Par 11-253 Page 11-117 TABLE 11-26. MINIMUM BENDING RADII FOR FLEXIBLE ALUMINUM OR BRASS
CONDUIT Nominal ID of Conduit (inches) Minimum Bending Radius Inside (inches) 3/16 2 1/4 1/4 2 3/4 3/8 3 3/4 1/2 3 3/4 5/8 3 3/4 3/4 4 1/4 1 5 3/4 1 1/4 8 1 1/2 8 1/4 1 3/4 9 2 9 3/4 2 1/2 10
11-254.–11-259. [RESERVED.]
Par 11-260 Page 11-118 SECTION 19. UNUSED CONNECTORS AND UNUSED WIRES
11-260. GENERAL. Connectors may have one or more contact cavities that are not used.
Depending on the connector installation, unused connector contact cavities may need to be properly sealed to avoid damage to the connector, or have string wire installed. Unused wires can be secured by tying into a bundle or secured to a permanent structure; individually cut with strands even with insulation; or pre-insulated closed end connector or 1-inch piece of insulating tubing folded and tied back.
11-261. QUICK REFERENCE CHART. A quick reference chart of unused connector contact cavity requirements is given in Table 11-27. These requirements apply to harness manufacturing or connector replacement only.
TABLE 11-27. CONTACT CAVITY SEALING-QUICK REFERENCE Sealing Means Connector Installation Types Unpressurized Area Firewall Non-Firewall Sealing Plugs or Teflon Sealing Rods No Yes Stub Wires (Note 2) Yes No Spare Contacts Yes Yes NOTE 1: Sealing plugs may be included with the spare connector and may be used for sealing unused contacts. Sealing rods are procured from stock by the foot. (See Table 11-28 for sealing rod dimensions.)
NOTE 2: Stub wires must be of the same type as the other wires of the bundle.
11-262. UNPRESSURIZED AREA CONNECTORS. Connectors may be installed in unpressurized areas of the aircraft. Unused connector contact cavities installed in unpressurized areas should be properly sealed as follows:
a. Firewall Connectors Installations. Firewall unused connector contact cavities should be filled with spare contacts and stub wires. (See Figure 11-39.)
Par 11-262 Page 11-119 FIGURE 11-39. STUB WIRE INSTALLATION (
1) Construct stub wires using high-temperature wire (260 °C). Ensure that stub wires are of the same type of wires in the bundle.
(2) Crimp the proper contact, for the connector and cavity being used, onto the wire.
Install the crimped contact into the unused cavity.
(3) Extend stub wires beyond the back of the connector clamp from 1.5 to 6 inches.
Feather trim stub wires to taper wire bundle.
(4) Secure wire ends with high-temperature (greater than 250 °C) lacing cord. Nylon cable ties are not allowed for this installation.
NOTE: Both connectors mating through the engine fire-seal are considered firewall connectors. Connectors mounted on or near, but not through, the engine fire-seal are not considered firewall connectors.
b. Non-firewall Connector Installations. In this type of installation, all unused connector cavities must also be filled with spare contacts. It is not required, however, to crimp stub wires on filling contacts. Fill unused contact cavities with spare contacts and Teflon sealing plugs or rods. (See Figure 11-40.) Rods shall be cut so that they extend 1/8 to 1/4 inch beyond the surface of the grommet when bottomed against the end of the spare contact. (See Table 11-28 for dimensions.)
Par 11-262 Page 11-120 FIGURE 11-40. SEALING UNUSED CONTACT CAVITIES—UNPRESSURIZED AREAS (CUT-AWAY VIEW) TAB LE 11-28. SEALING ROD DIMENSIONS
CONTACT SIZE (AWG)
DIAMETER (INCHES)
ROD LENGTH (INCHES)
MIN MAX 20 1/16 5/8” 3/4” 16 3/32 7/8” 1” 12 1/8 7/8” 1”
11-263. PRESSURIZED AREAS. Connectors installed in pressurized areas of the aircraft may be divided into two main installation categories, sealed and unsealed.
a. Sealed Connector Installations. Sealed connectors installed in pressurized areas must have their unused contact cavities filled with Teflon sealing plugs or rods. (See Figure 11-40.)
