The BA 747-400 Tech Manual states: "If both Body Gear are not extended, the aircraft may tip tail down on the ground. Door 1 escape slides are then unusable". At my annual Safety Equipment Procedures Test this week, I specifically queried this point and was assured the Upper Deck slides would still be usable. The practice computer exam also confirms this.
I wonder if there are options when you order the equipment for a 747 as to the standard of the sliderafts? Like on the order form:
Car Stereo....Yes/No
IFE Crew bunks.....Yes/No
Extended U/D Door Slide......Yes/No
etc!