GlueBall, was it a feeling?
It is interesting to note the points raised by the FO. From the report:
At around 140 knots the pilot flying observed a speed trend vector in the negative direction.
Did he effectively communicate that info to the Captain?
That information may remain in house at the company.
The goal of the investigation was to answer the investigative questions as desribed in chapter 1 paragraph 1.2.2 with the facts that are available. The takeoff roll was described using the available information from the flight data recorder and the statements made by the crew during interviews. Because the Cockpit Voice Recorder was not available there was no factual evidence available that would allow the assessment of the cockpit crew co-ordination. To asses the cockpit crew co-ordination based on statements alone is insufficient.
The captain stated that at the same time he observed a large trend vector in the positive direction.
The captain did not find this discrepancy an issue and made no comments about this. As the airspeed reached V1, the ‘V1‘and ‘VR’ calls were made and the captain removed his hand from the thrust levers.
According to the first officer when the aircraft reached the V
1 speed the control column was moving aft without the application of force. The first officer stated that he experienced back pressure from the column and the aircraft rotated on its own.
At this time he had the feeling that the aircraft was unsafe to fly and pulled back the thrust levers. {My thought: Is this a case of "what's it doing now?" leading to a decision?}
The auto brake system and speed brakes were automatically activated and a rejected takeoff was initiated.
Also interesting ...
The pilots informed maintenance that there was a airspeed indication problem. Therefore troubleshooting and maintenance actions focused on finding the cause of the unreliable airspeed.
First, an inspection for unreliable airspeed without disturbing the aircraft systems and components was carried out. The result of this test was an airspeed indication disagreement between the left and right side.
Next the unreliable airspeed procedure was carried out according to the steps described in the Fault Isolation Manual. To fulfil the requirements and complete the unreliable airspeed test the
right hand angle of attack sensor (alpha vane) required adjustment. The result of the test wassatisfactory and no airspeed disagreement between the left and ride side was found.
Pages 18 through 20 were the most interesting part of the report, to me.