00A-520A-A.

NOTE
It is suggested to start the inspection on all the MR
dampers at the same time.

NOTE
As an alternative to the dye penetrant inspection
described at following step 4, it is allowed to perform
the Eddy Current inspection, according to Annex B.
4. With reference to figures 1 thru 6, perform the dye penetrant inspection of the MR
damper. Operative conditions and inspection sequence shall be compliant with ASTM
E1417, in particular the following steps shall be followed:
4.1 Put the MR damper on a suitable work bench, as shown in figure 2.
4.2 With reference to figure 3, on each spherical bearing, protect the liner with
masking tape as follows:

NOTE
The areas to be inspected are shown in figure 1 (one
side shown, the other is symmetrical), identified by the
red boxes.

CAUTION
Make sure that the solvent does not come in contact
with the spherical bearing liner.
4.2.1 Clean the surface on both sides of both ends with a clean cloth (C011)
soaked with solvent. Let the solvent air dry.

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 10 of 58 REVISION: D - May 28, 2019
 NOTE
If there are slippage marks in the areas to be
inspected, remove the paint, from the damper end
surface only, using solvent.

CAUTION
Make sure that the adhesive masking tape adheres
completely to the damper ends surface, when
performing following step 4.2.2.
4.2.2 Protect the surface all around the areas to be inspected according to
figures 3 thru 5, using adhesive masking tape. Make sure that the tape
is tangent to the bearing seat, according to figures 4 and 5.
4.3 Inspect the damper ends as follows:

CAUTION
Make sure that, during the inspection, the part is
always under appropriate illumination. The lighting
system shall provide at least 1000 lx (100 fc) at the
examination surface. Use the luxmeter to confirm this
condition.
4.3.1 Clean the areas to be inspected, on both sides of both ends, with a
clean cloth (C011) soaked with solvent. Let the solvent air dry.

CAUTION
Make sure that the recipient is clean, dry and free from
any contaminant.
4.3.2 Put a few drops of penetrant in a small recipient (beaker or equivalent).

CAUTION
Make sure not to apply too much penetrant, when
performing following step 4.3.3.
4.3.3 Apply the penetrant with a clean, dry, fine tipped brush on all the areas
to be inspected, according to figure 6 (same application to be carried
out on the other side). Let the penetrant dwell.

NOTE
Dwell time must be at least one hour and no more than
two hours.
4.3.4 Clean the penetrant in excess by first with a clean, dry, lint-free cloth
(C011) or absorbent towelling.

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 11 of 58
 4.3.5 If penetrant in excess remain, remove it with a solvent dampened lint-
free cloth (C011) or towel, until the penetrant in excess has been
completely removed. Let the solvent air dry.
4.3.6 Let the penetrant develop for at least thirty minutes without developer.
4.3.7 Inspect the areas shown in figure 1 using the magnifying glass.
4.3.7.1 If you don’t find indication of cracks, go to step 4.4.
4.3.7.2 If you find indication of cracks, confirm the crack by wipe-off.
4.3.7.3 If, at step 4.3.7.2, you have confirmed presence of cracks on
the body end or on the rod end, contact Product Support
Engineering (CSE.AW139.AW@leonardocompany.com) for
further instruction.
4.4 Remove the adhesive masking tape from all the serviceable damper ends.

CAUTION
Make sure that the solvent does not come in contact
with the spherical bearing liner.
4.5 Clean all the surfaces on both sides of both ends using a cloth (C011) soaked
with solvent until all the penetrant has been removed.
4.6 Mark a black dot, using polyurethane black paint, on the rod end and on the body
end, in positions shown in figure 7.
4.7 If you have removed slippage marks, cleaning the damper end surface at step
4.2.1, restore the slippage mark using the applicable paint colour: yellow, green
or blue. Use commercially available varnish such as thread securing/sealing
product or equivalent alternatives. Let dry for one hour at 25°C, or as otherwise
specified by product specification.
5. Install the MR damper/dampers. Refer to AMP, see DM n° 39-A-62-22-02-00A-720A-A.
6. Remove the platform (GG-01-00) from the left side of the fuselage.
7. Return the helicopter to flight configuration.
8. Record for compliance with part I of this Service Bulletin on the MR damper logcard.
9. Send the attached compliance form to the following mail box:
cse.aw139.aw@leonardocompany.com
As an alternative, gain access to My Communications section on Leonardo WebPortal
and compile the “Service Bulletin Application Communication”.

