Enstrom TH-28/480 Series Maintenance Manual
ENSTROM 480B TURBINE · Maintenance Manual
Overview
The Enstrom TH-28/480 Series Maintenance Manual provides detailed maintenance instructions and airworthiness limitations for the Enstrom TH-28/480 helicopter series. It includes revisions and updates to ensure compliance with FAA and EASA regulations.
- Revision 28 dated 20 May 2025 applies to the manual.
- The manual includes an Airworthiness Limitations section approved by the FAA.
- Inspections and maintenance must comply with 14 CFR §§ 43.16 and 91.403.
- The document is proprietary to Enstrom Helicopter Corporation.
- Users must have written authorization to reproduce or disclose the manual.
- The manual contains effective page lists for tracking revisions.
Summary written by AI from the source document. Check the original before relying on it. See which parts of Sprinkle are written by AI.
Reference only, not for flight. Use the current approved manual for your aircraft. See terms, section 5.
Document
Source
Copy found at enstromhelicopter.com. Sprinkle hosts a reference copy with an added summary, specifications and searchable full text.
Document details
- Type ·
- Maintenance Manual
- Year ·
- 2025
- File size ·
- 2.0 MB
- Copy found at ·
- enstromhelicopter.com
- Language ·
- en
What is the Enstrom TH-28/480 Series Maintenance Manual?
The Enstrom TH-28/480 Series Maintenance Manual is a maintenance manual for the ENSTROM 480B TURBINE, dated 2025.
What year was the Enstrom TH-28/480 Series Maintenance Manual published?
The Enstrom TH-28/480 Series Maintenance Manual — the ENSTROM 480B TURBINE maintenance manual on file — is dated 2025.
Common. More common than 77% of the aircraft models we track.
Most owners only have the POH. Here's the essential set for the ENSTROM 480B TURBINE.
- Pilot's Operating Handbook / AFM
- Checklist
- Maintenance Manual
- Parts Catalog (IPC)
- Systems & Wiring
- Service Bulletins on file
- Type Certificate (TCDS)
ENSTROM 480B TURBINE for sale now
Free — save the 480 to your watchlist and track it in one place.
More ENSTROM 480B TURBINEmanuals & documents
- SIL Turbine IndexService Bulletins
- ENSTROM 480B TURBINE Model GuideModel Guide
- ENSTROM 480B OPERATOR'S MANUALPilot's Operating Handbook
- ENSTROM 480B OPERATOR’S MANUAL AND FAA APPROVED ROTORCRAFT FLIGHT MANUALPilot's Operating Handbook
- SERVICE INFORMATION LETTER NO. T-039Service Bulletins
- ENSTROM TH-28/480 SERIES ILLUSTRATED PARTS CATALOGParts Catalog
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In this document
Airworthiness Limitations
Specifies inspections and maintenance required under FAA regulations.
Effective Page List
Tracks revisions and updates to the manual pages.
Proprietary Information
Details the proprietary nature of the manual and reproduction restrictions.
Summary written by AI from the source document. Check the original before relying on it. See which parts of Sprinkle are written by AI.
Full document text
2209 22nd Street | Menominee, MI 49858 EnstromHelicopter.com | 906.863.1200 October 7, 2025 Page 1 of 1 Enstrom TH-28/480 Series Maintenance Manual Revision 28 Change Pages Revision 28, dated 20 May 2025, applies to the Enstrom TH-28/480 Series Maintenance Manual, 2001 Edition. Place this cover sheet behind the “Record of Revisions” card after removing and inserting the pages listed below. Remove Pages Insert Pages Cover through ii Cover through ii vii through xviii vii through xx MM-1-5 through MM-1-6 MM-1-5 through MM-1-6 MM-2-11 through MM-2-16 MM-2-11 through MM-2-16 MM-3-1 through MM-3-4 MM-3-1 through MM-3-4 MM-4-1 through MM-4-2 MM-4-1 through MM-4-2 MM-4-7 through MM-4-10 MM-4-7 through MM-4-10 MM-4-39 through MM-4-40 MM-4-39 through MM-4-40 MM-4-43 through MM-4-48 MM-4-43 through MM-4-48 MM-4-51 through MM-4-52 MM-4-51 through MM-4-52 MM-4-57 through MM-4-58 MM-4-57 through MM-4-58 MM-4-61 through MM-4-62 MM-4-61 through MM-4-62 MM-4-81 through MM-4-82 MM-4-81 through MM-4-82 MM-4-91 through MM-4-92 MM-4-91 through MM-4-92 MM-5-7 through MM-5-8 MM-5-7 through MM-5-8 MM-6-5 through MM-6-6 MM-6-5 through MM-6-6 MM-6-61 through MM-6-64 MM-6-61 through MM-6-64 MM-6-68.1 through MM-6-68.2 MM-6-68.1 through MM-6-68.2 MM-7-33 through MM-7-38 MM-7-33 through MM-7-38 MM-7-41 through MM-7-42 MM-7-41 through MM-7-42 MM-8-7 through MM-8-8 MM-8-7 through MM-8-8 MM-8-18.1 through MM-8-18.4 MM-8-18.1 through MM-8-18.4 MM-9-15 through MM-9-16 MM-9-15 through MM-9-16 MM-9-27 through MM-9-28 MM-9-27 through MM-9-28 MM-9-49 through MM-9-50 MM-9-49 through MM-9-50 MM-10-1 through MM-10-36 MM-10-1 through MM-10-66 MM-11-9 through MM-11-10 MM-11-9 through MM-11-10 MM-12-79 through MM-12-80 MM-12-79 through MM-12-80 MM-12-83 through MM-12-84 MM-12-83 through MM-12-84 MM-12-111 through MM-12-112 MM-12-111 through MM-12-112 MM-12-115 through MM-12-116 MM-12-115 through MM-12-116 ........................................................................... End of List .......................................................................... . INTENTIONALLY LEFT BLANK ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL The Airworthiness Limitations section is FAA approved and specifies inspections and other maintenance required under 14 CFR §§ 43.16 and 91.403 of the Federal Aviation Regulations unless an alternative program has been FAA approved. For EASA approval, this Airworthiness Limitations section is approved and variations must also be approved. Enstrom Helicopter Corporation 2209 22nd Street Menominee, Michigan 49858-3515 Telephone: 906-863-1200 Fax: 906-863-6821 www.enstromhelicopter.com ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 ii 20 May 2025 © 2001 Enstrom Helicopter Corporation The information contained herein is proprietary to the Enstrom Helicopter Corporation and shall not be reproduced or disclosed in whole or in part for any purpose except when such user possesses direct, written authorization from Enstrom Helicopter Corporation. ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 vii 20 May 2025 EFFECTIVE PAGE LIST Page Date Page Date i No Date ii 20 May 2025 iii 27 Jan 2025 iv Apr 25/13 v 27 Jan 2025 vi 27 Jan 2025 vii 20 May 2025 viii 20 May 2025 ix 20 May 2025 x 27 Jan 2025 xi 20 May 2025 xii 20 May 2025 xiii 20 May 2025 xiv 20 May 2025 xv 20 May 2025 xvi 20 May 2025 xvii 20 May 2025 xviii 20 May 2025 xix 20 May 2025 xx 20 May 2025 MM-1-1 27 Jan 2025 MM-1-2 Feb 9/01 MM-1-3 27 Jan 2025 MM-1-4 Feb 28/2020 MM-1-5 27 Jan 2025 MM-1-6 20 May 2025 MM-1-7 27 Jan 2025 MM-1-8 27 Jan 2025 MM-2-1 27 Jan 2025 MM-2-2 Oct 20/09 MM-2-3 Apr 25/13 MM-2-4 Apr 25/13 MM-2-5 Feb 28/2020 MM-2-6 Apr 25/13 MM-2-7 Apr 25/13 MM-2-8 Feb 9/01 MM-2-9 27 Jan 2025 MM-2-10 Feb 9/01 MM-2-11 27 Jan 2025 MM-2-12 20 May 2025 MM-2-13 20 May 2025 MM-2-14 Jul 3/15 MM-2-15 20 May 2025 MM-2-16 20 May 2025 MM-2-17 27 Jan 2025 MM-2-18 Feb 28/2020 MM-2-19 Feb 28/2020 MM-2-20 Feb 28/2020 MM-2-21 Feb 28/2020 MM-2-22 27 Jan 2025 MM-2-23 27 Jan 2025 MM-2-24 27 Jan 2025 MM-3-1 27 Jan 2025 MM-3-2 20 May 2025 MM-3-3 20 May 2025 MM-3-4 Dec 4/15 MM-3-5 27 Jan 2025 MM-3-6 Dec 4/15 MM-3-7 Dec 4/15 MM-3-8 Aug 22/16 MM-3-9 27 Jan 2025 MM-3-10 Dec 4/15 MM-4-1 27 Jan 2025 MM-4-2 20 May 2025 MM-4-3 27 Jan 2025 MM-4-4 Jun 24/11 MM-4-5 27 Jan 2025 MM-4-6 27 Jan 2025 MM-4-7 20 May 2025 MM-4-8 27 Jan 2025 MM-4-9 20 May 2025 MM-4-10 27 Jan 2025 MM-4-11 27 Jan 2025 MM-4-12 27 Jan 2025 MM-4-12.1 27 Jan 2025 MM-4-12.2 Oct 20/09 MM-4-13 27 Jan 2025 MM-4-14 Oct 20/09 MM-4-15 Feb 20/08 MM-4-16 Apr 25/13 MM-4-17 Oct 20/09 MM-4-18 Jun 24/11 MM-4-19 Jul 3/15 MM-4-20 Jul 3/15 MM-4-21 Feb 28/2020 MM-4-22 Feb 28/2020 MM-4-22.1 27 Jan 2025 MM-4-22.2 27 Jan 2025 MM-4-23 27 Jan 2025 MM-4-24 27 Jan 2025 MM-4-25 27 Jan 2025 MM-4-26 27 Jan 2025 MM-4-27 27 Jan 2025 MM-4-28 27 Jan 2025 MM-4-29 27 Jan 2025 MM-4-30 27 Jan 2025 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 viii 20 May 2025 EFFECTIVE PAGE LIST Page Date Page Date MM-4-31 27 Jan 2025 MM-4-32 27 Jan 2025 MM-4-33 Apr 25/13 MM-4-34 Feb 28/2020 MM-4-35 Apr 25/13 MM-4-36 Feb 20/08 MM-4-37 27 Jan 2025 MM-4-38 Feb 28/2020 MM-4-39 Nov 15/10 MM-4-40 20 May 2025 MM-4-41 27 Jan 2025 MM-4-42 27 Jan 2025 MM-4-43 20 May 2025 MM-4-44 20 May 2025 MM-4-45 27 Jan 2025 MM-4-46 20 May 2025 MM-4-47 27 Jan 2025 MM-4-48 20 May 2025 MM-4-49 27 Jan 2025 MM-4-50 27 Jan 2025 MM-4-51 20 May 2025 MM-4-52 27 Jan 2025 MM-4-53 27 Jan 2025 MM-4-54 27 Jan 2025 MM-4-55 Jun 24/11 MM-4-56 Jun 24/11 MM-4-57 20 May 2025 MM-4-58 Jun 24/11 MM-4-59 27 Jan 2025 MM-4-60 Jun 24/11 MM-4-61 20 May 2025 MM-4-62 20 May 2025 MM-4-63 Feb 28/2020 MM-4-64 Feb 28/2020 MM-4-65 Feb 28/2020 MM-4-66 Feb 28/2020 MM-4-67 Feb 28/2020 MM-4-68 Feb 28/2020 MM-4-69 Feb 28/2020 MM-4-70 Feb 28/2020 MM-4-71 Feb 28/2020 MM-4-72 Feb 28/2020 MM-4-73 Feb 20/08 MM-4-74 Jun 24/11
