AC 121-1A

Change 4Historical

Advisory circular · Standard Operations Specifications - Aircraft Maintenance Handbook

Approved
July 7, 1978
Last reviewed
October 25, 2024
Cancels
AC121-1A CHG 3AC120-21AC120-24A
Family
AC 121-1 · 1 version
Revision
A, change 4
14 CFR parts
1

Guidance, not mandatory unless a rule or AD requires it. DRS record last changed November 22, 2025.

Show pages 110–121
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(61F) Main Cabin Cargo Door Hydraulic System (Same as 55F) O.C. See Note * (61F) Cylinder Assembly, Main Cabin Cargo Door Actuating O.C. See Note * NOTE:

* The design of the main cabin cargo door installation is such that in the normally latched and locked position, it can be structurally compared to any fixed portion of the fuselage.

It is only when the door is actuated open on the ground during cargo loading operations that the heaviest loads are incurred. These loads would be greatest at the upper door hinge and hydraulic actuating cylinder attach points. The door seal would also be subject to damage at this time.

Thus, door utilization establishes inspection frequency.

Under these conditions, Douglas suggests the following procedure for purposes of inspection.

(1) Conduct a general visual area inspection of the upper cargo door hinge attachments, door jamb, door actuating cylinder attachments, door seal and latching mechanism at the scheduled "D" service following use of the aircraft in cargo configuration.

(2) If the aircraft is operated solely in the passenger configuration, conduct a general visual area inspection (as above) no later than "E" frequency.

Effective date _____________________ Page 3 of 9

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE DOUGLAS DC-8-61/61F

STRUCTURE INSPECTION PROGRAM E Check - 4000 Hours Overhaul Inspection & D Check - 500 Hours Period Check Period Demountable Powerplant Aft Surface of Nose Cowl, Firewall, Engine Control and Accessory Brackets, Zone 1, 2, 3 and 4 D

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Wings Wing Tip, Zone 5 L/R 5E D Wing Outboard of Sta. Xrs 727, Zone 6 L/R & Zone 9 L/R 5E Wing Leading Edge Sta. Xfs 710 to Xw 761, Zone 7 L/R E Wing Leading Edge Sta. Xw 485 to Xfs 710, Zone 8 L/R E No. 1 & 4 Alternate Fuel Tanks, Zone 9 L/R 5E Wing Trailing Edge Sta. Xw 408 to Xw 761 Aft of Rear Spar, Zone 10 L/R E Aileron Hinge Brackets and Bolts 4D Aileron and Tab, Zone 11 L/R E Hinges & Attachments 4D Aileron Leading Edge Balance Weights 2E Wing Leading Edge at Outboard Pylon Sta. Xw 454 to Xw 485, Zone 12 L/R E Outboard Pylon, Apron and Nacelle Access Doors, Zone 13 L/R 4D Top Side of Upper Spar, Zone 13 L/R 2E Effective date _____________________ Page 4 of 9

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE DOUGLAS DC-8-61/61F

STRUCTURE INSPECTION PROGRAM Overhaul Inspection & Period Check Period

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Wings (continued) Inboard Pylon, Apron and Nacelle Access Doors, Zone 14 L/R 4D Top Side of Upper Spar, Zone 14 L/R 2E Wing Leading Edge Sta. Xw 408 to Xw 454, Zone 15 L/R E Wing Leading Edge Sta. Xw 257 to Xw 408, Zone 16 L/R E No. 1 & 4 Main Fuel Tanks, Zone 17 L/R 5E Wing Trailing Edge from Outboard Auxiliary Spar to Sta. Xw 408, Zone 18 L/R E Main Leading Gear Support Fittings and Auxiliary Spars, Zone 19 L/R 2E Wing Leading Edge at Inboard Pylon Sta. Xw 223 to Xw 257, Zone 20

L/R E Wing Leading Edge Sta. Xfs 107 to Xw 223, Zone 21 L/R E Wing Leading Edge Sta. Xwo to Xfs 107 External Inspection, Zone 22 L/R E Internal Inspection, Zone 22 L/R 5E No. 2 & 3 Alternate Fuel Tanks, Zone 23 L/R 5E No. 2 & 3 Main Fuel Tanks, Zone 24 L/R 5E Outboard Wing Flap Interior Structure, Zone 25 L/R E Flap Hinge Support Fittings, Zone 25 L/R 2E