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 12 of 58 REVISION: D - May 28, 2019
 PART II
1. In accordance with DM 39-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. Put the platform (GG-01-00), or an approved alternative, adjacent to the left side of the
fuselage.
3. Remove the affected MR damper. Refer to AMP, see DM n° 39-A-62-22-02-00A-520A-
A.

NOTE
As an alternative to the dye penetrant inspection
described at following step 4, it is allowed to perform
the Eddy Current inspection, according to Annex B.
4. With reference to figures 1 thru 6, perform the dye penetrant inspection of the affected
MR damper rod end. Operative conditions and inspection sequence shall be compliant
with ASTM E1417, in particular the following steps shall be followed:
4.1 Put the MR damper on a suitable work bench, as shown in figure 2.
4.2 With reference to figure 3 view B, on the rod end spherical bearing, protect the
liner with masking tape as follows:

NOTE
The area to be inspected is shown in figure 1 view B
(one side shown, the other is symmetrical), identified
by the red boxes.

CAUTION
Make sure that the solvent does not come in contact
with the spherical bearing liner.
4.2.1 Clean the surface on both sides of the rod end with a clean cloth
(C011) soaked with solvent. Let the solvent air dry.

NOTE
If there are slippage marks in the areas to be
inspected, remove the paint, from the damper end
surface only, using solvent.

CAUTION
Make sure that the adhesive masking tape adheres
completely to the damper end surface, when
performing following step 4.2.2.

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 13 of 58
 4.2.2 Protect the surface all around the areas to be inspected according to
figures 3 thru 5, using adhesive masking tape. Make sure that the tape
is tangent to the bearing seat, according to figures 4 and 5.
4.3 Inspect the damper rod end as follows:

CAUTION
Make sure that, during the inspection, the part is
always under appropriate illumination. The lighting
system shall provide at least 1000 lx (100 fc) at the
examination surface. Use the luxmeter to confirm this
condition.
4.3.1 Clean the areas to be inspected, on both sides of the rod end, with a
clean cloth (C011) soaked with solvent. Let the solvent air dry.

CAUTION
Make sure that the recipient is clean, dry and free from
any contaminant.
4.3.2 Put a few drops of penetrant in a small recipient (beaker or equivalent).

CAUTION
Make sure not to apply too much penetrant, when
performing following step 4.3.3.
4.3.3 Apply the penetrant with a clean, dry, fine tipped brush on all the areas
to be inspected, according to figure 6 view B (same application to be
carried out on the other side). Let the penetrant dwell.

NOTE
Dwell time must be at least one hour and no more than
two hours.
4.3.4 Clean the penetrant in excess by first with a clean, dry, lint-free cloth
(C011) or absorbent towelling.
4.3.5 If penetrant in excess remain, remove it with a solvent dampened lint-
free cloth (C011) or towel, until the penetrant in excess has been
completely removed. Let the solvent air dry.
4.3.6 Let the penetrant develop for at least thirty minutes without developer.
4.3.7 Inspect the areas shown in figure 1 using the magnifying glass.
4.3.7.1 If you don’t find indication of cracks, go to step 4.4.
4.3.7.2 If you find indication of cracks, confirm the crack by wipe-off.

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 14 of 58 REVISION: D - May 28, 2019
 4.3.7.3 If, at step 4.3.7.2, you have confirmed presence of cracks on
the rod end, contact Product Support Engineering
(CSE.AW139.AW@leonardocompany.com) for further
instruction.
4.4 Remove the adhesive masking tape from the serviceable rod end.

