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A MD88 experienced an in-flight engine shutdown and return to the field due to engine drive case input shaft bearing failure.
| Attributes | |
| ACN | 464435 |
| Time | |
| Date | 200002 |
| Day | Sat |
| 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 | MD-88 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | ground : parked ground : maintenance |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | maintenance : lead technician |
| Qualification | technician : powerplant |
| Experience | maintenance lead technician : 7 maintenance technician : 6 |
| ASRS Report | 464435 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | maintenance : lead technician |
| Qualification | technician : airframe technician : powerplant |
| Experience | maintenance lead technician : 3 maintenance technician : 22 |
| ASRS Report | 464251 |
| Events | |
| Anomaly | aircraft equipment problem : critical maintenance problem : improper maintenance non adherence : published procedure non adherence : far non adherence : company policies |
| Independent Detector | other other : 940 |
| Consequence | other other |
| Factors | |
| Maintenance | contributing factor : schedule pressure performance deficiency : testing performance deficiency : installation performance deficiency : inspection |
| Supplementary | |
| Problem Areas | Maintenance Human Performance Aircraft |
| Primary Problem | Maintenance Human Performance |
Narrative:
I assigned a mechanic to build up the intermediate case on engine serial number wxxx. The first gearbox drive housing would not go in correctly, so I got another housing for him to try. This housing went in correctly. After seeing the housing would fit, I left the mechanic to finish building the case. The mechanic forgot to remove the outer race from the first housing and install it in the second. After we found out that the second housing would fit. After the mechanic installed the housing, retaining plate and wired the bolts, he got me to give him the ok to install the tower shaft. Leaning over and looking inside the intermediate case, I didn't see that the bearing outer race was missing. After tower shaft and oil nozzle were installed, I gave the shaft a spin, and felt no movement. This shaft has 2 bearings, so the bottom one was supporting the shaft in this condition. The engine was built and passed test cell. When the shaft eventually failed, it caused the N2 gear box to uncouple, shutting down the engine.
Original NASA ASRS Text
Title: A MD88 EXPERIENCED AN INFLT ENG SHUTDOWN AND RETURN TO THE FIELD DUE TO ENG DRIVE CASE INPUT SHAFT BEARING FAILURE.
Narrative: I ASSIGNED A MECH TO BUILD UP THE INTERMEDIATE CASE ON ENG SERIAL NUMBER WXXX. THE FIRST GEARBOX DRIVE HOUSING WOULD NOT GO IN CORRECTLY, SO I GOT ANOTHER HOUSING FOR HIM TO TRY. THIS HOUSING WENT IN CORRECTLY. AFTER SEEING THE HOUSING WOULD FIT, I LEFT THE MECH TO FINISH BUILDING THE CASE. THE MECH FORGOT TO REMOVE THE OUTER RACE FROM THE FIRST HOUSING AND INSTALL IT IN THE SECOND. AFTER WE FOUND OUT THAT THE SECOND HOUSING WOULD FIT. AFTER THE MECH INSTALLED THE HOUSING, RETAINING PLATE AND WIRED THE BOLTS, HE GOT ME TO GIVE HIM THE OK TO INSTALL THE TWR SHAFT. LEANING OVER AND LOOKING INSIDE THE INTERMEDIATE CASE, I DIDN'T SEE THAT THE BEARING OUTER RACE WAS MISSING. AFTER TWR SHAFT AND OIL NOZZLE WERE INSTALLED, I GAVE THE SHAFT A SPIN, AND FELT NO MOVEMENT. THIS SHAFT HAS 2 BEARINGS, SO THE BOTTOM ONE WAS SUPPORTING THE SHAFT IN THIS CONDITION. THE ENG WAS BUILT AND PASSED TEST CELL. WHEN THE SHAFT EVENTUALLY FAILED, IT CAUSED THE N2 GEAR BOX TO UNCOUPLE, SHUTTING DOWN THE ENG.
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.