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MM-4-75 27 Jan 2025 MM-4-76 27 Jan 2025 MM-4-77 27 Jan 2025 MM-4-78 27 Jan 2025 MM-4-79 27 Jan 2025 MM-4-80 Feb 20/08 MM-4-81 20 May 2025 MM-4-82 Feb 20/08 MM-4-83 Apr 25/13 MM-4-84 Feb 20/08 MM-4-85 Jun 24/11 MM-4-86 Feb 20/08 MM-4-87 Feb 20/08 MM-4-88 Feb 20/08 MM-4-89 Feb 20/08 MM-4-90 27 Jan 2025 MM-4-91 20 May 2025 MM-4-92 20 May 2025 MM-4-93 Apr 25/13 MM-4-94 27 Jan 2025 MM-4-95 Feb 28/2020 MM-4-96 27 Jan 2025 MM-4-97 27 Jan 2025 MM-4-98 27 Jan 2025 MM-5-1 27 Jan 2025 MM-5-2 Feb 9/01 MM-5-3 Apr 25/13 MM-5-4 Feb 28/2020 MM-5-5 Feb 9/01 MM-5-6 Feb 9/01 MM-5-7 Feb 9/01 MM-5-8 20 May 2025 MM-5-9 27 Jan 2025 MM-5-10 Dec 21/09 MM-5-11 27 Jan 2025 MM-5-12 27 Jan 2025 MM-5-13 Apr 25/13 MM-5-14 Apr 25/13 MM-5-15 Apr 25/13 MM-5-16 Apr 25/13 MM-6-1 27 Jan 2025 MM-6-2 27 Jan 2025 MM-6-3 27 Jan 2025 MM-6-4 27 Jan 2025 MM-6-5 27 Jan 2025 MM-6-6 20 May 2025 MM-6-6.1 27 Jan 2025 MM-6-6.2 Nov 15/10 MM-6-7 Nov 15/10 MM-6-8 Nov 15/10 MM-6-9 Nov 15/10 MM-6-10 Nov 15/10 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 ix 20 May 2025 EFFECTIVE PAGE LIST Page Date Page Date MM-6-11 Nov 15/10 MM-6-12 Nov 15/10 MM-6-13 Nov 15/10 MM-6-14 Nov 15/10 MM-6-14.1 Nov 15/10 MM-6-14.2 Apr 30/14 MM-6-15 Nov 15/10 MM-6-16 Nov 15/10 MM-6-17 Nov 15/10 MM-6-18 27 Jan 2025 MM-6-18.1 27 Jan 2025 MM-6-18.2 Nov 15/10 MM-6-19 Nov 15/10 MM-6-20 Nov 15/10 MM-6-21 Nov 15/10 MM-6-22 Nov 15/10 MM-6-22.1 Nov 15/10 MM-6-22.2 Nov 15/10 MM-6-23 Nov 15/10 MM-6-24 Nov 15/10 MM-6-25 Nov 15/10 MM-6-26 Nov 15/10 MM-6-27 Nov 15/10 MM-6-28 Nov 15/10 MM-6-28.1 Apr 30/14 MM-6-28.2 Apr 30/14 MM-6-28.3 Apr 30/14 MM-6-28.4 Apr 30/14 MM-6-28.5 Apr 30/14 MM-6-28.6 Apr 30/14 MM-6-28.7 Apr 30/14 MM-6-28.8 Apr 30/14 MM-6-29 Apr 25/13 MM-6-30 Apr 25/13 MM-6-31 Nov 15/10 MM-6-32 Nov 15/10 MM-6-33 Nov 15/10 MM-6-34 Nov 15/10 MM-6-35 Nov 15/10 MM-6-36 Feb 28/2020 MM-6-36.1 27 Jan 2025 MM-6-36.2 Feb 28/2020 MM-6-37 Feb 28/2020 MM-6-38 Feb 28/2020 MM-6-39 Nov 15/10 MM-6-40 Apr 30/14 MM-6-41 Apr 25/13 MM-6-42 Apr 30/14 MM-6-43 Sep 12/08 MM-6-44 Sep 12/08 MM-6-45 Sep 12/08 MM-6-45.1 Dec 12/08 MM-6-45.2 Dec 12/08 MM-6-46 Dec 12/08 MM-6-46.1 Dec 12/08 MM-6-46.2 Dec 12/08 MM-6-46.3 Apr 30/14 MM-6-46.4 Apr 30/14 MM-6-47 27 Jan 2025 MM-6-48 Feb 28/2020 MM-6-49 Nov 15/10 MM-6-50 Apr 30/14 MM-6-51 Nov 15/10 MM-6-52 27 Jan 2025 MM-6-53 Nov 15/10 MM-6-54 Nov 15/10 MM-6-55 Apr 30/14 MM-6-56 Apr 30/14 MM-6-56.1 Nov 15/10 MM-6-56.2 Nov 15/10 MM-6-57 Nov 15/10 MM-6-58 Nov 15/10 MM-6-59 Nov 15/10 MM-6-59.1 Nov 15/10 MM-6-59.2 Nov 15/10 MM-6-60 Nov 15/10 MM-6-61 20 May 2025 MM-6-62 20 May 2025 MM-6-63 20 May 2025 MM-6-64 Nov 15/10 MM-6-65 Jul 3/15 MM-6-66 Jul 3/15 MM-6-67 Jul 3/15 MM-6-68 Jul 3/15 MM-6-68.1 Jul 3/15 MM-6-68.2 20 May 2025 MM-6-68.3 Feb 28/2020 MM-6-68.4 Jul 3/15 MM-6-69 Mar 15/05 MM-6-70 Mar 15/05 MM-6-71 Mar 15/05 MM-6-72 Mar 15/05 MM-6-73 Mar 15/05 MM-6-74 Mar 15/05 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 27 x 27 Jan 2025 EFFECTIVE PAGE LIST Page Date Page Date MM-6-74.1 Nov 15/10 MM-6-74.2 Nov 15/10 MM-6-74.3 Feb 28/2020 MM-6-74.4 Feb 28/2020 MM-6-75 Apr 30/14 MM-6-76 Apr 30/14 MM-6-77 Feb 28/2020 MM-6-78 Feb 28/2020 MM-6-78.1 Nov 15/10 MM-6-78.2 Nov 15/10 MM-6-79 Apr 16/07 MM-6-80 Apr 16/07 MM-6-81 Dec 4/15 MM-6-82 Dec 4/15 MM-6-82.1 Nov 15/10 MM-6-82.2 Nov 15/10 MM-6-82.3 Apr 30/14 MM-6-82.4 Apr 30/14 MM-6-83 Mar 15/05 MM-6-84 Mar 15/05 MM-6-85 Mar 15/05 MM-6-86 Mar 15/05 MM-6-87 Mar 15/05 MM-6-88 Jul 7/10 MM-6-89 Jul 7/10 MM-6-89.1 Feb 28/2020 MM-6-89.2 Jul 7/10 MM-6-90 Mar 15/05 MM-6-91 Mar 15/05 MM-6-92 Mar 15/05 MM-6-93 Mar 15/05 MM-6-94 Mar 15/05 MM-6-95 Jul 7/10 MM-6-96 Jul 7/10 MM-6-96.1 Jul 7/10 MM-6-96.2 Jul 7/10 MM-6-97 Jun 25/14 MM-6-97.1 Jun 25/14 MM-6-97.2 Jun 25/14 MM-6-98 Jun 25/14 MM-6-98.1 27 Jan 2025 MM-6-98.2 27 Jan 2025 MM-6-98.3 Mar 15/05 MM-6-98.4 Mar 15/05 MM-6-98.5 Aug 4/06 MM-9-98.6 Aug 4/06 MM-6-98.7 Aug 4/06 MM-6-98.8 Aug 4/06 MM-6-98.9 Aug 4/06 MM-6-98.10 Aug 4/06 MM-6-98.10.1 Dec 4/15 MM-6-98.10.2 Dec 4/15 MM-6-98.10.3 Dec 4/15 MM-6-98.10.4 Dec 4/15 MM-6-98.11 Aug 4/06 MM-6-98.12 Aug 4/06 MM-6-98.13 Aug 4/06 MM-6-98.14 Aug 4/06 MM-6-98.15 Aug 4/06 MM-6-98.16 Aug 4/06 MM-6-98.17 Aug 4/06 MM-6-98.18 Aug 4/06 MM-6-98.19 Jul 3/15 MM-6-98.20 Jul 3/15 MM-6-98.21 Jul 3/15 MM-6-98.22 Jul 3/15 MM-6-98.23 Jun 24/11 MM-6-98.24 Jun 24/11 MM-6-98.25 27 Jan 2025 MM-6-98.26 27 Jan 2025 MM-6-98.27 27 Jan 2025 MM-6-98.28 27 Jan 2025 MM-6-99 Nov 15/10 MM-6-99.1 Nov 15/10 MM-6-99.2 Nov 15/10 MM-6-100 Jun 24/11 MM-6-101 Nov 15/10 MM-6-102 Jun 24/11 MM-6-103 Mar 15/05 MM-6-104 Mar 15/05 MM-6-105 Mar 15/05 MM-6-106 Mar 15/05 MM-6-106.1 Dec 4/15 MM-6-106.2 Dec 4/15 MM-6-106.3 Jun 25/14 MM-6-106.4 Jun 25/14 MM-6-106.5 Nov 15/10 MM-6-106.6 Nov 15/10 MM-6-106.7 Dec 4/15 MM-6-106.8 Dec 4/15 MM-6-107 Nov 15/10 MM-6-108 Nov 15/10 MM-6-108.1 Nov 15/10 MM-6-108.2 Nov 15/10 MM-6-108.3 Apr 30/14 MM-6-108.4 Apr 30/14 MM-6-108.5 Apr 30/14 MM-6-108.6 Apr 30/14 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 xi 20 May 2025 EFFECTIVE PAGE LIST Page Date Page Date MM-6-108.7 Apr 30/14 MM-6-108.8 Apr 30/14 MM-6-109 Feb 9/01 MM-6-110 Feb 9/01 MM-6-110.1 Sep 12/08 MM-6-110.2 Sep 12/08 MM-6-110.3 Dec 12/08 MM-6-110.4 Dec 12/08 MM-6-111 Feb 9/01 MM-6-112 Feb 9/01 MM-6-113 Nov 15/10 MM-6-113.1 Nov 15/10 MM-6-113.2 Nov 15/10 MM-6-114 Feb 28/2020 MM-6-115 Jul 3/15 MM-6-116 Jul 3/15 MM-6-116.1 Jul 3/15 MM-6-116.2 Jul 7/10 MM-6-117 Apr 16/07 MM-6-118 Feb 28/2020 MM-6-118.1 Apr 16/07 MM-6-118.2 Apr 16/07 MM-6-119 Feb 28/2020 MM-6-120 Jul 3/15 MM-6-121 Jul 3/15 MM-6-122 Nov 15/10 MM-6-123 Feb 28/2020 MM-6-124 Jul 3/15 MM-6-125 Apr 30/14 MM-6-126 27 Jan 2025 MM-6-127 Feb 28/2020 MM-6-128 Feb 28/2020 MM-6-129 Feb 28/2020 MM-6-130 Feb 28/2020 MM-7-1 27 Jan 2025 MM-7-2 27 Jan 2025 MM-7-3 27 Jan 2025 MM-7-4 27 Jan 2025 MM-7-5 Feb 9/01 MM-7-6 Feb 9/01 MM-7-7 Feb 9/01 MM-7-8 Feb 9/01 MM-7-9 Nov 15/10 MM-7-10 Nov 15/10 MM-7-11 Feb 9/01 MM-7-12 Feb 9/01 MM-7-13 Feb 9/01 MM-7-14 Feb 9/01 MM-7-15 Feb 9/01 MM-7-16 27 Jan 2025 MM-7-17 27 Jan 2025 MM-7-18 Feb 28/2020 MM-7-19 Feb 28/2020 MM-7-20 Feb 9/01 MM-7-21 Feb 9/01 MM-7-22 Feb 9/01 MM-7-23 Feb 9/01 MM-7-24 Feb 9/01 MM-7-25 Apr 25/13 MM-7-26 Apr 25/13 MM-7-27 Feb 9/01 MM-7-28 Feb 9/01 MM-7-29 Apr 25/13 MM-7-30 Apr 25/13 MM-7-31 Feb 9/01 MM-7-32 Feb 9/01 MM-7-33 Feb 9/01 MM-7-34 20 May 2025 MM-7-35 20 May 2025 MM-7-36 20 May 2025 MM-7-37 20 May 2025 MM-7-38 20 May 2025 MM-7-39 Jun 25/14 MM-7-40 Jun 25/14 MM-7-41 20 May 2025 MM-7-42 Jun 25/14 MM-7-43 Jun 25/14 MM-7-44 Jun 25/14 MM-7-45 Jun 25/14 MM-7-46 Jun 25/14 MM-8-1 27 Jan 2025 MM-8-2 27 Jan 2025 MM-8-3 27 Jan 2025 MM-8-4 Oct 20/09 MM-8-5 27 Jan 2025 MM-8-6 27 Jan 2025 MM-8-7 27 Jan 2025 MM-8-8 20 May 2025 MM-8-9 Feb 9/01 MM-8-10 Feb 9/01 MM-8-11 Feb 9/01 MM-8-12 Feb 9/01 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 xii 20 May 2025 EFFECTIVE PAGE LIST Page Date Page Date MM-8-13 Jul 3/15 MM-8-14 Jul 3/15 MM-8-15 Jul 3/15 MM-8-16 Jul 3/15 MM-8-17 Jul 3/15 MM-8-18 Jul 3/15 MM-8-18.1 Feb 28/2020 MM-8-18.2 20 May 2025 MM-8-18.3 20 May 2025 MM-8-18.4 Jul 3/15 MM-8-19 Oct 20/09 MM-8-20 Oct 20/09 MM-8-21 Oct 20/09 MM-8-22 Oct 20/09 MM-8-23 Oct 20/09 MM-8-24 Oct 20/09 MM-8-25 Oct 20/09 MM-8-26 Oct 20/09 MM-8-27 Oct 20/09 MM-8-28 Oct 20/09 MM-8-29 Oct 20/09 MM-8-30 Oct 20/09 MM-8-31 Oct 20/09 MM-8-32 Oct 20/09 MM-8-33 Oct 20/09 MM-8-34 Oct 20/09 MM-8-35 Oct 20/09 MM-8-36 Oct 20/09 MM-8-37 Oct 20/09 MM-8-38 Oct 20/09 MM-8-38.1 Oct 20/09 MM-8-38.2 Oct 20/09 MM-8-38.3 Oct 20/09 MM-8-38.4 Oct 20/09 MM-8-38.5 Oct 20/09 MM-8-38.6 27 Jan 2025 MM-8-38.7 27 Jan 