CAUTION
Make sure that the solvent does not come in contact
with the spherical bearing liner.
4.5 Clean all the surfaces on both sides of the rod end using a cloth (C011) soaked
with solvent until all the penetrant has been removed.
4.6 Mark a black dot, using polyurethane black paint, on the rod end, in position
shown in figure 7.
4.7 If you have removed slippage marks, cleaning the damper end surface at step
4.2.1, restore the slippage mark using the applicable paint colour: yellow, green
or blue. Use commercially available varnish such as thread securing/sealing
product or equivalent alternatives. Let dry for one hour at 25°C, or as otherwise
specified by product specification.
5. Install the MR damper. Refer to AMP, see DM n° 39-A-62-22-02-00A-720A-A.
6. Remove the platform (GG-01-00) from the left side of the fuselage.
7. Return the helicopter to flight configuration.
8. Record for compliance with part II of this Service Bulletin on the MR damper logcard.
9. Send the attached compliance form to the following mail box:
cse.aw139.aw@leonardocompany.com
As an alternative, gain access to My Communications section on Leonardo WebPortal
and compile the “Service Bulletin Application Communication”.

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 15 of 58
 PART III
1. In accordance with DM 39-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. Put the platform (GG-01-00), or an approved alternative, adjacent to the left side of the
fuselage.

NOTE
Refer to the “Compliance” section to define the
applicability of the following steps 3 thru 5.
3. With reference to figure 8, turn the MR head to move the applicable MR damper above
the platform and get access to the work area.

NOTE
As an alternative to the detailed inspection described
at following step 4, it is allowed to perform the Eddy
Current inspection, according to Annex B, on the areas
shown in figure 19.
4. With reference to figures 8 and 19, perform a detailed inspection on the MR damper,
using the magnifying glass and mirror:

NOTE
The areas to be inspected on the MR damper are
shown in figure 19 (top side shown, bottom side is
symmetrical).

CAUTION
Make sure that the aliphatic naphtha (C059) does not
come in contact with the spherical bearing liner.
4.1 Clean the surface to be inspected, on both sides of both ends, with a clean cloth
(C011) soaked with aliphatic naphtha (C059).
4.2 Do a detailed inspection of the damper rod end (3) for cracks. If you find cracks,
contact Product Support Engineering (CSE.AW139.AW@leonardocompany.com)
for further instruction.
4.3 Do a detailed inspection of the damper body end (2) for cracks. If you find cracks,
contact Product Support Engineering (CSE.AW139.AW@leonardocompany.com)
for further instruction.
5. Repeat steps 3 and 4 until you have checked all the applicable MR dampers.
6. Remove the platform (GG-01-00) from the left side of the fuselage.

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 16 of 58 REVISION: D - May 28, 2019
 7. Return the helicopter to flight configuration and record for compliance with part III of this
Service Bulletin.

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 17 of 58
 PART IV
1. In accordance with DM 39-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
Refer to the “Compliance” section to define the
applicability of the following steps 2 thru 4.
2. With reference to figure 8, get access to the work area.

NOTE
Damper (1) and/or rod end (3) removal is not
necessary to perform the inspection.
3. With reference to figures 8 and 9 perform the inspection as follows:
3.1 Examine the bearing of the rod end (3) for rotation in the damper seat by looking
for slippage marks misalignment. If you find rotation (as shown in figure 9),
replace the rod end. Refer to AMP, see DM n° 39-A-62-22-02-01A-921A-B.
3.2 Examine the bearing of the body end (2) for rotation in the damper seat by looking
for slippage marks misalignment. If you find rotation (as shown in figure 9),
replace the damper (1). Refer to AMP, see DM n° 39-A-62-22-02-00A-520A-A
and 39-A-62-22-02-00A-720A-A.

4. Repeat step 3 to inspect the other MR dampers.

5. Return the helicopter to flight configuration and record for compliance with Part IV of this
Service Bulletin on the helicopter logbook.

6. Send the attached compliance form to the following mail box:

cse.aw139.aw@leonardocompany.com
As an alternative, gain access to My Communications section on Leonardo WebPortal
and compile the “Service Bulletin Application Communication”.

