Narrative:

Per normal murphy's law operations, I was informed by an inspector who is on the air carrier safety committee at the close of shift on a friday that an aircraft in the hangar (xyz) had some questionable maintenance previously performed in abc. He explained that 'they' had cut 3 inches of cable in an attempt to 'rig' the forward drum, and 'they' filed on structure as an attempt to provide clearance for the drum drive chain. I immediately grabbed a flashlight to inspect the aircraft. I found as he had said, a modified structure, very tight cables and a bad feeling inside. On the way home, I called my supervisor and asked him what action would be taken on this issue. He stated that there was no paperwork ('squawk') for that issue. I then called the air carrier 800 safety hotline and got a recording. I felt that no action would be taken until 'normal' business hours. I then pulled into a closed gas station and left an anonymous message on the FAA hotline number. I hope that inspection was not involved with the modification I viewed in the nose of that aircraft. I find it hard to believe that someone would go to such extremes to make a mistake operate in such a fashion on a part 121 aircraft. It was explained to me that abc had removed and replaced the stabilizer trim actuator. They had trouble with the cable rig and 'programmed' it to be checked later. XXX checked it on a routine overnight check and evidently signed it off. Now it is in ZZZ for a yaw damper and cargo fire modification and there is no concern about this problem, except a certain few people in the flight safety program. I must ask -- where is maintenance supervision? Callback conversation with reporter revealed the following information: the reporter stated when abc replaced the jackscrew assembly it was done with poor workmanship. The reporter said 3 inches of cable were cut off in order to keep the cables from drooping after rigging. The reporter said either the wrong cable was installed or a loop was missed on the forward drum or the aft stabilizer drum. The reporter stated there is no record of engineering authority/authorized to allow filing and alteration on the forward drum support structure for drive chain clearance. The reporter said the FAA safety inspector looked the job over and required the replacement and rerig of the cable drive system.

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Original NASA ASRS Text

Title: A B737-400 WAS DISPATCHED IN NON COMPLIANCE WITH A NON STANDARD AND UNAUTH REPAIR TO THE HORIZ STABILIZER TRIM CTL SYS.

Narrative: PER NORMAL MURPHY'S LAW OPS, I WAS INFORMED BY AN INSPECTOR WHO IS ON THE ACR SAFETY COMMITTEE AT THE CLOSE OF SHIFT ON A FRIDAY THAT AN ACFT IN THE HANGAR (XYZ) HAD SOME QUESTIONABLE MAINT PREVIOUSLY PERFORMED IN ABC. HE EXPLAINED THAT 'THEY' HAD CUT 3 INCHES OF CABLE IN AN ATTEMPT TO 'RIG' THE FORWARD DRUM, AND 'THEY' FILED ON STRUCTURE AS AN ATTEMPT TO PROVIDE CLRNC FOR THE DRUM DRIVE CHAIN. I IMMEDIATELY GRABBED A FLASHLIGHT TO INSPECT THE ACFT. I FOUND AS HE HAD SAID, A MODIFIED STRUCTURE, VERY TIGHT CABLES AND A BAD FEELING INSIDE. ON THE WAY HOME, I CALLED MY SUPVR AND ASKED HIM WHAT ACTION WOULD BE TAKEN ON THIS ISSUE. HE STATED THAT THERE WAS NO PAPERWORK ('SQUAWK') FOR THAT ISSUE. I THEN CALLED THE ACR 800 SAFETY HOTLINE AND GOT A RECORDING. I FELT THAT NO ACTION WOULD BE TAKEN UNTIL 'NORMAL' BUSINESS HRS. I THEN PULLED INTO A CLOSED GAS STATION AND LEFT AN ANONYMOUS MESSAGE ON THE FAA HOTLINE NUMBER. I HOPE THAT INSPECTION WAS NOT INVOLVED WITH THE MODIFICATION I VIEWED IN THE NOSE OF THAT ACFT. I FIND IT HARD TO BELIEVE THAT SOMEONE WOULD GO TO SUCH EXTREMES TO MAKE A MISTAKE OPERATE IN SUCH A FASHION ON A PART 121 ACFT. IT WAS EXPLAINED TO ME THAT ABC HAD REMOVED AND REPLACED THE STABILIZER TRIM ACTUATOR. THEY HAD TROUBLE WITH THE CABLE RIG AND 'PROGRAMMED' IT TO BE CHKED LATER. XXX CHKED IT ON A ROUTINE OVERNIGHT CHK AND EVIDENTLY SIGNED IT OFF. NOW IT IS IN ZZZ FOR A YAW DAMPER AND CARGO FIRE MODIFICATION AND THERE IS NO CONCERN ABOUT THIS PROB, EXCEPT A CERTAIN FEW PEOPLE IN THE FLT SAFETY PROGRAM. I MUST ASK -- WHERE IS MAINT SUPERVISION? CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED WHEN ABC REPLACED THE JACKSCREW ASSEMBLY IT WAS DONE WITH POOR WORKMANSHIP. THE RPTR SAID 3 INCHES OF CABLE WERE CUT OFF IN ORDER TO KEEP THE CABLES FROM DROOPING AFTER RIGGING. THE RPTR SAID EITHER THE WRONG CABLE WAS INSTALLED OR A LOOP WAS MISSED ON THE FORWARD DRUM OR THE AFT STABILIZER DRUM. THE RPTR STATED THERE IS NO RECORD OF ENGINEERING AUTH TO ALLOW FILING AND ALTERATION ON THE FORWARD DRUM SUPPORT STRUCTURE FOR DRIVE CHAIN CLRNC. THE RPTR SAID THE FAA SAFETY INSPECTOR LOOKED THE JOB OVER AND REQUIRED THE REPLACEMENT AND RERIG OF THE CABLE DRIVE SYS.

Data retrieved from NASA's ASRS site as of July 2007 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.