MLG UNABLE TO EXTEND L MAIN LNDG GEAR. MAKES EMER LNDG.

Narrative

ON FINAL APCH TO ORD; UPON PUTTING THE GEAR DOWN ON THE B-737-100; WE HAD 2 GREEN LIGHTS AND A RED UNSAFE LIGHT ON THE L MAIN LNDG GEAR. A COUPLE OF QUICK CHKS WERE UNSUCCESSFUL AND A GAR WAS INITIATED. WE RECEIVED VECTOR OUT OVER LAKE MICHIGAN WHERE WE RECYCLED THE GEAR NUMEROUS TIMES. WE WENT THROUGH THE MANUAL GEAR EXTENSION PROC; AND A CHK OF THE VIEWING PORT IN THE MAIN CABIN REVEALED THAT THE L MAIN GEAR WAS JAMMED ONLY 3 FT OUT OF THE WHEEL WELL. A FEW MORE ATTEMPTS TO RECYCLE THE GEAR WERE MADE AND ALSO ATTEMPTS TO SHAKE IT DOWN WERE MADE. AT THIS POINT; WE WERE DOWN TO ABOUT 35 MINS FUEL ON BOARD AND IT WAS TIME TO PREPARE FOR THE PARTIAL GEAR UP LNDG. THE EMER HAD BEEN DECLARED EARLIER WHEN IT WAS DISCOVERED THAT THE L MAIN GEAR WAS HUNG UP. WE WENT THROUGH ALL ABNORMAL AND EMER CHKLISTS AND THE CABIN WAS PREPARED. THE LNDG WAS SMOOTH AND SHUTDOWN OF THE #1 ENG WAS ACCOMPLISHED JUST PRIOR TO ENG CONTACT WITH THE RWY. WE STOPPED THE ACFT ON THE CTRLINE OF RWY 32L. NO FIRE WAS NOTED AND THE FIRE CHIEF INFORMED US OF A SMALL AMOUNT OF WHAT APPEARED TO BE ENG OIL COMING FROM ENG #1. THE PAX WERE TAKEN OFF THE ACFT VIA STAIRS AND LOADED ONTO BUSSES AND TAKEN TO THE TERMINAL. NO INJURIES TO PAS OR CREW; AND MINOR COWL DAMAGE ONLY TO THE #1 ENG. SO ACFT DAMAGE WAS MINOR. SUPPLEMENTAL INFO FROM ACN 263553: WHILE MAINT WAS IN CTL OF A 737-100; WHEEL CHOCKS WERE INADVERTENTLY PLACED IN THE L WHEEL WELL AND WERE NOT REMOVED PRIOR TO THE NEXT FLT. THIS CAUSED THE LNDG GEAR ON THE L SIDE TO BECOME JAMMED IN THE RETRACTED POS. THE L MAIN LNDG GEAR WOULD NOT EXTEND AND CAUSED ACFT TO MAKE A 2 POINT LNDG.