CASE STUDIES

THE IMPORTANCE OF EARLY AND REGULAR SAMPLING AND TRENDING

The indications are that the extensive damage could have been reduced if a detailed investigation had been carried out after the first SOAP sample.

INTRODUCTION

Some JT15 engines were placed on a SOAP program with results on the Spectro ECHO^® program.

ANALYSIS

Almost immediately on the first sample, Iron results gave an indication of a problem (Picture 1). The next sample gave an unusually low reading of 0.1ppm for Iron, which could be explained by an oil change taking place before the SOAP sample (Picture 2). During the subsequent four months of sampling, the Iron content climbed again to 1.9 ppm before tailing off.

The engine was finally removed when a major amount of metal was found in the filter.

ACTION/FOLLOW UP

Investigation revealed the following: bevel gear nut loose, nut threads worn and distorted, nut lock washer two tangs broken, with possible damage to the intermediate case.

CONCLUSION

Following repair, the Iron trends returned to a regular 0.2 to 0.3 ppm of Iron.

It was unfortunate in this particular case that no previous history was known as it is likely that higher levels of Iron would have occurred much earlier in the SOAP program, triggering an investigation before further damage occurred. All the indications are that the extensive damage could have been reduced if a detailed investigation had been carried out after the first SOAP sample.

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Case Studies

First Sample (Picture 1)

SOAP Sample (Picture 2)

Third Sample