Mechanic reports using an incorrect aircraft maintenance manual reference to remove; replace and tes...

Narrative:

I used an incorrect aircraft maintenance manual reference to remove replace; and test a left main landing gear ground sense proximity sensor. This was done on a B727-200 aircraft. I used the remove and replace and test procedure for the main landing gear down lock proximity switch. The test procedure was different. I checked the operation of the ground sense system and the proximity sensor that I changed and the system tested 'good.' the aircraft has flown multiple legs without a repeat of the original problem. The safety and airworthiness of this aircraft was not affected. I know this because I verified the operation of the ground sense proximity sensor. It was operating normally. I incorrectly used the wrong aircraft maintenance manual reference due to lack of sleep. I will; in the future; take time to research the component I am changing; and operationally testing to ensure compliance with the proper aircraft maintenance manual reference. The aircraft flew 2 legs and was scheduled to have the ground sense proximity sensor installation and functional test to be completed in accordance with the proper aircraft maintenance manual reference procedure. This inspection and operations check proved that the sensor was installed correctly and functionally tested 'good' in accordance with the aircraft maintenance manual for that component. Callback conversation with reporter revealed the following information: reporter stated he had changed the left main landing gear ground shift (sensor) proximity switch due to the B727-200 was still in the 'air' mode instead of the 'ground' mode. The main landing gear inner piston strut was found to be too high on the gear strut and not allowing the ground shift mechanism to position for a 'ground' mode. Reporter stated the aircraft's entire 'air-ground' system was checked at their maintenance base and found to be operating correctly.

Original NASA ASRS Text

Title: MECHANIC REPORTS USING AN INCORRECT ACFT MAINT MANUAL REFERENCE TO REMOVE; REPLACE AND TEST A LEFT MAIN LNDG GEAR GROUND SENSE (SHIFT) PROX SENSOR ON A B727-200. PROCEDURE USED WAS FOR MLG DOWN LOCK PROX SWITCH.

Narrative: I USED AN INCORRECT ACFT MAINT MANUAL REF TO REMOVE REPLACE; AND TEST A L MAIN LNDG GEAR GND SENSE PROX SENSOR. THIS WAS DONE ON A B727-200 ACFT. I USED THE REMOVE AND REPLACE AND TEST PROC FOR THE MAIN LNDG GEAR DOWN LOCK PROX SWITCH. THE TEST PROC WAS DIFFERENT. I CHKED THE OP OF THE GND SENSE SYS AND THE PROX SENSOR THAT I CHANGED AND THE SYS TESTED 'GOOD.' THE ACFT HAS FLOWN MULTIPLE LEGS WITHOUT A REPEAT OF THE ORIGINAL PROB. THE SAFETY AND AIRWORTHINESS OF THIS ACFT WAS NOT AFFECTED. I KNOW THIS BECAUSE I VERIFIED THE OP OF THE GND SENSE PROX SENSOR. IT WAS OPERATING NORMALLY. I INCORRECTLY USED THE WRONG ACFT MAINT MANUAL REF DUE TO LACK OF SLEEP. I WILL; IN THE FUTURE; TAKE TIME TO RESEARCH THE COMPONENT I AM CHANGING; AND OPERATIONALLY TESTING TO ENSURE COMPLIANCE WITH THE PROPER ACFT MAINT MANUAL REF. THE ACFT FLEW 2 LEGS AND WAS SCHEDULED TO HAVE THE GND SENSE PROX SENSOR INSTALLATION AND FUNCTIONAL TEST TO BE COMPLETED IN ACCORDANCE WITH THE PROPER ACFT MAINT MANUAL REF PROC. THIS INSPECTION AND OPS CHK PROVED THAT THE SENSOR WAS INSTALLED CORRECTLY AND FUNCTIONALLY TESTED 'GOOD' IN ACCORDANCE WITH THE ACFT MAINT MANUAL FOR THAT COMPONENT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED HE HAD CHANGED THE LEFT MAIN LNDG GEAR GROUND SHIFT (SENSOR) PROX SWITCH DUE TO THE B727-200 WAS STILL IN THE 'AIR' MODE INSTEAD OF THE 'GROUND' MODE. THE MAIN LNDG GEAR INNER PISTON STRUT WAS FOUND TO BE TOO HIGH ON THE GEAR STRUT AND NOT ALLOWING THE GROUND SHIFT MECHANISM TO POSITION FOR A 'GROUND' MODE. REPORTER STATED THE ACFT'S ENTIRE 'AIR-GROUND' SYSTEM WAS CHECKED AT THEIR MAINT BASE AND FOUND TO BE OPERATING CORRECTLY.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	800106
Time
Date	200807
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B727-200
Flight Phase	ground : maintenance
Person 1
Affiliation	company : air carrier
Function	maintenance : technician
ASRS Report	800106
Events
Anomaly	aircraft equipment problem : less severe maintenance problem : improper maintenance maintenance problem : improper documentation non adherence : far non adherence : published procedure
Independent Detector	other other : 1
Resolutory Action	none taken : detected after the fact
Consequence	other
Factors
Maintenance	performance deficiency : non compliance with legal requirements performance deficiency : logbook entry
Supplementary
Problem Areas	Maintenance Human Performance Aircraft
Primary Problem	Maintenance Human Performance

Mechanic reports using an incorrect aircraft maintenance manual reference to remove; replace and test a left main landing gear ground sense (shift) proximity sensor on a B727-200. Procedure used was for medium large transport down lock proximity switch.