2025 MM-8-38.8 27 Jan 2025 MM-8-39 27 Jan 2025 MM-8-40 27 Jan 2025 MM-8-41 27 Jan 2025 MM-8-42 27 Jan 2025 MM-8-43 27 Jan 2025 MM-8-44 27 Jan 2025 MM-8-45 27 Jan 2025 MM-8-46 27 Jan 2025 MM-8-47 27 Jan 2025 MM-8-48 Feb 28/2020 MM-8-49 Feb 9/01 MM-8-50 Feb 28/2020 MM-8-51 Feb 9/01 MM-8-52 Feb 9/01 MM-8-53 Feb 28/2020 MM-8-54 Feb 28/2020 MM-8-55 Feb 28/2020 MM-8-56 Feb 28/2020 MM-8-57 Apr 25/13 MM-8-58 Jun 25/14 MM-8-59 Jun 25/14 MM-8-60 Jun 25/14 MM-8-61 Feb 9/01 MM-8-62 Aug 22/16 MM-8-63 Jun 25/14 MM-8-64 Jun 25/14 MM-8-65 Jun 24/11 MM-8-66 Feb 9/01 MM-8-67 Dec 4/15 MM-8-68 Feb 28/2020 MM-8-69 Feb 28/2020 MM-8-70 Feb 28/2020 MM-8-70.1 Jul 3/15 MM-8-70.2 Jun 25/14 MM-8-71 Jun 25/14 MM-8-72 27 Jan 2025 MM-8-73 Apr 25/13 MM-8-74 Apr 25/13 MM-8-74.1 Apr 25/13 MM-8-74.2 Jul 3/15 MM-8-75 Feb 9/01 MM-8-76 Apr 25/13 MM-8-77 Feb 9/01 MM-8-78 Feb 9/01 MM-8-79 Feb 9/01 MM-8-80 Feb 9/01 MM-8-81 Feb 9/01 MM-8-82 Jul 3/15 MM-8-83 Feb 28/2020 MM-8-84 27 Jan 2025 MM-8-85 27 Jan 2025 MM-8-86 27 Jan 2025 MM-8-87 Jul 3/15 MM-8-88 Jul 3/15 MM-8-89 Jul 3/15 MM-8-90 Jul 3/15 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 xiii 20 May 2025 EFFECTIVE PAGE LIST Page Date Page Date MM-8-91 27 Jan 2025 MM-8-92 27 Jan 2025 MM-9-1 27 Jan 2025 MM-9-2 27 Jan 2025 MM-9-3 Apr 25/13 MM-9-4 Apr 25/13 MM-9-5 Apr 25/13 MM-9-6 Apr 25/13 MM-9-7 Apr 25/13 MM-9-8 Apr 25/13 MM-9-9 Apr 25/13 MM-9-10 27 Jan 2025 MM-9-11 Apr 25/13 MM-9-12 Apr 25/13 MM-9-12.1 Apr 25/13 MM-9-12.2 Apr 25/13 MM-9-12.3 Apr 25/13 MM-9-12.4 Apr 25/13 MM-9-13 Apr 25/13 MM-9-14 Apr 25/13 MM-9-15 Aug 22/16 MM-9-16 20 May 2025 MM-9-17 Feb 9/01 MM-9-18 Feb 28/2020 MM-9-19 Feb 28/2020 MM-9-20 Feb 28/2020 MM-9-21 Feb 28/2020 MM-9-22 Feb 28/2020 MM-9-23 Feb 28/2020 MM-9-24 Apr 25/13 MM-9-25 Apr 25/13 MM-9-26 Apr 25/13 MM-9-27 27 Jan 2025 MM-9-28 20 May 2025 MM-9-29 27 Jan 2025 MM-9-30 Apr 25/13 MM-9-31 Feb 28/2020 MM-9-32 Feb 9/01 MM-9-33 Aug 22/16 MM-9-34 Jul 3/15 MM-9-35 Jun 24/11 MM-9-36 27 Jan 2025 MM-9-37 Feb 28/2020 MM-9-38 Feb 28/2020 MM-9-39 Jun 24/11 MM-9-40 Feb 28/2020 MM-9-41 Feb 28/2020 MM-9-42 Aug 22/16 MM-9-43 27 Jan 2025 MM-9-44 27 Jan 2025 MM-9-45 27 Jan 2025 MM-9-46 27 Jan 2025 MM-9-47 Feb 28/2020 MM-9-48 Feb 28/2020 MM-9-49 20 May 2025 MM-9-50 Feb 28/2020 MM-9-51 Feb 28/2020 MM-9-52 Feb 28/2020 MM-9-53 27 Jan 2025 MM-9-54 27 Jan 2025 MM-9-55 Apr 25/13 MM-9-56 Apr 25/13 MM-9-57 Feb 9/01 MM-9-58 Feb 9/01 MM-9-59 Feb 9/01 MM-9-60 Feb 9/01 MM-9-61 Oct 13/04 MM-9-62 Feb 28/2020 MM-9-63 Feb 28/2020 MM-9-64 Feb 28/2020 MM-9-65 Feb 28/2020 MM-9-66 Feb 28/2020 MM-9-67 Feb 28/2020 MM-9-68 Feb 28/2020 MM-9-69 Feb 28/2020 MM-9-70 Feb 28/2020 MM-9-71 Feb 28/2020 MM-9-72 Feb 28/2020 MM-9-73 Feb 28/2020 MM-9-73.1 Feb 28/2020 MM-9-73.2 Feb 28/2020 MM-9-73.3 Feb 28/2020 MM-9-73.4 Feb 28/2020 MM-9-74 Feb 28/2020 MM-9-75 Feb 9/01 MM-9-76 Feb 9/01 MM-9-77 27 Jan 2025 MM-9-78 Feb 9/01 MM-9-79 Apr 25/13 MM-9-80 Feb 9/01 MM-9-81 Feb 9/01 MM-9-82 Feb 9/01 MM-9-83 Feb 9/01 MM-9-84 Feb 9/01 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 xiv 20 May 2025 EFFECTIVE PAGE LIST Page Date Page Date MM-9-85 Feb 9/01 MM-9-86 Feb 9/01 MM-9-86.1 Jun 25/14 MM-9-86.2 Jun 25/14 MM-9-87 Aug 22/16 MM-9-88 27 Jan 2025 MM-9-89 27 Jan 2025 MM-9-90 27 Jan 2025 MM-9-91 27 Jan 2025 MM-9-92 27 Jan 2025 MM-9-93 27 Jan 2025 MM-9-93.1 27 Jan 2025 MM-9-93.2 27 Jan 2025 MM-9-93.3 Apr 25/13 MM-9-93.4 Apr 25/13 MM-9-94 Apr 25/13 MM-9-95 27 Jan 2025 MM-9-96 27 Jan 2025 MM-9-97 27 Jan 2025 MM-9-98 Apr 25/13 MM-9-99 Jun 25/14 MM-9-100 Apr 25/13 MM-9-101 Feb 9/01 MM-9-102 Feb 9/01 MM-9-103 Jun 25/14 MM-9-104 Apr 25/13 MM-9-105 Apr 25/13 MM-9-106 Jun 25/14 MM-9-106.1 Apr 25/13 MM-9-106.2 Jun 25/14 MM-9-106.3 Jun 25/14 MM-9-106.4 Jun 25/14 MM-9-106.5 Jun 25/14 MM-9-106.6 Apr 25/13 MM-9-107 Apr 25/13 MM-9-108 Feb 9/01 MM-9-109 Feb 9/01 MM-9-110 Feb 9/01 MM-9-111 Feb 9/01 MM-9-112 Feb 9/01 MM-9-113 Feb 28/2020 MM-9-114 Feb 28/2020 MM-9-115 Apr 25/13 MM-9-116 Feb 9/01 MM-9-117 Feb 9/01 MM-9-118 Feb 9/01 MM-9-119 Jul 3/15 MM-9-120 Feb 9/01 MM-9-121 27 Jan 2025 MM-9-122 27 Jan 2025 MM-9-123 27 Jan 2025 MM-9-124 27 Jan 2025 MM-9-125 Feb 9/01 MM-9-126 27 Jan 2025 MM-9-127 27 Jan 2025 MM-9-128 Apr 25/13 MM-10-1 20 May 2025 MM-10-2 20 May 2025 MM-10-3 20 May 2025 MM-10-4 20 May 2025 MM-10-5 20 May 2025 MM-10-6 20 May 2025 MM-10-7 20 May 2025 MM-10-8 20 May 2025 MM-10-8.1 20 May 2025 MM-10-8.2 20 May 2025 MM-10-9 20 May 2025 MM-10-10 20 May 2025 MM-10-11 20 May 2025 MM-10-12 20 May 2025 MM-10-13 20 May 2025 MM-10-14 20 May 2025 MM-10-15 20 May 2025 MM-10-16 20 May 2025 MM-10-17 20 May 2025 MM-10-18 20 May 2025 MM-10-19 20 May 2025 MM-10-20 20 May 2025 MM-10-20.1 20 May 2025 MM-10-20.2 20 May 2025 MM-10-21 20 May 2025 MM-10-22 20 May 2025 MM-10-23 20 May 2025 MM-10-24 20 May 2025 MM-10-25 20 May 2025 MM-10-26 20 May 2025 MM-10-27 20 May 2025 MM-10-28 20 May 2025 MM-10-29 20 May 2025 MM-10-30 20 May 2025 MM-10-31 20 May 2025 MM-10-32 20 May 2025 MM-10-33 20 May 2025 MM-10-34 20 May 2025 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 xv 20 May 2025 EFFECTIVE PAGE LIST Page Date Page Date MM-10-35 20 May 2025 MM-10-36 20 May 2025 MM-10-37 20 May 2025 MM-10-38 20 May 2025 MM-10-39 20 May 2025 MM-10-40 20 May 2025 MM-10-41 20 May 2025 MM-10-42 20 May 2025 MM-10-43 20 May 2025 MM-10-44 20 May 2025 MM-10-45 20 May 2025 MM-10-46 20 May 2025 MM-10-47 20 May 2025 MM-10-48 20 May 2025 MM-10-49 20 May 2025 MM-10-50 20 May 2025 MM-10-51 20 May 2025 MM-10-52 20 May 2025 MM-10-53 20 May 2025 MM-10-54 20 May 2025 MM-10-55 20 May 2025 MM-10-56 20 May 2025 MM-10-57 20 May 2025 MM-10-58 20 May 2025 MM-10-59 20 May 2025 MM-10-60 20 May 2025 MM-10-61 20 May 2025 MM-10-62 20 May 2025 MM-10-63 20 May 2025 MM-10-64 20 May 2025 MM-10-65 20 May 2025 MM-10-66 20 May 2025 MM-11-1 27 Jan 2025 MM-11-2 27 Jan 2025 MM-11-3 27 Jan 2025 MM-11-4 Feb 9/01 MM-11-5 Apr 25/13 MM-11-6 Apr 25/13 MM-11-7 27 Jan 2025 MM-11-8 Apr 25/13 MM-11-9 27 Jan 2025 MM-11-10 20 May 2025 MM-11-10.1 Dec 4/15 MM-11-10.2 Apr 25/13 MM-11-10.3 Apr 25/13 MM-11-10.4 Apr 25/13 MM-11-11 Feb 28/2020 MM-11-12 Feb 28/2020 MM-11-13 Apr 25/13 MM-11-13.1 Apr 25/13 MM-11-13.2 Apr 25/13 MM-11-14 Feb 28/2020 MM-11-15 Jun 24/11 MM-11-16 Apr 25/13 MM-11-17 Feb 28/2020 MM-11-18 27 Jan 2025 MM-11-19 27 Jan 2025 MM-11-20 27 Jan 2025 MM-11-21 27 Jan 2025 MM-11-22 27 Jan 2025 MM-11-23 27 Jan 2025 MM-11-24 27 Jan 2025 MM-11-25 27 Jan 2025 MM-11-26 27 Jan 2025 MM-11-27 27 Jan 2025 MM-11-28 27 Jan 2025 MM-11-29 27 Jan 2025 MM-11-30 Feb 9/01 MM-11-31 Feb 9/01 MM-11-32 27 Jan 2025 MM-11-33 27 Jan 2025 MM-11-34 Jul 7/10 MM-11-35 Feb 28/2020 MM-11-36 Feb 28/2020 MM-11-37 27 Jan 2025 MM-11-38 Apr 30/14 MM-11-39 27 Jan 2025 MM-11-40 Feb 28/2020 MM-11-41 Feb 28/2020 MM-11-42 Feb 28/2020 MM-11-43 Jun 25/14 MM-11-44 Dec 4/15 MM-11-45 Dec 4/15 MM-11-46 27 Jan 2025 MM-11-47 Feb 9/01 MM-11-48 Feb 9/01 MM-11-49 Feb 9/01 MM-11-50 Feb 28/2020 MM-11-51 Feb 9/01 MM-11-52 Feb 9/01 MM-11-53 27 Jan 2025 MM-11-54 Apr 25/13 MM-11-55 Apr 25/13 MM-11-56 Feb 28/2020 MM-11-57 Feb 28/2020 MM-11-58 Feb 9/01 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 xvi 20 May 2025 EFFECTIVE PAGE LIST Page Date Page Date MM-11-59 Feb 28/2020 MM-11-60 Feb 28/2020 MM-11-61 Jun 25/14 MM-11-62 Jun 25/14 MM-11-63 Feb 28/2020 MM-11-64 27 Jan 2025 MM-11-65 27 Jan 2025 MM-11-66 Feb 28/2020 MM-11-67 27 Jan 2025 MM-11-68 27 Jan 2025 MM-11-69 27 Jan 2025 MM-11-70 27 Jan 2025 MM-11-70.1 27 Jan 2025 MM-11-70.2 27 Jan 2025 MM-11-71 Dec 4/15 MM-11-72 Feb 9/01 MM-11-73 Feb 9/01 MM-11-74 Feb 9/01 MM-11-75 Aug 22/16 MM-11-76 Feb 9/01 MM-11-77 Feb 9/01 MM-11-78 Jul 3/15 MM-11-79 Jul 3/15 MM-11-80 Feb 9/01 MM-11-81 Jul 3/15 MM-11-82 Jul 3/15 MM-11-83 Dec 4/15 MM-11-84 Dec 4/15 MM-11-85 27 Jan 2025 MM-11-86 Feb 9/01 MM-11-87 Feb 28/2020 MM-11-88 Feb 28/2020 MM-11-89 Feb 28/2020 MM-11-90 Feb 28/2020 MM-11-91 Feb 28/2020 MM-11-92 Feb 28/2020 MM-11-93 Feb 28/2020 MM-11-94 Feb 28/2020 MM-12-1 27 Jan 2025 MM-12-2 27 Jan 2025 MM-12-3 27 Jan 2025 MM-12-4 27 Jan 2025 MM-12-5 Feb 9/01 MM-12-6 Apr 30/14 MM-12-7 Feb 9/01 MM-12-8 Feb 9/01 MM-12-9 Nov 15/10 MM-12-10 Nov 15/10 MM-12-11 27 Jan 2025 MM-12-12 Nov 15/10 MM-12-13 Feb 9/01 MM-12-14 Feb 9/01 MM-12-15 Feb 9/01 MM-12-16 Feb 9/01 