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ENSTROM TH-28/480 Series Maintenance Manual

2001
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ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL
Revision 25, dated Aug 22/16, applies to the Enstrom TH-28/480 Series Maintenance Manual,
2001 Edition.
Place this cover sheet behind the "Record of Revisions" sheet after removing and inserting the
pages listed below. Avoid unintentional removal of pages by following this list carefully.
Remove Pages
i through ii
xxxv through xlvi
MM-1-3 through MM-1-4
MM-3-1 through MM-3-4
MM-4-29 through MM-4-30
MM-6-96.1 through MM-6-96.2
MM-8-5 through MM-8-6
MM-8-61 through MM-8-62
MM-8-69 through MM-8-70
MM-9-15 through MM-9-16
MM-9-23 through MM-9-24
MM-9-33 through MM-9-36
MM-9-41 through MM-9-44
MM-9-47 through MM-9-52
MM-9-87 through MM-9-90
MM-9-95 through MM-9-96
MM-9-125 through MM-9-128
MM-11-65 through MM-11-68
MM-11-75 through MM-11-76
MM-11-91 through MM-11-92
MM-12-43 through MM-12-46
MM-12-49 through MM-12-50
MM-12-115 through MM-12-116
MM-13-23 through MM-13-24
MM-13-75 through MM-13-76
................................................................... End of List ...................................................................
2001 Edition
Insert Pages
i through ii
xxxv through xlvi
MM-1-3 through MM-1-4
MM-3-1 through MM-3-4
MM-4-29 through MM-4-30
MM-6-96.1 through MM-6-96.2
MM-8-5 through MM-8-6
MM-8-61 through MM-8-62
MM-8-69 through MM-8-70
MM-9-15 through MM-9-16
MM-9-23 through MM-9-24
MM-9-33 through MM-9-36
MM-9-41 through MM-9-44
MM-9-47 through MM-9-52
MM-9-87 through MM-9-90
MM-9-95 through MM-9-96
MM-9-125 through MM-9-128
MM-11-65 through MM-11-68
MM-11-75 through MM-11-76
MM-11-91 through MM-11-92
MM-12-43 through MM-12-46
MM-12-49 through MM-12-50
MM-12-115 through MM-12-116
MM-13-23 through MM-13-24
MM-13-75 through MM-13-76

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  • Page 1 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 2001 Edition Revision 25, dated Aug 22/16, applies to the Enstrom TH-28/480 Series Maintenance Manual, 2001 Edition. Place this cover sheet behind the "Record of Revisions" sheet after removing and inserting the pages listed below. Avoid unintentional removal of pages by following this list carefully.
  • Page 2 INTENTIONALLY LEFT BLANK...
  • Page 3 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. Copyright 2001-2016 by...
  • Page 4 INTENTIONALLY LEFT BLANK Rev. 20 Apr 25/13...
  • Page 5 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL EFFECTIVE PAGE LIST Page Date Page Date Aug 22/16 MM-1-1 Apr 25/13 Apr 25/13 MM-1-2 Feb 9/01 Apr 25/13 MM-1-3 Aug 22/16 Apr 25/13 MM-1-4 Apr 30/14 Apr 25/13 MM-1-5 Apr 30/14 Jul 3/15 MM-1-6...
  • Page 6 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL EFFECTIVE PAGE LIST Page Date Page Date MM-4-11 Apr 25/13 MM-4-56 Jun 24/11 MM-4-12 Jun 25/14 MM-4-57 Jul 3/15 MM-4-12.1 Jul 3/15 MM-4-58 Jun 24/11 MM-4-12.2 Oct 20/09 MM-4-59 Jul 3/15 MM-4-13 Oct 20/09 MM-4-60...
  • Page 7 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL EFFECTIVE PAGE LIST Page Date Page Date MM-5-7 Feb 9/01 MM-6-28.3 Apr 30/14 MM-5-8 Jun 25/14 MM-6-28.4 Apr 30/14 MM-5-9 Apr 25/13 MM-6-28.5 Apr 30/14 MM-5-10 Dec 21/09 MM-6-28.6 Apr 30/14 MM-5-11 Apr 25/13 MM-6-28.7...