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 18 of 58 REVISION: D - May 28, 2019
 PART V
1. In accordance with DM 39-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. With reference to figure 10, get access to the work area.

3. With reference to figure 11, do a visual inspection of the lag damper broached ring nut
(6).

NOTE
Damper (1) and rod end (3) removal is not necessary
to perform the inspection. The parts are shown
removed/disassembled for better clarity purposes only.
3.1 With reference to figures 11 and 12, using a mirror, check the four teeth of the
broached ring (5) and relative four damper piston slots (4) for damage, correct
engagement and alignment.
3.2 In case of findings (a sample of possible damage is shown in figure 13) contact
Product Support Engineering (CSE.AW139.AW@leonardocompany.com) for
further instruction.
4. Repeat step 3 to inspect the other MR dampers.
5. Return the helicopter to flight configuration and record for compliance with Part V of this
Service Bulletin on the helicopter logbook.
6. Send the attached compliance form to the following mail box:
cse.aw139.aw@leonardocompany.com
As an alternative, gain access to My Communications section on Leonardo WebPortal
and compile the “Service Bulletin Application Communication”.

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 19 of 58
 PART VI
1. In accordance with DM 39-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. Put the platform (GG-01-00), or an approved alternative, adjacent to the left side of the
fuselage.
3. With reference to figure 16, turn the MR head to move the applicable MR damper above
the platform and get access to the work area.
4. With reference to figures 16 thru 18, perform the following checks on the first MR
damper:

NOTE
Before starting the friction check, lightly rotate the body
end around the damper axis to put it near the middle
position (0°).
4.1 Perform a bearing friction torque check of the damper body end according to
figure 18 view G. If the value is higher than 30.0 Nm (265.5 lb in), proceed with
step 4.1.1, otherwise go to step 4.2.
4.1.1 Replace the MR damper (see AMP DM n° 39-A-62-22-02-00A-520A-A
and DM n° 39-A-62-22-02-00A-720A-A).
4.1.2 Go to step 4.3.
4.2 Perform a bearing friction torque check of the damper rod end according to figure
18 view H. If the value is higher than 30.0 Nm (265.5 lb in), replace the damper
rod end (see AMP DM n° 39-A-62-22-02-01A-921A-B), otherwise proceed with
step 4.3.
4.3 With reference to figures 16 and 17 do a detailed inspection for wear of the
damper anti-rotation block as follows:
4.3.1 Mark a reference line on the MR hub lower arm at a distance of 55 mm
(2.16 in) from the body end blocking ring, according to figure 17 view
E. Use a digital centesimal caliper to measure the distance and an
erasable ink pen to mark the reference line.
4.3.2 With reference to figure 16 section D-D, move the body end to the fully
up position using a torque wrench, in order to measure dimension “A”.
4.3.3 Measure dimension “A” from the lower surface of the MR hub arm to
the lower surface of the body end, alongside the reference line
previously marked, using a digital centesimal caliper, as shown in
figure 17 view F.

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 20 of 58 REVISION: D - May 28, 2019
 4.3.4 Make sure that the measured dimension “A” is lower than 26.90 mm
(1.06 in).
4.3.5 With reference to figure 16 section D-D, move the body end to the fully
down position using a torque wrench, in order to measure dimension
“B”.
4.3.6 Measure dimension “B” from the lower surface of the MR hub arm to
the lower surface of the body end, alongside the reference line
previously marked, using a digital centesimal caliper, as shown in
figure 17 view F.
4.3.7 Make sure that the measured dimension “B” is higher than 24.35 mm
(0.96 in).
4.3.8 If the dimension measured are not within the given limits, replace the
anti-rotation block with a new one. Refer to AMP, see DM n° 39-A-62-
22-07-00A-520A-A and DM n° 39-A-62-22-07-00A-720A-A.
5. Repeat steps 3 and 4 until you have checked all the MR dampers.
6. Remove the platform (GG-01-00) from the left side of the fuselage.
7. Return the helicopter to flight configuration and record for compliance with part VI of this
Service Bulletin on the helicopter logbook.
8. Send the attached compliance form to the following mail box:
cse.aw139.aw@leonardocompany.com
As an alternative, gain access to My Communications section on Leonardo WebPortal
and compile the “Service Bulletin Application Communication”.

