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 38 

No. 104/53-003 DATE: July 22, 2013 

Subject: Fuselage Frame Inspection and Repair or Replacement 

Effectivity: MU-2B-36A/-60: S/N 661SA, 697SA through 799SA, and 

1501SA through 1569SA 

Purpose: To verify and restore, where required, structural integrity of main 

fuselage structural members. 

Background: As part of Mitsubishi Heavy Industries, Ltd (MHI) continuing aging 

aircraft program short body and long body airplanes were subjected 

to detailed teardown inspections. Structural cracks in the flanges of 

some long body aircraft frames were found at STA 4610 and STA 

5605. To assure continued safety of operation, all long body aircraft 

fuselage frames STA 4610 and 5605 need to be inspected and 

appropriate repairs made. 

Compliance: Mandatory 

Approval: Engineering aspects of this Service Bulletin are FAA Approved 

Time of Compliance: Within 1,000 flight hours or 3 years, after receipt of this Service 

Bulletin, whichever occurs first, comply with the initial inspection 

detailed herein. If cracks are found they must be repaired using the 

procedures outlined in this SB before next flight. 

Responsible Agency of 

Compliance : 

MU-2 Owners/Operators 

Disposition of Removed 

Parts: 

Scrap 

Spare Parts Affected: None 

Approximate Required 

Man Hours: 

Inspection ~ 100 Man hours 

Accessing for frame repair ~ 128 Man hrs 

Frame end replace/repair (per frame) ~ 40 Man hrs 

Side-Frame Replacement (per frame) ~ approx. 140 Man hrs 

Lower-Frame Replacement (per frame) ~ approx. 200 Man hrs 

Special Tools Required: Airplane support forms (to maintain geometry when frame segments 

are removed). Eddy current NDT inspection and Borescope 

capability is required for this inspection. 

Flight Manual Revision: None 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 2 of 38 

Table of Contents 

1.0 APPLICABLE REFERENCE MANUALS ................................................................... 3

2.0 GENERAL NOTES ..................................................................................................... 3

3.0 FRAME INSPECTION ................................................................................................ 5

3.1 PREPARATION FOR INSPECTION ........................................................................... 5

3.2 DETAILED INSPECTIONS ......................................................................................... 6

3.3 RESTORATION .......................................................................................................... 7

4.0. GENERAL PREPARATION FOR REPAIR/REPLACEMENT ................................... 7

5.0 LOWER FRAME SEGMENT-END REPLACING REPAIR ......................................... 9

5.1 STA 4610 FRAME SEGMENT-END REPLACING REPAIR (L/H OR R/H) ............... 10

5.2 STA 5605 FRAME SEGMENT-END REPLACING REPAIR (L/H OR R/H) ............... 11

6.0 REPLACEMENT OF SIDE-FRAME SEGMENTS (STA 4610 or STA 5605) ........... 13

6.1 REMOVAL OF LEFT SIDE-FRAME SEGMENT (STA 5605) .................................... 13

6.2 REMOVAL OF RIGHT SIDE-FRAME SEGMENT (STA 5605) ................................. 15

6.3 INSTALLATION OF REPLACEMENT SIDE-FRAME SEGMENT ............................. 16

7.0 REPLACEMENT OF LOWER-FRAME SEGMENT 

(CENTER SEGMENT AT STA 4610 OR STA 5605) ......................... 17

7.1 PREPARATIONS ...................................................................................................... 18

7.2 REMOVAL OF LOWER-FRAME SEGMENT STA 4610 ........................................... 19

7.3 REMOVAL OF LOWER-FRAME SEGMENT STA 5605 ........................................... 19

7.4 INSTALLATION OF LOWER-FRAME SEGMENTS.................................................. 19

8.0 RESTORATION ........................................................................................................ 20

9.0 LOGBOOK ENTRY .................................................................................................. 20

10.0 COMPLETION ........................................................................................................ 21

11.0 PARTS AND MATERIAL REQUIRED & SYMMETRICAL MEASUREMENTS..... 22

12.0 FIGURES ................................................................................................................ 28
MU-2 Service Bulletin

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Page 3 of 38 

1.0 APPLICABLE REFERENCE MANUALS 

Refer to the applicable MU-2 Maintenance Manual, Illustrated Parts Catalog, and Structural 

Repair Manual. 

2.0 GENERAL NOTES 

a. Repair Kit’s and/or Replacement frames may be purchased through Mitsubishi Heavy 

Industries America, Inc. (MHIA) Service Center Network. 

b. Unless there is an MHI, MHIA or FAA approved repair, the affected frame sections must be 

replaced. 

c. Properly identify all components removed or disrupted. 

d. Restoration of disrupted systems, including rigging/operational tests, should be 

accomplished in accordance with applicable Maintenance Manuals. 

e. Frames with surface corrosion should be repaired utilizing repairs outlined in the Structural 

Repair Manual (SRM). 

f. If additional information is needed, contact MHIA Engineering. 

This Service Bulletin covers three basic steps in the process of assuring the frame structure at 

STA 4610 and STA 5605 is sound. The three steps are: 

1) Detail visual inspection of the frame flanges [Paragraph 3], 

2) Repair or Replacement of damaged frame segments [Paragraph 4 thru 7] and 

3) Restoration of the Aircraft & Completion [Paragraph 8, 9 & 10]. 

Any cracking in the frame flanges at STA 4610 and STA 5605 is classified as “Damage 

Repairable by Replacement” in Section 1, Paragraph 6.5 of the SRM. That is, if the cracking is 

limited to the ends of the large lower frame segment it is simpler to replace only the damaged 

ends. If cracking extends over several inches and into the center section of the lower frame 

then the entire frame segment should be replaced. In Step 1, above, Eddy current inspection 

capability may be needed to verify crack-free condition of the frame flanges. In Step 2, repairs 

are presented for replacing only the damaged frame ends with Repair Kits or the entire lower 

frame segment with replacement parts for each frame. Assessment of the extent of damage to 

the lower frame segment will determine the choice of repair means. Replacement frames are 

also provided for the side-frame segments, at both STA 4610 and STA 5605, in case cracks are 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 4 of 38 

found in side frame segments. If repair or replacement of the side-frame segment and 

lower-frame segment in the same STA are required due to cracks and/or damage, replace the 

lower-frame segment first to stabilize the fuselage prior to removing the side-frame segment. 

MHI analysis determined that these cracks are likely the result of stress corrosion. Repair kits 

and replacement frame segments are manufactured from an aluminum material that has an 

improved resistance to stress corrosion cracking. 

For cracks found in other locations on the frames (i.e. side-frame segments), MHI recommends 

replacing the segment rather than attempt a repair not covered by this Service Bulletin or 

Service Bulletin 073/53-002B, due to the complex structure. Therefore, this Service Bulletin 

covers only replacement of damaged frame segments. Repair schemes may be evaluated by 

MHI Engineering on a case-by-case basis. Please contact MHIA Engineering to discuss 

proposed repair methods that are not covered in this Service Bulletin or the SRM.
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No.104/53-003 DATE: July 22, 2013 

Page 5 of 38 

3.0 FRAME INSPECTION 

3.1 PREPARATION FOR INSPECTION 

NOTE

Mark and store all removed parts and attaching hardware. 

Remove and store passenger seats, galley (if equipped), carpet and side panels to gain access to 

lower portion of fuselage frames at STA 4610 and STA 5605. Headliner removal is only necessary, 

if the upper area of the frames cannot be borescope inspected or there is evidence of corrosion on 

the upper frames. 

a. Remove insulation and acoustic package, as required. Take care to mark insulation and 

acoustic package so pieces can be reinstalled in the same location after completion of this 

Service Bulletin. 

b. It is recommended loosening left and right armrest rails and plumbing to allow inward 

movement of approximately three inches to gain access to areas of frames behind the 

structure as needed. Do not remove the armrest rails, remove only the upper and lower 

attach hardware to loosen them. Armrests will not be removed completely due to the wiring 

and plumbing running through them. 

