WX ENCOUNTER; NAV DEV APCH RADAR TURNED ON. PAX INJURIES CAUSED BY SEVERE TURB DURING HIGH ALT CRUISE IN A MLG.

Narrative

APPROX 20 NM W OF MUNDO (MIA-MEX) ENCOUNTERED OCCASIONAL LIGHT TURB AND SEAT BELT SIGN WAS TURNED ON AND AN ANNOUNCEMENT MADE. SLIGHT HAZE LAYER WAS ENCOUNTERED AT THIS TIME. ATC WAS CONTACTED FOR RIDE RPTS AT FL350 BUT WAS PUT ON STAND-BY. AN (ACR Y) FLT BEHIND US WAS CONTACTED WHO HAD DSNDED FROM FL350 TO FL310 BECAUSE OF CONTINUOUS CHOP AT FL350. ABOUT 20 NM W OF MUNDO THE TURB INCREASED FROM LIGHT TO MODERATE TO SEVERE. WE ENCOUNTERED SOME RAIN AND PROBABLY SOME HAIL; SOME LIGHTNING WAS PRESENT IN THE AREA BUT NO STRIKES WERE NOTICED. THE RADAR WAS TURNED ON IMMEDIATELY PRIOR TO THE TURB AND A STEEP GRADIENT OVAL CELL WAS RIGHT IN FRONT OF US ALMOST DEAD CTR! THE AUTOPLT KICKED OFF AND THE ACFT WAS HAND FLOWN BY MYSELF AND A L TURN STARTED TO BREAK OUT ON THE L SIDE. AN ATTEMPT TO CONTACT ATC WAS MADE TO NO AVAIL. AN ALT LOSS OF APPROX 500 FT WAS NOTICED. THE DURATION OF THIS WAS ONLY 15-25 SECONDS. PIREP ISSUED; DISPATCH NOTIFIED AND ATC NOTIFIED. WE WERE ADVISED 3 PAX WERE INJURED -- 2 HAD RELEASED THEIR SEAT BELTS AND 1 HAD IT ON LOOSE. ALL 3 EXAMINED UPON LNDG AND RELEASED; WALKED OFF THE AIRPLANE. NO FLT CREW WERE INJURED AND AN UNEVENTFUL APCH TO LNDG WAS MADE AT MEXICO CITY.