MM-12-17 Nov 15/10 MM-12-18 Nov 15/10 MM-12-19 Nov 15/10 MM-12-19.1 Jul 3/15 MM-12-19.2 Nov 15/10 MM-12-20 Nov 15/10 MM-12-21 Nov 15/10 MM-12-22 Nov 15/10 MM-12-23 27 Jan 2025 MM-12-24 Feb 20/08 MM-12-25 Feb 9/01 MM-12-26 27 Jan 2025 MM-12-27 27 Jan 2025 MM-12-28 Feb 20/08 MM-12-29 Feb 9/01 MM-12-30 Feb 9/01 MM-12-31 Jun 21/12 MM-12-32 27 Jan 2025 MM-12-33 27 Jan 2025 MM-12-34 Nov 15/10 MM-12-35 Feb 9/01 MM-12-36 Feb 9/01 MM-12-37 Feb 9/01 MM-12-38 Feb 9/01 MM-12-39 Feb 9/01 MM-12-40 Feb 9/01 MM-12-41 Feb 9/01 MM-12-42 Feb 9/01 MM-12-43 Aug 22/16 MM-12-44 Feb 9/01 MM-12-45 Aug 22/16 MM-12-46 Feb 9/01 MM-12-47 27 Jan 2025 MM-12-48 Feb 20/08 MM-12-49 27 Jan 2025 MM-12-50 27 Jan 2025 MM-12-51 27 Jan 2025 MM-12-52 27 Jan 2025 MM-12-53 Feb 20/08 MM-12-54 Feb 28/2020 MM-12-55 Feb 20/08 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 xvii 20 May 2025 EFFECTIVE PAGE LIST Page Date Page Date MM-12-56 Feb 20/08 MM-12-57 Feb 28/2020 MM-12-58 Feb 28/2020 MM-12-59 Jun 21/12 MM-12-60 Jun 21/12 MM-12-61 Feb 28/2020 MM-12-62 Feb 28/2020 MM-12-62.1 Feb 28/2020 MM-12-62.2 Feb 28/2020 MM-12-62.3 Feb 28/2020 MM-12-62.4 Feb 28/2020 MM-12-63 Feb 28/2020 MM-12-64 Feb 28/2020 MM-12-65 Feb 28/2020 MM-12-66 Feb 28/2020 MM-12-67 Feb 28/2020 MM-12-68 Feb 28/2020 MM-12-69 Feb 28/2020 MM-12-70 Feb 28/2020 MM-12-71 Feb 28/2020 MM-12-72 Feb 9/01 MM-12-73 Jun 25/14 MM-12-74 Apr 25/13 MM-12-75 Apr 25/13 MM-12-76 Feb 20/08 MM-12-77 Nov 15/10 MM-12-78 Jun 25/14 MM-12-79 20 May 2025 MM-12-80 Apr 25/13 MM-12-81 Feb 28/2020 MM-12-82 Apr 25/13 MM-12-83 20 May 2025 MM-12-84 Feb 9/01 MM-12-85 Feb 28/2020 MM-12-86 Feb 20/08 MM-12-86.1 Jul 2/04 MM-12-86.2 Jul 2/04 MM-12-86.3 Jul 2/04 MM-12-86.4 Jul 2/04 MM-12-87 Jul 3/15 MM-12-88 Feb 28/2020 MM-12-89 Feb 28/2020 MM-12-90 Feb 9/01 MM-12-91 Apr 25/13 MM-12-92 Nov 15/10 MM-12-93 Feb 9/01 MM-12-94 Feb 9/01 MM-12-95 Feb 9/01 MM-12-96 Feb 9/01 MM-12-96.1 Mar 15/05 MM-12-96.2 Mar 15/05 MM-12-97 Feb 9/01 MM-12-98 Feb 9/01 MM-12-99 Feb 9/01 MM-12-100 Feb 9/01 MM-12-101 Jul 2/04 MM-12-102 Feb 9/01 MM-12-103 Feb 9/01 MM-12-104 Jun 25/14 MM-12-105 27 Jan 2025 MM-12-106 Jun 25/14 MM-12-107 Feb 28/2020 MM-12-108 Feb 9/01 MM-12-109 27 Jan 2025 MM-12-110 Apr 25/13 MM-12-111 20 May 2025 MM-12-112 Feb 28/2020 MM-12-113 Feb 28/2020 MM-12-114 Jul 3/15 MM-12-115 20 May 2025 MM-12-116 Feb 9/01 MM-13-1 27 Jan 2025 MM-13-2 27 Jan 2025 MM-13-3 27 Jan 2025 MM-13-4 27 Jan 2025 MM-13-5 Apr 25/13 MM-13-6 Apr 25/13 MM-13-7 Apr 25/13 MM-13-8 Apr 25/13 MM-13-9 Feb 28/2020 MM-13-10 Feb 28/2020 MM-13-11 Apr 25/13 MM-13-12 Apr 25/13 MM-13-13 Apr 25/13 MM-13-14 27 Jan 2025 MM-13-15 Apr 25/13 MM-13-16 Apr 25/13 MM-13-17 Oct 20/09 MM-13-18 Feb 28/2020 MM-13-19 Feb 28/2020 MM-13-20 Jul 3/15 MM-13-20.1 Jul 3/15 MM-13-20.2 Oct 20/09 MM-13-21 Feb 9/01 MM-13-22 Feb 28/2020 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 xviii 20 May 2025 EFFECTIVE PAGE LIST Page Date Page Date MM-13-23 Aug 22/16 MM-13-24 Feb 28/2020 MM-13-25 Feb 9/01 MM-13-26 Feb 9/01 MM-13-27 27 Jan 2025 MM-13-28 Feb 9/01 MM-13-29 27 Jan 2025 MM-13-30 Feb 9/01 MM-13-31 Apr 16/07 MM-13-32 Jul 3/15 MM-13-33 Jul 3/15 MM-13-34 Jul 3/15 MM-13-35 Oct 20/09 MM-13-36 Oct 20/09 MM-13-36.1 Oct 20/09 MM-13-36.2 Oct 20/09 MM-13-37 Apr 25/13 MM-13-38 Feb 9/01 MM-13-39 Apr 25/13 MM-13-40 27 Jan 2025 MM-13-41 27 Jan 2025 MM-13-42 Feb 9/01 MM-13-43 27 Jan 2025 MM-13-44 27 Jan 2025 MM-13-45 27 Jan 2025 MM-13-46 Nov 15/10 MM-13-47 Nov 15/10 MM-13-48 Nov 15/10 MM-13-49 Nov 15/10 MM-13-50 Nov 15/10 MM-13-51 Nov 15/10 MM-13-52 Nov 15/10 MM-13-52.1 Nov 15/10 MM-13-52.2 Nov 15/10 MM-13-52.3 Jul 3/15 MM-13-52.4 Jul 3/15 MM-13-52.5 Jul 3/15 MM-13-52.6 Jul 3/15 MM-13-52.7 27 Jan 2025 MM-13-52.8 27 Jan 2025 MM-13-52.9 Jul 3/15 MM-13-52.10 27 Jan 2025 MM-13-53 27 Jan 2025 MM-13-54 Jul 3/15 MM-13-55 Jul 3/15 MM-13-56 Jul 3/15 MM-13-57 Nov 15/10 MM-13-58 Nov 15/10 MM-13-59 Feb 9/01 MM-13-60 Feb 9/01 MM-13-61 Nov 15/10 MM-13-62 Apr 25/13 MM-13-63 27 Jan 2025 MM-13-64 Apr 25/13 MM-13-64.1 Apr 25/13 MM-13-64.2 Apr 25/13 MM-13-64.3 Nov 15/10 MM-13-64.4 Nov 15/10 MM-13-64.5 Oct 20/09 MM-13-64.6 Oct 20/09 MM-13-65 Apr 16/07 MM-13-66 Apr 16/07 MM-13-67 Apr 16/07 MM-13-68 Apr 30/14 MM-13-69 Apr 16/07 MM-13-70 Apr 16/07 MM-13-71 Apr 16/07 MM-13-72 Feb 28/2020 MM-13-73 Feb 28/2020 MM-13-74 Feb 28/2020 MM-13-75 Feb 28/2020 MM-13-76 Jun 24/11 MM-14-1 27 Jan 2025 MM-14-2 27 Jan 2025 MM-14-3 27 Jan 2025 MM-14-4 Aug 4/06 MM-14-5 Feb 9/01 MM-14-6 Feb 9/01 MM-14-7 Feb 9/01 MM-14-8 Feb 9/01 MM-14-9 Feb 9/01 MM-14-10 Feb 9/01 MM-14-11 Feb 9/01 MM-14-12 27 Jan 2025 MM-14-13 Feb 9/01 MM-14-14 27 Jan 2025 MM-14-15 27 Jan 2025 MM-14-16 Feb 9/01 MM-14-17 Feb 9/01 MM-14-18 Feb 9/01 MM-14-19 Feb 9/01 MM-14-20 Feb 9/01 MM-14-21 Feb 9/01 MM-14-22 Feb 9/01 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 xix 20 May 2025 EFFECTIVE PAGE LIST Page Date Page Date MM-14-23 Feb 9/01 MM-14-24 Feb 9/01 MM-14-25 Feb 9/01 MM-14-26 Feb 9/01 MM-14-27 Feb 9/01 MM-14-28 Feb 9/01 MM-14-29 Aug 4/06 MM-14-30 Feb 28/2020 MM-14-31 Aug 4/06 MM-14-32 Aug 4/06 MM-14-33 Aug 4/06 MM-14-34 Aug 4/06 MM-14-35 Aug 4/06 MM-14-36 Jun 24/11 MM-14-37 Aug 4/06 MM-14-38 Aug 4/06 MM-14-39 Jun 24/11 MM-14-40 Feb 28/2020 MM-14-41 Jun 24/11 MM-14-42 Jun 24/11 MM-15-1 27 Jan 2025 MM-15-2 Feb 9/01 MM-15-3 Jul 3/15 MM-15-4 Feb 9/01 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 xx 20 May 2025 EFFECTIVE PAGE LIST Page Date Page Date INTENTIONALLY LEFT BLANK ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 27 MM-1-5 27 Jan 2025 1-5. Application of Warnings, Cautions, and Notes Warnings, Cautions, and Notes emphasize important and critical instructions and are used for the following conditions. WARNING Calls attention to use of materials, processes, methods, or procedures that must be followed to avoid personal injury or loss of life. CAUTION Calls attention to methods and procedures which must be followed to avoid damage to the aircraft or equipment. NOTE Calls attention to information essential to highlight for clarification of procedures. 1-6. Definitions and Abbreviations Table 1-1. List of Definitions Airframe Means the fuselage, stabilizers, tailcone, cowlings, fairings, rotors, and landing gear of the helicopter and their accessories and controls. Annually With respect to an annual inspection, annually means within the preceding 12 calendar months. Approved Unless used with reference to another person, means approved by the FAA or any person to whom the FAA has delegated its authority in the matter concerned, or approved under the provisions of a bilateral agreement between the United States and a foreign country or jurisdiction. Empty Weight Standard empty weight of a standard helicopter including unusable fuel, full operating fluids, and full engine oil. Basic empty weight is standard empty weight plus weight of installed optional equipment. FAR Means the Federal Aviation Regulations (FARs) prescribed by the Federal Aviation Administration (FAA). The FARs comprise Title 14 of the Code of Federal Regulations (14 CFR). Life-Limited Component Any part for which a mandatory replacement limit is specified in the type design, the Instructions for Continued Airworthiness, or the maintenance manual. (Refer to Section 3, Airworthiness Limitations, Table 3-1.) ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 MM-1-6 20 May 2025 Table 1-2. List of Abbreviations A/R As Required AC Advisory Circular AGL Above Ground Level ALT Altitude APU Auxiliary Power Unit ASTM American Society for Testing and Materials B.L. Butt Line C Celsius CAS Calibrated Airspeed cc Cubic centimeter CCW Counterclockwise CFR Code of Federal Regulations C.G. Center of Gravity C.L. Center Line cm Centimeter CPC Corrosion Prevention Compound CRFS Crash Resistant Fuel System ° Degree EA Each EASA European Union Aviation Safety Agency EFIS Electronic Flight Instrument System EMI Electromagnetic Interference F Fahrenheit FAA Federal Aviation Administration FAR Federal Aviation Regulations Fig. Figure FIM Full Indicator Movement FLT Flight FPM Feet per Minute FSII Fuel System Icing Inhibitor ft Foot ft-lb or ft-lbs Foot-Pound (Force) ft/min Feet per Minute FWD Forward gal Gallon gal/hr Gallon per Hour GCU Generator Control Unit GW Gross Weight hr or hr(s) Hour(s) Hz Hertz (Cycles per Second) ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 27 MM-2-11 27 Jan 2025 2-20. Vendor Information A. The following components listed in Table 2-2 are to be maintained I/A/W the manufacturer's instructions to ensure the continued airworthiness of the aircraft. B. The owner/operator is responsible for ensuring that current maintenance publications are available to ensure continued airworthiness of the aircraft. Table 2-2. Vendor Contact Information Component Part Number Manufacturer Engine 250-C20W Rolls-Royce 450 S. Meridian Street Indianapolis, IN 46206 Tel: (317) 230-2000 http://www.rolls-royce.com/ Starter/Generator 524-080 Thales Avionics Inc. (Auxilec) 140 Centennial Avenue Piscataway Township, NJ 08854 Tel: (732) 494-6300 https://customeronline.thalesgroup.com/en Starter/Generator 150SG117Q-3-1 150SG117Q-4-1 Skurka Aerospace, Inc. 4600 Calle Bolero Camarillo, CA 93011 Tel: (805) 484-8884 http://www.skurka-aero.com/ Generator Control Unit (GCU) VR1528-11B Thales Avionics Inc. (Auxilec) 140 Centennial Avenue Piscataway Township, NJ 08854 Tel: (732) 494-6300 https://customeronline.thalesgroup.com/en Generator Control Unit (GCU) GCSG501-2 Avionic Instruments, LLC 1414 Randolph Avenue Avenel, NJ 07001 Tel: (732) 388-3500 http://www.avionicinstruments.com/ Battery(1) TSP-1728-20-17SP100 Marathon Power Technologies P.O. Box 8233 Waco, TX 76712-8233 Tel: (254) 776-0650 http://www.mptc.com/ Battery (2) G-641 Teledyne Battery Products (Gill Batteries) 840 West Brockton Avenue Redlands, CA 92374 Tel: (800) 456-0070 Tel: (909) 793-3131 http://www.gillbatteries.com/ Fuel Cells (Standard) 4122052-“X” Floats & Fuel Cells, Inc. 4010 Pilot Drive, Suite 103 Memphis, TN 38118 Tel: (800) 647-6148 https://www.ffcfuelcells.com) ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 MM-2-12 20 May 2025 Table 2-2. Vendor Contact Information Component Part Number Manufacturer Fuel Cells (Standard) 4122052-“X” United Fuel Cells Corporation 853 Adams Road Eagle River, WI 54521 Tel: (715) 479-6149 https://unitedfuelcells.com/contact/ Fuel Cells 4122009-“X” Zodiac Aerazur Caudebec 4, rue Lesage-Maille Caudebec 76320, France Tel: +33 (1) 6486-6922 http://www.zodiacaerospace.com/en/zodiac- aerosafety-systems-elastomer Fuel Cell Crossover 500123 Vent Crossover 500122 Zodiac Aerazur Caudebec 4, rue Lesage-Maille Caudebec 76320, France Tel: +33 (1) 6486-6922 http://www.zodiacaerospace.com/en/zodiac- aerosafety-systems-elastomer Tension-Torsion (TT Strap) (STC SR03465CH) AA-ECD-084-480 Airwolf Aerospace LLC 15369 Madison Rd. Middlefield, OH 44062-8404, U.S.A. Tel: (440) 632-1687 / Fax: (440) 632-1685 www.airwolfaerospace.com / info@airwolfaerospace.com Cargo Hook (option) 2A20B-17149-2 Breeze-Eastern Corporation 35 Melanie Lane Whippany NJ, 07981 U.S.A. (800) 929-1919 / (973) 602-1083 / (973) 602-1090 Fax: (973) 739-9344 customerserives@breeze-eastern.com www.breeze-eastern.com 528-023-01 Onboard Systems International, Inc. 13915 NW 3rd Court Vancouver, WA 98685 U.S.A. Tel: (800) 275-0883 / (360) 546-3072 Fax: (360) 546-3073 www.onboardsystems.com Roll Over Valve Assembly (3) 549448 SAFRAN AEROSYSTEMS 4, rue Lesage Maille 76320 Caudebec-lès-Elbeuf, France Tel: +33 (0) 2.32.96.56.00 https://www.safran-group.com/companies/safran- aerosystems Breakaway Coupling, Vent (3) ECD115-11 Breakaway Coupling, Fuel Line(3) ECD115-15 Breakaway Coupling, Cross Fill (3) ECD115-17 LH Fuel Bladder (3) (CRFS) ECD4097-1 RH Fuel Bladder (3) (CRFS) ECD4097-3 Frangible Ring(3) ECD4098-11 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 MM-2-13 20 May 2025 Notes: 1. This is the standard battery for the TH-28 and 480. Refer to the correct publication if an optional or special battery is installed. 2. This is the standard battery for the 480B. Refer to the correct publication if an optional or special battery is installed. 3. Refer to the following Safran Aerosystems reports for instructions for continued airworthiness: a. Report DT-00013426, Maintainability Analysis Report Enstrom B480, latest revision. b. Report DT-00013493, Storage and Condition Requirement Sheet 480 Series, latest revision. 2-21. Special Tools A. The special tools listed in Table 2-3 are used for removal, installation, and overhaul of components used on the TH-28/480 Series aircraft: NOTE The special tools listed in Table 2-3 are available through Enstrom’s Tool Rental Program. Contact Enstrom Helicopter Product Support for details. Table 2-3. Special Tools Part Number Nomenclature T-0003 Main Rotor Lead/Lag Lower Nut Tool T-0005 Damper Rod End Removal Tool T-0009 Main Rotor Blade Bolt Guide Bullet T-0011 Main Rotor Hoist Sling T-0013 Main Rotor Lamiflex Nut Socket T-0014 Needle Point Grease Adapter T-0016 Lower Swashplate Gimbal Tool T-0017 Transmission Hoist Eye T-0022 Collective Spring Capsule Retainer Tool T-0026 Main Rotor Blade Tab Bending Tool T-0027 Main Rotor Blade Tab Angle Tool T-0035 Oleo Disassembly Tool (Holding) T-0036 Blade Grip Seal Installation Tool T-0045-1 Lower Swashplate Dogleg Puller T-0048 Main Rotor Mast Nut Tool ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 MM-2-14 20 May 2025 Table 2-3. Special Tools Part Number Nomenclature T-0051-3 Main Rotor Flapping Nut Tool T-0054 Swashplate Dogleg Alignment Tool T-0056-3 Tail Rotor Thrust Bearing Retention Nut Tool T-0057 Damper Bleeding Fixture T-0068-3 Tail Rotor Xmsn Output Shaft Runout Tools T-0079-1 Swashplate Swaging Tool T-0086 Upper Guidetube Nut Tool T-0087-15 Tail Rotor Assembly Static Balance Mandrel T-0092-5 Taper Pin Removal Tool T-0095 Damper Tool T-0100-1 Swashplate DU Bushing Removal Tool T-0102-1 Guidetube Disassembly Tool T-0104 Swashplate Bushing Installation Tool T-0121-1 Tail Rotor Static Balance Stand T-0134 Plate Assembly (Lower Swashplate Assembly) T-0135-1-SET Main Rotor Transmission Pinion Crows Foot T-0136-1 Clutch Removal/Installation Wrench T-0137-1 Engine Hoist Assembly T-0139-1 Belt Tension Tool T-0140 Tail Rotor Rigging Tool T-0141 Drive Pulley Alignment Tool T-0143-1 Tail Rotor Driveshaft Alignment Tool T-0149 Seal Installation Tool (T-T Strap) T-0151-1 Universal Block Bearing Tool Set (Grease Lubricated) T-0152 Tail Rotor Balance Tool (Photo Cell Bracket) T-0160-1 Damper Ring Seal Installation Tools T-0161-1 Seal Installation Tool T-0162-1 Universal Block Bearing Tool (Oil Lubricated) T-0164-1 Upper Pulley Wrench T-0166-11 Alignment Tool, Oil Cooler Shaft ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 MM-2-15 20 May 2025 Table 2-3. Special Tools Part Number Nomenclature T-0168-1 Tail Rotor Assembly Holder T-0169-1 Oleo Disassembly Tool T-0172-1 Seal Installation Tool (Double Lip Seal) T-0174-1 Hub Puller T-0186-1 Overrunning Bearing Seal Tool Set T-0194-1 Bore Concentricity Indicator Tool Set T-0197-7 Torque Multiplier T-0198-11 Main Rotor Gearbox Oil Draining Enabler T-0199-1 Laser Alignment Emitter T-0200-5 Target (Laser) Fixture T-0203-1 Seal Puller Assembly T-1575 Swashplate Centering Tool T-1656-3 Main Rotor Blade Plug Tool T-1709 Guidetube Bearing Collar Tool T-1758 Guidetube Clamps T-2889 Tail Rotor Transmission Rigging Tool T-2893 Tail Rotor Needle Teeter Bearing Removal/Installation Tool Kit T-2896-1 Damper Bleeding/Servicing Tool (2 Required) T-4122100-1 Fuel Bladder Install Tool (CRFS) RBT18560(2) Seal Removal Tool (Double Lip Seal) ( 1) Engine Stand ( 1) Main Rotor Transmission Stand ( 1) Main Rotor Hub Stand Notes: 1. Contact the Enstrom Helicopter Product Support for assistance in obtaining these tools. 