NOTE 

Use care when disconnecting tubing, there are 

 several smaller hoses that are hidden. 

c. Remove the plenum chambers at frames STA 4610 and STA 5605 floor area: 

Use caution not to damage the air hose connecting to the plenum chambers 

P/N 030A-63370-1, Fwd Left 

P/N 030A-63370-2, Fwd Right 

P/N 030A-63371-1, Aft Left 

P/N 030A-63371-2, Aft right 

d. Remove access panels from the belly of the aircraft between left and right keels in landing 

gear area to provide access for inspecting frames at STA 4610 and STA 5605. Mark and 

store all removed parts and attaching hardware. 
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No.104/53-003 DATE: July 22, 2013 

Page 6 of 38 

CAUTION 

To avoid damaging the frame surface 

use only non-metallic scrapers to remove sealant 

e. Clean frames of any loose debris and excessive sealant, paying particular attention to 

frames at STA 4610 and STA 5605 where the floor meets the frames on the left and right 

sides of the aircraft. The area around the rivets on the inner flange going from the floor line 

up approximately 4 inches needs to be thoroughly cleaned of sealant and corrosion. 

Typical areas where cracks have been detected at each frame location are shown in Figures 

1 and 2. However, the entire frame flange must be inspected. 

3.2 DETAILED INSPECTIONS 

a. Conduct detailed visual inspection of both inner and outer frame flange areas of side and 

lower frames for cracks and corrosion at frame STA 4610 and STA 5605. Pay particular 

attention to the area between rivet centerlines. 

NOTE 

If the visual inspection is inconclusive (indicated by hairline cracks in the paint), 

a fluorescent penetrant inspection or Eddy Current NDT technique should be used. 

NOTE 

Personnel performing NDT must be qualified and certified as a LevelII or 

higher based on the requirements of National Aerospace Standard NAS410 

or equivalent international standard. 

b. Using a borescope, visually inspect the frame flange areas of side-frames behind the 

armrest rail for cracks at STA 4610 and STA 5605. 

c. Visually inspect upper frame at STA 5605 for signs of surface corrosion where the 

air-conditioning ducting is mounted in the frame (a borescope may be required if the 

headliner is not removed). (S/N 731SA and up)

d. Record the location of any cracks detected on Figures 1 and 2. 

e. If crack indications are found, repair the cracked area in accordance with Paragraph 4 and 5 

of this Service Bulletin or replace the affected frame segment in accordance with Paragraph 

4, 6 and 7 of this Service Bulletin. 
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No.104/53-003 DATE: July 22, 2013 

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f. If surface corrosion is found, repair the damaged area in accordance with SRM. If severe 

corrosion is found, contact MHIA engineering for disposition. 

3.3 RESTORATION 

a) If no cracks are found, reverse the process to restore the airplane to an original 

condition. 

b) Continue with Paragraph 9 and 10 to return the aircraft to service. 

4.0. GENERAL PREPARATION FOR REPAIR/REPLACEMENT 

NOTE 

The following instructions assume all segments will be 

repaired/replaced in sequence. If only an individual repair 

(i.e. one frame end) is to be made, modify these instructions 

by deleting the steps not required to the repairs being done. 

NOTE 

If several frame repairs are to be made or both frame segments are to be replaced, 

it is recommended that only one frame end/frame is removed and repaired/replaced 

at a time to maintain fuselage alignment. 

a. Remove aircraft batteries and pull landing gear circuit breakers. 

b. Defuel aircraft leaving only unusable fuel in the tanks. 

c. Place aircraft on jacks, utilizing all four jack points and place a tail stand support under 

tailskid. Once aircraft is jacked with wheels clear of the ground, verify that the aircraft is 

level in both axes in accordance with Chapter 2 of applicable Maintenance Manual. 

d. Build additional braces to support the fuselage dead weight and stabilize the aircraft while 

repairs/replacements are being performed. Forward brace is to be placed at the fuselage 

centerline directly under frame STA 4025 and Aft brace is to be placed directly under frame 

STA 6495. Take care to support only the dead weight at the frame and not induce any 

vertical load into the frame by the brace. 
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No.104/53-003 DATE: July 22, 2013 

Page 8 of 38 

e. Symmetrical measurements should be obtained in accordance with Section I, Paragraph 3.4 

Symmetry and Alignment Inspection Procedure of the Structural Repair Manual. Record 

dimensions in Table 7 for later reference. 

f. Remove forward and aft main gear doors on the side of the aircraft that is being worked on. 

g. Verify landing gear is in the down and locked position. Mechanically move traveling nut 

against the down stop, and then record the length of main landing gear drag strut “exposed 

threads” or any other reference from the drag strut gearbox. This will aid in restoration and 

gear rigging. 

NOTE 

Do not rotate or move gear components once torque tubes are removed. 

NOTE 

Mark location and direction of torque tubes to aid in restoration. 

h. Remove main landing gear door lock mechanism (R/H Only) 

a. P/N 030A-38530 (Torque tube assembly forward of STA 4610) 

b. P/N 030A-38450 (Bearing assembly at STA 4610) 

c. P/N 030A-38449-31 (Torque tube assembly aft of STA 4610) 

i. Remove main landing gear control torque tubes (L/H Only) 

a. P/N 030A-38605-11 (Between STA 4610 and STA 5605) 

b. P/N 030A-38605-21 (Fwd of STA 4610) 

c. P/N 030A-38720 (Bearing box Assembly at STA 4610) 

d. P/N 030A-38730 (Bearing box Assembly at STA 5605) 

j. Remove brake lines from STA 5605 to STA 4610. 

k. Remove wiring from gear well area and frame to be repaired. Label wires for restoration. 

l. Remove main landing gear assembly in accordance with the applicable Maintenance 

Manuals. 

m. On the lower side of the aircraft, drill attaching hardware from left and right center bulge 

assemblies between STA 4285 and STA 5890. Detach the ribs from the keel and remove 

with the skin. Remove both center bulge assemblies to gain access as required. 

n. From gear well area, remove gear wheel cover assembly (P/N 030A-91411 L/H or P/N 

030A-91411-11 R/H) on the side to be repaired. Use care when removing insulation and 
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No.104/53-003 DATE: July 22, 2013 

Page 9 of 38 

mark/record location of insulation during removal for later restoration. Store removed parts 

for restoration. 

o. Remove seat rails (P/N 030A-91296-3/-5 LH/RH, and 030A-91298 LH/RH). 

p. Remove air duct assembly (P/N 030A-63366-31 L/H, P/N 030A-63366-32 R/H) between 

STA 4610 and STA 5605, and stiffener (P/N 030A-32312-7 L/H, P/N 030A-32312-8 R/H). 

q. Remove floorboards P/N 030A-30014 and/or P/N 030A-30015, be very careful not to 

damage the floorboard. 

r. Remove Floor support between STA 4610 and STA 5605 (P/N 030A-32381-1 L/H, P/N 

030A-32381-2 R/H). 

s. Proceed to applicable section, one at a time, for repair and/or replacement. 

5.0 LOWER FRAME SEGMENT-END REPLACING REPAIR 

NOTE 

Disassemble and repair only one frame segment-end 

at a time to assure fuselage alignment. 

