DHC-8 PIC UNABLE TO RETRACT LNDG GEAR AFTER TKOF.

Narrative

DEPARTING AS FLT FROM SEA TO PDX THIS MORNING (APPROX XX15 LCL) THE LNDG GEAR FAILED TO RETRACT. AFTER CYCLING THE LNDG GEAR HANDLE WITHOUT SUCCESS; WE LOOKED FOR OBVIOUS PROBS; IE; GEAR PINS STOWED. I CHKED THE ALTERNATE GEAR EXTENSION DOOR ON THE FLOOR. I THEN REQUESTED THE LNDG GEAR MALFUNCTIONS CHKLISTS. THERE WAS NOTHING THAT ADDRESSED THE GEAR NOT RETRACTING. (WITH THE GEAR HANDLE SELECTED TO THE UP POS THE GEAR DOORS WOULD CYCLE; BUT THE RED LNDG GEAR UNSAFE LIGHTS WOULD REMAIN ILLUMINATED AS WELL AS THE 3 GREEN DOWN AND LOCKED LIGHTS. WITH THE GEAR HANDLE DOWN WE HAD NORMAL INDICATIONS). AT THIS POINT I REQUESTED VECTORS FOR A RETURN TO SEA; GAVE CTL OF THE ACFT TO THE FO (IT WAS MY LEG); AND CALLED MAINT VIA SELCAL FOR SUGGESTIONS. FORTUNATELY; THEY SUGGESTED CHKING THE OVERHEAD ALTERNATE GEAR EXTENSION DOOR -- IT WAS OPEN. AFTER CLOSING THE DOOR THE GEAR RETRACTED NORMALLY AND I ASKED FOR CLRNC TO PDX SINCE THE PROB HAD BEEN ALLEVIATED. WE CONTINUED ON TO PDX WITHOUT FURTHER COMPLICATION. THE REASON THE OVERHEAD ALTERNATE EXTENSION GEAR DOOR WAS OPEN WAS THAT DURING OUR SHORT STOPOVER FROM GEG I HAD TOLD A MECH THAT THE HYD FLUID NEEDED SVCING; AND HE HAD DROPPED THE GEAR DOORS TO DO THIS. I HAD NOTICED THE GEAR DOORS OPEN ON RETURN TO THE ACFT BUT WAS DISTRACTED AS I ENTERED THE COCKPIT AND DID NOT NOTICE THE OVERHEAD GEAR RELEASE DOOR WAS LEFT OPEN; AND NEITHER DID THE FO. SUBSEQUENT FLOWS AND CHKLISTS FAILED TO ALERT US TO THE OPEN DOOR. THERE WERE SEVERAL FACTORS THAT MAY HAVE LED UP TO THIS EVENT. MAINT USUALLY CLOSES THIS DOOR AFTER LOWERING THE GEAR DOORS; AND BEING OUT OF THE COCKPIT FOR LESS THAN 25 MIN; I DIDN'T DEEM AN ORIGINATING CHKLIST NECESSARY. HOWEVER; I AM RESPONSIBLE AND SHOULD HAVE NOTICED THE ANOMALY. IN RETROSPECT; I HAVE LEARNED FROM THIS AND WILL ALTER FLOW AND HABIT PATTERNS APPROPRIATELY SO THAT THE SAME OR SAME TYPE OF SIT DOES NOT OCCUR AGAIN. LACK OF SLEEP DUE TO NEW HOTEL; AND IN THE LAST FEW DAYS; FROM 7 MONTH OLD SON WHO WE'RE TRYING TO GET TO SLEEP IN HIS CRIB. WE'RE SLEEP DEPRIVED SOMEWHAT. I HAD A XX00 DEP OUT OF GEG THIS PARTICULAR MORNING WITH AN XX30 WAKEUP CALL. EVEN THOUGH IN BED BY 2000 LCL; I STILL SLEPT FITFULLY. WITH THE OVCST IT WAS DARK IN THE COCKPIT WITHOUT OVERHEAD LIGHTS ON. VERY EASY TO MISS THIS OVERHEAD ALTERNATE GEAR RELEASE DOOR. IT WAS MY BELIEF THAT; IF ALL GEAR DOORS CLOSED AS HYD PRESSURE BUILT ON STARTUP; THAT THE OVERHEAD RELEASE DOOR IS CLOSED (A FEW PLTS I'VE TALKED TO BELIEVE THIS TOO; SO I THINK THAT WE WERE TAUGHT THIS IN GND SCHOOL).