2. Available from Dart Helicopter Services ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 MM-2-16 20 May 2025 INTENTIONALLY LEFT BLANK ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 27 FAA Approved: 25 Feb 2025 MM-3-1 27 Jan 2025 SECTION 3 AIRWORTHINESS LIMITATIONS The Airworthiness Limitations section is FAA approved and specifies inspections and other maintenance required under 14 CFR §§ 43.16 and 91.403 of the Federal Aviation Regulations unless an alternative program has been FAA approved. For EASA approval, this Airworthiness Limitations section is approved, and variations must also be approved. FAA APPROVED BY DATE MANAGER CHICAGO AIRCRAFT CERTIFICATION OFFICE CENTRAL REGION FEDERAL AVIATION ADMINISTRATION ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 FAA Approved: 1 Aug 2025 MM-3-2 20 May 2025 SECTION 3 LOG OF REVISIONS Rev. Num. Rev. Date Pages Affected Approval Date FAA Approved 1 Oct 10/03 MM-3-2, MM-3-40, MM-3-41 Oct 28/03 Joe McGarvey 2 Jun 2/04 MM-3-2, MM-3-5, MM-3-13, MM-3-14, MM-3-40 Sep 8/04 Joe McGarvey 3 Oct 13/04 MM-3-2, MM-3-11 thru MM-3-18, MM-3- 40 Nov 09/04 Gregory Michalik 4 Mar 15/05 MM-3-2, MM-3-8, MM-3-33, and MM-3- 40 Mar 25/05 Gregory Michalik 5 Aug 4/06 MM-3-2, MM-3-7, MM-3-8, MM3-31 thru MM-3-36 Aug 30/06 Shawn Malekpour 6 Apr 16/07 MM-3-2, MM-3-15 thru MM-3-18, MM-3- 31 thru MM-3-36, MM-3-39 thru MM-3- 42 Apr 24/07 Shawn Malekpour 7 Feb 20/08 MM3-1 through MM-3-8 Oct 2/08 Gregory Michalik 8 N/A None N/A N/A 9 Dec 12/08 MM-3-7 through MM-3-8 Mar 3/09 Gregory Michalik 10 N/A None N/A N/A 11 Dec 21/09 MM-3-1, MM-3-2, MM-3-5 thru MM-3-8 Jan 6/10 Gregory Michalik 12 N/A None N/A N/A 13 N/A None N/A N/A 14 N/A None N/A N/A 15 N/A None N/A N/A 16 N/A None N/A N/A 17 Jun 24/11 MM-3-6 Jul 15/11 Gregory Michalik 18 N/A None N/A N/A 19 Dec 10/12 MM-3-6 Jan 10/13 Gregory Michalik 20 Apr 25/13 MM-3-1, MM-3-2, MM-3-6, MM-3-7 May 9/13 Gregory Michalik 21 Apr 30/14 None N/A N/A 22 Jun 25/14 None N/A N/A 23 Jul 3/15 None N/A N/A 24 Dec 4/15 MM-3-2 through MM-3-10 Dec 15/15 Gregory Michalik 25 Aug 22/16 MM-3-2, MM-3-3 Aug 26/16 Gregory Michalik 26 Feb 28/20 None N/A N/A 27 27 Jan 2025 MM-3-1 through MM-3-3, MM-3-5, MM-3-9 25 Feb 2025 Boubacar Felix T. Diakhite 28 20 May 2025 MM-3-2, MM-3-3 1 Aug 2025 John Raspanti ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 FAA Approved: 1 Aug 2025 MM-3-3 20 May 2025 SECTION 3 EASA LOG OF REVISIONS Rev. Number Date EASA Approved 1 May 29/05 2005-4678 2 May 29/05 2005-4678 3 May 29/05 2005-4678 4 Sep 16/10 EASA 10031817 5 Sep 16/10 EASA 10031817 6 Sep 16/10 EASA 10031817 7 Sep 16/10 EASA 10031817 8 N/A N/A 9 Sep 16/10 EASA 10031817 10 N/A N/A 11 Mar 9/11 EASA 10033495, Rev. 1 12 N/A N/A 13 N/A N/A 14 N/A N/A 15 N/A N/A 16 N/A N/A 17 May 8/14 EASA 10044744 18 N/A N/A 19 Apr 1/14 FAA/EASA T.I.P.,FAA Approved on Behalf of EASA by G. Michalik* 20 Apr 1/14 FAA/EASA T.I.P.,FAA Approved on Behalf of EASA by G. Michalik* 21 May 24/17 EASA 10061805 22 N/A N/A 23 N/A N/A 24 Jun 22/17 FAA/EASA T.I.P.,FAA Approved on Behalf of EASA by M. Javed♦ 25 N/A N/A 26 N/A N/A 27 25 Feb 2025 FAA/EASA T.I.P.▼ 28 TBD TBD * T.I.P., Rev. 3 dated April 23, 2013, Section 3.2.11 ♦ T.I.P., Rev. 5 dated September 15, 2015, Section 3.2.11 ▼T.I.P., Rev. 7 dated October 19, 2023, Sections 3.3 and 3.5.12.4 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 24 FAA Approved: December 15, 2015 MM-3-4 Dec 4/15 INTENTIONALLY LEFT BLANK ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 27 MM-4-1 27 Jan 2025 SECTION 4 SERVICING, RECOMMENDED OVERHAULS, INSPECTIONS, AND GENERAL MAINTENANCE TABLE OF CONTENTS Paragraph Description Page Table of Contents................................................................................... MM-4-1 4-1. Servicing ................................................................................................ MM-4-5 4-2. Description .................................................................................... MM-4-5 4-3. Fuel System ......................................................................................... MM-4-14 4-4. Servicing ..................................................................................... MM-4-14 4-5. Draining ....................................................................................... MM-4-14 4-6. Engine Oil System ............................................................................... MM-4-15 4-7. Servicing ..................................................................................... MM-4-15 4-8. Draining ....................................................................................... MM-4-16 4-9. Overrunning Clutch .............................................................................. MM-4-19 4-10. Servicing ..................................................................................... MM-4-19 4-10.1. Draining ....................................................................................... MM-4-20 4-11. Main Rotor Transmission ..................................................................... MM-4-20 4-12. Servicing ..................................................................................... MM-4-20 4-13. Draining ....................................................................................... MM-4-21 4-13.1. Flushing ...................................................................................... MM-4-21 4-14. Oil Filter Replacement ................................................................. MM-4-22 4-15. Tail Rotor Transmission .....................................................................MM-4-22.1 4-15.1. Oil Level Check .........................................................................MM-4-22.1 4-16. Servicing ...................................................................................MM-4-22.1 4-17. Draining .....................................................................................MM-4-22.2 4-17.1. Flushing ...................................................................................... MM-4-23 4-18. Main Rotor Dampers ............................................................................ MM-4-25 4-19. Servicing ..................................................................................... MM-4-25 4-20. Main Rotor Flapping Bearings .............................................................. MM-4-26 4-21. Servicing ..................................................................................... MM-4-26 4-22. Draining ....................................................................................... MM-4-26 4-23. Lower Pulley Bearings ......................................................................... MM-4-30 4-24. Servicing ..................................................................................... MM-4-30 4-25. Draining ....................................................................................... MM-4-30 4-26. Oleos ................................................................................................... MM-4-31 4-27. Servicing ..................................................................................... MM-4-31 4-28. Battery ................................................................................................. MM-4-34 4-29. Servicing ..................................................................................... MM-4-34 4-30. Lubrication ........................................................................................... MM-4-34 4-31. Description .................................................................................. MM-4-34 4-32. Lower Pulley ........................................................................................ MM-4-35 4-33. Lubrication................................................................................... MM-4-35 4-34. Main Rotor Blade Grip.......................................................................... MM-4-35 4-35. Lubrication................................................................................... MM-4-35 4-36. Main Rotor Flapping Bearings .............................................................. MM-4-37 4-37. Lubrication................................................................................... MM-4-37 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 MM-4-2 20 May 2025 SECTION 4 SERVICING, RECOMMENDED OVERHAULS, INSPECTIONS, AND GENERAL MAINTENANCE TABLE OF CONTENTS – CONTINUED (PAGE MM-4-2) Paragraph Description Page 4-38. Tail Rotor Pitch Control Bearing ........................................................... MM-4-37 4-39. Lubrication, Preferred Method ..................................................... MM-4-37 4-39.1. Lubrication, Alternate Method ...................................................... MM-4-38 4-39.2. Blower Assembly Bearing .................................................................... MM-4-38 4-39.3. Lubrication................................................................................... MM-4-38 4-39.4. Tail Rotor Feathering Bearing .............................................................. MM-4-38 4-39.5. Lubrication................................................................................... MM-4-38 4-40. Recommended Overhaul Cycles .......................................................... MM-4-39 4-41. Periodic Inspections ............................................................................. MM-4-41 4-42. General Information ..................................................................... MM-4-41 4-43. Daily Inspection.................................................................................... MM-4-41 4-44. Periodic Inspection Checklists .............................................................. MM-4-41 4-45. 