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 21 of 58
 PART VII
1. In accordance with DM 39-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. Put the platform (GG-01-00), or an approved alternative, adjacent to the left side of the
fuselage.
3. Get access to the cockpit. Set the rotor brake lever to OFF.
4. With reference to figure 14, turn the MR head to move the applicable MR damper above
the platform and get access to the work area.

NOTE
Do not remove the damper rod end (2) from the pitch
control lever during this procedure. The damper (1) is
shown removed in some figures for better clarity
purposes only.
5. With reference to figure 14 section C-C, do a visual inspection of the damper rod end
installation.
5.1 Make sure that the special washer P/N 3G6220A05052 is installed.
5.2 If the special washer P/N 3G6220A05052 is present, go to step 6.
5.3 If the special washer P/N 3G6220A05052 is not present, do as follows:
5.3.1 Remove the MR damper. Refer to AMP, see DM n° 39-A-62-22-02-
00A-520A-A.
5.3.2 Perform disassembly, inspections and assembly of the damper as
prescribed by the compliance instructions (paragraph 8) in Annex A.

CAUTION
Install special washer P/N 3G6220A05052 according to
BT 139-402 when you install the lag damper at
following step 5.3.3.
5.3.3 Install the MR damper. Refer to AMP, see DM n° 39-A-62-22-02-00A-
720A-A.
5.3.4 Go to step 7.
6. With reference to figure 14 view A and to figure 15, check the torque of the damper
broached ring nut (3) on the first MR damper.

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 22 of 58 REVISION: D - May 28, 2019
 WARNING
MAKE SURE THAT THE ROTOR BRAKE ENGAGES
WHEN YOU PERFORM THE TORQUE CHECK. AN
INJURY TO PERSONS OR DAMAGE TO THE
EQUIPMENT CAN OCCUR IF THE MAIN ROTOR
HEAD TURNS.
6.1 Set the rotor brake lever to ON.
6.2 Get access to the damper rod end (2).

NOTE
Identify and record the wiring scheme before removing
the safety wire.
6.3 Cut and remove the safety wire from the damper. Discard the safety wire.
6.4 With reference to figures 14 and 15, move the ring nut (3) away from the
broaching of the rod end (2) toward the damper body (1). Use a plastic mallet
and a soft plunger to disengage it from the broaching of the rod end (2). When
you do this operation, make sure not to disengage the ring nut (3) from the lock
ring (5).
6.5 Protect the rod end (2) with a film of antifretting tape PERMACEL P422 or
equivalent.
CAUTION
To torque the ring nut at following step 6.6, make sure
to rotate the ring nut clockwise (looking outboard from
the MR hub), according to figure 15.
6.6 Set the torque wrench to 53 Nm (469 lb in), lock the rod end with a spanner, and
try to torque the ring nut (3).
6.6.1 Verify that the ring nut (3) does not rotate with respect to the rod end
(2).
6.6.2 If rotation is not found go to step 6.7, otherwise proceed with following
step 6.6.3.
6.6.3 Remove the MR damper. Refer to AMP, see DM n° 39-A-62-22-02-
00A-520A-A.
6.6.4 Perform disassembly, inspections and assembly of the MR damper as
prescribed by steps 8 thru 23 of the compliance instructions (paragraph
8) in annex A.
6.6.5 Install the MR damper. Refer to AMP, see DM n° 39-A-62-22-02-00A-
720A-A.

