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 346–357
Page 358Open in PDF

Temperature regulating valve OC X X X Replacement of brushes; 2800/4 yrs. I/C, OP check of actuator condition.

AUTO PILOT, CHAPTER 22 OC X X X X To be determined by assigned inspector.

COMMUNICATIONS, CHAPTER 23 OC X X X X To be determined by assigned inspector.

Effective date ____________________ Page 4 of 12

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE FAN JET FALCON-10

OVERHAUL INSPECTION AND CHECK PERIOD HOURS/YRS. A B C 2C OTHER

ELECTRICAL POWER, CHAPTER 24 OC X X X X Battery OC X X X X Removal for servicing 2 mos. S Starter-generator 1500 hrs. X X X Check of brush wear 300 hrs. I/C, OP and slip ring condition Battery Blower OC X X X X Check of brushes 5600/8 yrs. I/C, OP

EQUIPMENT FURNISHINGS, CHAPTER 25 OC X X X X To be determined by assigned inspector.

Shoulder Harness & Harness Reels OC X X X

Page 359Open in PDF

FIRE PROTECTION, CHAPTER 26 OC X X X X Freon extinguisher bottle **5 yrs. X X X * NOTE (3) Weighing 1 yr. X X X I/C Replacement of squibs 2 yrs. X X X I/C CO2 extinguisher **5 yrs. X X X * NOTE (4) Weighing 6 mos. X X X X I/C

FLIGHT CONTROLS, CHAPTER 27 OC X X X X Elevator servo-control 8 yrs. X X Check of travel speed FC/S and check for leakage 2800/4 yrs on stop;

Lubrication of bearings Rudder servo-control 8 yrs. X X Check of travel speed FC/S and check for leakage 2800/4 yrs on stop;

Lubrication of bearings Effective date ____________________ Page 5 of 12

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE FAN JET FALCON-10

OVERHAUL INSPECTION AND CHECK PERIOD HOURS/YRS. A B C 2C OTHER

FLIGHT CONTROLS, CHAPTER 27 (Cont'd) Aileron servo-control 8 yrs. X X RH side LH side Check of travel speed FC/S and check for leakage 2800/4 yrs.

on stop;

Lubrication of bearings.

Page 360Open in PDF

Trim jack (rudder and aileron) 10 yrs. X X Check of axial clearance, FC travel and electric 2800/4 yrs.

motor (brushes, insulation) Trim control box 10 yrs. X X X FC 1000/1 yr.

Main AFS OC X X X Internal lubrication FC/S and check of radial 2800/4 yrs.

clearance.

Secondary AFS (aileron) 10 yrs. X X X I/C, S 2800/4 yrs.

AMEDEE COUPLING OC X X X X Measurement of gear FC, S teeth meshing play; 2800/4 yrs.

Lubrication Pressure Relief Valves 8 yrs. X X X FC, 1000/1 yr.

Anti-gust valve 8 yrs. X X X X FC, 150 Main AFS OC X X X Internal lubrication FC, S and check of radial 2800/4 yrs.

clearance.

Secondary AFS (rudder) OC X X X Internal lubrication FC, S and check of radial 2800/4 yrs.

clearance.

Main AFS OC X X X Internal lubrication FC, S and check of radial 2800/4 yrs.

clearance.

Effective date ____________________ Page 6 of 12

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE FAN JET FALCON-10

OVERHAUL INSPECTION AND CHECK PERIOD

Page 361Open in PDF

HOURS/YRS. A B C 2C OTHER

FLIGHT CONTROLS, CHAPTER 27 (Cont'd) Rudder Linear ARTHUR Jack 8 yrs. X X X FC, S 1000/1 yr.

Secondary AFS (elevator) 10 yrs. X X X I/C, S 2800/4 yrs.

Electrical ARTHUR Jack 3000 hrs. X X X X OP Check of motor (brushes, 2800/4 yrs.

insulation, motor stop overrun) Electrical stabilizer jack 3000 hrs. X X X X OP Check of motor (brushes, 2800/4 yrs.

insulation) Potentiometer box 10 yrs. X X X FC 1000/1 yr.

Airbrake jack 8 yrs. X X X FC 1000/1 yr.

Airbrake distributor 8 yrs. X X X FC 1000/1 yr.

Microswitch box 2800 hrs. X X X X FC 1000/1 yr.

Switches Stabilizer Trim OC X X X X FC, S 1000/1 yr.

Reduction gear motor 2400 hrs. X X X FC 1000/1 yr.

Screw jacks 2400 hrs. X X X FC LH outboard jack 1000/1 yr.

