AN MDT AIRCREW RETURNED AND LANDED BECAUSE THEY COULDN'T RAISE THE LNDG GEAR.

Narrative

DURING TKOF AFTER A POSITIVE RATE OF CLB; I SAID GEAR UP; THE FO SELECTED GEAR UP. THE UNSAFE ADVISORY LIGHT (RED) CAME ON AND THE (GREEN) DOWN AND LOCK LIGHTS STAYED ON. THE GEAR DID NOT RETRACT. I TOLD THE FO TO LOOK IN THE EMER CHKLIST UNDER GEAR INOP. THE FO SAID THERE WAS NOTHING LISTED UNDER 'GEAR WILL NOT RETRACT.' UPON HEARING THAT; I TOLD THE FO TO TELL THE TWR WE WANTED TO RETURN TO LAND. THE TWR CLRED US TO LAND. WHEN THE FO SELECTED GEAR DOWN THE UNSAFE ADVISORY LIGHTS (RED) WENT OUT. THE 3 GREEN LIGHTS STAYED ON. WE MADE A NORMAL LNDG TAXIED CLR OF THE RWY. UPON DOING THE AFTER LNDG CHKLIST; WE FOUND THAT THE LNDG GEAR ALTERNATE RELEASE DOOR WAS OPEN; CLOSED IT; TAXIED BACK IN LINE FOR TKOF AFTER RECEIVING A NEW RELEASE. I FEEL TO PREVENT A RECURRENCE; A CAUTION WARNING LIGHT SHOULD BE INCORPORATED INTO THE ANNUNCIATOR PANEL INDICATING THAT THE LNDG GEAR ALTERNATE RELEASE DOOR IS OPEN. SUPPLEMENTAL INFO FROM ACN 225141. CAPT REQUESTED I PULL THE EMER; ABNORMAL CHKLIST FOR APPROPRIATE GEAR INDICATION. I ADVISED HIM THAT THERE WAS NO CHKLIST FOR OUR GEAR INDICATION. AFTER LNDG CHKLIST WE NOTED THE ALTERNATE LNDG GEAR RELEASE DOOR WAS OPEN WHICH INHIBITS HYDRAULICS FOR GEAR RETRACTION. I FEEL WE SHOULD HAVE A CAUTION WARNING LIGHT INDICATING THIS DOOR IS OPEN. HAD WE LOST AN ENG AND COULDN'T RETRACT THE GEAR THE RESULTS COULD HAVE BEEN QUITE DIFFERENT.