  • Page 8 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL EFFECTIVE PAGE LIST Page Date Page Date MM-6-59.2 Nov 15/10 MM-6-90 Mar 15/05 MM-6-60 Nov 15/10 MM-6-91 Mar 15/05 MM-6-61 Nov 15/10 MM-6-92 Mar 15/05 MM-6-62 Nov 15/10 MM-6-93 Mar 15/05 MM-6-63 Nov 15/10 MM-6-94...
  • Page 9 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL EFFECTIVE PAGE LIST Page Date Page Date MM-6-100 Jun 24/11 MM-6-122 Nov 15/10 MM-6-101 Nov 15/10 MM-6-123 Jul 3/15 MM-6-102 Jun 24/11 MM-6-124 Jul 3/15 MM-6-103 Mar 15/05 MM-6-125 Apr 30/14 MM-6-104 Mar 15/05 MM-6-126...
  • Page 10 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL EFFECTIVE PAGE LIST Page Date Page Date MM-7-42 Jun 25/14 MM-8-38.1 Oct 20/09 MM-7-43 Jun 25/14 MM-8-38.2 Oct 20/09 MM-7-44 Jun 25/14 MM-8-38.3 Oct 20/09 MM-7-45 Jun 25/14 MM-8-38.4 Oct 20/09 MM-7-46 Jun 25/14 MM-8-38.5...
  • Page 11 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL EFFECTIVE PAGE LIST Page Date Page Date MM-8-74.2 Jul 3/15 MM-9-26 Apr 25/13 MM-8-75 Feb 9/01 MM-9-27 Apr 25/13 MM-8-76 Apr 25/13 MM-9-28 Feb 9/01 MM-8-77 Feb 9/01 MM-9-29 Feb 9/01 MM-8-78 Feb 9/01 MM-9-30...
  • Page 12 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL EFFECTIVE PAGE LIST Page Date Page Date MM-9-68.4 Jun 24/11 MM-9-106.3 Jun 25/14 MM-9-69 Apr 25/13 MM-9-106.4 Jun 25/14 MM-9-70 Apr 25/13 MM-9-106.5 Jun 25/14 MM-9-71 Apr 25/13 MM-9-106.6 Apr 25/13 MM-9-72 Feb 9/01 MM-9-107...
  • Page 13 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL EFFECTIVE PAGE LIST Page Date Page Date MM-10-21 Feb 9/01 MM-11-27 Feb 20/08 MM-10-22 Feb 9/01 MM-11-28 Feb 20/08 MM-10-23 Jun 25/14 MM-11-29 Feb 9/01 MM-10-24 Feb 9/01 MM-11-30 Feb 9/01 MM-10-25 Jun 25/14 MM-11-31...
  • Page 14 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL EFFECTIVE PAGE LIST Page Date Page Date MM-11-72 Feb 9/01 MM-12-25 Feb 9/01 MM-11-73 Feb 9/01 MM-12-26 Feb 9/01 MM-11-74 Feb 9/01 MM-12-27 Feb 20/08 MM-11-75 Aug 22/16 MM-12-28 Feb 20/08 MM-11-76 Feb 9/01 MM-12-29...
  • Page 15 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL EFFECTIVE PAGE LIST Page Date Page Date MM-12-71 Jun 21/12 MM-12-113 Jul 3/15 MM-12-72 Feb 9/01 MM-12-114 Jul 3/15 MM-12-73 Jun 25/14 MM-12-115 Aug 22/16 MM-12-74 Apr 25/13 MM-12-116 Feb 9/01 MM-12-75 Apr 25/13 MM-13-1...
  • Page 16 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL EFFECTIVE PAGE LIST Page Date Page Date MM-13-39 Apr 25/13 MM-13-70 Apr 16/07 MM-13-40 Apr 25/13 MM-13-71 Apr 16/07 MM-13-41 Apr 25/13 MM-13-72 Jul 3/15 MM-13-42 Feb 9/01 MM-13-73 Apr 16/07 MM-13-43 Apr 25/13 MM-13-74...
  • Page 17 The maintenance data presented in this manual is applicable to all TH-28, 480, and 480B model Enstrom helicopters with standard equipment. Optional equipment maintenance procedures are included in the TH-28/480 Series Maintenance Manual for common optional equipment that is installed before aircraft delivery (This does not include avionics installations).
