 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Two aircraft maintenance technicians (amts) report a right main landing gear (medium large transport) on a fairchild (swearingen) sa-227DC merlin had collapsed as the aircraft was towed into the hangar across an asphalt to concrete transition line. Three of the four bolts attaching one of the two crescent shaped cams on the right medium large transport were found sheared.
| Attributes | |
| ACN | 1308695 |
| Time | |
| Date | 201511 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | SA-227 AC Metro III |
| Operating Under FAR Part | Part 135 |
| Flight Phase | Parked |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Main Gear |
| Person 1 | |
| Function | Lead Technician |
| Qualification | Maintenance Airframe Maintenance Powerplant |
| Person 2 | |
| Function | Technician |
| Qualification | Maintenance Powerplant Maintenance Airframe |
| Events | |
| Anomaly | Aircraft Equipment Problem Critical Ground Event / Encounter Ground Strike - Aircraft |
Narrative:
Was brought out to tow aircraft to hangar for hangar installation. Hooked up tow bar after shutdown; hooked tug to towbar; got okay to tow; wing walkers thumbs up; towing was successful until aft right main landing gear (medium large transport) tires hit a small one inch lip at asphalt to concrete change point; right main gear folded at this point and right side of aircraft hit the ground asphalt/concrete.it was discovered that the cause of the problem was shearing of the main gear cam bolts. My only recommendations are a fleet campaign and or; if the problem proves to be affiliated with specific design of the aircraft possibly a service bulletin (sb) or airworthiness directive (ad) that makes the change of the bolts at regular intervals mandatory. Towing after ferry flight.
Original NASA ASRS Text
Title: Two Aircraft Maintenance Technicians (AMTs) report a right Main Landing Gear (MLG) on a Fairchild (Swearingen) SA-227DC Merlin had collapsed as the aircraft was towed into the hangar across an asphalt to concrete transition line. Three of the four bolts attaching one of the two crescent shaped cams on the right MLG were found sheared.
Narrative: Was brought out to tow aircraft to hangar for hangar installation. Hooked up tow bar after shutdown; hooked tug to towbar; got okay to tow; wing walkers thumbs up; towing was successful until aft right Main Landing Gear (MLG) tires hit a small one inch lip at asphalt to concrete change point; right main gear folded at this point and right side of aircraft hit the ground asphalt/concrete.It was discovered that the cause of the problem was shearing of the main gear cam bolts. My only recommendations are a fleet campaign and or; if the problem proves to be affiliated with specific design of the aircraft possibly a Service Bulletin (SB) or Airworthiness Directive (AD) that makes the change of the bolts at regular intervals mandatory. Towing after ferry flight.
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.