LOSS OF ACFT CTL -- WX FACTORS -- AN ACR CRUISING ABOVE THE CLOUDS ENTERS OR COMES NEAR THE TOP OF A TSTM AND GAINS 1000 FT AND HAS GREAT AIRSPD EXCURSIONS; BUT NO INJURIES OR DAMAGE.

Narrative

IN CRUISE AT FL390 IN THIN TOPS WITH HAZY VISIBILITY; ACFT ABRUPTLY ENCOUNTERED MODERATE TURB AND MODERATE PRECIPITATION IN UPDRAFT CONDITIONS. ACFT SPD VARIED FROM OVERSPD TO VLS (STALL PLUS 5 PERCENT). ENGS SPOOLED DOWN; RATE OF CLB PLUS 3600 FPM WITH AIRSPD AT OVERSPD TO FULL PWR WITH RATE OF CLB NEGATIVE 2500 FPM IN MODERATE TURB AND PRECIPITATION LASTING ABOUT 45 SECONDS. DISCONNECTED AUTOPLT; HELD ATTITUDE. ALT EXCURSION TO 40000 FT. EVENT ENDED ABRUPTLY; CALLED ATC AND RETURNED TO FL390. NO ACFT DAMAGE OR PAX INJURIES. 1 FLT ATTENDANT BUMPED HER HEAD; SLIGHT INJURY. FLT RETURNED TO NORMAL TO DEST. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR WAS FLYING AN A320 ACFT ABOVE THE TOPS OF SOME TSTMS AT NIGHT WHEN HE ENCOUNTERED AN UPDRAFT THAT CAUSED THE ACFT TO ACCELERATE AND START TO CLB. HE DISCONNECTED THE AUTOPLT AND FLEW AN ATTITUDE THAT WOULD MAINTAIN A STABLE PLATFORM FOR A RECOVERY FROM THE UPSET. THE ACFT CLBED; DUE TO THE UPDRAFT; TO 40000 FT AND THE AUTOTHROTTLES STARTED TO RETARD TO SLOW THE INDICATED OVERSPD. THE CAPT WAS CONCERNED THAT THE AUTOTHROTTLE COMPUTER WOULD OVERREACT SO HE WATCHED CAREFULLY THAT THE THROTTLES DID NOT GO TO IDLE. THE THROTTLES DID RETARD ABOUT 20 PERCENT BELOW CRUISE SETTING WHICH WAS ACCEPTABLE. DURING THE RECOVERY; THE CAPT GENTLY LOWERED THE NOSE ABOUT 4 DEGS BELOW THE CRUISE ATTITUDE AND RETURNED TO FL390. THE FO WAS AT THAT TIME RPTING THE INCIDENT TO THE ARTCC RADAR CTLR. THE FO WAS VERY HELPFUL DURING THE INCIDENT; READING OFF AIRSPD; ALT AND PWR SETTINGS AND COMMUNICATING WITH CTR. THERE WERE NO INJURIES AND NO DAMAGE AND THE COMPANY AND THE FAA HAD NO FOLLOW UP.