747 Cargolux emergency landing
Evertonian
A testament to the skill of the engineers & designers of the 747 this!
not too sure I’d like to see it happen to a 777F though… 🤔
not too sure I’d like to see it happen to a 777F though… 🤔
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Seem to remember that the A340 steering restrictions came in after this Sabena incident https://aviation-safety.net/database...?id=19980829-1 .....which did sheer the MLG.
As for the CargoLux....just wondering if it could be a tilt actuator failure or failure of supply pressure to it so the gear presented at incorrect angle on touchdown?
As for the CargoLux....just wondering if it could be a tilt actuator failure or failure of supply pressure to it so the gear presented at incorrect angle on touchdown?
Last edited by Tom Sawyer; 16th May 2023 at 23:00.
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Seem to remember that the A340 steering restrictions came in after this Sabena incident https://aviation-safety.net/database...?id=19980829-1 .....which did sheer the MLG.
As for the CargoLux....just wondering if it could be a tilt actuator failure or failure of supply pressure to it so the gear presented at incorrect angle on touchdown?
As for the CargoLux....just wondering if it could be a tilt actuator failure or failure of supply pressure to it so the gear presented at incorrect angle on touchdown?
For those above, note:- B747 main Wing gear has tilt actuator, and body gear, has body gear steering actuators!
Last edited by aeromech3; 18th May 2023 at 05:22.
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As you mentioned the BLG steering system, I guess it is also feasible that a yoke failure or disconnection, or an actuator structural failure could possibly cause the bogie to present at the wrong angle.
Like I said, been a while so I maybe incorrect?
Truck vs Bogie. As far as I know only Boeing refers to this as truck. Every other manufacturer (Douglas, Lockheed, Convair, Airbus) called it a Bogie.
Looking at the pictures in the AvHerald a couple of things standout.
1. In the view of the bogie in the grass the inner cylinder of the shock absorber is clearly fractured. Also the upper end of the lower torque link is ruptured where it connected to the spindle that connected it to the steering actuators.
2. In the picture of the rear of the RH Body gear the steering actuators are intact as is the vertical pin that connects the actuators to the spindle that in turn connects to the lower torque link. Said spindle appears to be intact with the nut that secures the lower torque link still in place. The spindle is now hanging vertically.
I have never heard of either of these parts fracturing before and the spindle appears to be complete so if the torque links did not became disconnected what initiated such a huge failure? I doubt a truck positioner fault could cause such a failure mode.
Looking at the pictures in the AvHerald a couple of things standout.
1. In the view of the bogie in the grass the inner cylinder of the shock absorber is clearly fractured. Also the upper end of the lower torque link is ruptured where it connected to the spindle that connected it to the steering actuators.
2. In the picture of the rear of the RH Body gear the steering actuators are intact as is the vertical pin that connects the actuators to the spindle that in turn connects to the lower torque link. Said spindle appears to be intact with the nut that secures the lower torque link still in place. The spindle is now hanging vertically.
I have never heard of either of these parts fracturing before and the spindle appears to be complete so if the torque links did not became disconnected what initiated such a huge failure? I doubt a truck positioner fault could cause such a failure mode.
Last edited by CV880; 18th May 2023 at 19:05. Reason: Had not finished typing
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Brittleness
The steel alloy the landing gear is made of is very sensitive to hydrogen.
When hydrogen molecules penetrate the material, which can happen when the chrome coating is damaged, a phenomenon called Hydrogen Brittleness will occur.
This causes tension and subsequent cracking of the part.
My educated guess is failure of the gear inner cylinder, preventing gear retraction after T/O.
When hydrogen molecules penetrate the material, which can happen when the chrome coating is damaged, a phenomenon called Hydrogen Brittleness will occur.
This causes tension and subsequent cracking of the part.
My educated guess is failure of the gear inner cylinder, preventing gear retraction after T/O.
