Page:CAB Accident Report, Eastern Air Lines Flight 21.pdf/21

 However, in this event, the altimeters would probably register the static pressure prevailing in the cockpit which would result in an error which would not be sufficient to account for the accident as it happened. The possibility of any other kind of mechanical or structural defect being present in both altimeters, which would result in both of them being erroneous to the same extent (i.e., indicating an altitude about 800 feet higher than the actual altitude) would be a coincidence so extraordinary as to be highly improbable. However, we have no evidence upon which to exclude definitely the possibility of the malfunctioning of the one altimeter which was supposed to have been set at airport barometric pressure and upon which presumably reliance was being place in the conduct of the instrument approach.

The only other probable explanation is that the altimeter by which operations were being conducted was not correctly set to airport barometric pressure during the conduct of the instrument approach. The record indictes that no error was made in transmitting the setting from the ground station for the radio log of the Eastern radio station at Atlanta and the testimony of the operator on duty indicate that the correct barometric setting was given to Trip 21 about the time it was over Stone Mountain. This is substantiated by the testimony of Eastern's dispatcher in charge of the flight who stated that he heard the correct setting broadcast to Trip 21 and on his own initiative verified the setting transmitted. In reply to this message the setting was acknowledged correctly by either Captain Perry or Pilot Thomas.

However, it is not known whether any adjustment was made in the setting of either altimeter after receipt of this message and there remains