A B737-700 ACFT NOSE LNDG GEAR DOWN-LOCK ACTUATOR REPLACED. MAINT CHOSE A GROUND TEST THAT DOES NOT REQUIRE A GEAR SWING. DOWN-LOCK ACTUATOR FAILED TO RELEASE INTERNALLY AND NOSE LNDG GEAR WOULD NOT RETRACT AFTER TAKE-OFF.

Narrative

I WAS GIVEN ACFT TO REMOVE AND REPLACE A BORROWED NOSE LNDG GEAR DOWN-LOCK ACTUATOR. I PRINTED A COPY OF THE MAINT MANUAL REF AND PROCEEDED TO ACFT. I REMOVED AND REPLACED THE NOSE LNDG GEAR DOWN-LOCK ACTUATOR AS PER THE MAINT MANUAL REF TASK. I THEN OPS AND LEAK CHKED IT AND FOUND TO PASS AS PER MAINT MANUAL. HOWEVER I DID NOT KNOW IT WAS AN RII ITEM. BECAUSE IN THE PAST RII PART I CHANGED THE RII WAS OUTLINED OR SHOWN IN THE TASK PAPERWORK OR AN INSPECTOR WAS ALREADY PRESENT TO PERFORM THE SIGNOFF; SO THE NOSE LNDG GEAR DOWN-LOCK ACTUATOR FAILED TO RECEIVE AN RII THIS TIME. I NOW KNOW WHERE TO LOOK UP WHAT ITEMS REQUIRE RII SIGNOFFS IN THE MAINT MANUAL PAPERWORK. IN REF TO THE ABOVE DURING A FACT FINDING REVIEW; I WAS INFORMED THAT I MISUNDERSTOOD THE MAINT MANUAL INSTALLATION TEST FOR THE LOCK ACTUATOR TASK. IN THE MAINT MANUAL IT GIVES 2 METHODS TO DO THE TEST CHK. THE FIRST ONE IS TO USE JACKS AND SWING THE GEAR IF YOU HAVE THEM. THE SECOND IS TO DO A TEST ON THE GND. I CHOSE TO DO THE ONE ON THE GND. OUR MAINT MANUAL LED ME TO THINK I COULD CHOOSE WHICH METHOD TO USE. THE SENTENCE READS 'CHOOSE ONE METHOD TO TEST THE LOCK ACTUATOR.' BUT IN THE FACT FINDING IT WAS SHOWN TO ME I SHOULD HAVE CHOSEN THE FIRST TEST AND SWUNG THE GEAR BECAUSE WE HAVE JACKS. IT WAS A HVY WORKLOAD NIGHT. I WAS GIVEN 2 ACFT AND WAS ASKED TO HELP WORK ON 2 OTHERS; ONE WITH A BLEED TRIP THAT NEEDED A HIGH PWR RUN AND THE OTHER WAS A SVC CHK. WE HAD 23 RON (ROUTINE OVERNIGHTS) THAT NIGHT. SO SINCE I THOUGHT I COULD CHOOSE WHICH DOWN-LOCK TEST TO DO I CHOSE THE GND TEST SO I COULD HELP WITH THE OTHER ACFT. WHEN I PERFORMED THE GND TEST WITH A FELLOW MECH I SAW THE NOSE LNDG GEAR DOWN-LOCK ACTUATOR MOVE ACCORDING TO THE TEST OUTLINE AND THE MECH IN THE COCKPIT WAS ABLE TO HEAR AND FEEL THE MOVEMENTS THROUGH THE FLOOR AND WITH NO HYD LEAKS; IT APPEARED TO OPS CHK GOOD. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THIS WAS AN AIR TURNBACK SITUATION DUE TO THE FAILURE OF AN INTERNAL O-RING THAT PREVENTED THE NOSE LNDG DOWN-LOCK ACTUATOR FROM RELEASING AND ALLOWING THE NOSE LNDG GEAR TO RETRACT. REPORTER ALSO STATED THE MM REFERENCE ALLOWING HIM TO CHOOSE BETWEEN DOING A GEAR SWING OR A GROUND TEST WAS CONFUSING. SO; HE HAS SUBMITTED A REQUEST TO CHANGE THE MM LANGUAGE CLARIFYING THE USE OF ACFT JACKS.