Installation of spare contacts is optional, except for future wiring addition requirements. (See paragraph 11-234). No stub wires are required.
b. Unsealed Connector Installations. It is not required to fill unused contact cavities of unsealed connectors installed in pressurized areas with Teflon sealing plugs or rods. Installation of spare contacts is optional, except for future wiring addition requirements.
(See paragraph 11-234.)
11-264.–11-270. [RESERVED.]
Par 11-271 Page 11-121 SECTION 20. ELECTRICAL AND ELECTRONIC SYMBOLS
11-271. GENERAL. The electrical and electronic symbols shown here are those that are likely to be encountered by the Aviation Maintenance Technician (AMT). They are in accordance with IEEE/ANSI 315-1975.
11-272. SYMBOLS. Only those symbols associated with aircraft electrical and electronic wiring have been listed in general. Refer to IEEE/ANSI 315-1975 for more specific detail on each symbol.
TABLE 11-29. ELECTRONIC/ELECTRICAL SYMBOLS
TABLE 11-29. ELECTRONIC/ELECTRICAL SYMBOLS (CONTINUED) Symbol Meaning Resistor Capacitor YVDE Anterna ЛГ Battery Thermal Element Thermomechanical Transducer Thermocouple Spark Gap Ignitor Cap Continuous Loop Fire Detector (Temperature Sensor) Ignitor Flug Par 11-272 Page 11-122
TABLE 11-29. ELECTRONIC/ELECTRICAL SYMBOLS (CONTINUED) Symbol Meaning www + Transmission Patch Conductor Cable Winng F Distribution Lines Transmission Lines Alternative or Conditioned Wiring Associated or Future Par 11-272 Page 11-123
TABLE 11-29. ELECTRONIC/ELECTRICAL SYMBOLS (CONTINUED) Symbol Meaning Intentional Isclation of Direct-Current Path in Coaxial or Waveguide Applications Waveguide Strip-Type Transmission Line Temination + 0411 Circuit Return Fressure-Tight Bulkhead Cable Gland Cable Sealing End Switching Function
- > • 11L Electrical Contact Par 11-272 Page 11-124
TABLE 11-29. ELECTRONIC/ELECTRICAL SYMBOLS (CONTINUED) Symbol Meaning 7706779 It to for fis fine Basic Contact Assemblies 177- Magnetic Blowout Coil Operating Coil Relay Coil J_
• Switch -.
ale ale Pushbutton, Momentary, or Spring- Retum Par 11-272 Page 11-125
TABLE 11-29. ELECTRONIC/ELECTRICAL SYMBOLS (CONTINUED) Symbol Meaning ojo Two-Circuit, Maintained, or Not Spring- Return Nonlocking Switching, Momentary, or Spring-Retur Locking Switch Combiration Locking and Nonlocking Switch Key-Type Switch Lever Switch Par 11-272 Page 11-126
TABLE 11-29. ELECTRONIC/ELECTRICAL SYMBOLS (CONTINUED) Symbol Meaning 8000 .... 29000 Selector or Multiposition Switch Safety Interlock a te Sensitive Switch Limit Switch 11100 Switches with Time-Delay Feature Flow-Actuated Switch Par 11-272 Page 11-127
TABLE 11-29. ELECTRONIC/ELECTRICAL SYMBOLS (CONTINUED) Symbol Meaning Liquid-Level Actuated Switch Pressure- or Vacuum-Actuated Switch Temperature-Actuated Switch Thermostat Flasher Self-Interrupting Switch Foot-Operated Switch Foot Switch Switch Operated by Shaft Rotation and Responsive to Speed or Direction Chai aIo Switches with Specific Features Par 11-272 Page 11-128