|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||airport : zzz.airport|
|Altitude||agl single value : 0|
|Make Model Name||MD Helicopter 500/C/D/E/L|
|Operating Under FAR Part||other : 133|
|Flight Phase||ground : maintenance|
cruise : level
|Function||maintenance : inspector|
|Qualification||technician : airframe|
technician : inspection authority
technician : powerplant
|Anomaly||non adherence : published procedure|
non adherence : far
non adherence : company policies
other anomaly other
|Independent Detector||other other : 1|
|Resolutory Action||none taken : detected after the fact|
|Maintenance||contributing factor : schedule pressure|
performance deficiency : scheduled maintenance
performance deficiency : non compliance with legal requirements
performance deficiency : logbook entry
Maintenance Human Performance
During a review of aircraft historical records, a mathematical error was discovered. This error was the reason that the number 1 and 2 wheels of the turbine were flown 89 hours beyond their time life limit. The component sheet that tracks time remaining on the time limit parts was basing the time remaining on 'aircraft total time' instead of 'engine total time.' this was discovered during scheduled maintenance that resulted in no damage to the aircraft or injury to persons. The aircraft was returned to service after the turbine was replaced and the mathematical error corrected.
Original NASA ASRS Text
Title: H500 WAS FOUND TO HAVE EXCEEDED MAXIMUM TIME ON TIME LIMITED ENG TURBINE DISCS.
Narrative: DURING A REVIEW OF ACFT HISTORICAL RECORDS, A MATHEMATICAL ERROR WAS DISCOVERED. THIS ERROR WAS THE REASON THAT THE NUMBER 1 AND 2 WHEELS OF THE TURBINE WERE FLOWN 89 HOURS BEYOND THEIR TIME LIFE LIMIT. THE COMPONENT SHEET THAT TRACKS TIME REMAINING ON THE TIME LIMIT PARTS WAS BASING THE TIME REMAINING ON 'ACFT TOTAL TIME' INSTEAD OF 'ENG TOTAL TIME.' THIS WAS DISCOVERED DURING SCHEDULED MAINT THAT RESULTED IN NO DAMAGE TO THE ACFT OR INJURY TO PERSONS. THE ACFT WAS RETURNED TO SVC AFTER THE TURBINE WAS REPLACED AND THE MATHEMATICAL ERROR CORRECTED.
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.