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Effective date _____________________ Page 5 of 9

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE DOUGLAS DC-8-61/61F

STRUCTURE INSPECTION PROGRAM Overhaul Inspection & Period Check Period Wings (Continued) Aft Side of Flap Spar, Zone 25 L/R 4E Inboard Wing Flap & Links at the Outboard End of the Flap, which Connect to the Inboard End of the Outboard Flap, Zone 26 L/R E Flap Hinge Support Fittings and Aft Side of Flap Spar, Zone 26 L/R 4E Interior or Center Wing Sta. Xcw 0 to Xcw 69.5 (Front to Rear Spar), Zone 27 L/R 5E Fuselage (All Stations are DC-8-61/61F) Radome, Zone 51 E Fuselage Turbo Compressor Compt., Zone 52 4E Navigation Antenna Compt., Zone 53 E Nose Gear Wheel Well, Zone 54 4E Nose Wheel Well Tunnel, Zone 55 L/R 4E Air Conditioning Accessory Compt.

Sta. 8 to 70, Zone 56 E Forward Cargo Compartment Sta. 70 to 640, Zone 57 4E

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Forward Cargo Compartment Tunnel Sta. 70 to 640, Zone 57 L/R 4E Fuselage Accessory Compartment Sta. 640 to 680, Zone 58 E Effective date _____________________ Page 6 of 9

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE DOUGLAS DC-8-61/61F

STRUCTURE INSPECTION PROGRAM Overhaul Inspection & Period Check Period Fuselage (Continued) Upper and Lower Front Spar Cap, Forward Face of Front Spar Web Upper and Lower Front Spar Caps and Splice Plates at Sta. Xcw 0, Zone 58 4E Aft Cargo Compartment Sta. 980 to 1540, Zone 59 4E Aft Cargo Compartment Tunnel, Sta.

980 to 1540, Zone 59 L/R 4E Fuselage Belly Compartment Sta.

1540 to Pressure Panel at Sta.

1766, Zone 60 E Aft Fuselage Sta. 1766 to 1890, Zone 61 E Aft Face and Periphery of Pressure Panel at Fuselage Sta. 1766, Zone 61 E Fuselage Tail Cone, Zone 62 E Fuselage Sta. -131 to -117 above Cockpit Floor, Zone 63 4E Fuselage Cockpit Sta. -117 to -52, Zone 64 4E

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Fuselage Cockpit Sta. -52 to 25 above Floor, Zone 65 L/R E Fuselage Sta. 8 to -131 between Cockpit Floor and Horizontal Pressure Panel, Zone 66 E Forward and Aft Galley Areas Sta.

360 to 460 and Sta. 1500 to 1620 R. Side, Zone 67 E Effective date _____________________ Page 7 of 9

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE DOUGLAS DC-8-61/61F

STRUCTURE INSPECTION PROGRAM Overhaul Inspection & Period Check Period Fuselage (Continued) Scuff Plates at Forward and Aft Service Door Jambs, Internal Inspection of Door Jambs.

Intercostals and Frames at Fuselage Sta. 395, 430, 1538 and 1575. Inspection of Door Hinge Attachments and Door Snubber Attachments to Jambs, Zone 67 4E Forward and Aft Lavatory Area, Zone 68 4E Vertical Stabilizer Front and Center Spar Attachments to Fuselage Longerons, between Fuselage Sta's. 1700 and 1766, Zone 68 4E Upper and Lower Attachments of Aft Pressure Panel Vertical Beam (Center Line-Forward Face of Pressure Panel) Fuselage Sta.

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1766, Zone 68 4E Fuselage Entrance Doors, Zone 69 4E Cargo Doors, Zone 69 4E Exit Doors, All Types, Zone 69 4E Fuselage Sta. 680 to 980 between Bottom of Floor and Top of Wing and Wheel Well, Zone 70 4E Upper Wing to Fuselage Fillet, Zone 71 L/R 4E Lower Wing to Fuselage Fillet Sta.

