Any person subject to this Act who is guilty of any act or neglect in flying or in the use of any aircraft belonging to or in the service of the Coast Guard, or in relation to any such aircraft or aircraft material, which causes or is likely to cause loss of life or bodily injury to any person shall, on conviction by a Coast Guard Court,--
         (a) if he acts wilfully or with wilful neglect, be liable to suffer imprisonment for a term which may extend to seven years or such less punishment as is in this Act mentioned; and
         (b) in any other case, be liable to suffer imprisonment for a term which may extend to two years or such less punishment as is in this Act mentioned.