MILITARY STANDARD
SHIPBOARD GUIDED MISSILE LAUNCHING
SAFETY REQUIREMENTS, MINIMUM
MIL-STD-1658(OS)
NOTICE 2
1 March 1978
SYSTEM
TO ALL HOLDERS OF MIL-STD-1658(OS):
1. Add new paragraphs to the following pages:
Page 3, add
3.11 Firing Circuit.
All circuits Used to control and
sequence functions required to ignite the rocket motor.
3.12 Ignition Circuit. The electrical circuit, from the
ignition power source, used t
O
provide energy for igniting the rocket
motor.
Page 5, paragraph 5.14 to 5.14.6, delete and substitute:
5.14 Firing Circuit. An inadvertent firing shall not be
possible without the occurrence of at least two independent failures
when there is power available to the ignition circuit, and at least
three independent failures when no power is applied to the ignition
circuit.
5.14.1 The ignition circuit to the missile shall be interrupted
until firing is imminent. Both the "hot" side and return side of the
ignition circuit shall be interrupted. Interlocks shall be provided
in the firing circuit to insure proper missile/launching system prelaunch
conditions are satisfied before ignition is allowed.
5.14.2 Prior to completion of the ignition circuit the portion
of the ignition circuit nearest to the missile shall be electrically
interrupted by an electro-mechanical device such as open relay or switch
5.14.3 The ignition circuit hot and return sides shall be
isolated from ground except that for missile rounds employing grounded
bridge squib circuits, a firing transformer having isolated primary and
secondary wiring may be used with one side of the secondary wiring grounded.
5.14.4 The ignition circuit wiring shall be isolated from other
wiring and cables in the system in accordance with OD 30393. This may
be accomplished by shielding or by the physical separation of the wiring.
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