RH outboard jack Inboard jack Inboard jack Slat distributor 8 yrs. X X X FC 1000/1 yr Effective date ____________________

Page 362Open in PDF

Page 7 of 12

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE FAN JET FALCON-10

OVERHAUL INSPECTION AND CHECK PERIOD HOURS/YRS. A B C 2C OTHER

FLIGHT CONTROLS, CHAPTER 27 (Cont'd) Stand-by slat distributor 8 yrs. X X X FC 1000/1 yr.

Slat jacks 8 yrs. X X X FC 1000/1 yr.

Slat jacks 8 yrs. X X X FC 1000/1 yr.

Slat jacks 8 yrs. X X X FC 1000/1 yr.

Stand-by outboard slat jacks 8 yrs. @ X X X FC 1000/1 yr.

Yaw damper jack 8 yrs. X X X FC 1000/1 yr.

FUEL, CHAPTER 28 OC X X X X Booster pump OC X X X FC 2800/4 yrs.

Replacement of brushes 1200 hrs. OP Replacement of bearings 2400 hrs. OP LP crossfeed valve actuator OC X X X *NOTE (2) Check of brushes and OP, slip ring 2800/4 yrs.

Pressure switch OC X X X Check of calibration CAL.

2800/4 yrs.

Indicator 2800 hrs. X X X OP

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1000/1 yr.

HYDRAULIC POWER, CHAPTER 29 OC X X X X Pressurization reducing valves OC X X X Replacement of diaphragm FC, 2800/4 yrs.

Effective date ____________________ Page 8 of 12

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE FAN JET FALCON-10

OVERHAUL INSPECTION AND CHECK PERIOD HOURS/YRS. A B C 2C OTHER

HYDRAULIC POWER, CHAPTER 29 (Cont'd) Pressure switch OC X X X Check of calibration CAL.

2800/4 yrs.

Hydraulic pump 2400 hrs. X X X OP 1000/1 yr.

Electropump 4800 hrs. X X X OP 1000/1 yr.

Pressure switch OC X X X CAL.

2800/4 yrs.

Pressure transmitter OC X X X CAL.

2800/4 yrs.

ICE AND RAIN PROTECTION, CHAPTER 30 OC X X X X Wing anti-icing air valve 2800 hrs. X X X X OP, 1000/1 yr.

Windshield wiper OC X X X X FC, 1000/1 yr.

Page 364Open in PDF

Servicing S, 5600/8 yrs.

Anti-icing valve 2800 hrs. X X X OP, 1000/1 yr.

INSTRUMENTS, CHAPTER 31 OC X X X X To be determined by assigned inspector.

LANDING GEAR, CHAPTER 32 OC X X X X Pressure switch OC X X X CAL.

2800/4 yrs.

Main gear struts 5600 hrs. X X X X Effective date ________________ Page 9 of 12

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE FAN JET FALCON-10

OVERHAUL INSPECTION AND CHECK PERIOD HOURS/YRS. A B C 2C OTHER

LANDING GEAR, CHAPTER 32 (Cont'd) Ball joint bearings 5600 hrs. X X X X Front Rear Main shock strut 5600 hrs. X X X X Actuating cylinder assembly 5600 hrs. X X X X LH side RH side Nose gear 5600 hrs. X X X X Actuating cylinder assembly 5600 hrs. X X X X Pressure reducing solenoid valve 4800 hrs. X X X

Page 365Open in PDF

Main gear wheel OC X X X X Visual inspection, At each lubrication of bearings. wheel Eddy current or ultra change sonic inspection. 1500 hrs., then at each tire change.

Nose gear wheel OC X X X X Visual inspection, At each lubrication of bearings. wheel Eddy current or ultra change sonic inspection. 2800 hrs., then at each tire change.

Servo-valve 3600 hrs. X X X FC 1000/1 yr.

Anti-skid speed sensor OC X X X CAL., 2800/4 yrs.

LIGHTS, CHAPTER 33 OC X X X X Anti-collision light OC X X X Check of motor OP, 2800/4 yrs.

Effective date ____________________ Page 10 of 12

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE FAN JET FALCON-10

OVERHAUL INSPECTION AND CHECK PERIOD HOURS/YRS. A B C 2C OTHER NAVIGATION, CHAPTER 34 OC X X X X To be determined by assigned inspector.

Encoder altimeter OC X X X CAL/2 yrs.

Altimeter OC X X X CAL/2 yrs.

PER IDC Overhaul

Page 366Open in PDF

Manual.

Mach Meter OC X X X CAL/2 yrs.

PER IDC Overhaul Manual.

Overspeed warning device OC X X X CAL/2 yrs OXYGEN, CHAPTER 35 OC X X X X Oxygen cylinder **3 yrs. X X X X S Service life 15 yrs * NOTE (7) Pressure reducing valve OC X X X CAL., 2800/4 yrs.

