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-
49 C.F.R. §831.51