  • Page 18 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 1-4. Maintenance Manual Changes and Revisions Subsequent to the publication of the initial issue of the Enstrom TH-28/480 Series Maintenance Manual, changes in aircraft equipment, support concepts and procedures, as well as information developed by experience, may affect the contents of the manual. To ensure that coverage in the...

  • Page 19: Airworthiness Limitations

    ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 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.

  • Page 20: Section 3 Log Of Revisions

    ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL SECTION 3 LOG OF REVISIONS Rev. Rev. Pages Approval Num. Date Affected Date Approved Oct 10/03 MM-3-2, MM-3-40, MM-3-41 Oct 28/03 Joe McGarvey Jun 2/04 MM-3-2, MM-3-5, MM-3-13, MM-3-14, Sep 8/04 Joe McGarvey MM-3-40 Oct 13/04 MM-3-2, MM-3-11 thru MM-3-18, MM-3-...
  • Page 21 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL SECTION 3 EASA LOG OF REVISIONS Rev. FAA Approval on Behalf Date EASA Approved Num. of EASA May 29/05 2005-4678 May 29/05 2005-4678 May 29/05 2005-4678 Sep 16/10 EASA 10031817 Sep 16/10 EASA 10031817 Sep 16/10...
  • Page 22 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 24 FAA Approved: December 15, 2015 MM-3-4 Dec 4/15...
  • Page 23 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 4-23. Lower Pulley Bearings (See Figure 4-7) NOTE The following procedures only apply to aircraft equipped with oil lubricated lower pulley bearings. Refer to paragraph 4-33 for grease lubricated lower pulley bearings. 4-24. Servicing - Lower Pulley Bearings NOTE Refer to Table 4-1 for system capacity and approved oil.
  • Page 24 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL D. Inspect the sight plugs for staining. Remove and clean or replace the sight plugs as required. E. Replace the O-ring on the sight plug as required. Install the sight plug and torque (150 in-lbs/17 Nm). Install a torque slippage mark.
  • Page 25 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Sheet 3 of 3 S/N 5042 and Subsequent Diagram 6-11. N Indicating System Rev. 25 MM-6-96.1 Aug 22/16...
  • Page 26 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 12 MM-6-96.2 Jul 7/10...
  • Page 27 A. Replace damaged or missing hardware. B. Repair damage to the cabin shell, cockpit bulkhead, or the cockpit floor I/A/W AC 43.13-1B. Contact The Enstrom Helicopter Corporation Customer Service for detailed damage and repair limitations. MM-8-5...
  • Page 28 A. Replace damaged or missing hardware. B. Repair damage to the keel assembly I/A/W AC 43.13-1B. Contact The Enstrom Helicopter Corporation Customer Service for detailed damage and repair limitations. 8-9. Pylon Assembly 8-10.
  • Page 29 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Figure 8-7. Oleo Strut Installation MM-8-61 Feb 9/01...
  • Page 30 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Valve Assembly Cylinder Assembly Piston Shaft Wiper Washer Brass Guide Valve Piston Guide Shaft Assembly Spring O-ring Shaft Backup Ring Step O-ring Bolt Spacer Washer Rebound Rings Rivet Piston Figure 8-8. Oleo Strut Assembly Rev. 25...
  • Page 31 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL P. Slowly open the oleo valve and allow the oleo to fill until the piston shaft is fully extended and the oleo pressure has equalized to the regulator pressure. Close the oleo valve. Close the nitrogen tank valve, set the regulator pressure back to zero, and disconnect the nitrogen pressure line from the oleo valve.
  • Page 32 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Use a beam type in/lb torque wrench to record the torque on the nut that is installed on the bolt facing aft. Place a light washer on each side of the universal link and connect the bottom universal block to the landing gear leg in accordance with step B above.
  • Page 33 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 9-6. Main Rotor Hub 9-7. Removal – Main Rotor Hub A. Remove the main rotor blades (para. 9-34). CAUTION Foreign objects dropped down the mast must be immediately removed to prevent damaging the flight controls.
  • Page 34 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 9-8. Disassembly – Main Rotor Hub (Figure 9-4 or 9-5) A. Remove main rotor hub from the aircraft (para. 9-7). NOTE Mark all parts for reassembly in the same respective positions. B. Remove the pitch change links and the pitch change bellcranks from the pitch horns (para.
