(b)
Any person subject to this chapter who, without an intent to kill or inflict great bodily harm, unlawfully kills a human being—
(1)
by culpable negligence; or
(2)
while perpetrating or attempting to perpetrate an offense, other than those named in clause (4) of section
918 of this title (article 118), directly affecting the person;
is guilty of involuntary manslaughter and shall be punished as a court-martial may direct.