680 to 980, Zone 72 L/R 4E Fuselage Less Zones 67 & 68, from Sta. 25 to 1645 above Cusp., Zone 73 4E Effective date _____________________ Page 8 of 9

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE DOUGLAS DC-8-61/61F

STRUCTURE INSPECTION PROGRAM Overhaul Inspection & Period Check Period Fuselage (Continued) (61F) Internal Inspection of Main Cabin Cargo Door Jamb Intercostals and Frames at Fuselage Sta. 130 and 270, Zone 73 4E Internal Inspection of Type I Emergency Exit Door Jambs, Intercostals and Frames at Approx. Fuselage Sta. 392, 416, 1312 & 1336, Zone 73 4E Left and Right Main Landing Gear and Wheel Well, Zone 74 L/R 4E

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Wheel Well Keel, Zone 74 L/R E Left and Right Horizontal Stabilizer Leading Edge, Zone 75 L/R 2E Forward Face of Stabilizer Front Spar, Zone 75 L/R E Left and Right Horizontal Stabilizer Outer Panel, Zone 76 L/R 4E Horizontal Stabilizer Center Section, Zone 77 2E Left and Right Elevator and Tabs, Zone 78 L/R E Vertical Stabilizer Leading Edge, Zone 79 2E Vertical Stabilizer Front Spar to Rear Spar, Zone 80 2E Effective date _____________________ Page 9 of 9

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE DOUGLAS DC-8-61/61F

STRUCTURE INSPECTION PROGRAM Overhaul Inspection & Period Check Period Fuselage (Continued) Vertical Stabilizer Tip, Zone 81 3E Rudder and Tab, Zone 82 2E Rudder Hinge Fittings and Damper E Horizontal Stabilizer Tip, Zone 83 L/R 2E Left and Right Aft Fillet, Zone 84

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L/R 2E ---------------------------------------------------------------- ---------------------------------------------------------------- FIGURE 22. OPERATIONS SPECIFICATIONS AIRCRAFT MAINTENANCE

- DOUGLAS DC-8/F DC-8 INSPECTION AND MAINTENANCE PROGRAM [FIGURE NOT INCLUDED] ---------------------------------------------------------------- ---------------------------------------------------------------- FIGURE 23. OPERATIONS SPECIFICATIONS AIRCRAFT MAINTENANCE - LOCKHEED MODEL 382 Form Approved.

UNITED STATES OF AMERICA Budget Bureau FEDERAL AVIATION AGENCY No. 04-R075.

WASHINGTON PART D Page 1 of 12 Pages

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE LOCKHEED MODEL SERIES 382, 382B, D, E, F & G

INSPECTION/CHECK REQUIREMENTS The basic requirements for performing these inspections and checks are as specified in PART I of Lockheed Service Manual Publication SMP 515, revised June 1, 1970, and subsequent revisions thereto.

"A" INSPECTION/CHECK To be accomplished each service calendar day.

"B" INSPECTION/CHECK To be accomplished at intervals not exceeding 200 hours time in service after the preceding "B" or "C" inspection/check period.

"C" INSPECTION/CHECK To be accomplished at intervals not exceeding 600 hours time in service after the preceding "C" inspection/check period.

AIRFRAME STRUCTURAL INSPECTIONS The frequency and procedure for performing these inspections will

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be accomplished as specified in PART I and PART III of Lockheed Service Manual Publication SMP 515, revised June 1, 1970, and subsequent thereto.

"SP" SPECIAL INSPECTIONS The frequency and procedure for performing these inspections will be accomplished as specified in PART IV of Lockheed Service Publication SMP 515, revised June 1, 1970, and subsequent revisions thereto.

Effective date _____________________ Page 2 of 12 Pages

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE LOCKHEED MODEL SERIES 382, 382B, D, E, F & G Overhaul Inspection & Period Check Period Air Conditioning, Chapter 21 OC A B C SP Condenser, Water Separator (Cargo Compt.) OC C Condenser, Water Separator (Flt.