  • Page 35 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL D. Place the spacer (16) on the lower hub plate and align the bolt holes. NOTE Ensure the DU washers are seated in the recessed areas of the upper hub plate. E. Lubricate the bearing bores of the upper hub plate and install the upper hub plate onto the U-blocks.
  • Page 36 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Rotate the U-block to one of the stops and install a hinge pin into the retention pin hole until the inside edge of the flange is 7.1 inches/18 cm from the center of the universal block.
  • Page 37 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 9-16. Inspection - Retention Assembly CAUTION Do not submerge the lamiflex bearing in any type of cleaning fluid while cleaning the parts for inspection. Clean the bearing by hand using alcohol. A. See Table 9-2 for detailed inspection requirements of the retention assembly.
  • Page 38 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Table 9-2. Retention Assembly Inspection Requirements* Fig. 9-7 Part Name Inspection Serviceable Limits Repair Limits Repair or Action Item # 28-14240-1 Droop Stop General Condition .003 wear Not Repairable Replace Stop 28-14282-13 Spindle Lamiflex bearing tab +.002...
  • Page 39 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Table 9-2. Retention Assembly Inspection Requirements* Fig. 9-7 Part Name Inspection Serviceable Limits Repair Limits Repair or Action Item # 40NBC20- Bearing O.D. 3.2492 to 3.2500 No Tolerance Not Repairable Replace Bearing 52YZP Allowed I.D. 2.4993 to 2.5000...
  • Page 40 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Table 9-2. Retention Assembly Inspection Requirements* Fig. 9-7 Part Name Inspection Serviceable Limits Repair Limits Repair or Action Item # 28-14279-3 Blade Grip (Cont'd) Thru bore Dia. 1.5145 +.0015 Not Repairable Replace Blade Grip to 1.5165 Drag link ear width .745...
  • Page 41 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Table 9-2. Retention Assembly Inspection Requirements* Fig. 9-7 Part Name Inspection Serviceable Limits Repair Limits Repair or Action Item # 28-14384-15 Pin bore Dia. .750 to +.002 Not Repairable Replace Lug .752 Nicks, scratches, or None Allowed ≤...
  • Page 42 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Lubricate (MIL-PRF-81322) the bearing surface and install the bearing (9) using a plastic mallet. NOTE Ensure the bearings are seated firmly against the spindle shoulders. Install the retaining ring (10). Install the DU washer (11) with the chamfered side of the washer facing the bearings.
  • Page 43 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL (19) Install the cotter pin after the nut has been properly shimmed and torqued. Bend the cotter pin ends to secure. CAUTION To prevent lamiflex bearing damage, do not over-rotate the grip with the pitch change links disconnected.
  • Page 44 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 7 MM-9-44 Feb 20/08...
  • Page 45 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL (15) Remove tool (T-0036) and tap the blade grip until fully seated on the spindle. (16) Install one of the retaining rings (31) into the lug. Align the tension-torsion strap to the lug and install the retention pin (30). Install the other retaining ring.
  • Page 46 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL CAUTION Use brass protector plates in the vise jaws to prevent from damaging the retention assembly. Clamp the spindle in a vise in the vertical position. If removed, apply a small amount of Loctite 635 (green) to the alignment pin (32) and press the alignment pin into the spindle until the end is slightly recessed from the seal surface.
  • Page 47 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL (18) Install the tension-torsion strap into the spindle and ensure the groove in the cylinder engages the pin in the spindle. (19) Install one of the retaining rings (31) into the lug. Align the tension-torsion strap to the lug and install the retention pin (30).
  • Page 48 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Install the sleeves into the seals if equipped with oil lubricated flapping bearings. NOTE Install the shims (if installed) behind the DU washers in the same position as previously installed. NOTE If new parts are installed in the flapping axis, begin with a 0.005” shim and follow the shimming procedure in para.
  • Page 49 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL (11) Lubricate the retention assembly (para. 4-35). (12) Service the flapping bearing reservoir if equipped with oil lubricated flapping bearings (para. 4-21). (13) Perform a maintenance test flight (para. 4-61). B. Use the following procedure to install a retention assembly until the flapping bearings are installed in the universal blocks using the shimming procedure in paragraph 9-24,B or C.
