ii
CONTENTS Paragraph Page
Chapter 1. General1-1
1.1 Purpose of This Advisory Circular (AC)1-1
1.2 Audience1-1
1.3 Where You Can Find This AC1-1
1.4 What This AC Cancels1-1
1.5 Reference1-1
1.6 AC Feedback Form1-2
Chapter 2. Structural Data2-1
2.1 General2-1
2.2 Structural Design Process2-1
2.3 Types of Loads and Stresses2-1
2.4 Static Loads2-2
2.5 Structural Sizing and Analysis2-3
2.6 Static Tests2-4
2.7 Materials and Workmanship2-5
2.8 Material Strength Properties and Design Values2-5
2.9 Fasteners2-6
2.10 Protection of Structure2-6
2.11 Accessibility2-7
2.12 Effects on Weight and Balance (W&B)2-7
2.13 Effects on Safe Operation2-7
2.14 Controls and Indicators2-7
2.15 Placarding2-7
Chapter 3. Communication, Navigation, and Emergency Locator Transmitter System
Installations3-1
3.1 Purpose3-1
3.2 Hazards and Warnings3-1
3.3 Considerations When Installing Avionics Equipment3-2
3.4 Instrument Panel Mounting3-4
3.5 Other Mounting Areas3-5
iii
3.6 Fabrication of Supporting Brackets for Attachment to a Structure Other Than
Flooring3-7
3.7 Reinforcement of the Supporting Structure3-8
3.8 Electrical Requirements3-11
3.9 Electrical Load Analysis Procedure3-13
3.10 Electromagnetic Compatibility (EMC)3-13
3.11 Functional Hazard Assessment (FHA)3-16
Chapter 4. Antenna Installation4-1
4.1 Purpose4-1
4.2 Hazards and Warnings4-1
4.3 Additional References4-1
4.4 Structural Support4-1
4.5 Physical Interference4-2
4.6 Antenna Selection4-3
4.7 Antenna Location4-3
4.8 Antenna Bonding4-4
4.9 Electromagnetic Interference (EMI)4-5
4.10 Mechanical Installation4-5
4.11 Ground Plane Requirement (Wood/Fabric and Composite Aircraft)4-6
4.12 Antenna Feed Line Balun4-8
4.13 Antenna Repair4-10
Chapter 5. Anticollision and Supplementary Light Installation5-1
5.1 Purpose5-1
5.2 Hazards and Warnings5-1
5.3 Regulations and Other References5-1
5.4 Operational Considerations: Crew Vision5-2
5.5 Installation Considerations5-2
5.6 Markings and Placards5-2
5.7 Electrical Installation5-2
5.8 Alteration of Structure5-3
Chapter 6. Ski Installations6-1
6.1 Purpose6-1
iv
6.2 Hazards and Warnings6-1
6.3 Additional References (current editions)6-1
6.4 Installation Considerations6-1
6.5 Fabrication and Installation6-3
6.6 Rigging of Skis6-7
6.7 Documentation6-11
6.8 Flight and Handling Operational Checks6-12
6.9 Maintenance (Including Inspection)6-12
Chapter 7. Oxygen System Installations in Nonpressurized Aircraft7-1
Section 1. General7-1
7.1 Purpose7-1
7.2 Hazards and Warnings to Consider When Installing an Oxygen System7-1
7.3 Additional References (current editions)7-1
Section 2. Installation of the Oxygen System7-2
7.4 System Requirements7-2
7.5 Installation and Design Considerations7-4
7.6 Equipment Location and Mounting7-6
7.7 Thread Compound7-6
7.8 Functional Test7-6
7.9 Operating Instructions7-8
Section 3. Airworthiness Compliance Check Sheet: Oxygen System Installation in
Unpressurized Aircraft7-12
7.10 General7-12
7.11 Applicable Federal Aviation Regulations7-12
7.12 Structural Requirements7-12
7.13 Hazards to the Aircraft or its Occupants7-12
7.14 Operating Aspects7-12
7.15 Detail Design Standards7-13
7.16 Instructions for Continued Airworthiness (ICA)7-13
7.17 Recordkeeping7-14
v Chapter 8. Rotorcraft External-Load Device Installations, Cargo Slings, and External Racks ... 8-1
Section 1. General8-1
8.1 Purpose8-1
8.2 Hazards and Warnings8-1
8.3 References8-1
8.4 Installation Considerations8-1
8.5 Fabrication and Installation8-2
Section 2. Cargo Racks8-11
8.6 General8-11
8.7 Fabrication of Cargo Racks8-11
8.8 Static Test8-11
8.9 Supplemental Flight Information8-11
Chapter 9. Glider and Banner Tow-Hitch Installations9-1
9.1 Purpose9-1
9.2 Hazards and Warnings9-1
9.3 References9-1
9.4 Installation Considerations9-1
9.5 Fabrication and Installation Procedures9-1
9.6 Structural Testing9-3
9.7 Angles of Tow9-3