Refer to Figure 3 for STA 4610 frame segment-end replacing repair (L/H) 

Refer to Figure 4 for STA 4610 frame segment-end replacing repair (R/H) 

Refer to Figure 5 for STA 5605 frame segment-end replacing repair (L/H) 

Refer to Figure 6 for STA 5605 frame segment-end replacing repair (R/H) 

Detail installation information is presented in Install Drawings 035A-32107 (STA4610) & 

035A-32306 (SAT5605). 

NOTE 

Procure Repair Kit for segment-end to be repaired from MU-2 Service Center Network. 

The Repair Kit contains the install drawings, necessary parts and full size cut template. 

Prior to starting repair work read the entire repair instruction in this Service Bulletin 

and verify Kit contents per Tables 1 and Table 2 of this Service Bulletin. 
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No.104/53-003 DATE: July 22, 2013 

Page 10 of 38 

5.1 STA 4610 FRAME SEGMENT-END REPLACING REPAIR (L/H OR R/H) 

5.1.1 PREPARATIONS 

a. Prepare lower frame segment-end Repair Kit 035A-900019-101 (L/H) or 035A-900019-102 

(R/H). Locate full-sized template 016A-99443-101 (L/H) or 016A-99443-102 (R/H) from 

Repair Kit. 

b. Remove or temporary remove parts in accordance with Install Drawing 035A-32107 sheet 1 

(L/H) or Install Drawing 035A-32107 sheet 2 (R/H). 

5.1.2 REMOVAL OF FRAME SEGMENT-END 

a Clean area around location of the frame to be cut and mark using template 

016A-99443-101 (L/H) or 016A-99443-102 (R/H). 

b Cut on outboard side of the marked line no more than 1/8 in (3 mm) and remove damaged 

frame segment-end per Install Drawing 035A-32107 sheet 1 (L/H) or Install Drawing 

035A-32107 sheet 2 (R/H). 

c Temporarily set new frame segment-end into location for trial fit aligning the floor and 

side-frame as a guide. File existing frame segment as needed for the two pieces to be 

properly aligned and joined together. 

d If cut line intersects with any existing holes in the original frame, blend the intersections. 

e Once cut edge has been filed to remove all sharp edges apply Alodine #1200 or equivalent 

MIL-C-5541 and two coats of Zinc-Chromate primer to all bare surfaces per Install Drawing 

035A-32107 sheet 1 (L/H) or Install Drawing 035A-32107 sheet 2 (R/H) . 

5.1.3 FRAME SEGMENT-END PREPARATION AND INSTALLATION 

a. Put frame segment-end P/N 035A-32115-101/-102(LH/RH) in place and clamp to remaining 

lower frame. 

b. Verify alignment location of frame segment-end by making sure the floor flange edge and 

contour edge outboard on the frame is smooth and measure the gap between the remaining 

existing frame segment and the new frame segment-end, and fill the existing gap with 

laminated shim per the Install Drawing 035A-32107 sheet 1 (L/H) or Install Drawing 

035A-32107 sheet 2 (R/H). 

c. Temporarily install removed splice angles and doubler, measure the gap between the 

flanges and the splice angles, and fill the existing gap with laminated shim per Install 

Drawing 035A-32107 sheet 1 (L/H) or Install Drawing 035A-32107 sheet 2 (R/H). 
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No.104/53-003 DATE: July 22, 2013 

Page 11 of 38 

d. Prior to final assembly verify symmetrical measurements in accordance with Section 1 

Paragraph 3.4 Symmetry and Alignment Inspection Procedure of the Structural Repair 

Manual and compare with the dimensions previously recorded in Table 7. 

e. Drill and countersink the holes in frames per Install Drawing 035A-32107 sheet 1 (L/H) or 

Install Drawing 035A-32107 sheet 2 (R/H). Use of a drill guide is recommended to 

maintain alignment. Ream holes to final size. 

f. Temporary remove the new frame segment-end, deburr all holes. Clean all debris from 

the area. 

g. Apply faying surface sealant to the splice joint per Install Drawing 035A-32107 sheet 1 (L/H) 

or Install Drawing 035A-32107 sheet 2 (R/H). 

h. Install splice angles, shims and doublers. 

i. Install fasteners per Install Drawing 035A-32107 sheet 1 (L/H) or Install Drawing 

035A-32107 sheet 2 (R/H). 

j. Install all other parts to the Frame per Install Drawing 035A-32107 sheet 1 (L/H) or Install 

Drawing 035A-32107 sheet 2 (R/H). 

k. Repeat process for repair of other side of frame STA4610, if required. 

l. If that completes the required repairs, proceed to “Restoration” Paragraph 8.0 

5.2 STA 5605 FRAME SEGMENT-END REPLACING REPAIR (L/H OR R/H) 

NOTE 

Disassemble and repair only one frame segment-end 

at a time to assure fuselage alignment. 

NOTE 

Procure Repair Kit for segment to be repaired from MU-2 Service Center Network. 

Prior to starting repair read entire repair sequence in this Service Bulletin 

and verify Kit contents per Table 2 of this Service Bulletin. 

5.2.1 PREPARATIONS 

a. Prepare lower frame segment-end Repair Kit 035A-900019-201 (L/H) or 035A-900019-202 

(R/H). Locate full-sized template 016A-99443-201 (L/H) or 016A-99443-202 (R/H) from 

Repair Kit. 
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No.104/53-003 DATE: July 22, 2013 

Page 12 of 38 

b. Remove or temporary remove parts in accordance with Install Drawing 035A-32306 sheet 1 

(L/H) or Install Drawing 035A-32306 sheet 2 (R/H). 

5.2.2 REMOVAL OF FRAME SEGMENT-END 

a. Temporary remove main landing gear leg attachment fitting assembly 030A-32315-1 (L/H) 

or 030A-32315-2 (R/H). 

b. Clean area around location of the frame to be cut and mark using template 016A-99443-201 

(L/H) or 016A-99443-202 (R/H). 

c. Cut on outboard side of the marked line no more than 1/8 in (3 mm) and remove damaged 

frame segment-end per Install Drawing 035A-32306 sheet 1 (L/H) or Install Drawing 

035A-32306 sheet 2 (R/H). 

d. Temporarily set new frame segment into location for trial fit aligning with the floor and sideframe as guides. File existing frame segment as needed for the two pieces to be properly 

aligned and joined together. 

e. If cut line intersects with any existing holes in the original frame, blend the intersections 

f. Once cut edge has been filed to remove all sharp edges apply Alodine #1200 or equivalent 

MIL-C-5541 and two coats of Zinc-Chromate primer to all bare surfaces per Install Drawing 

035A-32306 sheet 1 (L/H) or Install Drawing 035A-32306 sheet 2 (R/H). 

