FLC OF AN MDT ACR ACFT RETURNED TO LAND AFTER THE NOSEWHEEL WOULD NOT RETRACT AFTER TKOF DUE TO THE NOSE GEAR SCISSOR PIN NOT REINSTALLED AFTER PUSHBACK.

Narrative

ABOUT 30 MINS BEFORE FLT TIME I RETURNED TO THE ACFT AND DID A COMPLETE PREFLT WALKAROUND. WHILE THE CAPT AND I WORKED IN THE COCKPIT; THE LAVATORY AND FUEL TRUCKS BEGAN TO SVC THE ACFT. WHILE SVCING THE LAVATORY; THE HOSE; WHICH WAS NOT PROPERLY ATTACHED TO THE ACFT; CAME LOOSE. GALLONS OF WASTE POURED OUT ONTO THE RAMP. WHEN THE FUELER WAS DONE I WENT OUTSIDE THE ACFT TO VERIFY THE FUEL AND LAVATORY DOORS WERE SHUT PER COMPANY PROC. THE SPILLED WASTE HAD BEGUN TO SPREAD UNDER THE ACFT NEAR THE BOARDING STAIRS. CAPT DECIDED THAT IT WAS NOT ACCEPTABLE CONDITIONS FOR BOARDING PAX AND NOTIFIED OPS. OPS INFORMED US THAT THEY WERE WORKING ON THE PROB. WHILE WAITING FOR AN ANSWER; WE COMPLETED ALL REMAINING CHKLIST ITEMS. THE FLC WAS STRAPPED IN WAITING FOR A DECISION WHEN A TOWING CREW SHOWED UP; HOOKED ONTO THE NOSE GEAR AND PUSHED THE ACFT BACK ABOUT 10 YARDS. AT NO TIME DURING THE PROCESS DID ANY RAMP AGENT COME ON BOARD TO INFORM THE CREW OF THEIR INTENTIONS. THEY ALSO DID NOT; PER COMPANY PROCS; INSTALL THE MAIN GEAR GND LOCK PINS AS THEY WERE ALWAYS IN THEIR COCKPIT STORAGE POUCH. IMMEDIATELY UPON UNHOOKING THE TUG; THE PAX BEGAN TO BOARD. A NORMAL ENG START; TAXI AND TKOF FOLLOWED. WHEN THE GEAR WAS SELECTED UP; THE MAIN GEAR RETRACTED BUT THE NOSE GEAR DID NOT. THE GND CREW HAD PULLED THE NOSE GEAR GND LOCK AND DID NOT TELL US. WE RETURNED FOR A NORMAL LNDG AND AT THE GATE; MECHS STOWED THE GND LOCK AND WE PROCEEDED TO OUR DEST WITHOUT ANY FURTHER PROBS