  • Page 50 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Install the main rotor damper (para. 9-31), connect the pitch change link to the pitch change bellcrank and the pitch horn (para. 12-96), and install the main rotor blade (para. 9-38). (10) Lubricate the retention assembly (para. 4-35).
  • Page 51 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 9-36. Repair – Main Rotor Blades A. Repair small areas of the paint finish using the following: NOTE Refinish the blades equally if refinishing a larger area (outboard leading edge for example) to maintain the continuity of the weight between the blades.
  • Page 52 C. Repair blade spars with flaking or slivering exceeding .032"/0.8 mm in depth but not the limits in Figure 9-24 as follows: Apply corrosion inhibitor to the affected area daily. Contact the Enstrom Customer Service Department for further instructions. Rev. 20 MM-9-88...
  • Page 53 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL NOTE Main rotor blades with intergranular spar corrosion (exfoliation) exceeding the limits of Figure 9-24 must be rejected as unairworthy. D. Repair voids in the spar to skin bond lines that do not exceed the limits of Figure 9-25...
  • Page 54 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Inspect repairs outboard of Sta. 101 using the coin tap method at the normal periodic inspection interval. Inspect repairs inboard of Sta. 101 using the coin tap method at 25 hour intervals. Repair voids in the root doubler and retention plate edge bond lines not exceeding the limits in Figure 9-25 using the procedure in paragraph 9-36, D.
  • Page 55 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL (14) Seal the space between the patch and the older pre-existing leading edge tape, and the trailing edges of the patch with the DP190 epoxy adhesive using the following procedure (Figure 9-31.2, c): a. Mask off both sides of the edge of the patch, all the way around the patch, with masking tape approximately 1/16 inch (.157 cm) from the edge of the...
  • Page 56 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL WARNING Use the proper protective equipment when working with the chemical conversion coating. Observe the precautionary information and instructions provided with the chemical conversion coating. Treat the blade as required with a chemical conversion coating complying with MIL- DTL-5541/MIL-DTL-81706.
  • Page 57 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Figure 9-38. Tail Rotor Installation Orientation MM-9-125 Feb 9/01...
  • Page 58 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 9-52. Consumable Materials List ITEM DESCRIPTION PART NUMBER Abrasive pad Pad, 3M Brand (Scotch-Brite) 7447B Acetone Acetone solvent Adhesion promoter Adhesion promoter, 3M Brand (primer) Adhesive Epoxy adhesive, 3M Brand DP190 Adhesive Epoxy adhesive, 3M Brand...
  • Page 59 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL ITEM DESCRIPTION PART NUMBER Paint Acrylic aerosol touch up paint, flat black or flat light grey Paint Any quality brand urethane paint Paint Stripper Paint stripper, PPG Aerospace Brand Eldorado PR-3500 Primer Epoxy primer MIL-PRF-23377...
  • Page 60 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 20 MM-9-128 Apr 25/13...
  • Page 61 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Table 11-3. Upper Pulley and Aft Pinion Bearing Assemblies Inspection Requirements* Fig. 11-11 Part Name Inspection Serviceable Limits Repair Limits Repair or Action Item # 28-13142 Width .3105 to .3125 -.001 Not Repairable Replace Key...
  • Page 62 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL D. Install the six bolts (for alignment) in the pulley hub (3) and the hub adapter (2), and install the hub and adapter into the pulley. E. Set the upper pulley (1) in a press with the aft side up.
  • Page 63 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL CAUTION Apply lubricant to the bore of the pulley hub and aft pinion bearing adapter, not to the pinion shaft. CAUTION Ensure the aft face of the pinion bearing adapter is clean and does not have lubricant on it.
  • Page 64 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL NOTE (Keyed pinion) If a cup washer is installed, torque to 15-18 in-lbs/1.7-2.0 Nm (AN364 nut), otherwise torque to 25 in-lbs/2.8 Nm (AN365 nut). (Keyed Pinion) Install the tail rotor drive shaft hub into the pinion shaft. Install the taper pin and torque the nut.