5.2.3 FRAME SEGMENT-END PREPARATION AND INSTALLATION 

a. Put frame segment-end P/N 035A-32334-101/-102(LH/RH) in place and clamp to remaining 

lower frame. 

b. Verify alignment location of frame segment-end by making sure the floor flange edge and 

contour edge outboard on the frame is smooth and measure the gap between the remaining 

existing frame segment and the new frame segment-end, and fill the existing gap with 

laminated shim per Install Drawing 035A-32306 sheet 1 (L/H) or Install Drawing 035A-32306 

sheet 2 (R/H). 

c. Temporarily install removed splice angles and doubler, measure the gap between the 

flanges and the splice angles, and fill the existing gap with laminated shim per Install 

Drawing 035A-32306 sheet 1 (L/H) or Install Drawing 035A-32306 sheet 2 (R/H). 

d. Prior to final assembly verify symmetrical measurements in accordance with Section 1 

Paragraph 3.4 Symmetry and Alignment Inspection Procedure of the Structural Repair 

Manual and compare with the dimensions previously recorded in Table 7. 
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Page 13 of 38 

e. Drill and countersink the holes in frames per Install Drawing 035A-32306 sheet 1 (LH) or 

Install Drawing 035A-32306 sheet 2 (R/H). Use of a drill guide is recommended to 

maintain alignment. Ream holes to final size. 

f. Temporary remove the new frame segment-end, deburr all holes. Clean all debris 

from the area. 

g. Apply faying surface sealant to the splice joint per Install Drawing 035A-32306 sheet 1 (L/H) 

or Install Drawing 035A-32306 sheet 2 (R/H). 

h. Install splice angles, shims and doublers. 

i. Install fasteners per Install Drawing 035A-32306 sheet 1 (L/H) or Install Drawing 

035A-32306 sheet 2 (R/H). 

j. Install all other parts to the frame per Install Drawing 035A-32306 sheet 1 (L/H) or 

Install Drawing 035A-32306 sheet 2 (R/H). 

k. Repeat process for repair of other side of Frame STA 5605, if required. 

l. If that completes the required repairs proceed to “Restoration” Paragraph 8.0. 

6.0 REPLACEMENT OF SIDE - FRAME SEGMENTS (STA 4610 or STA 5605)

If a crack is found in the side-frame segment of STA 4610, contact MHIA engineering for 

disposition. 

NOTE 

If repair or replacement of the lower-frame segment in same Frame STA 

is required due to cracks/damage, replace the lower-frame segment first 

to stabilize the fuselage prior to removing the side-frame segment. 

6.1 REMOVAL OF LEFT SIDE-FRAME SEGMENT (STA 5605) 

a. Remove side wall seat rails from left side of cabin (left fwd P/N 030A-91296-3, and left aft 

P/N 030A-91298). 

b. Remove fasteners securing armrest support structure (P/N 030A-91800) from the sideframes and side seat track support stiffener the full length of the cabin. 

c. Disconnect plumbing and hoses, as necessary, to move armrest support structure (P/N 

030A-91800) inboard to allow access of fasteners securing inner panel and seat track 

stiffeners to frame section. 
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Page 14 of 38 

NOTE 

Use care when disconnecting tubing as there are 

several smaller hoses that are hidden. 

d. Remove and retain seat track support stiffeners between STA 4610 and STA 6495. 

e. Remove and retain left stiffener plate (P/N 030A-32312-53) to gain access to the hardware 

securing the upper main landing gear attach fitting.

f. Remove left upper main landing gear fitting (P/N 030A-32314-1). 

NOTE 

Record the number of washers installed, location of washers 

 under the bolts and nuts and bag for reinstallation. 

g. Cut two (2) access holes forward of STA 5605 just below the window lower longeron (P/N 

030A-32310-35) and just above the #5 longeron (P/N 030A-32310-59) as shown in Figure 8. 

If an access hole has been previously made in accordance with service bulletin 

073/53-002B, remove and retain doubler for reinstallation. 

h. Remove longerons between STA 5605 and STA 5890 in the side-frame area (P/N 

030A-32310-75, 030A-32310-73, 030A-32310-79, 030A-32310-77, 030A-32310-37/-95) 

i. On Exterior of aircraft, remove and retain skin fairing (P/N 030A-35201-9), Plate (P/N 

030A-35201-193) and plate (P/N 030A-35201-135). Remove rib (P/N 030A-35201-137), 

rib (P/N 030A-35201-125), and plate (P/N 030A-32306-9), located under the top portion of 

fairing. 

j. Remove as necessary, aft door hinge and rivets on skin panel P/N 030A-35201-3 to gain 

access to fasteners on internal longerons. 

NOTE 

If STA 5605 LH frame has been repaired in accordance with 

Service Bulletin 073/53-002B, remove and scrap all reinforcing parts. 

Fabricate a new shim to span between existing longeron fitting (PN 

010A-31431-103) and new frame segment. Fill all unused fastener 

holes drilled for the strap installation with AD rivets. 
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Page 15 of 38 

k. Remove and retain splice angles (Upper P/N 030A-32335 and P/N 030A-32336, Lower P/N 

030A-32337 and 030A-32338), attaching doublers (Upper P/N 030A-32306-7and Lower P/N 

030A-32306-5.), attaching hardware, and longerons from frame segment. 

l. Remove remaining rivets and fasteners holding frame section in place. 

m. Remove frame section. 

n. Refer to Paragraph 6.3 “INSTALLATION OF REPLACEMENT SIDE-FRAME SEGMENT” of 

this Service Bulletin for installation of the new frame segment. 

6.2 REMOVAL OF RIGHT SIDE-FRAME SEGMENT (STA 5605) 

a. Remove side wall seat rails from right side of cabin (right fwd P/N 030A-91296-5 and right 

aft P/N 030A-91298). 

b. Remove fasteners securing armrest support structure (P/N 030A-91800) from the sideframes and side seat track support stiffener the full length of the cabin. 

c. Disconnect plumbing and hoses, as necessary, to move armrest support structure (P/N 

030A-91800) inboard to allow access of fasteners securing inner panel and seat track 

stiffeners to frame section. 

NOTE 

Use care when disconnecting tubing as there are several 

smaller hoses that are hidden. 

d. Remove and retain seat track support stiffeners between STA 4610 and STA 7450. 

e. Remove and retain right stiffener plate (P/N 030A-32312-54) to gain access to the hardware 

securing the upper main landing gear attach fitting. 

f. Remove right upper main landing gear fitting (P/N 030A-32314-2). 

NOTE 

Record the number of washers installed and location of washers 

under the bolts and nuts and bag for re-installation. 

g. Cut an access hole forward of STA 5605 between the #4 longeron (P/N 030A-32310-49) 

and the #5 longeron (P/N 030A-32310-60) as shown in Figure 9. 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 16 of 38 

h. Remove longerons between STA 5605 and STA 5890 in the side frame area (P/N 

030A-32310-76, 030A32310-74, 030A-32310-80, 030A-32310-78, 030A-32310-53, 

030A-32310-39). 

i. Drill rivets attaching the emergency exit striker to the side-frame and cut sealant using care 

to not bend the striker. 

j. On Exterior of aircraft, remove and retain skin fairing (P/N 030A-35201-10), plate (P/N 

030A-35201-194) and plate (P/N 030A-35201-136). Remove rib (P/N 030A-35201-138), 

rib (P/N 030A-35201-126) and plate (P/N 030A-32306-9), located under the top portion of 

fairing. 

k. Remove as necessary, aft door hinge and rivets on skin panel (P/N 030A-35201-4) to gain 

access to fasteners on the internal longerons. 

NOTE 

If STA 5605 RH frame has been repaired in accordance with 

Service Bulletin 073/53-002B, remove and scrap all reinforcing parts. 

Fill all unused fastener holes drilled for the strap installation with AD rivets. 

l. Remove and retain splice angles (Upper P/N 030A-32335 and P/N 030A-32336, Lower P/N 

030A-32337 and 030A-32338), attaching doublers (Upper P/N 030A-32306-7and Lower P/N 

030A-32306-5.), attaching hardware, and longerons from frame segment. 

m. Remove remaining rivets and fasteners holding frame section in place. 

n. Remove frame section. 

o. Refer to Paragraph 6.3 “INSTALLATION OF REPLACEMENT SIDE-FRAME SEGEMENT” 

of this Service Bulletin for installation of the new frame segment. 

