SMT HAS GEAR MALFUNCTION; MUST LAND GEAR PARTIALLY EXTENDED.

Narrative

DURING LCL FLT IN THE FDK AREA; I NOTICED THAT THE GEAR UP INDICATOR ON THE SMT HAD GONE OUT. I PLACED THE GEAR LEVER IN THE UP POS. THE LIGHT DID NOT GO ON AND THE HANDLE DID NOT RETURN TO NEUTRAL POS AS NORMAL. THIS WAS THE FIRST INDICATION OF A GEAR MALFUNCTION. I PROCEEDED TOWARDS THE FDK ARPT. THIS ACFT IS EQUIPPED WITH AN ELECTRIC HYD BACKUP PUMP. I THEN TRIED TO EXTEND THE GEAR WITH THE ELECTRIC PUMP SYS. THE GEAR DID NOT COME DOWN. THIS SO FAR WOULD INDICATE A LOSS OF HYD FLUID. I THEN TRIED THE HAND PUMP. THE RESISTANCE ON THE HAND PUMP DID NOT FEEL NORMAL. IT FELT 'SPONGY'... LIKE AIR IN THE SYS? I WENT THROUGH THE PRECEDING STEPS A SECOND TIME. THE SAME RESULTS OCCURRED. I HAD ONE LAST BACK-UP SYS LEFT TO USE... CO2. THEN I CONTACTED MY OFFICE FOR ANY OTHER OPINIONS BEFORE USING THE CO2. A CHASE PLANE OBSERVED THE UNDERCARRIAGE IN THE UP POS. THEN I DECIDED TO USE THE CO2 AND OBSERVED THE NOSE GEAR STARTING TO EXTEND. IT EXTENDED ONLY HALFWAY. NO OTHER GEAR WERE OBSERVED BY THE CHASE PLANE. THE CHASE PLANE RETURNED TO FDK. I CALL THE OFFICE TO INFORM THEM THAT I WAS GOING TO HAVE TO LAND THE ACFT 'GEAR UP.' I ALSO ASKED THEM TO CALL HGR AND IAD TO DETERMINE THE BEST PLACE TO LAND GEAR UP. THEY ADVISED ME TO LAND IAD. I HAD MY OFFICE SEND ANOTHER ACFT TO FOLLOW ME TO IAD. I HAD HIM OBSERVE MY UNDERCARRIAGE AND RPT THAT THE L GEAR WAS SOMEWHAT EXTENDED...THE NOSE GEAR HAD RETRACTED SOMEWHAT. I CALLED IAD AND DECLARED AN EMER. THEY GAVE ME PRIORITY LNDG ON 1R. I CARRIED 110 MPH ON 1/4 MI FINAL AT 1000 AGL. THROTTLES WENT TO IDLE; PROP TO FEATHER; MIXTURE-IDLE-CUTOFF. TURNED ALL ELECTRICAL OFF EXCEPT MASTER. I BUMPED THE STARTERS ON BOTH ENGS TO MAKE PROPS HORIZONTAL; THEN MASTER OFF. I LANDED THE ACFT SMOOTHLY ON THE RWY WITH NO LOSS OF CTL. THE ACFT CAME TO A STOP AND WE EVACUATED THE ACFT. AT THIS TIME; I BELIEVE THERE MUST HAVE BEEN A HYD LEAK DOWNSTREAM OF THE SHUTTLE. VALVES THAT SEPARATE THE HYD/CO2 SYSTEMS. I BELIEVE THE HYD LEAK WAS SUCH THAT WHEN I INITIALLY OBSERVED THE UP INDICATOR OUT AND PUT THE GEAR HANDLE IN THE UP POS; THE REMAINING FLUID NECESSARY TO PUMP THE GEAR DOWN WAS EXHAUSTED.