Problem: We detected high levels of high-frequency wideband vibration and harmonics at multiples near the outer race defect frequency on the inboard fan bearing. The vibration level was 411% above average and the highest we’ve seen to date. We recommended replacing the inboard fan bearing. Solution: A new inboard fan bearing was put in service. We detected a significant improvement in high levels of high-frequency wideband vibration along with harmonics on the outer race defect frequency on the inboard fan bearing. Vibration levels decreased to below the long-term average.

We repaired the pinion shaft and replaced the bearings on the high speed side of the 101 gearbox. We also installed a new primary drive motor on the intermediate belt. You really saved the day on the 101 belt. Thanks to you we avoided a major catastrophe.”