Abstract: Illuminating flare has an igniter in which a two-part inertial mass is gud for relative aftward movement from a safe position to an armed position under launching forces. One part of the mass undergoes relative forward movement to an ignition position under parachute-opening, deceleration forces while the other part of the mass is restrained from moving as far forward as the first part. This separation of the parts of the mass releases locking balls to unlock a firing pin, which stabs a primer and initiates ignition of the flare. The primer is contained in a rotor, and as the mass traverses from the safe position to the armed position it rotates and the rotor rotates with the mass. In the safe position the primer is out of communication with an ignition passage through which ignition of the illuminant composition occurs. Rotation of the rotor as the mass traverses to the armed position places the primer in communication with the ignition passage where it remains until activated by the firing pin.