Altitude sensitive valve 4 yrs. X X X FC, 1000/1 yr.

PNEUMATIC, CHAPTER 36 OC X X X X (P2) Unit 2400 hrs. X X X X I/C, 150/6 mos.

HP isolation pneumatic valve 2800 hrs. X X X X I/C, 150/6 mos.

DOORS, CHAPTER 52 OC X X X X Inspect areas in accordance with Falcon-10 Maintenance Manual.

Effective date ____________________ Page 11 of 12

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE FAN JET FALCON-10

OVERHAUL INSPECTION AND CHECK PERIOD HOURS/YRS. A B C 2C OTHER

Page 367Open in PDF

FUSELAGE, CHAPTER 53 OC X X X X Inspect areas in accordance with Falcon-10 Maintenance Manual.

NACELLES, CHAPTER 54 OC X X X X Inspect areas in accordance with Falcon-10 Maintenance Manual.

STABILIZERS, CHAPTER 55 OC X X X X Inspect areas in accordance with Falcon-10 Maintenance Manual.

WINDOWS, CHAPTER 56 OC X X X X Inspect areas in accordance with Falcon-10 Maintenance Manual.

WINGS, CHAPTER 57 OC X X X X Inspect areas in accordance with Falcon-10 Maintenance Manual.

ENGINE, CHAPTER 72 OC X X X X Service, inspection and * NOTE (5) overhaul life limits to be in accordance with Garrett Air Research Service Bulletins TFE731-72-3001 and TFE-731-72-3002.

ENGINE CONTROLS, CHAPTER 76 OC X X X X Power control mechanical linkage 4000 hrs. X X X X * NOTE (1) Scrap S, 1000/1 yr.

Effective date ____________________

Page 368Open in PDF

Page 12 of 12

OPERATIONS SPECIFICATIONS

AIRCRAFT MAINTENANCE FAN JET FALCON-10

OVERHAUL INSPECTION AND CHECK PERIOD HOURS/YRS. A B C 2C OTHER

ENGINE CONTROLS, CHAPTER 76 (Cont'd) Power control linkage OC X X X X IC/S (cable and box assembly) LH side RH side Lubrication of bearings and cable. 1000/1 yr.

OIL, CHAPTER 79 OC X X X X Oil pressure switch OC X X X CAL.

2800/4 yrs.

Effective date ____________________ ---------------------------------------------------------------- ---------------------------------------------------------------- FIGURE 42. OPERATIONS SPECIFICATIONS, AIRCRAFT MAINTENANCE - GATES LEARJET MODELS 35/36 Form Approved UNITED STATES OF AMERICA OMB. No. 04-R0075

DEPARTMENT OF TRANSPORTATION

FEDERAL AVIATION ADMINISTRATION

WASHINGTON PART D Preface Page 1 of 1

OPERATIONS SPECIFICATIONS

PREFACE PAGE

AIRCRAFT MAINTENANCE

ABC AIRLINES LEAR 35/36 Irrespective of the type of operation to be conducted by ABC

Page 369Open in PDF

Airlines, the continuous airworthiness and inspection program limitations which are described and specified in these Operations Specifications shall be applicable to all ABC Airlines aircraft listed and authorized for use under Federal Aviation Regulations Part _____. ABC Airlines shall provide in its currently effective Maintenance Manual a comprehensive program necessary to fulfill the responsibility to maintain the aircraft in an airworthy condition in accordance with the applicable Federal Aviation Regulations and standards prescribed and approved by the Administrator.

Aircraft shall not be utilized in air carrier _____ operations unless:

a. The aircraft and its component parts, accessories, and appliances are maintained in an airworthy condition in accordance with the schedule of maintenance and inspection procedures and functions set forth in the operator's maintenance manual.

b. OC "on condition" items will be maintained in continuous airworthiness condition by periodic and progressive inspections, checks, services, repair, and/or preventive maintenance and shall be appropriately described in the operator's maintenance manual.

c. Parts or subcomponents, not listed below, will be checked, inspected, and/or overhauled at the same time limits specified for the component or accessory to which such parts or subcomponents are related.

AVIONICS SYSTEMS. The term "system" means all those interdependent subassemblies, component parts, etc., necessary for the proper functioning of the system as a whole. The term "Bench Check" includes calibration, if necessary, to return the unit to service in accordance with the manufacturer's procedures.

Abbreviations used in the maintenance specifications are defined as follows:

FC - Indicates "Functional Check" BC - Indicates "Bench Check" EO - Indicates "Engine Overhaul" EC - Indicates "Engine Change" OC - Indicates "On Condition" HYD - Indicates "Hydrostatic Test" C - Indicates "Calibration" SI - Indicates "Special Inspections" ESV - Indicates "Engine Shop Visit"