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A line aircraft maintenance technician (amt) reports noticing an increase in the number of loose and sheared tie-bolts on B737-800 main landing gear (medium large transport) tire wheel-half assemblies. He recently found one tire with five tie-bolts sheared near the smooth shank and threaded portion of the tie-bolt with all the locking nuts for the tie-bolts gone.
| Attributes | |
| ACN | 1326800 |
| Time | |
| Date | 201601 |
| Local Time Of Day | 1801-2400 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Light | Night |
| Aircraft 1 | |
| Make Model Name | B737-800 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Parked |
| Component | |
| Aircraft Component | Wheel Assemblies |
| Person 1 | |
| Function | Technician |
| Qualification | Maintenance Airframe Maintenance Powerplant |
| Experience | Maintenance Technician 37 |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical Deviation - Procedural Published Material / Policy |
Narrative:
Six months ago we started seeing main landing gear (medium large transport) wheel mount bolts broken off. At that time it was reported to management. It started with one or two bolts broken off and in the past month we have found four sets of wheels with as many as five bolts being broken or very loose. Last night; on another B737-800; we found #3 medium large transport tire with two bolts where the nuts where sheared off and three bolts that were so loose you could push them in and out [of the wheel half]. On this tire; the loose bolts had the same amount of bolt threads coming through the nuts as did the tight ones. As a mechanic; we see no urgency [by our air carrier] to address this problem since it's now been over six months. These tires are being overhauled by a tire repair station in ZZZ1. What is causing these bolts to loosen and come apart?
Original NASA ASRS Text
Title: A Line Aircraft Maintenance Technician (AMT) reports noticing an increase in the number of loose and sheared tie-bolts on B737-800 main landing gear (MLG) tire wheel-half assemblies. He recently found one tire with five tie-bolts sheared near the smooth shank and threaded portion of the tie-bolt with all the locking nuts for the tie-bolts gone.
Narrative: Six months ago we started seeing main landing gear (MLG) wheel mount bolts broken off. At that time it was reported to Management. It started with one or two bolts broken off and in the past month we have found four sets of wheels with as many as five bolts being broken or very loose. Last night; on another B737-800; we found #3 MLG tire with two bolts where the nuts where sheared off and three bolts that were so loose you could push them in and out [of the wheel half]. On this tire; the loose bolts had the same amount of bolt threads coming through the nuts as did the tight ones. As a Mechanic; we see no urgency [by our air carrier] to address this problem since it's now been over six months. These tires are being overhauled by a Tire Repair Station in ZZZ1. What is causing these bolts to loosen and come apart?
Data retrieved from NASA's ASRS site 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.