AIC.

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MIL-DTL-27467B

3.2.1 Pure tin. The use of pure tin, as an underplating or final finish, is prohibited both internally and externally.

Tin content of headset components and solder shall not exceed 97 percent. Tin shall be alloyed with a minimum of 3

percent lead (see 6.3).

3.2.2 Recycled, recovered, or environmentally preferable materials. Recycled, recovered, or environmentally

preferable materials should be used to the maximum extent possible, provided that the material meets or exceeds the

operational and maintenance requirements, and promotes economically advantageous life cycle costs.

3.3 Construction.

3.3.1 General design. The headset shall be designed to be inherently stable in mechanical construction (see

figure 1), electrical characteristics, and acoustical performance and shall be suitable for extended military aircraft use.

The detailed mechanical and electrical design of this headset shall be accomplished by the contractor subject to the

requirements of Drawing 7136036 and this specification; these requirements being detailed herein only to the extent

deemed necessary to obtain the desired mechanical and electrical characteristics and performance.

3.3.2 Complete assembly. Headset, Electrical H-154A/AIC shall consist of the following components, assembled

in accordance with Drawing 7136036:

Quantity

Item

Earphone, H-143/AIC in accordance with MIL-PRF-25670/2

2 ea.

Shell, Earphone, in accordance with Drawing 7136037

1 ea.

Cord Assembly, Electrical, Branched CX-4707C/AIC in accordance with

MIL-DTL-22442/33, P/N: M22442/33-4707.

1 ea.

Cord Assembly, Electrical, Branched CX-4708A/AIC in accordance with

MIL-DTL-22442/37, P/N: M22442/37-4708

1 ea.

Installation Kit, Electronic Equipment MK-634/AIC in accordance with

Drawing 7136032

2 ea.

Cushion, Earphone Shell, 7136038-10 in accordance with Drawing

7136038

2 ea.

Pad, Earphone, in accordance with Drawing 7136039

3.4 Cord assemblies. Cord assemblies are In accordance with MIL-DTL-22442 specification sheets referenced.

3.5 Performance characteristics.

3.5.1 Electrical.

3.5.1.1 Circuitry. The two earphones shall be connected in parallel, see figure 2 for schematic diagram.

3.5.1.2 DC resistance of the headset circuit. The dc resistance of the headset circuit shall be between 8.5 and

11.5 ohms inclusive (see 4.5.2).

3.5.1.3 DC resistance of microphone circuit. The dc resistance of the microphone circuit shall not exceed the total

allowable resistance of the conductors in the circuit (microphone not included in assembly) (see 4.5.3).

3.5.2 Acoustical.

3.5.2.1 Acoustic distortion. There shall be no buzzes, rattles, or voice distortion when the headset is operated as

specified herein (see 4.5.4).

3.5.2.2 Functional operation. The headset shall perform satisfactorily when used with Intercommunication Sets

AN/AIC-10( ) or AN/AIC-18 and when subjected to the functional operation test specified herein (see 4.5.5).