9.8 Placards9-4
9.9 Installation Procedures―Types of Hitches9-4
9.10 Tow Release Mechanism9-6
Chapter 10. Shoulder Harness Installations10-1
Section 1. General10-1
10.1 Purpose10-1
10.2 Hazards and Warnings10-1
10.3 Additional References10-1
10.4 Installation Methods10-1
10.5 Restraint System Configurations10-3
10.6 Advantages of Different Configurations10-3
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10.7 Manufacturing Standards10-4
10.8 Compliance With Standards10-4
10.9 Materials10-5
10.10 Parts Produced by Owners/Others10-6
Section 2. Geometry and Attachment10-8
10.11 General10-8
10.12 Mounting Configurations10-8
10.13 Belt Length10-8
10.14 Attachment Geometry10-8
10.15 Area and Angle Deviations10-15
10.16 Structural Attachment10-15
Section 3. Static Strength and Testing10-21
10.17 Proof of Compliance10-21
10.18 Load and Distribution―Airplanes10-21
10.19 Load and Distribution―Normal Category Helicopters10-22
10.20 Demonstrating Static Loads10-22
Section 4. Installation and Inspection Checklists10-26
10.21 General10-26
Chapter 11. Aircraft Battery Installations11-1
Section 1. General11-1
11.1 Purpose11-1
11.2 Hazards and Warnings: Handling Precautions11-1
11.3 Additional References (current editions)11-1
11.4 Location Requirements11-1
11.5 Aircraft Storage Battery Design and Installation11-2
11.6 Duplication of the Manufacturer’s Installation11-3
11.7 Other Installations11-3
11.8 Delivery Inspection11-3
11.9 Battery Installation and Removal11-4
Section 2. Lead-Acid Battery Installations11-6
11.10 General11-6
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11.11 Battery Box11-6
11.12 Securing the Battery11-6
11.13 Sump Jar11-6
11.14 Venting11-7
11.15 Drains11-8
11.16 Electrical Installation11-8
11.17 Quick Disconnect11-10
11.18 Weight and Balance (W&B)11-10
Section 3. Nickel-Cadmium Battery Installations11-11
11.19 General11-11
11.20 Electrical Analysis11-11
11.21 Maintenance Considerations11-11
11.22 Structural Requirements11-11
11.23 Isolation of Battery Case11-12
11.24 Ventilation11-12
11.25 Preinstallation Requirements11-12
11.26 Nickel-Cadmium Battery Installation11-13
11.27 Securing the Battery11-13
11.28 Quick Disconnect11-13
11.29 Voltage and Current Regulation11-14
11.30 Weight and Balance (W&B)11-14
Section 4. Battery Installation Checklist11-15
11.31 Structural Requirements11-15
11.32 Hazards to the Aircraft and its Occupants11-16
11.33 Operating Aspects11-16
11.34 Detail Design Standards11-16
11.35 Recordkeeping11-17
Section 5. Instructions for Continued Airworthiness11-18
11.36 Lead-Acid Batteries11-18
11.37 Nickel-Cadmium Batteries11-19
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Chapter 12. Adding or Relocating Instruments12-1
12.1 Purpose12-1
12.2 Hazards and Warnings12-1
12.3 Additional References12-1
12.4 Preparation12-1
12.5 Installation12-3
12.6 Testing, Marking, and Placarding12-9
12.7 Electronic Display Instrument Systems or Electronic Display Indicators12-11
12.8 Environmental Conditions12-12
Chapter 13. Cargo Tiedown Device Installations13-1
13.1 Purpose13-1
13.2 Hazards and Warnings13-1
13.3 Installation Considerations13-1
13.4 Fabrication and Installation13-1
13.5 Operating Limitations, Loading Instructions, and Placards13-9
13.6 Airworthiness Compliance Check Sheet: Cargo Tiedown Device Installations13-9
Chapter 14. Larger Tire Installations14-1
14.1 Purpose14-1
14.2 Hazards and Warnings14-1
14.3 Additional Reference (current editions)14-1
14.4 Installation Considerations14-2
14.5 Flight and Ground Handling Operational Checks14-4
14.6 Testing the Modification14-6
14.7 Maintenance (Including Inspection)14-7
14.8 Interchanging of Skis and Wheels14-9
14.9 Documentation14-9
14.10 Summary of Considerations for Approval of Larger Tire Installation (may be
used as a job aid)14-9
ix List of Figures
Figure 2-1. Bending of a Beam2-2
