ACR LGT SUFFERS TAIL STRIKE DURING LNDG PROC. TAIL STRIKE ALSO OCCURS ALONG WITH PAX CAB INJURIES.

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AT ORD; HAD MAINT CHK BOTH MAIN STRUT EXTENSIONS (APPARENTLY QUITE LOW). TKOF RWY 4L AT ORD (RWY SEEMED ROUGH -- LOW STRUTS?). AT YYZ CLRED FOR APCH; INTERCEPT GS AT 4000 FT; 180 KTS TO MARKER. APPROX 1000 FT CLRED TO LAND (ACFT ON RWY STARTED TKOF ROLL). COMPLETED CHKLIST. 500-200 FT IN SLOT 600 FT SINK. 200 FT CALL. 50-40-30-20 CALLOUTS (FO) DON'T REMEMBER HEARING 10 FT. FLARED APPROX 30 FT. PULLED PWR OFF APPROX 10 FT. HARD LNDG; NO BOUNCE. ROLLOUT: NOTIFIED OF SPARKS BY TWR (TAIL STRIKE). TXWY: FLT ATTENDANT CALLED (3 FLT ATTENDANTS INJURED; 1 BACK; 1 NECK). FO CALLED COMPANY TO HAVE MEDICAL ASSISTANCE STANDING BY. NO PAX RPTS OF INJURIES UNTIL AT GATE. POSSIBLE CONTRIBUTING FACTORS: STRUTS NOT PROPERLY SVCED (REDUCING DECK ANGLE REQUIRED TO HAVE TAIL STRIKE WITH HARD LNDG). 'BLACK HOLE' RWY (EDGE LIGHTS DIM; NO CTRLINE LIGHTS). ACFT WEIGHED MORE THAN ONBOARD FMC COMPUTER CALCULATED; GIVING LOWER REF SPD; HIGHER DECK ANGLE. CONDITIONED TO LAND AT SHORT AND OR HIGH AIR FIELDS; IE; SNA; EGE; JAC. PROC AT 30 FT IS TO SET LNDG ATTITUDE (FLARE); SLOW SINK AND THEN REDUCE THROTTLES TO IDLE BY TOUCHDOWN (TO AVOID RWY FLOAT). WAKE TURB FROM DEPARTING ACFT (BELIEVED TO BE MLG); WINDS LIGHT TO NIL. SUPPLEMENTAL INFO FROM ACN 233510: AT APPROX 10 FT (OR LESS); PF SHARPLY REDUCED THROTTLES AND THE ACFT LANDED HARD WITH TAIL STRIKE. PNF LOST HEADSET ON IMPACT. CAPT WITH TWR ABOUT SPARKS. AT GATE; 2 PAX RPTED INJURIES. PROCS AND TECHNIQUES UP TO THE IMPACT WERE NOT OUT OF THE ORDINARY. THOUGHTS ON FACTORS: GET DOWN TO INITIAL APCH ALT MORE QUICKLY TO STABILIZE THE APCH. ALTHOUGH HIGH AND FAST AT THE MARKER; I NEVER FELT UNCOMFORTABLE. HAVE THE RWY LIGHTS TURNED TO A HIGHER INTENSITY. RWY HAD NO CTRLINE LIGHTS. THE IDENTIFIERS DIM! NOSE ATTITUDE MIGHT HAVE BEEN HIGH. LNDG STRUTS COULD HAVE BEEN SVCED. POSSIBLE WT DISCREPANCY (SPECULATION).