6.3 INSTALLATION OF REPLACEMENT SIDE-FRAME SEGMENT(STA5605) 

a. Completely remove all flanges from the removed side-frame. This is to be used as a 

drilling template for duplicating the holes which are common to the main landing gear fitting 

(Left P/N 030A-32314-1 and/or Right P/N 030A-32314-2). 

b. Locate the new side-frame segment in place. 

c. Verify no gap condition between existing longerons and new frame segment to match 

original location. 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 17 of 38 

d. Verify alignment location of frame segment by making sure the contour edge outboard on 

the frame is smooth, install the splice angles and doublers and fill the gap between the 

existing splice angles and frame. Maximum allowable gap is 0.004 in (0.1 mm), if 

necessary fabricate shim to fill the gap. (Refer to Figure 7) 

e. Symmetrical measurements should be obtained in accordance with Section 1 Paragraph 3.4 

Symmetry and Alignment Inspection Procedure of the SRM and compare with dimensions 

recorded in Table 7. 

f. Drill fastener holes and countersink holes, as needed. 

g. Remove frame, using the removed side-frame segment as a template, duplicate the MLG 

fitting attachment holes to new frame and deburr all holes. 

h. For the frame which has been repaired in accordance with Service Bulletin 073/53-002B; 

1) Fill all unused fastener holes drilled for reinforcing straps with AD rivets of proper length. 

2) Install splice angle and doubler using fasteners as shown in Figure 10. 

3) For LH frame, fabricate a shim and install between existing longeron fitting (PN 

010A-31431-103) and new frame segment. (Refer to Figure 10) 

i. Apply faying surface & fillet sealant (PR-1422 or equivalent) as needed and re-install 

fasteners. 

j. Fabricate doubler(s) for the access hole(s) just forward of STA 5605 and install doubler(s) 

per Figure 8 and Figure 9) 

k. If that completes the required repairs proceed to “Restoration” Paragraph 8.0. 

7.0 REPLACEMENT OF LOWER-FRAME SEGMENT (CENTER SEGMENT AT STA 4610 OR 

STA 5605) 

NOTE 

The following instructions assume both lower-frame segments at STA 4610 and 

STA 5605 are to be replaced. If only one frame is to be replaced, modify 

these instructions appropriately. 

NOTE 

If replacement of the side-frame segment at the same STA is required due to 

cracks/damage, install lower-frame segment first to stabilize the fuselage 

prior to removing the side-frame segment. 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 18 of 38 

7.1 PREPARATIONS 

a. Open aircraft for cable removal. All cables that run through the fuselage center section will 

be removed aft of STA 4025 per Maintenance Manual instruction; this includes engine, 

spoiler, rudder, elevator, rudder trim, and elevator trim. Remove lower fuselage panels as 

required for access. 

b. Secure flight and engine controls in neutral position with streamer marked rig pins. 

c. Clamp cables on the aft side of STA 4025 before tension is removed from cables. This is to 

prevent unspooling of cables forward of this point and to assist in maintaining cable routing. 

d. Label cables in relation to holes in frames. Also to assist in restringing cables aft of STA 

5605; wax string can be attached to the cables during removal. 

e. Remove cables from the center section of the fuselage aft of STA 4025. Carefully coil and 

stow cables to prevent them from getting damaged. 

f. Remove doubler P/N 030A-32388 from the round access hole between STA 5605 and STA 

5890 on the belly of the aircraft. 

g. Mark skin for cutting line as shown in Figure 11. Drill rivets out of skin between STA 5605 

and STA 5890. With rivets removed cut skin on the mark made. 

CAUTION 

When cutting, place a piece of stainless steel between skin 

and keel to prevent cutting into the keel.

h. The center section of keel between STA 4610 and STA 5605 will be removed as an 

assembly with skin intact. Drill rivets attaching center keel section of skin to the forward 

skin section. 

i. Drill to remove the angle brackets on the left and right sides of the keel that attach the keel 

to frame STA 4610. (This will allow center keel section to slide forward to clear landing 

gear bushing.) Remove any remaining attaching structure/hardware preventing keel 

removal. Remove keel section. 

NOTE 

If only the frame segment at STA 5605 is 

to be replaced proceed to Paragraph 7.3 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 19 of 38 

7.2 REMOVAL OF LOWER-FRAME SEGMENT STA 4610 

a. Remove parts and attaching hardware from the lower portion of frame STA 4610. 

b. Cut sealant around lower portion of frame STA 4610. 

c. Remove lower portion of frame STA 4610. Frame segment is removed in an aft direction 

only. 

NOTE 

If only the frame segment at STA 4610 is 

to be replaced, proceed to paragraph 7.4. 

7.3 REMOVAL OF LOWER-FRAME SEGMENT STA 5605

a. Remove parts and attaching hardware from the lower portion of frame STA 5605. 

b. Cut sealant around lower portion of frame STA 5605. 

c. Remove lower portion of frame STA 5605. Frame segment is removed in a forward 

direction only. 

7.4 INSTALLATION OF LOWER-FRAME SEGMENT 

a. Clean area of all debris, previously drilled fasteners, and sealant. 

b. Locate the new lower frame in place. 

c. Verify alignment location of frame segment by making sure the contour edge outboard on 

the frame is smooth, install the splice angles/doublers and fill the gap between the existing 

splice angles and frame. Maximum allowable gap is 0.004 in (0.1 mm), if necessary 

fabricate shim to fill the gap. (Refer to Figure 7) 

d. Symmetrical measurements should be obtained in accordance with Section 1 Paragraph 3.4 

Symmetry and Alignment Inspection Procedure of the SRM and compare with dimensions 

recorded in Table 7. 

e. Drill fastener holes and countersink holes, as needed, and deburr all holes. 

f. Apply faying surface & fillet sealant (PR-1422 or equivalent) as needed and install fasteners. 

g. Install other frame segment at this time by repeating steps a through f or reinstall center keel 

section if other frame segment is not to be replaced. 

h. Reinstall doubler P/N 030A-32388 and restore the skin in accordance with Figure 11. 

i. If that completes the required repairs proceed to Paragraph 8.0, “Restoration.” 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 20 of 38 

8.0 RESTORATION 

a. Restore cables, set cable tensions, and check deflections per applicable Maintenance 

Manuals. 

b. Verify all rig pins are removed upon completion.

c. Reverse the process used in previous sections to restore the airplane to an airworthy 

condition. 

1. Restore parts removed from gear well in reverse sequence. 

2. If the floorboard was removed, install floorboards, resealing the floorboards at the outer 

edges only to assure a positive pressure seal. Sealant is not needed in the center 

part of the floorboard. 

3. Once sealant is dry, comply with pressurization leakage check per the applicable 

Maintenance Manuals. 

4. Reinstall insulation and acoustic package, as required 

5. Reinstall seats, galley (if equipped), carpet and side panels as necessary. 

d. Complete landing gear retraction test, after gear installation, in accordance with the 

applicable Maintenance Manuals. 

e. Symmetrical measurements should be obtained in accordance with Section 1 Paragraph 3.4 

Symmetry and Alignment Inspection Procedure of the SRM and compare with dimensions 

recorded in Table 7. 

f. Continue with Paragraph 9 and 10 to return the aircraft to service. 

g. Comply with satisfactory functional check flight before final approval for return to service. 

9.0 LOGBOOK ENTRY 

Upon completion of this service bulletin, complete FAA form 337 if applicable, and make an 

appropriate maintenance entry in the logbook similar to “Service Bulletin No. 104/53-003 

complied with on (date) by (name).” Be specific in noting which frame and section was 

repaired or replaced, if applicable. 

For continued airworthiness, Maintenance Requirement Manual (MRM) will be revised. The 

revised MRM will require a recurring inspection every 2400 hours after complying with this 

Service Bulletin, regardless of the repair method and regardless of whether cracks were found. 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 21 of 38 

10.0 COMPLETION 

Complete the enclosed compliance card and mail back to Mitsubishi Heavy Industries America, Inc. 

in care of Turbine Aircraft Services, Inc. 

