AC 20-64 CHG 1 10/26/73 Appendix 6 APPENDIX 6. MAINTENANCE NOTES FOR WING STRUCTURAL AREAS
1. INTRODUCTION. These maintenance notes have been compiled to assist L-188 series aircraft owners/operators in maintaining the wing of their airplanes for a long and useful service life. Summarized herein are structural areas of the wing which have shown need for special inspections and/or maintenance during the service history of the L-188 fleet. Types of discrepancies which may be found, the locations, and corrective action measures are listed. The purpose of this information is to acquaint maintenance planning personnel with specific areas of the wing which should be included in an overall wing inspection/ maintenance program.
This documentation has been assembled for reference usage and is not intended to replace nor be used in lieu of any maintenance/ inspection material or manual. Detail methods for inspections, maintenanc.
and repairs/reinforcements are contained in these existing documents and in the service bulletins referenced herein.
Direct assistance for your maintenance/inspection activities can be obtained by contacting the aircraft manufacturer.
2. SERIAL NUMBER (S/N) CODING FOR AIRCRAFT.
1001, 1002, 1004, thru 1148, 2001 thru 2022.
b. 1002, 1004 thru 1043, 1045 thru 1120, 2001 thru 2012.
c. 1001, 1002, 1004 thru 1056, 1058, (Right Wing Only), and 1059 thru 1069.
3. LOCKHEED STRUCTURAL SERVICE BULLETIN INDEX• 88/SB-334 - Wing - Wing Leading Edge Attaching Screws - Replacement Of 88/SB-564 - Wing - Inspection of Wing Plank Depressions 88/SB-587 - Wing - No. 4 Wing Plank - Inspection Of 88/SB-591 - Wing - Flap Track Attaching Bolts - Inspection Of 88/SB-593 - Wing - Main Landing Gear Actuating Cylinder Attach Fitting Intercostal - Inspection Of 88/SB-599 - Wing - Main Landing Gear Actuator Support Fittings - Inspection Of 88/ SB - 600 - Wing - Upper Skin Planks - Inspection and Repair Of 88/SB-616 - Wing - Upper & Lower Access Door Lands - Inspection Of 88/SB-619 - Wing - Upper Surface at W.S. 167 and W.S. 209 - Reinforcement 88/SB-620 - Wing - Wing Plank Splices Corrosion and Stress Corrosion Cracks - Inspection and Repair Of 88/SB-625 - Wing - Wing Plank Splices Aft of Main Landing Gear Fulcrum Fittings - Inspection Of 88/SB-628 - Wing - Corrosion of Wing Panels at Centroid Risers - Prevention Of 88/SB-631 - Wing - MLG Ribs - Inspection and Rework Of Par 1
Appendix 6 AC 20-64 CHG 1 Page 2 10/26/73 88/SB-632 - Wing - Upper Surface Cracks at Fastener Holes - Inspection and Repair Of 88/SB-633 - Wing - Outer Wing to Center Wing Attach Fittings - Inspection 88/SB-634 - Wing - Upper Surface Cracks at Trailing Edge - Inspection and Repair - W.S. 143 88/SB-638 - Wing - Wing to Nacelle Attachment Plates - Inspection and Repair Of 88/SB-639 - Wing - Main Landing Gear Rib Caps - Inspection and Rework Of 88/SB-649 - Wing - No. 1 and No. 2 Upper Plank Surface Cracks at Nacelle Fillet Attachment - Inspection and Repair Of 88/SB-652 - Wing - Cracks in No. 3 Upper Wing Panel at W.S. 346 - Preventive and Repair Of 88/SB-653 - Wing - Plank No. 1, Lower Attachment to Spar Cap, W.S.
205-275 - Repair or Reinforcement Of 88/SB-654 - Wing - Rear Beam C11p Inspection - W.S. 179/197 88/SB-655 - Wing - Trailing Edge Rib Panels - Repair and Preventive Reinforcement 88/SB-665 - Wing - Upper Plank No.1, W.S. 168 to W.S. 174, and Upper Forward Spar Cap, W.S. 156 to 178 - Preventive Reinforcement and Repair Of 88/SB-669 - Wing - Repair for Cracks in Wing Lower Surface, Planks Nos. 1 thru 8, W.S. 157 to 219 88/SB-670 - Wing - Crack in Upper Forward Spar Cap Vertical Leg at W.S.
168 - Repair and Preventive Reinforcement 88/SB-675 - Wing - Upper Surface - Repair of Wing Plank Nos. 2 to 4 on Each Side of Inboard Nacelles 88/SB-676 - Wing - Preventive Reinforcement of Upper Planks 1 thru 5 at Inboard Side of Outboard Nacelle 88/SB-678 - Wing - Center Section - Corrosion Repair at B.L. 65 L/R 88/SB-682 - Wing - Upper Surface - Repair for crack in Upper Forward Spar Cap and Web at W.S. 209 88/SB-685 - Wing - Corrosion Around Splice Fasteners, Rework and Repair
4. SERVICE INFORMATION LETTERS (SILS).
a . 88/SIL- 58 Inspection of Wing Planks Under Wing to Fuselage Fillets and Lavatory Drain Valve
b. 88/SIL-61 Inspection and Repair of Wing Lower Skin Planks
c. 88/SIL-87 General Structures - Sealants for Fuel Sealing, Pressurization Sealing, and Corrosion Protection Par 3
1C 20-64 CHG 1 10/26/73
FUEL PROBES
FUEL TANK FILLER
ACCESS DOOR
- VERTICAL CRACK
- HORIZONTAL CRACK 5
SECTION A-A 3 2 PLANK#1
FUEL PROBE
FUEL PUMP ACCESS DOOR PROBES
FUEL PROBES
REAR SPAR WS 516 380 359 329 INBD
ACCESS DOOR
• INBOARD NACELLE
SKATE ANGLES FWD
ACCESS DOORS WS 380
UPPER PANEL LH
LOOKING DOWN INBD
Appendix 6 Page 3 (and 4)
FUEL PUMP ACCESS DOOR-
FUEL TANK FILLER 6 5
• 4
• 2
209)( 188 65.3.