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 23 of 58
 6.6.6 Go to step 7.
6.7 Torque the ring nut (3) to 63 Nm (558 lb in).
6.8 After torque application, move the ring nut (3) backwards to the damper (1) and
do as follows:
6.8.1 Make sure that the broached teeth (4) of the rod end are perfectly
aligned to the lock ring (5).
6.8.2 If they are aligned, go to step 6.11, otherwise proceed with step 6.9.
CAUTION
Do not release the torque to align the teeth. Unscrew
action will introduce potential loosening of rod end
during in flight operation.
6.9 If the teeth are misaligned, increase the torque value to reach the correct
alignment, up to a maximum of 80 Nm (708 lb in). Do not exceed 80 Nm (708 lb
in).
6.10 If it is not possible to align the teeth within this range, do as follows:
6.10.1 Remove the MR damper. Refer to AMP, see DM n° 39-A-62-22-02-
00A-520A-A.
6.10.2 Remove the rod end (2) from the MR damper according to the
applicable steps of AMP DM n° 39-A-62-22-02-01A-921A-B.
6.10.3 Perform steps 19 thru 23 of the compliance instructions (paragraph 8)
in Annex A.
6.10.4 Install the MR damper. Refer to AMP, see DM n° 39-A-62-22-02-00A-
720A-A.
6.10.5 Go to step 7.
6.11 Remove the protective tape from the rod end (2).
6.12 Make sure that there are not scratches or dents on the rod end (2).
6.13 Move the ring nut (3) in its position on the broaching of the rod end (2). Do this
until top and bottom holes on the ring nut (3) come in view for the installation of
the wire.
6.14 Safety the damper with new safety wire (C241), according to the scheme
recorded at step 6.3.
6.15 Record for compliance with part VII of this Service Bulletin on the component
logcard.
7. Repeat steps 3 thru 6 until you have checked all the MR dampers.
8. Remove the platform (GG-01-00) from the left side of the fuselage.
9. Return the helicopter to flight configuration.
10. Record for compliance with part VII of this Service Bulletin on the helicopter logbook.

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 24 of 58 REVISION: D - May 28, 2019
 11. Send the attached compliance form to the following mail box:
cse.aw139.aw@leonardocompany.com
As an alternative, gain access to My Communications section on Leonardo WebPortal
and compile the “Service Bulletin Application Communication”.

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 25 of 58
 PART VIII
1. Perform the torque check on the MR damper according to the compliance instructions
(paragraph 8) in Annex A.

NOTE
If the damper is in new condition (zero FH since new),
when performing the torque check according to Annex
A, do not apply steps 8.7 thru 8.16.
2. Send the attached compliance form to the following mail box:
cse.aw139.aw@leonardocompany.com
As an alternative, gain access to My Communications section on Leonardo WebPortal
and compile the “Service Bulletin Application Communication”.

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 26 of 58 REVISION: D - May 28, 2019
 VIEW A VIEW B

BODY END ROD END

Areas to be inspected (two on body end and two on rod end) shown in red boxes
(one side shown, the other is symmetrical)

Figure 1

Damper must be removed from the helicopter and positioned on a suitable work bench

Figure 2

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 27 of 58
 VIEW A VIEW B

BODY END ROD END

Body end and rod end must be protected with masking tape as shown (on both sides)

Figure 3

On the rod end apply the masking tape as shown. Red line (shown on the picture for
reference only) is tangent to the spherical bearing seat (yellow line, shown on the
picture for reference only).

Figure 4

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 28 of 58 REVISION: D - May 28, 2019
 On the body end apply the masking tape as shown. Red line (shown on the picture for
reference only) is tangent to the spherical bearing seat (yellow line, shown on the
picture for reference only).

Figure 5

VIEW B VIEW A

ROD END BODY END

Apply dye penetrant on both sides of both ends in the areas shown.
Figure 6

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 29 of 58
 Figure 7
S.B. N°139-450 ALERT
DATE: April 20, 2016
Page 30 of 58 REVISION: D - May 28, 2019
 Figure 8
S.B. N°139-450 ALERT
DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 31 of 58
 Sample of bearing rotation (slippage marks misalignment)

Figure 9
S.B. N°139-450 ALERT
DATE: April 20, 2016
Page 32 of 58 REVISION: D - May 28, 2019
 Figure 10
S.B. N°139-450 ALERT
DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 33 of 58
 Figure 11
S.B. N°139-450 ALERT
DATE: April 20, 2016
Page 34 of 58 REVISION: D - May 28, 2019
 View A

