Firstly, you cannot pronounce death in flight. It can only - legally - be done at destination and his place and time of death would be once a suitably qualified medic examined him, probably in the seat once everyone else had left. If there is a qualified doctor on board, who conducts all the correct tests, it would (I think) make no differance to the legal declaration in another country. As to the practical side. When someone is dead - you know! The legal bit is just the legal bit.
Likewise, if you die at home with no one to witness and call for help, and are only found two days later, your death (in the UK) will be listed as the day you are found. It does not matter what the forensics say, that is the legal date of your death as it is the only certainty.
Rigor mortis will set in at different times for each person. It might start very rapidly, it might not. It might last for only an hour or two, or a prolonged period. It might affect the whole body to be rigid or hardly at all. You can never tell and the temperature of the room can also affect it's progress.
However, during a 12 hour sector it would have started and, possibly, have completed.
Sorry if these answers are too detailed but it is one of my fields of knowledge!
Last edited by PAXboy; 23rd July 2012 at 23:11.
Reason: Typographical