What happened
The flight crew completed taxi and pre-departure checklists for a departure on runway 04. During the procedure, the crew entered V-speeds into the Flight Management System (FMS), including a V1 of 139 knots and a Vr of approximately 143 knots. The captain also programmed a V2 speed of 143 knots and an extended speed of 250 knots for 10,000 feet.
During the takeoff roll, the first officer checked the engine diagnostic page to monitor vibrations on the #2 engine. Upon returning his attention to the Primary Flight Display (PFD), the first officer observed that the V-speeds were no longer displayed and the V2 speed had reset to 100 knots. Although the raw speed data on the left side of the PFD remained correct, the visual indicators had changed.
The first officer called for rotation at V1, and the captain responded with an aircraft pitch of approximately 12 degrees. However, the captain soon realized the Boeing 777 (implied by weight/systems) was not climbing or accelerating as expected. The first officer noted the airspeed was only between 120 and 125 knots, which was below V2, and instructed the captain to lower the nose.
The captain executed a rejected takeoff by pulling the throttles to idle. During this sequence, the aircraft experienced a tail strike, though neither crewmember recalled the aft end of the airplane striking the runway. The flight control computer applied maximum autobrakes, and the aircraft slowed before taxiing off the runway. There were no injuries and no fatalities.
The investigation
Data from the Digital Flight Data Recorder (DFDR) showed that the aircraft became airborne for approximately 4 seconds. During the roll, the pitch reached 13.4 degrees with the elevator at 16.6 degrees trailing edge up. When the main landing gear touched down, the pitch decreased to approximately 6 degrees, and the aircraft experienced a vertical acceleration of 1.844 g's. The airspeed was recorded at 114 knots when the nose gear left the ground, eventually reaching 138 knots after the nose gear touchdown.
Testing of the Flight Control Computer, Flight Management Computer, Flight Warning Computer, ECAM, Flight Augmentation Computer, and Signal Generator Unit revealed no faults. Physical examination of the aircraft found no anomalies that would have prevented normal operation prior to the tail strike.