A-A-52421 Accessory Kit; Warning Device, Demountable, For Emergency VehiclesThis CID covers a 14 volt and 28 volt demountable warning device consisting of a support bar and brackets for rain gutter mounting and gutterless mounting of two rotating warning lights, speaker, electrical harness, electronic siren and public address (P/A) system with microphone for use on security and other emergency vehicles having 12 or 24 volt electrical systems. The accessory kit and its associated hardware is referred to herein as "warning kit".

Pages 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11

A-A-52421A(AT)

a. Wail - The tone range shall be accomplished in a steady rise and fall in 5 to 7 seconds and repeated indefinitely.

b. Yelp - The tone range shall be accomplished in a steady rise and fall in 0.25 to 0.40 seconds and repeated indefinitely.

2.2.4.3 Public address system. Audio frequency response of the public address system shall be flat within ±3 db from 250 to 4000 Hz at rated power.

2.2.5 Harness. The harness shall be as shown in figure 3. A harness connector shall be included to mate with the amplifier connector of figure 2 (see 2.2.4). The power input wire shall conform to SAE J1128 and shall be a minimum of 108 inches long. The ground wire shall conform to SAE J1127 and shall be a minimum of 22 inches long. The cable shall be 0.295 inches outside diameter, jacketed and flexible, with four number 20 AWG shielded conductors. The cable shall be medium duty, 600 volt maximum, oil resistant and heat resistant with low temperature capability.

2.3 Performance.

2.3.1 Rotating warning lights. Rotating warning lights shall meet the performance requirements of A-A-52418.

2.3.2 Electronic siren and public address system. The sound intensity of all siren modes of the system shall be a minimum of 115 decibels at six feet from the speaker on the speaker axis when tested in an anechoic chamber in accordance with ANSI S1.4, ANSI S12.1, ANSI/ASA-S12.51/ISO-3741and ANSI S1.13.

2.3.3 Warning kit. All system functions shall operate with both a 14 volt and a 28 volt power source. All system functions shall operate satisfactorily without interruption during extension of the mounting bar from minimum length to maximum length, and then during contraction from maximum length to minimum length.

2.3.4 Environmental.

2.3.4.1 Vibration. The warning kit excluding the electronic siren and public address system shall be subjected to a simple harmonic motion having an amplitude of 0.03 inch (0.06 inch maximum total excursion), the frequency being varied uniformly between the approximate limits of 10 and 30 Hz. The entire frequency range, from 10 to 30 Hz and return to 10 Hz, shall be traversed in approximately 1 minute. This motion shall be applied for a period of 1 hour in each of three mutually perpendicular directions (total of 3 hours). After the vibration test, the warning kit shall meet the performance of 2.3.3 and shall evidence no permanently deformed, cracked, or broken parts.

2.3.4.2 Extreme temperature. The warning kit shall commence operation within 60 seconds from the time the function of the warning kit is energized after soaking for six hours at both -50±5 °F and 140±5 °F.