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A B767-200 was dispatched in non compliance with an integrated drive generator oil leak beyond the MEL limits.
| Attributes | |
| ACN | 430168 |
| Time | |
| Date | 199903 |
| Day | Fri |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | agl single value : 0 |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B767-200 |
| Operating Under FAR Part | Part 121 |
| Flight Plan | None |
| Aircraft 2 | |
| Flight Phase | ground : parked ground : maintenance |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | other personnel other oversight : supervisor |
| Qualification | technician : powerplant technician : airframe technician : inspection authority |
| ASRS Report | 430168 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | maintenance : technician |
| Qualification | technician : powerplant technician : airframe |
| Events | |
| Anomaly | aircraft equipment problem : critical maintenance problem : non compliance with mel maintenance problem : improper maintenance non adherence : far non adherence : published procedure other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : idg oil temp indicator |
| Resolutory Action | none taken : detected after the fact other |
| Consequence | other |
| Factors | |
| Maintenance | contributing factor : manuals contributing factor : schedule pressure performance deficiency : non compliance with legal requirements performance deficiency : repair |
| Supplementary | |
| Problem Areas | Aircraft Maintenance Human Performance |
| Primary Problem | Maintenance Human Performance |
Narrative:
On mar/xa/99 at ZY00Z, I received a call from the maintenance department of air carrier airlines in ZZZ. The call was in reference to an oil leak on the r-hand engine. The oil leak was detached as coming from the seal drain of the integrated drive generator. The aircraft maintenance technician informed me that the oil leak was approximately 10 drops per min. Looking at the maintenance manual I ascertained that the allowable leakage rate was in fact 3 drops per min. The reference for the leak rate is found in maintenance manual xx-xx-yy page 605. Looking at the next page the table has a number of footnotes regarding extra information in determining the disposition of the leak and its rectification. I mistakenly looked at footnote 3. The note allows a one time fly-back limit in excess of the 3 drops per min normally allowed. As the aircraft was past its scheduled departure time with passenger already boarded, I was hoping that we could in fact preserve the departure and address the leak at a more convenient time. I mistakenly associated that footnote with the integrated drive generator allowable leak rate and therefore allowed the leak to be deferred and planned for the rectification at the next station, thus mitigating any disservice to our customers. Unfortunately, as I looked at the table again after allowing the deferral, I realized that in fact the footnote did not apply in this situation. The aircraft had already departed and I was unable to correctly address the leak. I then arranged for the leak to be rectified in YYY -- the next destination for the aircraft. On arrival, the integrated drive generator was in fact replaced and the carbon seal also. The leak caused no in-flight operational difficulties on the ZZZ to YYY sector. It was my desire to preserve the flight that prompted me to look through the table of allowable leaks looking for a reference that may be used in this instance. The numbering system used in the table was where I made my mistake applying the extra limit.
Original NASA ASRS Text
Title: A B767-200 WAS DISPATCHED IN NON COMPLIANCE WITH AN INTEGRATED DRIVE GENERATOR OIL LEAK BEYOND THE MEL LIMITS.
Narrative: ON MAR/XA/99 AT ZY00Z, I RECEIVED A CALL FROM THE MAINT DEPT OF ACR AIRLINES IN ZZZ. THE CALL WAS IN REF TO AN OIL LEAK ON THE R-HAND ENG. THE OIL LEAK WAS DETACHED AS COMING FROM THE SEAL DRAIN OF THE INTEGRATED DRIVE GENERATOR. THE ACFT MAINT TECHNICIAN INFORMED ME THAT THE OIL LEAK WAS APPROX 10 DROPS PER MIN. LOOKING AT THE MAINT MANUAL I ASCERTAINED THAT THE ALLOWABLE LEAKAGE RATE WAS IN FACT 3 DROPS PER MIN. THE REF FOR THE LEAK RATE IS FOUND IN MAINT MANUAL XX-XX-YY PAGE 605. LOOKING AT THE NEXT PAGE THE TABLE HAS A NUMBER OF FOOTNOTES REGARDING EXTRA INFO IN DETERMINING THE DISPOSITION OF THE LEAK AND ITS RECTIFICATION. I MISTAKENLY LOOKED AT FOOTNOTE 3. THE NOTE ALLOWS A ONE TIME FLY-BACK LIMIT IN EXCESS OF THE 3 DROPS PER MIN NORMALLY ALLOWED. AS THE ACFT WAS PAST ITS SCHEDULED DEP TIME WITH PAX ALREADY BOARDED, I WAS HOPING THAT WE COULD IN FACT PRESERVE THE DEP AND ADDRESS THE LEAK AT A MORE CONVENIENT TIME. I MISTAKENLY ASSOCIATED THAT FOOTNOTE WITH THE INTEGRATED DRIVE GENERATOR ALLOWABLE LEAK RATE AND THEREFORE ALLOWED THE LEAK TO BE DEFERRED AND PLANNED FOR THE RECTIFICATION AT THE NEXT STATION, THUS MITIGATING ANY DISSERVICE TO OUR CUSTOMERS. UNFORTUNATELY, AS I LOOKED AT THE TABLE AGAIN AFTER ALLOWING THE DEFERRAL, I REALIZED THAT IN FACT THE FOOTNOTE DID NOT APPLY IN THIS SIT. THE ACFT HAD ALREADY DEPARTED AND I WAS UNABLE TO CORRECTLY ADDRESS THE LEAK. I THEN ARRANGED FOR THE LEAK TO BE RECTIFIED IN YYY -- THE NEXT DEST FOR THE ACFT. ON ARR, THE INTEGRATED DRIVE GENERATOR WAS IN FACT REPLACED AND THE CARBON SEAL ALSO. THE LEAK CAUSED NO INFLT OPERATIONAL DIFFICULTIES ON THE ZZZ TO YYY SECTOR. IT WAS MY DESIRE TO PRESERVE THE FLT THAT PROMPTED ME TO LOOK THROUGH THE TABLE OF ALLOWABLE LEAKS LOOKING FOR A REF THAT MAY BE USED IN THIS INSTANCE. THE NUMBERING SYS USED IN THE TABLE WAS WHERE I MADE MY MISTAKE APPLYING THE EXTRA LIMIT.
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.