The following definitions apply throughout this subpart.

IIC means the NTSB investigator-in-charge.

Investigative activity means an activity performed by or under the direction of the NTSB during a casualty investigation led by the USCG.

Major marine casualty is defined in joint regulations of the NTSB and USCG at 49 CFR 850.5(e) and 46 CFR 4.40-5(d), respectively.

Marine casualty means—

(1) Any casualty, accident or event described in 46 CFR 4.03-1

(2) An occurrence that results in an abandonment of a vessel

(3) Other marine occurrences that the NTSB or USCG, or both, determine require investigation.