PISTON SLOT BROACHED

RING TOOTH

Area to be inspected for damage, correct engagement and alignment

Figure 12
S.B. N°139-450 ALERT
DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 35 of 58
 Sample of damage on piston slot

Figure 13
S.B. N°139-450 ALERT
DATE: April 20, 2016
Page 36 of 58 REVISION: D - May 28, 2019
 Figure 14
S.B. N°139-450 ALERT
DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 37 of 58
 Figure 15
S.B. N°139-450 ALERT
DATE: April 20, 2016
Page 38 of 58 REVISION: D - May 28, 2019
 Figure 16
S.B. N°139-450 ALERT
DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 39 of 58
 Figure 17
S.B. N°139-450 ALERT
DATE: April 20, 2016
Page 40 of 58 REVISION: D - May 28, 2019
 Figure 18
S.B. N°139-450 ALERT
DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 41 of 58
 Figure 19
S.B. N°139-450 ALERT
DATE: April 20, 2016
Page 42 of 58 REVISION: D - May 28, 2019
 ANNEX A

ANNEX A
MAG IN SERVICE QUERY RECORD N° ISQR-16-002

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 43 of 58
 ANNEX A

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 44 of 58 REVISION: D - May 28, 2019
 ANNEX A

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 45 of 58
 ANNEX A

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 46 of 58 REVISION: D - May 28, 2019
 ANNEX A

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 47 of 58
 ANNEX A

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 48 of 58 REVISION: D - May 28, 2019
 ANNEX A

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 49 of 58
 ANNEX A

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 50 of 58 REVISION: D - May 28, 2019
 ANNEX B

ANNEX B
MR DAMPER EDDY CURRENT INSPECTION

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 51 of 58
 ANNEX B

REQUIRED EQUIPMENT

For this inspection the following equipment is required:

 Eddy Current instrument model MIZ-21 SR manufactured by Zetec Inc. (US) (see NOTE
below),
 90° pencil, absolute shielded probe with frequency range 200kHz-2MHz (manufactured by
VM Products Inc. USA with adaptor VM99Z21-M/H for Zetec instrument) and relevant
cable (see NOTE below),
 a flat calibration block be made in 15-5PH Steel with a reference notch of 0.5 mm depth
manufactured by electro discharge machining (see figure B3),
 adhesive PTFE tape to protect the tip of the probe from wear damage,
 Solvent or aliphatic naphtha (C059).

NOTE

Other instruments and probes can be used provided that the following mandatory
conditions are observed:

 the probe is absolute and shielded type with central frequency range of 2.0MHz;
 the system “instrument plus probe” shall obtain equivalent results from the calibration;
 the setup is at least carried out by a Level 2 in accordance with EN4179/NAS410 and
the relevant Work Instruction is approved by the Level 3 in accordance with
EN4179/NAS410.

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 52 of 58 REVISION: D - May 28, 2019
 ANNEX B

COMPLIANCE INSTRUCTIONS

WARNING
THE INSPECTIONS PERFORMED IN ACCORDANCE
WITH THIS PROCEDURE SHALL BE CARRIED OUT
BY PERSONNEL QUALIFIED AT LEAST LEVEL 2 IN
THE EDDY CURRENT METHOD IN ACCORDANCE
WITH THE REQUIREMENTS OF EN4179/NAS410.

NOTE
As required by PART I, PART II and PART III of this
Service Bulletin, the inspection areas are localised on
the body end and rod end close to the spherical
bearing. Refer to figures B1 and B2 to identify the
areas on body end and rod end, respectively.

CAUTION
Make sure that the solvent does not come in contact
with the spherical bearing liner.
1. Make sure that the whole surfaces of the areas of inspection are free from any grease,
scale, conductive sealants or other excessive contaminants that can interfere with the
inspections. If necessary, clean the surface on both sides with a clean cloth (C011)
soaked with solvent. Let the solvent air dry.

