H500 was found to have exceeded maximum time on time limited engine turbine discs.

Attributes
ACN	527859
Time
Date	200110
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Environment
Light	Daylight
Aircraft 1
Make Model Name	MD Helicopter 500/C/D/E/L
Operating Under FAR Part	other : 133
Flight Phase	ground : maintenance cruise : level
Person 1
Function	maintenance : inspector
Qualification	technician : airframe technician : inspection authority technician : powerplant
ASRS Report	527859
Events
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
Consequence	other
Factors
Maintenance	contributing factor : schedule pressure performance deficiency : scheduled maintenance performance deficiency : non compliance with legal requirements performance deficiency : logbook entry
Supplementary
Problem Areas	Aircraft Company Maintenance Human Performance
Primary Problem	Company

Narrative:

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.