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)