100 Hour Inspection .................................................................... MM-4-43 4-46. 200 Hour Inspection .................................................................... MM-4-57 4-47. 300 Hour Inspection .................................................................... MM-4-59 4-48. Special Scheduled Inspection...................................................... MM-4-61 4-48.1 Unscheduled Inspection Checklist ............................................... MM-4-62 4-49. Special Inspections .............................................................................. MM-4-63 4-50. General Information ..................................................................... MM-4-63 4-51. Main Rotor Blade Strike/Sudden Stoppage (Minor) ..................... MM-4-63 4-52. Main Rotor Blade Strike/Sudden Stoppage (Major) ..................... MM-4-64 4-53. Tail Rotor Blade Strike/Sudden Stoppage ................................... MM-4-65 4-54. Hard Landing ............................................................................... MM-4-66 4-55. Main Rotor Overspeed ................................................................ MM-4-67 4-56. Overtorque .................................................................................. MM-4-67 4-57. Main Rotor or Tail Rotor Transmission Chip Indication ................ MM-4-68 4-58. Engine Overspeed....................................................................... MM-4-70 4-59. Engine Overtemp ........................................................................ MM-4-70 4-60. Maintenance Ground Run .................................................................... MM-4-70 4-61. Maintenance Test Flight ....................................................................... MM-4-73 4-62. Ground Handling .................................................................................. MM-4-81 4-63. Ground Handling Wheels ..................................................................... MM-4-81 4-64. Installation/Removal .................................................................... MM-4-81 4-65. External Power..................................................................................... MM-4-82 4-66. Parking................................................................................................. MM-4-82 4-67. Leveling ............................................................................................... MM-4-83 4-68. Hoisting ................................................................................................ MM-4-83 4-69. Jacking................................................................................................. MM-4-83 4-70. Cleaning............................................................................................... MM-4-89 4-71. Exterior ........................................................................................ MM-4-89 4-72. Interior ......................................................................................... MM-4-90 4-73. Plexiglass .................................................................................... MM-4-90 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 MM-4-7 20 May 2025 Table 4-2. Servicing Intervals, Methods, and Locations System Location Consumable Identification Frequency (hr) Capacity Method 25 50 100 Other As Required Fuel, Standard (P/N 4122052) 1 C001 X 91.7 gal (US) (90.0 gal (US) usable) 347.08 L (340.65 L usable) (Note 1) Fuel, Aerazur (P/N 4122009) 1 C001 X 90.0 gal (US) (89.7 gal (US) usable) 340.65 L (339.51 L usable) (Note 1) Fuel, CRFS (P/N 4122100) 1 C001 X 90.2 gal (US) (89.5 gal (US) usable) 341.44 L (338.79 L usable) (Note 1) Engine Oil 2 C004 (Note 2) C005 (Note 2) X X 6.0 qt (US) 5.7 L Oil can Overrunning Clutch 3 C004 C005 X (3) (4) X (3) (4) X 3.8 fl oz (US) 110 mL Oil can Syringe Overrunning Clutch with Vented Clutch Oil Reservoir 3 C004 C005 X (5) X (5) X 6.5 fl oz (US) 192 mL Oil can Syringe Main Rotor Transmission 4 C006 X X 6 pt (US) 2.8 L (dry) Oil can 5.5 pt (US) 2.6 L (reservicing) Main Rotor Transmission (equipped with oil filter and cooling installation) 4 C006 X X 6.5 pt (US) 3.1 L (dry) Oil can 6.0 pt (US) 2.8 L (reservicing) Tail Rotor Transmission 5 C006 X X 5 fl oz (US) 0.15 L Oil can Main Rotor Dampers 6 C007 X X Until full Tool T-2896 Main Rotor Blade Grips (T-T strap) 7 C011 primary C008 alternate (Note 6) X As required Grease gun Main Rotor Lead-Lag Bearings 8 C011 primary C008 alternate (Note 6) X As required Grease gun Main Rotor Flapping Bearings (grease- lubricated) 9 C011 primary C008 alternate (Note 6) X As required Grease gun ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 27 MM-4-8 27 Jan 2025 Table 4-2. Servicing Intervals, Methods, and Locations - continued System Location Consumable Identification Frequency (hr) Capacity Method 25 50 100 Other As Required Main Rotor Flapping Bearings (oil- lubricated) 9 C005 X (7) X As required Oil can Pitch Change Bellcrank Pivot Bearing 10 C011 primary C008 alternate (Note 6) X As required Grease gun Upper Pulley Bearing 11 C008 X As required Grease gun Lower Pulley Bearings (grease- lubricated) 12 C008 X As required (Note 8) Grease gun Lower Pulley Bearings (oil- lubricated) 12 C005 X 0.27 fl oz (US) 8 mL (dry) 6 mL (reservicing) Syringe Blower Assembly Bearings 13 C008 X (9) As required (Note 10) Syringe Tail Rotor Drive Shaft Bearings 14 C008 X As required Grease Gun Tail Rotor Pitch Control Bearing 15 C008 X As required Syringe Tail Rotor Feathering Bearings 16 C011 primary C008 alternate (Note 6) X (11) X As required Grease Gun Tail Rotor Teeter Bearings 17 C011 primary C008 alternate (Note 6) X As required Grease Gun Collective Guidetube Bearing 18 C008 X As required Grease Gun Cyclic Swashplate Bearing 19 C008 X As required Grease Gun Tail Rotor Control Pivot Points 20 C009 X As required Oil Can Pitch Change Bellcrank Inboard Pivot Points 21 C009 X As required Oil Can Collective Walking Beam Pivot Strap Bushings 22 C009 X As required Oil Can ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 MM-4-9 20 May 2025 Table 4-2. Servicing Intervals, Methods, and Locations - continued System Location Consumable Identification Frequency (hr) Capacity Method 25 50 100 Other As Required Lateral Push/Pull Rod 23 C009 X As required Oil Can Trim Motor Attachment Points 24 C009 X As required Oil Can Tail Rotor Pedal Pivot Points 25 C009 X As required Oil Can Landing Gear Oleos 26 C010 X X As required Oil Can Battery 27 (Note 12) (Note 13) X (Note 13) Ground Handling Wheels 28 C008 X As required Hand pack Main Rotor Blades 29 C013 X (14) As required Pump or Aerosol NOTES 1. Differences in the open cell foam (standard), baffle (Aerazur), and open cavity (CRFS) fuel bladder systems will result in a slight variance in total fuel capacity between aircraft (refer to Paragraph 10-2 for serial number effectivity). 2. Recommended oil for the specified average daily temperatures: Outside Temperature Recommended Oil -40°C (-40°F) and above MIL-PRF-23699 (C005) or MIL-PRF-7808 (C004) -40°C (-40°F) and below MIL-PRF-7808 (C004) 3. If the overrunning clutch (ORC) cover is equipped with a sight glass, service the ORC when oil does not fill the sight glass. ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 27 MM-4-10 27 Jan 2025 4. If the overrunning clutch (ORC) cover is equipped with a sight glass and oil completely fills the sight glass, the servicing interval can be extended to 100 hours. If the ORC cover is equipped with a sight glass and the ORC requires servicing after less than 10 flight hours, inspect the ORC bearing housing seal and power output shaft seal for leaks and replace the seal(s) as required. If the ORC bearing housing and power output shaft seals are not leaking, replace the double lip seals (2 each) in the engine gearbox assembly at or before the next 100 hour/annual inspection. 5. If the overrunning clutch (ORC) is equipped with a vented clutch oil reservoir, the servicing interval can be extended to 100 hours. Service the vented clutch oil reservoir if oil does not fill the reservoir sight glass. The oil level between the reservoir sight glass and the ORC cover sight glass should be the same. Service the reservoir until the oil level is just below the reservoir service port. Allow sufficient time for the oil to flow into the ORC. 6. Do not mix alternate greases unless component is purged of existing grease. 7. 600 hr 8. Do not purge lubricate the lower pulley bearings. Refer to Paragraph 4-33. 9. 300 hr 10. Do not purge lubricate the blower assembly bearings. Refer to Paragraph 4-39.2. 11. Applicable for helicopters operating with infrequent inputs to the tail rotor pitch control system (for example: extended flight with unchanging blade pitch). 12. The battery is located in the right side of the engine compartment in a TH-28 and 480/B. An alternate location is in the baggage box. 13. Service in accordance with manufacturer's instructions. 14. Refer to Paragraph 4-48, 6. ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 15 MM-4-39 Nov 15/10 4-40. Recommended Overhaul Cycles A. Refer to Table 4-8 for components with recommended overhaul cycles established by Enstrom Helicopter Corporation and other component manufacturers. NOTE Refer to the Rolls-Royce 250-C20 Series Operation and Maintenance Manual for the overhaul cycle items associated with the engine. B. Overhaul cycle components authorized for installation on the TH-28,480, and 480B must use the shorter overhaul cycle for the duration of the component overhaul cycle if the component is removed from one model of aircraft and installed on a model with a different overhaul cycle. ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 MM-4-40 20 May 2025 Table 4-8. Recommended Overhaul Cycles COMPONENT ITEM OVERHAUL CYCLE TH-28 480 480B 524-080 150SG117Q-3-1 150SG117Q-4-1 Starter/Generator 1,200 Hrs Not Authorized Not Authorized 1,200 Hrs 1,000 Hrs 1,000 Hrs 1,200 Hrs 1,000 Hrs 1,000 Hrs 20306-2 Valve Assembly (Optional Pop-Out Floats) Not Authorized 3 years to coincide with hydrotesting of reservoir cylinder or after valve activation 3 years to coincide with hydrotesting of reservoir cylinder or after valve activation 28-13525-9 Tail Rotor Transmission 1,000 Hrs 1,200 Hrs 1,000 Hrs 4130020 (All dash numbers) 4130030-1 4130060 (All dash numbers) Main Rotor Transmission 1,200 Hrs 1,200 Hrs (1) Not Authorized 1,200 Hrs 1,200 Hrs (1) Not Authorized Not Authorized Not Authorized 1,200 Hrs (2) 4131001-101 4131001-105 4131001-131 Overrunning Clutch 2,400 Hrs 2,400 Hrs 2,400 Hrs 2,400 Hrs 2,400 Hrs 2,400 Hrs 2,400 Hrs 2,400 Hrs 2,400 Hrs 2A20B-17149-2 528-023-01 Cargo Hook (Optional) (3) (3) (3) 549448 Roll Over Valve Assembly (4) Not Authorized (3) (3) ECD4097-1 ECD4097-3 Bladder Tank LH (4) Bladder Tank RH (4) Not Authorized (3) (3) ECD115-17 ECD115-11 ECD115-15 Breakaway Coupling (4) Not Authorized (3) (3) Notes: 1. These Main Rotor Transmissions can only be installed if the aircraft has been modified for installation of main rotor transmissions equipped with the oil filtration/cooling system. 2. Requires a 600 Hour Mandatory Inspection. This is a temporary restriction pending data analysis from the component tear-down inspections. Refer to paragraph 3-2 and Table 3-2 for more information. 3. Refer to the manufacturer’s maintenance publications (See Table 2-2). 4. CRFS installation (Refer to Para. 10-2). ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 MM-4-43 20 May 2025 4-45. 100 Hour/Annual Inspection - Periodic Inspection Checklist AIRCRAFT REGISTRATION NUMBER: SIGNATURE: AIRCRAFT SERIAL NUMBER: DATE: HOURS: Engine: Flight: CYCLES (Start Counter): 100 HOUR/ANNUAL INSPECTION CHECKLIST INITIAL EACH ITEM AFTER ACCOMPLISHMENT INITIAL REF 1. GENERAL INSPECTION A. Inspect the aircraft records and discrepancy sheets _______ B. Check the aircraft and engine records for TBO and Retirement Life items _______ C. Check for special airframe or engine inspections _______ D. Check compliance with applicable Service Information Letters, Service Directive Bulletins, and Airworthiness Directives _______ E. Inspect the aircraft for evidence of fuel and oil leaks _______ F. Clean the aircraft thoroughly _______ G. Remove the following cowling, access panels, and components: 1) Keel access panels _______ 2) Engine access panels _______ 3) Bottom engine access panel _______ 4) Aft side access panels _______ 5) Bottom aft access panel _______ 6) Horizontal stabilizer spar access panels _______ 2. AIRCRAFT STRUCTURE & FUSELAGE A. Inspect the structure and fuselage for: 1) Cleanliness & corrosion _______ 2) Evidence of damage _______ 3) Cracks, tears, or buckling of skins _______ B. Inspect the fuel system for: 1) Condition and security of the crossover, vent, and supply line _______ Fig. 10-3 2) Proper operation of the drain valves and the fuel shutoff valve _______ Fig. 10-3 a) CRFS: Condition, security, and open valve indication of the breakaway coupling valves _______ Fig. 10-3.1 3) Scupper drain lines for obstructions _______ Fig. 10-3 4) Condition and security of the fuel quantity and low fuel warning electrical connectors and fuel system electrical grounding connections _______ ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rev. 28 MM-4-44 20 May 2025 100 HOUR/ANNUAL INSPECTION CHECKLIST INITIAL EACH ITEM AFTER ACCOMPLISHMENT INITIAL REF 5) Verify fuel quantity at the indicator. If indication does not correlate to the fuel level, perform fuel quantity transmitter calibration check. _______ Para. 7-85 6) Condition and security of the external fuel filter (if applicable) _______ Para. 10-56 7) Condition of the fuel cell cap O-ring and proper operation of the cap _______ NOTE Step 8) below applies only to aircraft having an EMI/RFI shielding system (S/N 5134, 5136 through 5197). 8) Transmit for 10 seconds on 136 MHz and observe the fuel gauge for movement. _______ Para. 8-74 Para. 10-49,D 3. COMPONENTS (Equipment not specifically listed in this checklist) A. Inspect components for: 1) Security of installation _______ 2) Cleanliness and evidence of corrosion _______ 3) Evidence of damage _______ 4) Cracks, nicks, and scratches _______ 4. ENGINE Refer to the Rolls-Royce 250-C20 Series Operation and Maintenance Manual (10W2), for the specific inspection requirements and procedures for the engine assembly. NOTE The procedure for bleeding the engine oil system in the Rolls- Royce 250-C20 Series Operation and Maintenance Manual (10W2) covers only top-mounted filters. Refer to paragraph 13-58.1 for bleeding the oil system. A. Inspect the pylon for cracks and corrosion _______ B. Inspect the engine mounts for cracks, bends, corrosion, or wear marks and check the condition of the engine mount bolt torque stripes on the side mounts _______ SDB T-038 C. Inspect the fuel control and power turbine governor controls for proper rigging, worn or loose connections, and freedom of operation _______ Para. 13-109 Para. 13-111 D. Inspect the exhaust stacks and the eductor for condition, proper installation, and security _______ Para. 13-8 Para. 13-17 E. Inspect the engine fire detector for condition, chaffing, and security _______ F. Inspect the engine panels for: 1) Damage or chafing _______ 2) Security of the hinges and fasteners _______