Mitsubishi Heavy Industries America, Inc. 

c/o Turbine Aircraft Services, Inc. 

4550 Jimmy Doolittle Drive 

Addison, Texas 75001 

Attention: Manager, Publication 

Phone: (972) 248-3108 X 209 

Fax: (972) 248-3321 

 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 22 of 38 

11.0 PARTS AND MATERIAL REQUIRED & SYMMETRICAL MEASUREMENTS 

 The following parts and material may be required to comply with this Service Bulletin. 

 The following Tables do not include any fasteners which may be removed and reinstalled during 

repair and replacement per this Service Bulletin. 

Table 1: REPAIR – LOWER FRAME SEGMENT-END REPLACEMENT (STA. 4610) 

 The repair kits are available via MU-2 Service Centers. Kit contains installation drawing and 

following hardware except for rivets and consumable material. 

PART NUMBER DESCRIPTION QTY/SHIP REMARKS LH RH

Kit number 035A-900019-101 : to repair LH frame segment-end 

Kit number 035A-900019-102 : to repair RH frame segment-end 

016A-99443-101 Template 1 

016A-99443-102 Template 1 

035A-32115-101 Segment Frame 1 

035A-32115-102 Segment Frame 1 

035A-32342-113 Shim-Laminated 1 1 

035A-32342-115 Shim-Laminated 1 1 

035A-32342-117 Shim-Laminated 4 4 

035A-32342-119 Filler 2 2 

035A-32342-123 Shim 1 1 

035A-32343-105 Angle 1 

035A-32343-106 Angle 1 

035A-32344-103 Bracket 1 

035A-32344-105 Bracket 1 

035A-32371-103 Fitting 1 

035A-32371-104 Fitting 1 

AN3-6A Bolt 4 

AN960D10 Washer 8 8 

EA9309, 3NA or equivalent Adhesive AR AR not contained in the kit 

HL10VAP6-4 Hi-Lok Pin 4 4 

HL10VAP6-5 Hi-Lok Pin 18 19 

HL11VAP6-4 Hi-Lok Pin 1 1 

HL111VAP6-4 Hi-Lok Pin 1 

HL111VAP6-5 Hi-Lok Pin 1 1 

HL111VAP6-6 Hi-Lok Pin 1 

HL70-6 Collar 23 24 

HL79-6 Collar 2 2 

MS21059L3 Plate Nut 2 2 

MS20426AD3-4 Rivet 4 4 not contained in the kit 

 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 23 of 38 

Table 1 (Continued) 

PART NUMBER DESCRIPTION QTY/SHIP REMARKS LH RH

MS20426AD3-5 Rivet 4 4 

MS20426AD5-6 Rivet 2 2 not contained in the kit 

MS20470AD5-9 Rivet 1 1 not contained in the kit 

NAS1103-6 Bolt 8 11 

NAS1104-12 Bolt 2 2 

NAS1149D0463H Washer 24 24 

NAS1169DD10 Washer 2 2 

NAS463X-DD10 Nut Spacer 3 3 

NAS517-3-11 Screw 2 2 

NAS6204-4 Bolt 8 8 

NAS6204-6 Bolt 12 12 

NAS6204-7 Bolt 4 4 

NAS679A3W Nut 8 8 

NAS679A4W Nut 24 24 

AMS-S-8802 TypeII, Class 

B or equivalent 

Sealing Compound 

 (PR-1422) AR AR not contained in kit 

MIL-C-5541, Class 1A or 

equivalent 

Chemical Film 

 (Alodine #1200) AR AR not contained in kit 

TT-P-1757 or equivalent Primer AR AR not contained in kit 

Table 2: REPAIR – LOWER FRAME SEGMENT-END REPLACEMENT (STA.5605) 

The repair kits are available via MU-2 Service Centers. Kit contains installation drawing and 

following hardware except for rivets and consumable material. 

PART NUMBER DESCRIPTION QTY/SHIP REMARKS LH RH

Kit number 035A-900019-201: to repair LH frame segment-end 

Kit number 035A-900019-202: to repair RH frame segment-end 

016A-99443-201 Template 1 

016A-99443-202 Template 1 

035A-32334-101 Segment Frame 1 

035A-32334-102 Segment Frame 1 

035A-32342-103 Shim-Laminated 1 1 

035A-32342-105 Shim-Laminated 1 1 

035A-32342-107 Shim-Laminated 1 

035A-32342-109 Shim-Laminated 4 4 

035A-32342-125 Shim 1 1 

035A-32343-103 Angle 1 

035A-32343-104 Angle 1 

035A-32373-103 Fitting 1 

035A-32373-104 Fitting 1 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 24 of 38 

Table 2 (Continued) 

PART NUMBER DESCRIPTION QTY/SHIP REMARKS LH RH

412AS-2 Bracket 1 

AN3-8A Bolt 2 

AN960D10 Washer 3 3 

EA9309, 3NA or equivalent Adhesive AR AR Not contained in kit 

HL10VAP6-4 Hi-Lok Pin 3 3 

HL10VAP6-5 Hi-Lok Pin 4 4 

HL10VAP6-6 Hi-Lok Pin 7 11 

HL10VAP6-7 Hi-Lok Pin 8 8 

HL10VAP6-8 Hi-Lok Pin 1 1 

HL11VAP6-4 Hi-Lok Pin 1 1 

HL11VAP6-6 Hi-Lok Pin 8 6 

HL111VAP6-6 Hi-Lok Pin 1 1 

HL70-6 Collar 32 34 

HL79-6 Collar 1 1 

MS20004-12 Bolt 1 1 

MS20426AD3-5 Rivet 2 2 not contained in kit 

MS20426AD3-6 Rivet 4 4 not contained in kit 

MS20426AD5-5 Rivet 6 6 not contained in kit 

MS20470AD4-9 Rivet 2 not contained in kit 

MS20470AD5-5 Rivet 6 6 not contained in kit 

MS21061L3 Plate Nut 1 1 

MS21075L3 Plate Nut 1 1 

MS21250-05014 Bolt 1 1 

MS35206-231 Screw 4 

NAS1103-17 Bolt 2 2 

NAS1103-9 Bolt 4 4 

NAS1149D0463H Washer 14 14 

NAS1169DD10 Washer 2 2 

NAS1195DD3XH Nut Spacer 2 2 

NAS1203-17 Bolt 2 2 

NAS1203-8 Bolt 2 

NAS463Y-DD10 Nut Spacer 1 1 

NAS517-3-12 Screw 2 2 

NAS6204-12 Bolt 8 8 

NAS6204-7 Bolt 6 6 

NAS679A3W Nut 3 3 

NAS679A4W Nut 14 14 

AMS-S-8802 TypeII, Class 

B or equivalent 

Sealing Compound 

 (PR-1422) AR AR not contained in kit 

MIL-C-5541, Class 1A or 

equivalent 

Chemical Film 

 (Alodine #1200) AR AR not contained in kit 

TT-P-1757 or equivalent Primer AR AR not contained in kit 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 25 of 38 

Table 3: REPLACEMENT- SIDE FRAME SEGMENT (STA. 4610) 

 Contact MHIA engineering for details. 