Figure 2-2. Typical Load2-3
Figure 2-3. Hypothetical of Determining Static Test Loads2-8
Figure 3-1. Force Diagram Normal-Utility Category3-3
Figure 3-2. Typical Fabricated Panel Mounting3-3
Figure 3-3. Typical Layouts3-4
Figure 3-4. Typical Shock-Mounted Base (Wood or Composition Flooring)3-6
Figure 3-5. Typical Shock-Mounted Base (Metal Flooring)3-6
Figure 3-6. Typical Rigid Base Plate Mount3-7
Figure 3-7. Typical Underseat Installation3-8
Figure 3-8. Typical Remote Unit Mounting Base-Vertical or Horizontal Other Than
Structure to Floor3-9
Figure 3-9. Typical Shelf Installation3-10
Figure 3-10. Typical Attachment of Support Structure to Tubular Frame Other Than
Structure to Floor3-11
Figure 4-1. Antenna Mount With Saddle4-2
Figure 4-2. Antenna Ground Plane for Nonconductive Mount4-7
Figure 4-3. One Means to Provide Adequate Antenna Bonding Through a
Composite Airframe4-7
Figure 4-4. Use Bushings for All Screws4-8
Figure 4-5. Typical Dipole Antenna Assembly4-9
Figure 4-6. Typical VOR Balun4-10
Figure 4-7. ADF Loop4-11
Figure 4-8. ADF Combined Sense Loop4-11
Figure 4-9. Communications (COM) Whip4-11
Figure 4-10. COM Whip Bent4-12
Figure 4-11. Emergency Locator Transmitter4-12
Figure 4-12. Global Positioning System4-12
Figure 4-13. Glideslope4-13
Figure 4-14. Marker4-13
Figure 4-15. Combined COM/VOR4-13
Figure 4-16. VOR Rabbit Ear4-14
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Figure 4-17. VOR Blades4-14
Figure 4-18. Transponder/DME Probe4-15
Figure 4-19. DME/Transponder Blade4-15
Figure 5-1. Typical Anticollision or Supplementary Light Installation in a Skin
Panel (Unpressurized)5-3
Figure 5-2. Typical Anticollision or Supplementary Light Installation Involving a Cut
Stringer (Unpressurized)5-4
Figure 5-3. Typical Anticollision or Supplementary Light Installation in a Fin Tip5-5
Figure 6-1. Typical Hub Installation6-3
Figure 6-2. Typical Ski Installation6-4
Figure 6-3. Typical Fuselage Fittings6-6
Figure 6-4. Main Ski at Maximum Positive Incidence (Check Cable Taut)6-7
Figure 6-5. Main Ski at Maximum Negative Incidence (Safety Cable Taut)6-8
Figure 6-6. Main Ski Incidence Angles6-8
Figure 6-7. Typical Nose Ski Installation6-10
Figure 6-8. Typical Tail Ski Installation6-11
Figure 7-1. Typical Floor Mounting7-9
Figure 7-2. Typical Baggage Compartment Mounting7-10
Figure 7-3. Typical Oxygen Installation in Light Twin Aircraft7-11
Figure 8-1. Location of Cargo Release in Relation to the Rotorcraft’s Center of Gravity8-2
Figure 8-2. Typical Cargo Sling Wiring Diagram8-5
Figure 8-3. Typical Cargo Sling Installation No. 18-6
Figure 8-4. Typical Cargo Sling Installation No. 1 (Showing Fuselage Attachment Fitting)8-7
Figure 8-5. Typical Cargo Sling Installation No. 1 (Showing Fore Aft Limiting Stops)8-8
Figure 8-6. Typical Cargo Sling Installation No. 2 (Cargo Hook Attached Directly to
Underside of Fuselage)8-8
Figure 8-7. Typical Cargo Sling Installation No. 3 (4-Leg, Cable Suspended)8-9
Figure 8-8. Typical Cargo Sling Installation No. 3 (Showing Cable Sling Leg Attachment
to Landing Gear Crosstube Fitting)8-9
Figure 8-9. Typical Cargo Sling Installation No. 3 (Showing Cargo Sling in
Stowed Position)8-10
Figure 8-10. Typical Cargo Rack Installation No. 18-11
Figure 8-11. Typical Cargo Rack Installation No. 1 (Showing Attachment Detail)8-12
Figure 8-12. Typical Cargo Rack Installation No. 28-12
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Figure 8-13. Typical Cargo Rack Installation No. 2 (Showing Rack Partially Installed)8-13
Figure 8-14. Typical Cargo Rack Installation No. 38-13
Figure 9-1. Glider Tow Angle9-2
Figure 9-2. Banner Tow Angle9-2
Figure 9-3. Typical Tow-Hitch Release Handle9-7
Figure 9-4. Tricycle Gear Aircraft9-8
Figure 9-5. Conventional Gear Aircraft—Leaf Spring Type Tailwheel9-8
Figure 9-6. Conventional Gear Aircraft—Shock Strut Type Tailwheel9-9
