The ornamental design for an aircraftbulkhead, as shown and described.
FIG. 1 is a front perspective view of an aircraft bulkhead showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a bottom view thereof; and,
FIG. 5 is a top view thereof, the first and second side views forming no part of the claimed design.
The even length broken lines illustrate structure and environment that forms no part of the claimed design. The single long dash and single dot broken lines illustrate boundaries of the claimed design that form no part thereof.