MU-2 Service Bulletin No. 243

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M U - 2 S E R V I C E B U L L E T I N MITSUBISHI HEAVY INDUSTRIES, LTD. NAGOYA AEROSPACE SYSTEMS WORKS 10, OYE-CHO, MINATO-KU, NAGOYA, JAPAN Page 1 of 3 No. 243 DATE: June 30, 2015 Subject: Main Landing Gear Oleo Attach Fitting – Inspection of Effectivity: MU-2B-30/-35/-36: S/N 502 through 696 except 652 and 661 Purpose: Conduct a one-time visual inspection of the main landing gear oleo attach fittings to ensure that no visible crack exists in lugs of the fittings. Background: Cracks were found in the fittings of the main landing gear oleo strut on several long body airplanes. Since the fitting is very important structure for safe landing, a one-time inspection is required to ensure continued airworthiness. Compliance: Mandatory Approval: JCAB Approved Time of Compliance: Within 100 flight hours or 6 months, after receipt of this Service Bulletin, whichever occurs first Responsible Agency of Compliance: MU-2 Owners/Operators Disposition of Removed Parts: Scrap Spare Parts Affected: None Required Man Hours: Approximately 5 man hours Special Tools Required: None Weight and Balance Change: None Flight Manual Revision: None MU-2 Service Bulletin No. 243 DATE: June 30, 2015 Page 2 of 3 INSTRUCTIONS Refer to the applicable MU-2 Maintenance Manual, Illustrated Parts Catalog and Structural Repair Manual to comply with this Service Bulletin. 1. PREPARATION (1) Turn on electrical power to the airplane and open main landing gear forward doors using the ground open switch in accordance with the applicable maintenance manual for easier access to the fittings. If it is necessary to remove more parts for access, those parts may be removed. (2) Pull the circuit breakers “LG CONT” and “LG DOOR MOTOR”. (3) Electrically ground the aircraft. (4) Clean the fitting lug surface to be inspected with a solvent damped cloth to remove any dirt / dust / grease contaminants and make sure that the surface is exposed. 2. INSPECTION (1) Visually inspect the lugs of the oleo attach fittings on both sides for visible cracks. (Figure 1 & 2) Use a mirror and flashlight to check the entire surface of lugs of the fitting. If any cracks are found in the lug, replace with a new fitting in accordance with the applicable Maintenance Manual and discard the discrepant fitting. NOTE If the visual inspection is inconclusive, conduct a non-destructive inspection in accordance with the applicable maintenance manual. 3. LUBRICATION (1) Lubricate the pin assemblies with grease “GP” (MIL-PRF-23827). 4. RESTORATION (1) Close main landing gear forward doors. NOTE For continued airworthiness after completion of this SB, the Maintenance Requirement Manual requires recurring visual and non-destructive inspection of the fittings, and also, the Maintenance Manual requires lubrication for the pin assemblies. 5. LOGBOOK ENTRY Upon completion of this Service Bulletin, make an appropriate maintenance entry in the logbook similar to “Service Bulletin No. 243 complied with on (date) by (name), number/stamp.” 6. COMPLETION Complete the enclosed compliance card and mail back to Mitsubishi Heavy Industries America, Inc. in care of Turbine Aircraft Services, Inc. Turbine Aircraft Services, Inc. 4550 Jimmy Doolittle Drive, Addison, Texas 75001 Attention: Manager, Publications Phone: (972) 248-3108 X 209 Fax: (972) 248-3321 MU-2 Service Bulletin No. 243 DATE: June 30, 2015 Page 3 of 3 Figure 1: LOCATION OF FITTING LUG INSPECTION (Typically shown for L/H side) Figure 2: MOST LIKELY LOCATION OF CRACKS ON FITTING (Typically shown for L/H side) FWD Drag Strut Leg Oleo Strut Oleo Attach Fitting Frame (STA5605) Pin Assy Most likely location of cracks FWD UPR OUTB/D (L/H)