ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL SUPPLEMENT 1
Rev. 8
1-1 May 1/17
SECTION 1
INTRODUCTION
1-1. Aircraft Effectivity
A. The data presented in this TH-28/480 Series Maintenance Manual Supplement is
applicable to all Enstrom 480 and 480B model helicopters equipped with the optional air
conditioning system, Part Numbers 4222176-1, 4220176-2, 4220176-3, 4220176-5, 4220176-6,
or 4220176-7.
1-2. Supplemental Changes and Revisions
A. Subsequent to the publication of the initial issue of this supplement, changes in the air
conditioning equipment, support concepts and procedures, as well as information developed by
experience may affect the contents of this supplement. To ensure that coverage in the
supplement continues to reflect such changes, revised information is released by one of the
following methods:
1. Revision - A revision alters portions of the manual by replacement, addition, and/or
removal of pages.
2. Reissue - A reissue of this supplement will occur when the amount of changes
warrants complete reissue.
1-3. Service Document Publications
1. Service Directive Bulletins - Used to direct the owner/operator and/or maintenance
personnel to make mandatory changes, improvements, or inspections to the aircraft
applicable to the entire or a segment of the aircraft fleet that are typically
safety/airworthiness related. The
information provided in the Service Directive Bulletins
will be incorporated in the
maintenance manual supplement as needed at a later date.
At the time of incorporation, the Service
Directive Bulletin is superseded by the
maintenance manual supplement, and accomplishment or sign-
off of the Service
Directive Bulletin in the maintenance records book is no longer required.
A detailed
entry should be made in the maintenance records to indicate that the Service
Directive
Bulletin is superseded by the maintenance manual supplement.
2. Service Information Letters - Used to transmit information, recommendations, and
general
service instructions to the aircraft owner/operator and/or maintenance
personnel applicable to the entire or a segment of the aircraft fleet. The
information
provided in the Service Information Letters will be incorporated into the
maintenance
manual supplement as needed at a later date.
3. Service Instructions – Used to provide the owner/operator and/or maintenance
personnel with information that is applicable to specific aircraft and does not meet the
criteria of a Service Information Letter or Service Directive Bulletin. Service Instructions
will not be distributed to the entire fleet.
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