B747 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Communication Breakdown
Deviation / Discrepancy - Procedural Hazardous Material Violation; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
Flight Crew Overcame Equipment Problem; General Maintenance Action
Human Factors
I was occupying the first observer seat for this flight. I was reviewing the material in the briefing package and while I was reading the DOT-SP XXXX; I saw a note saying that only the required crew and essential personnel for this mission was allowed to be on board because we were carrying class one explosives. The Captain communicated with crew support and was told that the 2 pilots deadheading were ok to be on board. The Captain obtained time and initials from a chief pilot to 'authorize' the 2 deadheaders to remain on board. We then took off and flew to ZZZZ without any other issues. With the information available to us now; deadheaders are not allowed to be on board the aircraft when Class 1 explosives are on the airplane.
B747 First Officer reported Chief Pilot authorized two deadheading crewmembers on flight that allows only required crew due to Class 1 explosives on board.