On June 4, 2014, the U.S. Federal Aviation Administration (FAA) published a notice of availability for the legal interpretation issued on April 29, 2014 (“April 2014 Legal Interpretation”),clarifying the qualification requirements for pilots assigned as second in command (SIC) on flight operations that require three or more pilots and the pilot who relieves the assigned SIC during the cruise portion of the flight.
The April 2014 Legal Interpretation reaffirms a prior interpretation of 14 CFR § 121.432(a), known as Legal Interpretation 1978–27, which requires pilots who serve as SIC on flight operations that require three or more pilots to meet all pilot in command (PIC) qualifications except the requirement for PIC operating experience. The April 2014 Legal Interpretation also clarifies that the pilot relieving the assigned SIC during the cruise portion of the flight does not need to meet the additional SIC qualification requirements.
The April 2014 Legal Interpretation was provided in response to an internal request made by the Flight Standards Service - Eastern Region (AEA-200) to the Flight Standards Service – Air Transportation Division (AFS-200) to clarify the requirements of 14 CFR § 121.432(a) and14 CFR § 121.543(b)(3)(ii). Some operators had been relying on the requirements specified in § 121.543 rather than the requirements specified in § l21.432(a) for the qualification of SIC pilots. The FAA ultimately decided that § 121.543(b)(3)(ii) may not be used as a substitute for the qualification requirements in §121.432(a).
The FAA notice of availability can be found here.