No. AS350-05.01.02
Civil version(s): B2, B3
Revision 0 2021-06-18 Page 1/6
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SERVICE BULLETIN
PROTECTIVE MEASURE
TIME LIMITS - MAINTENANCE CHECKS - Main rotor
Inspection of the Main Rotor Mast (MRM) upper housing
ATA: 62
Revision No. Date of issue
Revision 0 2021-06-18
Summary:
The purpose of this Service Bulletin is to introduce a detailed inspection of the MRM upper housing at
5700 Flight Hours or 72 months and 180 days.
Compliance:
Airbus Helicopters recommends that you comply with this Service Bulletin.
For the attention of

No. AS350-05.01.02
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1. PLANNING INFORMATION
1.A. EFFECTIVITY
1.A.1. Helicopters/installed equipment or parts
Helicopters AS350 versions B2 and B3.
1.A.2. Non-installed equipment or parts
MRM upper housing all Part Numbers (P/N).
1.B. ASSOCIATED REQUIREMENTS
Not applicable.
1.C. REASON
A crack was found on the MRM upper housing during a 72 months inspection performed in a maintenance
center.
The purpose of this Service Bulletin is to introduce a detailed inspection of the MRM upper housing at
5700 Flight Hours or 72 months and 180 days.
1.D. DESCRIPTION
This Service Bulletin includes the work steps that follow:
- Do a detailed inspection of the MRM upper housing.
Then,
- Comply with the applicable Master Servicing Manual (MSM).
1.E. COMPLIANCE
1.E.1. Compliance at H/C manufacturer level
Not applicable.
1.E.2. Compliance in service
Helicopters/installed equipment or parts:
It is the operator who does the work on the helicopter.
Airbus Helicopters recommends that you comply with paragraphs 3. of this Service Bulletin during the next
maintenance scheduled at 5700 Flight Hours or 72 months and 180 days (the first limit you get to is
applicable).
Then,
Comply with the applicable Master Servicing Manual (MSM).

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Non-installed equipment or parts:
Before you install a MRM upper housing, do a check of the stock and change when applicable as given in
paragraph 3.B.2.
1.F. APPROVAL
Approval of modifications:
Not applicable.
Approval of this document:
The technical information contained in this Service Bulletin Revision 0 was approved on June 18, 2021 under
the authority of EASA Design Organization Approval No. 21J.700 for civil version helicopters subject to an
Airworthiness Certificate.
The technical information contained in this Service Bulletin Revision 0 was approved on June 18, 2021 under
the prerogatives of the recognition of design capability FRA21J-002-DGA for French Government
helicopters.
1.G. MANPOWER
Airbus Helicopters recommends that the personnel who will do this Service Bulletin have this qualification:
Qualification: 1 Mechanical Technician.
The man-hours are an estimate given for information only and for a standard helicopter configuration.
Estimated Man-hours: 8 hours for the Mechanical Technician.
The helicopter downtime is an estimate given for information only and for a standard helicopter configuration.
The estimate of the helicopter downtime is 1 day.
1.H. WEIGHT AND BALANCE
Not applicable.
1.I. POWER CONSUMPTION
Not applicable.
1.J. SOFTWARE UPGRADES/UPDATES
Not applicable.

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1.K. REFERENCES
Aircraft Maintenance Manual (AMM):
AMM: 62-31-00,6-14: Check - Detailed Inspection of the upper housing - Rotor mast
Standard Practices Manual (MTC):
MTC: 20-07-03-406: Instructions applicable when working on an aircraft electrical circuit and power
generating systems - Technical instructions
MTC: 20-07-03-408: Appearance checks on an aircraft after an inspection or repair - Technical instructions
Information Notices (IN):
IN: 3481-I-00: The Marketplace: an AirbusWorld eOrdering service
IN: 3643-I-00: Introduction of the digital Service Bulletin reporting R-Tex
1.L. OTHER AFFECTED PUBLICATIONS
This modification was added to the manuals that follow:
- Aircraft Maintenance Manual (AMM)
- Master Servicing Manual (MSM).
These documents are distributed as per subscription.
1.M. PART INTERCHANGEABILITY OR MIXABILITY
Not applicable.

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2. EQUIPMENT OR PARTS INFORMATION
2.A. EQUIPMENT OR PARTS: PRICE - AVAILABILITY - PROCUREMENT
Not applicable.
2.B. LOGISTIC INFORMATION
Not applicable.
2.C. EQUIPMENT OR PARTS REQUIRED PER HELICOPTER/COMPONENT
Not applicable.
2.D. EQUIPMENT OR PARTS TO BE RETURNED
Not applicable.

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3. ACCOMPLISHMENT INSTRUCTIONS
3.A. GENERAL
Not applicable.
3.B. WORK STEPS
3.B.1. Preliminary steps
- Disconnect all the electrical power supplies, refer to Work Card 20-07-03-406 (MTC).
- Install the access equipment.
3.B.2. Procedure
Do a detailed inspection of the upper housing of the MRM, refer to the Task 62-31-00,6-14 (AMM).
3.B.3. Final steps
- Do an aspect check on the helicopter after inspection or repair, refer to Work Card 20-07-03-408 (MTC).
- Connect all the electrical power supplies as per Work Card 20-07-03-406 (MTC).
- Remove the access equipment.
3.C. RECORD OF COMPLIANCE
Compliance with this document:
- Record the full compliance with this Service Bulletin, with the revision number, in the helicopter documents.
- Record compliance with this Service Bulletin (see IN 3643-I-00 for instructions):
QR-Code or hypertext link
NOTE
The recording of compliance with
Service Bulletins in the R-Tex tool does not replace the
recording in the helicopter documents.
SB AS350 05.01.02
3.D. OPERATING AND MAINTENANCE INSTRUCTIONS
Not applicable.