14 CFR § 121.436

No certificate holder may use nor may any pilot act as pilot in command of an aircraft (or as second in command of an aircraft in a flag or supplemental operation that requires three or more pilots) unless the pilot:

Holds an airline transport pilot certificate not subject to the limitations in § 61.167 of this chapter;

Holds an appropriate aircraft type rating for the aircraft being flown; and

If serving as pilot in command in part 121 operations, has 1,000 hours as:

Second in command in operations under this part;

Pilot in command in operations under § 91.1053(a)(2)(i) of this chapter;

Pilot in command in operations under § 135.243(a)(1) of this chapter;

Pilot in command in eligible on-demand operations that require the pilot to satisfy § 135.4(a)(2)(ii)(A) of this chapter; or

Any combination thereof.

No certificate holder may use nor may any pilot act as second in command unless the pilot holds an airline transport pilot certificate and an appropriate aircraft type rating for the aircraft being flown. A second-in-command type rating obtained under § 61.55 does not satisfy the requirements of this section.

For the purpose of satisfying the flight hour requirement in paragraph (a)(3) of this section, a pilot may credit 500 hours of military flight time provided the flight time was obtained—

As pilot in command in a multiengine, turbine-powered, fixed-wing airplane or powered-lift aircraft, or any combination thereof; and

In an operation requiring more than one pilot.

For the purpose of satisfying the flight hour requirement in paragraph (a)(3) of this section, a pilot may credit flight time obtained as pilot in command in operations under this part prior to July 31, 2013.

For those pilots who were employed as pilot in command in part 121 operations on July 31, 2013, compliance with the requirements of paragraph (a)(3) of this section is not required.