PART NUMBER DESCRIPTION QTY/SHIP REMARKS 

LH RH 

030A-32114-3 Frame Segment 1 Procure from MHIA 

030A-32114-4 Frame Segment 1 Procure from MHIA 

Table 4: REPLACEMENT- SIDE FRAME SEGMENT (STA. 5605) 

PART NUMBER DESCRIPTION QTY/SHIP REMARKS 

LH RH 

030A-32333-5 Frame Segment 1 Procure from MHIA 

030A-32333-6 Frame Segment 1 Procure from MHIA 

HL62PB-8-9 Hi-Lock Pin 6 6 

HL79-8 Collar 6 6 

MS20426AD5 Rivet 6 For CSK Washer 

MS20470AD10-11 Rivet 2 2 For plug unused holes 

MS20470AD6-9 or 

MS20470AD8-10 Rivet 6 

MS20470AD8-9 Rivet 6 6 For plug unused holes 

NAS1149D0563H Washer 12 12 

NAS1155-10 Screw 3 3 

NAS1155-8 Screw 3 3 

NAS1738B5-2 Rivet 18 

NAS1739B5-2 Rivet 36 

NAS679A5 Nut 6 6 

SB104/53-003-3 Doubler 2 Fabricate Locally 

SB104/53-003-5 Doubler 1 Fabricate Locally 

SB104/53-003-7 Shim 1 Fabricate Locally 

2024-T3C Sheet or 

AMS6387 Type 1 Shim AR AR Fabricate Locally, Adjust Thickness to Fill Gap 

AMS-S-8802 TypeII, Class 

B or equivalent 

Sealing Compound 

 (PR-1422) AR AR 

MIL-C-5541 Class 1A or 

equivalent 

Chemical Film 

 (Alodine #1200) AR AR 

TT-P-1757 or equivalent Primer AR AR 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 26 of 38 

Table 5: REPLACEMENT- LOWER FRAME SEGMENT (STA. 4610) 

PART NUMBER DESCRIPTION QTY/SHIP REMARKS 

030A-32115-3 Frame Segment 1 Procure from MHIA 

MS20426AD4 Rivet 16 For CSK washer 

MS20426AD4-4 Rivet 10 

MS20426AD4-5 Rivet 22 

MS20426AD4-6 Rivet 8 

SB104/53-003-9 Splice 1 Fabricate Locally 

SB104/53-003-10 Splice 1 Fabricate Locally 

SB104/53-003-11 Taper Shim 2 Fabricate Locally 

SB104/53-003-13 Shim 2 Fabricate Locally 

2024-T3C Sheet or 

AMS6387 Type 1 Shim AR Fabricate Locally, Adjust Thickness to Fill Gap 

AMS-S-8802 TypeII, Class 

B or equivalent 

Sealing Compound 

(PR-1422) AR 

MIL-C-5541 Class 1A or 

equivalent 

Chemical Film 

 (Alodine #1200) AR 

TT-P-1757 or equivalent Primer AR 

Table 6: REPLACEMENT- LOWER FRAME SEGMENT (STA.5605) 

PART NUMBER DESCRIPTION QTY/SHIP REMARKS 

030A-32334-3 Frame Segment 1 Procure from MHIA 

MS20426AD4 Rivet 16 For CSK washer 

MS20426AD4-4 Rivet 10 

MS20426AD4-5 Rivet 22 

MS20426AD4-6 Rivet 8 

SB104/53-003-9 Splice 1 Fabricate Locally 

SB104/53-003-10 Splice 1 Fabricate Locally 

SB104/53-003-11 Taper Shim 2 Fabricate Locally 

SB104/53-003-13 Shim 2 Fabricate Locally 

2024-T3C Sheet or 

AMS6387 Type 1 Shim AR Fabricate Locally, Adjust Thickness to Fill Gap 

AMS-S-8802 TypeII, Class 

B or equivalent 

Sealing Compound 

 (PR-1422) AR 

MIL-C-5541, Class 1A or 

equivalent 

Chemical Film 

 (Alodine #1200) AR 

TT-P-1757 or equivalent Primer AR 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 27 of 38 

Table 7: SYMMETRICAL MEASUREMENTS

FORMULA ALLOWABLE 

VALUE 

OBTAINED 

VALUE 

CHARACTERISTIC TO BE 

CHECKED 

9-11, 10-12 0 +/-0.12 Wing Incidence 

13-15, 14-16 -0.55 +/-0.12 Wash Out of Wing Tip 

(13-15)-(14-16) 0 +/-0.12 Twist of Wing Tip 

13-9, 14-10 1.89 +/-0.59 Wing Dihedral 

9-17, 10-18 18.35 +/-0.59 Relation of Horizontal Stab. To 

Wing 

23-21, 24-22 0.31 +/-0.12 Horizontal Stab. Incidence 

(23-21)-(24-22) 0 +/-0.12 Twist of H. Stab. Tip 

1-13, 2-14 222.24 +/-0.59 Wing Yaw 

7-13, 7-14 307.36 +/-0.79 Wing Yaw 

19-25, 20-26 82.48 +/-0.39 Relative Position for Emp. 

5-17, 6-18 95.45 +/-0.39 H. Stab. Yaw 

(Refer to Structural repair manual for instructions and formula reference) 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 28 of 38 

12.0 FIGURES

Figure 1: LOCATION OF FRAME INSPECTION FOR STA 4610

1. Complete a detailed visual inspection on the entire frame 

flanges for hairline cracks between rivets. 

2. NDT inspect if detailed visual inspection is inconclusive 

3. Visually inspect entire frame and surrounding area for 

corrosion. Repair IAW Structural Repair Manual 

Most Likely location of 

cracks
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 29 of 38 

Figure 2: LOCATION OF FRAME INSPECTION FOR STA 5605

1. Complete a detailed visual inspection on the entire 

 frame flange for hairline cracks between rivets. 

2. NDT inspect if detailed visual inspection is 

 inconclusive 

3. Visually inspect entire frame and surrounding area 

 for corrosion. Repair IAW MHI Structural Repair 

 Manual 

4. Pay particular attention to landing gear support 

 segment for cracking in the flanges. 

Most Likely location of 

cracks
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Figure 3: LOWER FRAME END SEGMENT REPLACING REPAIR - INSTALLATION & CUT OFF DIM

This 

See Install draw
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Figure 4: LOWER FRAME END SEGMENT REPLACING REPAIR - INSTALLATION & CUT OFF DIME

This 

See Install draw
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Figure 5: LOWER FRAME END SEGMENT REPLACING REPAIR - INSTALLATION & CUT OFF DIM

This 

See Install draw
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Figure 6: LOWER FRAME END SEGMENT REPLACING REPAIR - INSTALLATION & CUT OFF DIME

This 

See Install draw
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 34 of 38 

 

 

 

Figure 7: SHIMMING 

THE MAXIMUM GAP AFTER SHIMMING SHOULD 

BE LESS THAN 0.004 IN. (0.1 MM) PRIOR TO 

FASTENER INSTALLATION IN ANY PLACE. 