CAUTION
During the inspection, it is important to:
 always maintain the probe as perpendicular as
possible to the surface;
 move it slowly and uniformly;
 take care to the signal from the edge effect.
2. Connect the probe on the instrument by relevant cable.
3. Switch on the instrument and set up the parameters listed in figure B4.
4. Perform instrument calibration as follows:

NOTE
The calibration shall be carried out before the
inspection and rechecked after the end of the
inspection; it shall be performed on the requested
reference block in accordance with steps 4.1 thru 4.3.
4.1 Put the sensor of the probe on the reference standard away from the notch.

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 53 of 58
 ANNEX B

4.2 Press the compensation key and adjust the phase of the instrument in a way that
the lift-off signal results in horizontal deflection from the centre to the left, so that
it is clearly distinguished from the defect indication (see trace A on Figure B4),
4.3 Perform the scanning inspection on the reference block to verify that, in
correspondence of the reference notch 0.5 mm deep, a vertical deflection signal
and at least of four main divisions of the screen or at least 80% of full screen is
obtained (see trace B on Figure B4).
5. Perform the inspection as follows:

NOTE
Figures B1 and B2 are related to body end and rod
end, respectively. Performing the inspection described
in steps 5.1 thru 5.4, refer to the applicable figure for
the component to be inspected.
5.1 Put the probe on the area identified “balancing/compensation” in figure B1 / B2
and perform the balancing/compensation. Adjust the phase in a way that the lift-
off signal results in horizontal deflection.
5.2 Perform the detailed examination on the inspection areas identified in figure B1 /
B2 using circular path directions and, if possible, using the chamfering edge to
drive the sensor.

NOTE
Each indication of crack is typically associated with a
rapid variation of the signal on the screen in the
direction close to that due to the reference notch.
5.3 Process and consider relevant any vertical deflection, unless it can be attributed
to lift-off or edge effect. If any vertical deflection is found, verify the instrument
calibration and repeat the inspection to confirm the crack.
5.4 Recheck the instrument calibration as described in step 4.

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 54 of 58 REVISION: D - May 28, 2019
 ANNEX B

Upper side

Body end, inspection areas Balancing/compensation area

Lower side

Balancing/compensation area

Body end, inspection areas

Areas of inspection and balancing for Body end

Figure B1

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 55 of 58
 ANNEX B

Upper side

Balancing/compensation area

Rod end, inspection areas

Lower side

Balancing/compensation area

Rod end, inspection areas

Areas of inspection and balancing for Rod end

Figure B2

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 56 of 58 REVISION: D - May 28, 2019
 ANNEX B

REFERENCE STANDARD BLOCKS FOR EDDY CURRENT

NOTE

 The dimensions are in mm with ± 0,7 mm of tolerances for all the dimensions a
part from those of the notch (*) that shall be not higher than ± 0.02 mm; the
surface shall be flat and parallel within ± 0.05 mm; the roughness shall be equal
or better than 63 RMS.
 The reference notch shall be carried out by machining or EDM

Figure B3

S.B. N°139-450 ALERT

DATE: April 20, 2016
REVISION: D - May 28, 2019 Page 57 of 58
 ANNEX B

SETUP PARAMETERS FOR THE ZETEC “MIZ-21 SR” INSTRUMENT

90° absolute and shielded probe
EC F1 TEST DISP1 SRC F1 ALM SRC D1

SETUP# #29 MODE X-Y ALARM IN

CONFIG NAME neglect V SCALE D1 02 CHNG CENT

FREQ1 2.0M H SCALE D1 07 CHNG SIZE

024 (horizontal,
DIFFR F1 004 PHASE D1 OUTPUT S
as necessary)

GAIN F1 46 POSITION D1 neglect STOR SCN0

MARK/CLR #0 LPS 000 250 RULER OFF

AUTOSET F1 SCREEN A ON LCD ADJ

Typical signal from the calibration (A = lift-off signal, B = indication from reference notch 0.5
mm deep).

Figure B4

S.B. N°139-450 ALERT

DATE: April 20, 2016
Page 58 of 58 REVISION: D - May 28, 2019
 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.