FAA Federal Aviation Regulations (FARS, 14 CFR)

(a) General requirements. Each aircraft operator shall use the procedures, facilities, and equipment described in its security program to prevent or deter the carriage of unauthorized explosives or incendiaries on board aircraft in checked baggage.

(b) Acceptance. Each aircraft operator shall ensure that checked baggage carried in the aircraft is received by its authorized aircraft operator representative.

(c) Control. Each aircraft operator shall use the procedures in its security program to control checked baggage that it accepts for transport on an aircraft, in a manner that:

(1) Prevents the unauthorized carriage of any explosive or incendiary aboard the aircraft.

(2) Prevents access by persons other than an aircraft operator employee or its agent.

(d) Refusal to transport. Each aircraft operator shall refuse to transport any person's checked baggage or property if the person does not consent to a search or inspection of that checked baggage or property in accordance with paragraph (a) of this section.

(e) Firearms in checked baggage. No aircraft operator may knowingly permit any person to transport, nor may a person transport or offer for transport in checked baggage:

(1) Any loaded firearm(s);

(2) Any unloaded firearm(s) unless --

(i) The passenger declares to the aircraft operator, either orally or in writing before checking the baggage that any firearm carried in the baggage is unloaded;

(ii) The firearm is carried in a hard-sided container;

(iii) The container in which it is carried is locked, and only the person checking the baggage retains the key or combination; and

(iv) The baggage containing the firearm is carried in an area, other than the flightcrew compartment, that is inaccessible to passengers;

(3) Any unauthorized explosive or incendiary.

(f) Loaded firearm. For the purpose of this section, a loaded firearm means a firearm, which has a live round of ammunition, or any component thereof, in the chamber or cylinder or in a magazine inserted in the firearm.

(g) Ammunition. This section does not prohibit the carriage of ammunition in checked baggage or in the same container as a firearm. Title 49 CFR part 175 provides additional requirements governing carriage of ammunition on aircraft.