UPPER PANEL RH
LOOKING DOWN
CENTROID RISERS - PLANK
IDENTIFICATION NUMBER
FRONT SPAR
OUTBOARD NACELLE
SKATE ANGLES NOTE: LH AND RH WING
FUEL PROBE IDENTIFICATIONS
ARE THE SAME
•
WING SECTION
UPPER SURFACE FWD FIGURE F-1. Wing Section Upper Surface
AC 20-64 CHG 1 10/26/73
LEAP DOUBLER -
ACCESS DOORS WS WS 584 567 550 533 516 499 482 9 DRAI 8 7 5 4 3 2 PLANK #1 WS
55.35 155
CENTROID RISERS
LEAP DOUBLER
WS WS W'S 516 499 359 293
FRONT SPAR
• INBD
DRAIN HOLE
INBOARD NACELLE FWD
SKATE ANGLES
- FUEL QUANTITY GAGE OUTI SKAT WS 359
LOWER PANEL RH
VIEW LOOKING UP
Appendix 6 Page 5 (and 6)
QUANTITY GAGE 7 3 2 →A WS 83
FUEL OVERFLOW
- PLANK
JPPER PANEL LH IDENTIFICATION -OOKING DOWN HORIZONTAL NUMBER CRACK
RD NACELLE VERTICAL
VGLES CRACK
SECTION A-A
• REAR SPAR TYPICAL PLANK SPLICE
CRACK ORIENTATION NOTE: LH AND RH WING
IDENTIFICATIONS
ARE THE SAME
WING SECTION
WS LOWER SURFACE 499 50 567 D FWD FIGURE F-2. Wing Section Lower Surface.
AC 20-64 CHG 1 Appendix 6 10/26/73 Page 7 FIGURE F-3. SERVICE PROBLEM AREAS Pages 8 through 27 (and 28) refer to various service problem areas and are cross-referenced to the photographs in figures Figures F-4 through F-32.
Appendix 6 AC 20-64 CHG 1 Page 8 10/26/73 2 4 5 6 PAGE REF.
MAJOR FOR S/N NO. ASSEMBLY ITEM SERVICE HISTORY ILLUST. CODE W-1 Outer Wing Leading Attach Loosening has occurred of the 29 Edge inboard, Screws screws attaching the leading 30 Middle, & Outboard Upper and edge skins to the front spar Sections Lower caps.
W-2 Outer Wing Lower No. 1 and 3 Surface depressions have been 31 Surface Planks reported in planks between Wing Stations 478 and 528.
W-3 Outer Wing Lower No. 4 Plank Cracks have occurred at the 32 Surface, W.S. 159.6 lower No. 4 wing plank drain hole adjacent to Wing Station
159.6.
W-4 Outer Wing Lower Rear Spar Loose and failed flap track 33 Surface | attachment bolts have been found.
AC 20-64 CHG 1 Appendix 6 10/26/73 Page 9 7 8 9 10
RECOMMENDATIONS
METHOD FREQUENCY TYPE OR METHOD
OF OF OF PREVENTIVE INSP. INSPECTION REPAIR ACTION Visual Inspect at 50 flight hours intervals Remove existing screws and Accomplish and retighten all screws each 300 replace with new type fasteners 88/SB-334.
hours until LAC 88/SB-334 is per 88/SB-334.
incorporated.
Visual Inspect within next 300 hour interval. If depressions exceed limits reinspect each 100 hours until corrective action is taken.
Replace H-clips per instructions Same as Column 9.
of LAC Service Bulletin 88/SB-564.
Externa I Visual Repeat inspections at 1000 hour intervals until permanent repair is incorporated. Interim repairs have special inspection requirements.
Visual Inspect within 850 hours and reinspect at 5000 hour intervals.
(1) Preventive/temporary Same as Column 9, repair may be effected by Item (2).
installing 5/16 Hi-Lok fasteners in drain holes per 88/SB-587C with continued 1000 hr. repeat inspections.
(2) Permanent repair/reinforcement can be made by incorporating either SED/63-9015-101 or SED/63-9015-135 shown on Dwg. SED/63-9015B.
Replace and/or tighten bolts Same as Column 9.
and rework bolt holes per LAC 88/SB-591A.
Appendix 6 AC 20-64 CHG 1 Page 10 10/26/73 2 3 4 5 6 PAGE REF.
MAJOR FOR S/N NO. ASSEMBLY ITEM SERVICE HISTORY ILLUST. CODE W-5 Outer Wing Lower Wing Plank Cracks have occurred in the 34 Surface, W.S. No. 7 wing plank surface and plank 35 179-197 riser located under the main landing gear actuating cylinder attach fitting angles, P/N 802699.
W-6 Outer Wing Lower support Fatigue cracks have occurred at 35 Surface, W.S. 187 Fitting, MLG the aft end of the MLG actuator 36 Actuator support fittings in the radius P/N 800618-1 of the vertical legs.
P/N 800618-2 P/N 800618-3 P/N 800618-4