Avtrician,
Speed does have an effect on the altimeter if the plane flies outside the calibration envelope. These issues have already been covered. The plane was nearly level at the end so radalt would not have been upset by angles. The True altitude was calculated from the recorded pressure using the known baro and temp on that day. Radalt plus ground elevation should therefore have been the same as True altitude. They were the same while the plane was travelling at 310 knots at 2500 feet, as expected. They were not the same after the plane descended and picked up speed, therefore one can deduce that the plane was flying outside the calibration envelope for the altimeter. What I am hoping for is documentary evidence that the plane was flying outside its calibration envelope, and for that I need the Boeing calibration graph. Can anyone provide a copy?