  • Page 65 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Taper pin holes for elongation, excessive diameter, and cracks. Any of the preceding conditions are cause for rejection. Corrosion. Pits in excess of .030inch/.76 mm in depth are cause for rejection. B. Inspect the drive hubs in accordance with paragraph 11-84.
  • Page 66 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL C. If installed, remove the short tail rotor drive shaft (para. 11-63). NOTE Keep the shim stack-ups together for each of the drive shaft bearing assemblies. D. Remove the bolts securing the tail rotor drive shaft bearing housings to the tailcone and the drive shaft cover bracket from under the aft drive shaft bearing assembly.
  • Page 67 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 11-94. Consumable Materials List ITEM DESCRIPTION PART NUMBER Adhesive Adhesive, Loctite Fixmaster Flex 80 Putty 97422/97423 Brand Grease Grease, Lubriplate Brand 630-AA (06701) Grease Grease MIL-PRF-81322 Liquid Soap Soap, Joy Brand Lockwire Lockwire, .032” MS20995C32 Lockwire Lockwire, .041”...
  • Page 68 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK MM-11-92 Feb 9/01...
  • Page 69 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL B. Level the aircraft (para. 4-67). C. Install the lateral and longitudinal cyclic rigging pins. D. Place the collective full down and apply collective friction. E. Phase the main rotor blades 120° apart by moving each blade grip until one inch of the damper piston shaft is exposed on each damper.
  • Page 70 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Q. Move the cyclic to the full right position and measure the blade angle. The measurement should be 11.5° ± 1.0°. Move the cyclic full left and measure the blade angle. The measurement should be -5.3° ± 1.0°.
  • Page 71 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 12-50. Repair – Cyclic Stick A. Remove corrosion, nicks, and scratches that are less than .010 inch/.25 mm in depth. Replace the cyclic stick if cracked, bent, or damage exceeds .010 inch/.25 mm in depth.
  • Page 72 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL NOTE Stick socket, P/N 4167517-3, is used in the 480/480B removable cyclic stick assembly and is not shown. The repair procedure is the same for either cyclic stick assembly. Figure 12-11. Cyclic Stick Socket MM-12-46...
  • Page 73 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 12-52. Cyclic Torque Tube Assembly 12-53. Removal – Cyclic Torque Tube Assembly A. Remove the left and right side keel access panels. B. Remove the cyclic sticks (para. 12-48). C. Disconnect the push-pull rod from the torque tube arm.
  • Page 74 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL Heat the bearing housing to approximately 250°F/121°C. Remove the bearing from the clevis fittings. (-101 only) Remove the retaining rings from the clevis fittings and remove the pivot bearings and shims if installed. WARNING Acetone and Methylethylketone (MEK) are toxic and must be used with extreme caution.
  • Page 75 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 12-127. Consumable Materials List ITEM DESCRIPTION PART NUMBER Adhesive “Hot Stuff” Brand HS-3 Cleaner Contact Cleaner (any brand) Corrosion Preventive Corrosion Preventive Compound, Black Par-Al-Ketone Compound Bear Brand Grease Grease, Lubriplate Brand 630-AA (06701) Grease...
  • Page 76 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK MM-12-116 Feb 9/01...
  • Page 77 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 13-39. Inspection – Lower Plenum A. Inspect the lower plenum for cracks, damage, cleanliness, condition and security of mounting brackets, condition and security of the protective shield, and differential air pressure line fitting for condition and security. Ensure the drain holes are open and clean.
  • Page 78 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 13-41. Installation – Lower Plenum CAUTION Care must be used to prevent damage to the lower plenum during installation. A. Install the plenum in the airframe by reversing the removal procedure (paragraph 13- 38). B. Install the mounting hardware but do not tighten at this time.
  • Page 79 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL 13-148. Consumable Materials List ITEMS DESCRIPTION PART NUMBER Adhesive Acrylic Adhesive, IPS Corporation WELD-ON 45 Adhesive Acrylic Adhesive, Magnacryl Brand 506 with accelerator (#7) Adhesive Structural Adhesive, Loctite Brand EA 9359.3 AERO Adhesive Structural Adhesive, Loctite Brand...
  • Page 80 ENSTROM TH-28/480 SERIES MAINTENANCE MANUAL INTENTIONALLY LEFT BLANK Rev. 17 MM-13-76 Jun 24/11...