A B737-400 during a horizontal stabilizer center section hinge pin inspection; an FAA safety inspect...

Attributes
ACN	649804
Time
Date	200502
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-400
Operating Under FAR Part	Part 121
Person 1
Affiliation	company : air carrier
Function	maintenance : technician
ASRS Report	649804
Person 2
Affiliation	company : air carrier
ASRS Report	648853
Events
Anomaly	aircraft equipment problem : critical maintenance problem : improper maintenance non adherence : far non adherence : published procedure
Independent Detector	aircraft equipment other aircraft equipment : stab trim wheel lock other other : 3
Resolutory Action	none taken : detected after the fact
Consequence	faa : investigated other other
Factors
Maintenance	contributing factor : work cards contributing factor : manuals performance deficiency : scheduled maintenance performance deficiency : non compliance with legal requirements
Supplementary
Problem Areas	Maintenance Human Performance Chart Or Publication Environmental Factor FAA
Primary Problem	Maintenance Human Performance

Narrative:

First time completing task from start to finish. One other time doing this task was the installation only. Mechanics involved were myself and mr X. I was in charge of setting up the cockpit to accomplish the task. During accomplishing the task for inspecting the horizontal stabilizer center section hinge pins; which required the removal of the pin; we were approached by the FAA and as why the stabilizer trim lock was not installed. I informed the FAA inspector that by following the procedure in the maintenance manual; that the lock did not fit on the trim wheel. I had set the stabilizer to the maximum leading edge down position; to gain access to the pins; using the electrical trim switches on the pilot's control column. The trim lock was nearby the trim wheel but not installed. I had pulled and 'danger' tagged the circuit breakers for actuation of the stabilizer trim motor and felt that it was safe to continue with the task. We were the only ones working on the aircraft at the time and felt that no one would be actuating the controls. The task card does not address not having installing the stabilizer trim lock.

Original NASA ASRS Text

Title: A B737-400 DURING A HORIZ STABILIZER CTR SECTION HINGE PIN INSPECTION; AN FAA SAFETY INSPECTOR QUESTIONED WHY THE STABILIZER TRIM WHEEL LOCKOUT WAS NOT INSTALLED.

Narrative: FIRST TIME COMPLETING TASK FROM START TO FINISH. ONE OTHER TIME DOING THIS TASK WAS THE INSTALLATION ONLY. MECHS INVOLVED WERE MYSELF AND MR X. I WAS IN CHARGE OF SETTING UP THE COCKPIT TO ACCOMPLISH THE TASK. DURING ACCOMPLISHING THE TASK FOR INSPECTING THE HORIZ STABILIZER CTR SECTION HINGE PINS; WHICH REQUIRED THE REMOVAL OF THE PIN; WE WERE APCHED BY THE FAA AND AS WHY THE STABILIZER TRIM LOCK WAS NOT INSTALLED. I INFORMED THE FAA INSPECTOR THAT BY FOLLOWING THE PROC IN THE MAINT MANUAL; THAT THE LOCK DID NOT FIT ON THE TRIM WHEEL. I HAD SET THE STABILIZER TO THE MAX LEADING EDGE DOWN POS; TO GAIN ACCESS TO THE PINS; USING THE ELECTRICAL TRIM SWITCHES ON THE PLT'S CTL COLUMN. THE TRIM LOCK WAS NEARBY THE TRIM WHEEL BUT NOT INSTALLED. I HAD PULLED AND 'DANGER' TAGGED THE CIRCUIT BREAKERS FOR ACTUATION OF THE STABILIZER TRIM MOTOR AND FELT THAT IT WAS SAFE TO CONTINUE WITH THE TASK. WE WERE THE ONLY ONES WORKING ON THE ACFT AT THE TIME AND FELT THAT NO ONE WOULD BE ACTUATING THE CTLS. THE TASK CARD DOES NOT ADDRESS NOT HAVING INSTALLING THE STABILIZER TRIM LOCK.

Data retrieved from NASA's ASRS site as of January 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.

A B737-400 during a horizontal stabilizer center section hinge pin inspection; an FAA safety inspector questioned why the stabilizer trim wheel lockout was not installed.