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 top view thereof;
FIG. 4 is a bottom view thereof; and,
FIG. 5 is a back view thereof, the first and second side views forming no part of the claimed design.
The even length broken lines illustrate structures and environment that form no part of the claimed design. The long dash and single short dash broken lines illustrate boundaries of the claimed design that form no part thereof.