Figure 9-7. Conventional Gear Aircraft—Tubular Spring Type Tailwheel9-9
Figure 9-8. Typical TOST Hitch9-10
Figure 9-9. TOST Double Tow Rings9-10
Figure 9-10. Schweizer Type Hitch9-11
Figure 9-11. Typical Multiple Hitch for Banner Tow9-12
Figure 9-12. Typical TOST Mount for Tricycle Gear Aircraft9-12
Figure 9-13. Typical TOST Conventional Leaf Spring Mount9-13
Figure 10-1. Major Versus Minor Alterations10-3
Figure 10-2. The Three-Point Single Harness Positioning10-10
Figure 10-3. Side Mounted Single Diagonal Type Harness10-11
Figure 10-4. Acceptable Harness Mounting Areas10-11
Figure 10-5. Undesirable Horizontal Harness Positioning10-12
Figure 10-6. Undesirable Vertical Harness Positioning10-12
Figure 10-7. Ceiling Mounted Inertia Reel―Double Over-the-Shoulder Type Harness10-13
Figure 10-8. The Four-Point Independent Harnesses Positioning10-13
Figure 10-9. The Five-Point Harness Positioning10-14
Figure 10-10. “Y” Type Retractor Positioning10-14
Figure 10-11. Floor Mounted Inertia Reel―Double Over-the-Shoulder Type Harness10-16
Figure 10-12. Typical Floor Mounted Inertia Reel Installation10-16
Figure 10-13. Typical Seat Mounted Inertia Reel Installation10-17
Figure 10-14. Typical Wing Carry-Through Installation10-18
Figure 10-15. Typical Hat Section Reinforcement Installation10-18
Figure 10-16. Typical Bulkhead Reinforcement Installation10-19
Figure 10-17. Typical Stringer Section Reinforcement Installation10-19
Figure 10-18. Typical Localized Stringer Section Reinforcement Installation10-20
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Figure 10-19. Typical Attachments to Tubular Members10-20
Figure 10-20. Vertical Angle10-25
Figure 10-21. Horizontal Angle10-25
Figure 11-1. Typical Battery Installation in the Aircraft11-5
Figure 11-2. Typical Battery Installation With Sump Jar11-7
Figure 11-3. Battery Ventilation System11-8
Figure 11-4. Typical Battery Cutoff and Generator Alternator Control Circuit11-10
Figure 12-1. The Basic “T” Visual Meteorological Conditions (VMC)
Instrument Configuration12-2
Figure 12-2. Pressure Drop Data for Smooth Tubing12-7
Figure 13-1. Extruded Track, Anchor Plates, and Associated Fittings13-3
Figure 13-2. Miscellaneous Litter, Berth, and Cargo Tiedown Fittings13-4
Figure 13-3. Typical Attachment of Fittings to Honeycomb Structures13-5
Figure 13-3. Typical Attachment of Fittings to Honeycomb Structures – Continued13-6
Figure 13-4. Installation of Underfloor Support for Extruded Track13-6
Figure 13-5. Typical Cargo Tiedown Straps and Cargo Nets13-7
Figure 13-6. Example of Allowable Cargo Loading Diagram13-12
Figure 14-1. Diagram of Axle Height Measurement14-3
Figure 14-2. Typical Main Landing Gear Spring Strut and Axle Assembly14-8
List of Tables
Table 2-1. Ultimate Load Factors2-3
Table 2-2. Sample Load Factors2-4
Table 3-1. Typical Compass Calibration Card3-5
Table 3-2. Relationship Probabilities and Severity of Failure Conditions3-14
Table 3-3. Commonly Used Radio Frequencies on Aircraft3-15
Table 3-4. Aircraft Electrical and Electronic Systems3-16
Table 4-1. Wavelength in Feet = 984/Frequency in Megahertz (MHz)4-6
Table 6-1. Recommended Minimum Cable and Shock Cord Sizes6-5
Table 6-2. Approximate Main Ski Tension Forces6-9
Table 7-1. Typical Oxygen Duration Table7-8
Table 8-1. Cable Load Table8-3
Table 9-1. Representative Steel Cable Qualities9-7
Table 10-1. Static Test Requirements10-24
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Table 10-2. Calculated 1/Cosine Values10-24
Table 12-1. CFM/Vacuum Values12-5
Table 12-2. Instrument Air Consumption for Example Vacuum-Driven Autopilot and
Instrument Installations12-5
Table 12-3. Equivalent Straight Tube Line Drops for Each 90-Degree Elbow Installed
in Any Given System (By O.D.)12-6
Table 12-4. Differential Pressure Across the Instrument Inlet and Outlet of the Example
Instrument Packages12-6