What was found
FLT 126 - EN ROUTE PHL-LGW, FL390, CRUISING AT 1.38 EPR, BOTH ENGINES INCREASED TO 1.61 EPR, THEN DOWN TO .95, THEN BACK TO 1.41. THIS FLUCTUATION OCCURRED OVER A TIME SPAR OF ABOUT A MINUTE AN A HALF. FLIGHT CONTINUED ON TO DESTINATION AND LANDED WITHOUT FURTHER INCIDENT. DATA FROM THE FDR INDICATES THAT THE EPR WAS COMPENSATING FOR A FLUCTUATION IN AIRSPEED INFORMATION BEING PROVIDED. MAINTENANCE REPLACED THE NR 1 AIR DATA MODULE. (M)