A pratt & whitney JT8D compressor disk was improperly reworked during engine overhaul causing catast...

Attributes
ACN	370283
Time
Date	199706
Day	Wed
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : zzz
State Reference	US
Environment
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-200
Operating Under FAR Part	Part 121
Flight Phase	other
Flight Plan	None
Person 1
Affiliation	company : air carrier
Function	other personnel other
Qualification	other other : other
ASRS Report	370283
Person 2
Affiliation	company : air carrier
Function	other personnel other
Qualification	other other : other
Events
Anomaly	aircraft equipment problem : critical non adherence : far non adherence : published procedure other anomaly other
Independent Detector	other other : unspecified
Resolutory Action	other
Consequence	faa : assigned or threatened penalties faa : investigated Other
Supplementary
Air Traffic Incident	other

Narrative:

Part was repaired per maintenance manual and proper ar was used. Part failed, thus engine failed. Some parts of maintenance manual have been altered in my shop for yrs and now because of this incident, things will change to the proper methods. My stamp was used by me for the repair and I was questioned by the FAA and NTSB. Callback conversation with reporter revealed the following information: the reporter related the following information about the failure of the JT8D compressor disk which was plated in his shop. He said the disk was cadmium plated but was not nickel plated per the approved repair procedures. The error he suspects was caused by the mechanic trainee assigned to him who was not familiar with the plating shop procedures. He stated that after review of the approved repair procedures and the maintenance manual repair procedures it was discovered there was no after plating check or measurement of the amount of metal deposited on the disk. The reporter said the correct amount of plating was .0002 inches to .0004 inches. He related that in 12 yrs doing this work for 2 airlines no one has ever measured the plating thickness. The reporter said the FAA and the NTSB have contacted and interviewed him about this incident.

Original NASA ASRS Text

Title: A PRATT & WHITNEY JT8D COMPRESSOR DISK WAS IMPROPERLY REWORKED DURING ENG OVERHAUL CAUSING CATASTROPHIC AND UNCONTAINED ENG FAILURE.

Narrative: PART WAS REPAIRED PER MAINT MANUAL AND PROPER AR WAS USED. PART FAILED, THUS ENG FAILED. SOME PARTS OF MAINT MANUAL HAVE BEEN ALTERED IN MY SHOP FOR YRS AND NOW BECAUSE OF THIS INCIDENT, THINGS WILL CHANGE TO THE PROPER METHODS. MY STAMP WAS USED BY ME FOR THE REPAIR AND I WAS QUESTIONED BY THE FAA AND NTSB. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR RELATED THE FOLLOWING INFO ABOUT THE FAILURE OF THE JT8D COMPRESSOR DISK WHICH WAS PLATED IN HIS SHOP. HE SAID THE DISK WAS CADMIUM PLATED BUT WAS NOT NICKEL PLATED PER THE APPROVED REPAIR PROCS. THE ERROR HE SUSPECTS WAS CAUSED BY THE MECH TRAINEE ASSIGNED TO HIM WHO WAS NOT FAMILIAR WITH THE PLATING SHOP PROCS. HE STATED THAT AFTER REVIEW OF THE APPROVED REPAIR PROCS AND THE MAINT MANUAL REPAIR PROCS IT WAS DISCOVERED THERE WAS NO AFTER PLATING CHK OR MEASUREMENT OF THE AMOUNT OF METAL DEPOSITED ON THE DISK. THE RPTR SAID THE CORRECT AMOUNT OF PLATING WAS .0002 INCHES TO .0004 INCHES. HE RELATED THAT IN 12 YRS DOING THIS WORK FOR 2 AIRLINES NO ONE HAS EVER MEASURED THE PLATING THICKNESS. THE RPTR SAID THE FAA AND THE NTSB HAVE CONTACTED AND INTERVIEWED HIM ABOUT THIS INCIDENT.

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.

A pratt & whitney JT8D compressor disk was improperly reworked during engine overhaul causing catastrophic and uncontained engine failure.