LGT HAS 'L HYD QTY' MESSAGE ON EICAS. ON LNDG; NO GREEN ON L MAIN. GAR; DECLARE EMER LAND.

Narrative

I WAS SERVING AS THE PNF FO ON A FLT FROM LAX-PIT. TKOF AND DEP WERE UNEVENTFUL. AT APPROX FL300 WE RECEIVED AN EICAS MESSAGE 'L HYD QTY.' ALL APPROPRIATE ABNORMAL CHKLISTS WERE PERFORMED. UPON ARR IN THE PIT TERMINAL AREA; PIT APCH INFORMED US THEY WERE AWARE OF OUR SIT (VIA COMPANY) AND ASKED; DO WE NEED ANY SPECIAL ASSISTANCE. WE ADVISED THEM WE WOULD NEED EXTRA TIME ON THE APCH FOR OUR ALTERNATE FLAP AND GEAR PROCS AND A POSSIBLE TOW CLR OF THE RWY (28L PIT). AT THAT POINT THE FLT ATTENDANTS WERE AWARE OF OUR SIT. NO EMER HAD BEEN DECLARED. DURING THE ALTERNATE GEAR EXTENSION PROC; THERE WAS NO GREEN LIGHT INDICATION ON THE L MAIN GEAR. A GEAR DOOR LIGHT AND GEAR DISAGREE EICAS MESSAGE APPEARED. WE EXECUTED A MISSED APCH; ENTERED THE HOLDING PATTERN; PERFORMED ALL APPROPRIATE ABNORMAL CHKLISTS; DECLARED AN EMER AND CONTACTED THE COMPANY VIA RADIO. THE CAPT APPLIED A POSITIVE 'G' LOAD WHICH RESOLVED THE GEAR DISAGREEMENT. WE THEN PROCEEDED TO THE ARPT; MADE A TOUCH AND GO LNDG TO HELP LOCK THE L GEAR DOWN. THE CRASH FIRE RESCUE PERSONNEL RPTED THAT THE GEAR APPEARED TO BE DOWN. WE FINISHED BRIEFING THE FLT ATTENDANTS AND THEY BRIEFED THE PAX. THE CAPT MADE A LNDG HOLDING THE L MAIN OFF AS LONG AS POSSIBLE. AFTER ROLLOUT AND STOPPING; THE ACFT HAD TO BE TOWED TO THE GATE.