SPLICE ANGLE 

NOTE: FABRICATION OF SHIM

(CASE 1) MATERIAL: 2024-T3C AL SHEET (QQ-A-250/5) 

 ADJUST THICKNESS TO FILL THE GAP BETWEEN FRAME AND SPLICE ANGLE 

 FINISH: CHEM. FILM PER ALODINE #1200 (MIL-C-5541, CLASS 1) AND PRIME WITH 

ONE COAT OF ZINC-CHROMATE PRIMER (TT-P-1757) 

 OR 

(CASE 2) MATERIAL: 1100-H19 (MIL-S-22499, COMPOSITION 1, TYPE 1, CLASS 1), “LAMINATED SHIM” 

ADJUST THICKNESS TO FILL THE GAP BETWEEN FRAME AND SPLICE ANGLE 

 FINISH: AFTER DELAMINATION, CHEM. FILM PER #1200 (MIL-C-5541, CLASS 1) AND PRIME WITH

 ONE COAT OF ZINC-CHROMATE PRIMER (TT-P-1757) 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 35 of 38 

 

NOTE: 1. FABRICATION OF DOUBLER (SB104/53-003-3) 

 MATERIAL: 2024-T3CLAD AL SHEET (QQ-A-250/5), .063”T x 90 x100 

 FINISH: CHEM. FILM PER ALODINE #1200 (MIL-C-5541, CLASS 1A) 

AND PRIME WITH ONE COAT OF ZINC-CHROMATE PRIMER (TT-P-1757) 

 2. WET INSTALL RIVETS WITH ZINC-CHROMATE PRIMER 

 3. FILLET SEAL (PR-1422) AROUND THE DOUBLERS 

CUT OUT

INNER SKIN 

(TYP)

SB104/53-003-3 (2 REQ) 

(DOUBLER) 

40 50 

030A-91801 (REF) 

(FRAME ASSY)

030A-32312-13 (REF)

(FRAME) 

50 40 

4 EQUL 

SPACES (TYP) 

90 (TYP) 

10 10

(TYP) 

30 60 31 

(TYP) (TYP) (REF) 

 

STA 

5605 

UP 

 

 FWD 

030A-32312 (REF)

INNER SKIN 

#5 LONGERON REF PLANE 

(WP -215) 

030A-32312-59 (REF)

(#5 LONGERON) 

NAS1739B5-2 (36 REQ)

 COUNTERSINK on DOUBLER 

WINDOW LOWER LONGERON REF PLANE

 (WP 50)

VIEW LOOKING OUTBOARD

R10

(TYP) 

5 EQUAL SPACE 

 (TYP) 

030A-32306 (REF)

(FRAME ASSY) 

100

10 10 (TYP)

Figure 8: ACCESS HOLES ON INNER SKIN (LH SIDE) 

030A-32310 (REF)

LONGERON 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 36 of 38 

 

030A-32312 (REF)

(INNER SKIN) 

STA

5605

UP 

 

FWD 

#4 LONGERON REF PLANE 

(WP -115) 

#5 LONGERON REF PLANE 

(WP -215) 

NAS1738B5-2 (18 REQ) 100

SB104/53-003-5 (1 REQ) 

(DOUBLER) 10 10

 (TYP) 

R10

(TYP) 

34 60 20 

(REF)

EDGE OF INNER SKIN

10 10 

(TYP)

55

95

39

4 EQUAL 

SPACES (TYP) 

5 EQUAL SPACES 

 (TYP) 

VIEW LOOKING OUTBOARD

Figure 9: ACCESS HOLE ON INNER SKIN (RH SIDE) 

030A-32310-49 (REF)

(LONGERON) 

030A-32310-60 (REF)

(LONGERON) 

NOTE: 1. FABRICATION OF DOUBLER (SB104/53-003-5) 

 MATERIAL: 2024-T3 CLAD AL SHEET (QQ-A-250/5), .063”T x 95 x100 

 FINISH: CHEM. FILM PER ALODINE #1200 (MIL-C-5541, CLASS 1A) 

AND PRIME WITH ONE COAT OF ZINC-CHROMATE PRIMER (TT-P-1757) 

 2. WET INSTALL RIVETS WITH ZINC-CHROMATE PRIMER 

 3. FILLET SEAL (PR-1422) AROUND THE DOUBLERS 

CUT OUT

INNER SKIN 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 37 of 38 

 

HL62PB-8-9 (6 REQ)

HL79-8 ( 6 REQ) 

NAS1155-10 (3 REQ)

NAS1149D0563H (6 REQ) 

NAS679A5 (3 REQ) 

NAS1155-8 (3 REQ)

NAS1149D0563H (6 REQ) 

NAS679A5 (3 REQ) 

030A-32306-7 (REF)

(DOUBLER) 

010A-31431-103 (REF)

(FITTING) 

030A-32312-3 (REF)

(INNER SKIN)

SB104/53-003-7 (1 REQ)

(SHIM) .20” THICK 

MAKE FROM REMOVED 

REPAIR STRAP

030A-32336 (REF)

(SPLICE ANGLE)

SELECT PROPER RIVET

TYPE (BELOW) FOR RIVET 

HOLES IN THE INNER SKLIN; 

MS20470AD6-9 (6 REQ) 

 OR 

MS20470AD8-10 (6 REQ) 

APPLY CSK WASHER AT 

DIMPLE HOLES. 

CSK WASHER MAY BE MAKE 

FROM MS20426AD5 RIVET 

HEAD 

030A-32336 (REF)

(SPLICE ANGLE)

HL62PB-8-9 (6 REQ)

HL79-8 (6 REQ)

030A-32335 (REF)

(SPLICE ANGLE) 

NAS1155-10 (3 REQ)

NAS1149D0563H (6 REQ)) 

NAS679A5 (3 REQ) 

NAS1155-8 (3 REQ)

NAS1149D0563H (6 REQ)) 

NAS679A5 (3 REQ) 

030A-32306-7 

(DOUBLER) 

(REF) 

VIEW LOOKING 

OUTBOARD (LH SIDE) 

VIEW LOOKING 

OUTBOARD (RH SIDE) 

Figure 10: INSTALLATION OF REPLACEMENT FASTENERS

 AFTER REMOVAL OF REPAIR STRAPS

NOTE: UNLESS OTHERWISE NOTED USE EXISTING FASTENERS

STA

5605 

FWD

STA

5605

FWD 030A-32335 (REF)

(SPLICE ANGLE)

030A-32113-7 (REF)

(UPPER FRAME)

030A-32333-5 (REF)

(SIDE FRAME) 

030A-32113-7 (REF)

(UPPER FRAME) 

030A-32333-6 (REF)

(SIDE FRAME) 
MU-2 Service Bulletin

No.104/53-003 DATE: July 22, 2013 

Page 38 of 38 

 

SB104/53-003-13 1 

(SHIM) (2 REQ) 

2024-T3 CLAD SHT 

.040” x 18 x 18, (12F01) 

1 : INSERT SHIM BETWEEN SKIN AND BULGE SKIN

 (12F01): ALODINE #1200 AND ZINC CHROMATE PRIMER 

MS20426AD4 (EXISTING), CSK ON SPLICE

CSK WASHER (ADD) (SEE SECT B-B) 

MS20426AD4 (ADD) CSK ON SPLICE

MS20426AD4 (EXISTING)

INSTALL WITH BULGEE SKIN 

(SEE SECT A-A) 

NOTE

SPLICE

SKIN

CSK WASHER

MAKE FROM MS20426AD4 

RIVET HEAD 

MS20426AD4

 (RIVET)

“SKIN CUT LINE”

 TOUCH UP: 

 (12F01)

NAS686A08

(NUT PLATE) 

 (REF)

 8

(MIN) 

BULGEE

SKIN

KEEL ASSY

MID BULGE SKIN

SB104/53-003-11 (2 REQ) 1

(TAPER SHIM) 

2024-T3 CLAD SHT 

.040” x 18 x 45, (12F01)

030A-32388

(DOUBLER) 

REINSTALL 

SKIN

10 (TYP)

8 (MIN)

8 (MIN)

STA

5605 

STA

5830

STA

5890

UP 

20R

Figure 11: RESTORATION OF CUT SKIN – BELLY OF FUSELAGE

A

A B

B

SECT B-B

SECT A-A

INBD

TAPER SHIM

SKIN

MID BULGE SKIN

KEEL ASSY 

SB104/53-003-10 (1 REQ)

(SPLICE) 

2024-T3 CLAD SHT 

.040” (12F01) 

SB104/53-003-9 (1 REQ)

(SPLICE) 

2024 T3 CLAD SHT 

.040” (12F01)