ACR MLG HAD TO RETURN LAND FROM FERRY FLT ACCOUNT UNABLE TO RAISE GEAR. FAULT FOUND IN AIRLINE MAINT PROC WHICH WAS GOVERNED BY THE PROC AS SPELLED OUT IN THE ACFT MAINT MANUAL.

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ACFT HAD ROUTINE MAINT ON RIGHT MLG WHICH INVOLVED REMOVING AND REPLACEMENT OF RIGHT MLG UPPER AND LOWER TORQUE LINKS. MAINT WAS PERFORMED PER MAINT MANUAL 32-11- 04 OF FOREIGN MLG TYPE ACFT. PROB WAS DISCOVERED INFLT AFTER PLT ATTEMPTED TO RETRACT GEAR AND ABOVE 500 FT AGL. ON A FERRY FLT FOR ACFT POSITIONING PLT MADE DECISION TO RETURN TO FIELD. PLT GOT AIR/GND ADVISORY AND LIFT DUMPER INOP OR DO NOT DEPLOY. UPON MAINT INVESTIGATION ON GND; COULD NOT FIND ANY PROB WITH SENSORS ON LNDG GEAR THROUGH ONBOARD BITE TEST OF PROX BOX. UPON JACKING ACFT AND PUTTING IT IN THE AIR; MAINT COULD NOT RETRACT MLG WITHOUT USING THE GEAR OVERRIDE. PERFORMED BITE TEST OF MLG SENSORS. FOUND RIGHT MLG AIR/GND SENSOR SHOWS FAR POS. (IN AIR SENSOR SHOULD SHOW NEAR.) PROB/SOLUTION: ADJUSTED. RIGHT MLG AIR/GND SENSOR TARGET. SUGGESTED FINAL SOLUTION TO AVOID FUTURE PROBS: MAINT MANUAL SHOULD BE CHANGED TO REFLECT ACFT MUST BE JACKED AND THEN ACCOMPLISH CHANNEL TEST OF AIR/GND PROX SENSORS PER MAINT MANUAL 31-41-00-710-815. THE MAINT MANUAL ALLOWS YOU TO PERCEIVE THAT JACKING THE ACFT IS NECESSARY ONLY IF YOU REMOVED AND REPLACE THE SENSOR. HOWEVER; SINCE THE TARGET IS ON THE UPPER TORQUE LINK; IF YOU REMOVE AND REPLACED THE LINK THE FACTORY DRILLED HOLES MAY VARY FROM THE ORIGINAL EQUIP. THEREFORE; JACKING THE ACFT IS NECESSARY EVEN IF YOU HAVEN'T REMOVED AND REPLACED THE SENSOR DUE TO POSSIBLE TARGET MISALIGNMENT. SUPPLEMENTAL INFORMATION FROM ACN 244096: THIS WAS MY FIRST DEALING WITH THE FOREIGN MLG MAINT MANUALS. I FOUND THEY HAVE A DIFFERENT WAY OF DOING THINGS. I WENT BACK TO THE MAINT MANUAL TO SEE IF I HAD MISSED SOMETHING; AND HOW. ON THE FIRST PAGE OF THE MLG TORQUE LINKS REMOVAL/INSTALLATION IT LISTS THE TOOLS NEEDED; MATERIALS NEEDED; PARTS NEEDED AND AT THE BOTTOM OF THE PAGE 'REFERENCED PROCS.' IN THIS LIST OF PROCS WAS A REF TO A DIFFERENT ATA 31; OPS TEST OF THE PROX SWITCHING SYS. I GUESS I COMPLETELY OVERLOOKED THIS. THE TARGET FOR THE PROX SWITCH IS ATTACHED TO THE UPPER TORQUE LINK. POSSIBLY; I WAS TIRED FROM WORKING ALL NIGHT AND WAS ON ABOUT MY 10TH OR 11TH HR. I WAS TIRED AND WE HAD ALREADY BROKEN ABOUT 2 ETR'S AND I WAS HURRYING TO TRY TO GET THE ACFT OUT THE DOORS SO I COULD FLY. AFTER TALKING WITH THE MECH THAT WORKED ON THE PROB AFTER THE RETURN TO FIELD; HE SAID THAT THE TEST OF THE PROX SWITCHING SYS WOULDN'T AND DIDN'T MAKE A DIFFERENCE. HE SAID THE ONLY WAY TO AVOID THAT KIND OF PROB IS THE ACFT HAS TO BE COMPLETELY JACKED. THE MAINT IS PRETTY VOID IN THIS AREA. IT STATES THE ONLY REASON TO JACK THE ACFT IS TO CHANGE A PROX SWITCH. WE DID NOT CHANGE A SWITCH IN THE ORIGINAL PROB. ALL THAT WAS DONE WAS THE REPLACEMENT OF THE TORQUE LINK. I FEEL THE MAINT MANUAL NEEDS TO STATE MORE CLRLY TO JACK THE ACFT AFTER CHANGING THE TORQUE LINKS AND SWING THE LNDG GEAR.