Sta.) OC C Control Box, Temp. (Cargo Compt.) OC C Control Box, Temp. (Flt. Sta.) OC C Controller, Cabin Air Pressure 3,400 C Fan, Recirculation 6,300 C Heat Exchanger (Cargo Compt.) OC C Heat Exchanger (Flt. Sta.) OC C Indicator, Cabin Altitude 12,600 C Indicator, Cabin Rate of Climb 12,600 C Indicator, Differential Press. 12,600 C Separator, Water (Cargo Compt.) OC C Separator, Water (Flt. Sta.) OC C Switch, Differential Pressure 1,800 C Switch, Emergency Depressurization OC C Thermostat, Cabin Air Temp. 6,300 C Thermostat, Duct Anticipator (Cargo Compt.) OC C Thermostat, Duct Anticipator (Flt. Sta.) OC C Turbine, Cooling (Cargo Compt.) 1,800 C Turbine, Cooling (Flt. Sta.) 1,800 C Valve, Aux. Vent (Cargo Compt.) 12,600 C Valve, Aux. Vent (Flt. Sta.) 12,600 C Valve, Cargo Floor Heat 12,600 C

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Valve, Cargo Floor Heat Diverter 12,600 C Valve, Flow Cont. & Shut-Off (Cargo Compt.) 12,600 C Valve, Flow Cont. & Shut-Off (Flt. Sta.) 12,600 C Valve, Outflow 6,300 C Valve, Safety OC C Valve, Temp. Cont. (Cargo Compt.

Dual Butterfly) 12,600 C Valve, Temp. Cont. (Flt. Sta. Dual Butterfly) 12,600 C Auto Flight, Chapter 22 OC A B C 2C Amplifier, Electronic Control, Approach and Nav. 3,400 C Amplifier, Electronic Control, Auto Pilot (Main) 3,400 C Control, Engage & Approach 6,300 C Control, Gyro, Roll & Pitch 3,400 C Control, Servo 3,400 C 2C Control, Trim Tab Adapter 6,300 C Controller, Flight 6,300 C Drum and Bracket Assembly OC C Motor and Drive Assembly 6,300 C Relay, Servo Engage 6,300 C Effective date _____________________ Page 3 of 12 Pages

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE LOCKHEED MODEL SERIES 382, 382B, D, E, F & G Overhaul Inspection & Period Check Period Communications, Chapter 23 OC A B C SP May be determined by assigned inspector.

Electrical Power, Chapter 24 OC A B C Battery OC A B C Control Panel, AC 3,400 C Frequency Meter OC C Generator, 20 KVA, ATM Driven 12,600 C Generator, 40 KVA, Engine Driven EO B C Indicator, Loadmeter (AC) OC C

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Indicator, Loadmeter (DC) OC C Inverter, 250 VA 6,300 C Inverter, 2500 VA 6,300 C Regulator, Voltage, 20 KVA Generator 12,600 C Regulator, Voltage, 40 KVA Generator 3,400 C Relay, Battery OC C Relay, Bus 6,300 C Relay, Bus Off (AC) OC C Relay, Bus Off (DC) OC C Relay, External Power, AC OC C Relay, External Power, DC OC C Relay, Frequency Sensitive OC C Relay, Generator & Bus Tie (AC) 12,600 C Relay, Reverse Current 9,450 C Transformer, Instrument OC C Transformer, Instrument (Engine) OC C Transformer, Rectifier OC C Voltmeter, AC OC C Voltmeter, DC OC C Equipment & Furnishings, Chapter 25 OC A B C Kit, First Aid OC A B C Seat Belts and Harnesses OC A B C Seat, Flight Station, FAA Observer OC A B C Seats, Flight Station OC A B C Effective date _____________________ PAGE 4 of 12 PAGES

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE LOCKHEED MODEL SERIES 382B, D, E, & F Overhaul Inspection & Period Check Period Fire Protection, Chapter 26 OC A B C EC SP Amplifier, Control Unit OC C Amplifier, Control, Smoke Detection OC C Control Panel, Assembly OC C Control Relay (Unit) OC C Extinguisher, Portable * B C Flasher, Overheat OC C Inert Element, Fire Detection OC C Smoke Detector OC C Sensing Element, Fire Detection OC C EC