Tug Accident Clark Airport Philippines

[MichaelOLearyGenius]

Looks like main chocks still on
https://cimg9.ibsrv.net/gimg/pprune.org-vbulletin/960x720/917b42b1_e859_4af1_a871_5b5812e4c2f5_99a396a5dbd13ebaf269eb1 20bb1fff9f24fac1a.jpeg
https://cimg0.ibsrv.net/gimg/pprune.org-vbulletin/1500x1125/80bebe0b_aa8b_4978_990f_b41b137ff91b_3cfc8ec4734b982193a9240 5f44e685048a6f645.jpeg
https://cimg1.ibsrv.net/gimg/pprune.org-vbulletin/1500x1125/45a91616_d5a2_452a_aa35_9048850c5538_43cbd80bd4688c5228b6c41 fea93b0fc7abd8913.jpeg

[Pilot DAR]

I will speculate: Chocks wisely inserted after the event. Tug was towing the plane. Tug stopped, plane didn't. Towbar buckled, plane stopped on tug. 'Seen it before more than once. The nosewheel skid marks are a clue....

[MrNosy2]

When did it happen?

[Zar_1]

Looks like a A321ceo (with CFM), right?

The forces involved, to cause this at low speed would be pretty insane!
oof

[dixi188]

I will speculate: Chocks wisely inserted after the event. Tug was towing the plane. Tug stopped, plane didn't. Towbar buckled, plane stopped on tug. 'Seen it before more than once. The nosewheel skid marks are a clue....
Or aircraft tried to taxi with tug still connected. Happened before.

[Zar_1]

Wouldn't the NW STRG Disconnect message be present, in amber, on the ECAM? And anyways, the steering would be disabled cause of the pin. Seems pretty weird tbh.

[MechEngr]

I keep looking at the area of white paint near the buckling location. The paint adhered in the area of most extreme deformation at the top of the crease, so I don't believe the white area is topcoat releasing from primer. I wonder if sometime that tube got dented leaving it prone to buckling failure.

It's not an area I worked on so I won't give a number, but the strength reduction is considerable. I can give an example - a soda can wall is thinner than a sheet of paper, yet a large force can be applied the upright can and that thin wall will be sufficient. However if, while a force is applied to the top of a soda can, a slight dent is made, the can will buckle catastrophically.

https://www.youtube.com/watch?v=AXSG3q1Jqp0

Since a soda can has a low length to diameter ratio it collapses axially. The larger ratio tub on the tow bar can simply bend sideways to relieve the load.

It's even more impressive if the tube (or soda can) is filled with a fluid that resists the wall buckling inward.

https://youtu.be/YP_UBNwEoGs?t=242

I won't spoil the surprise. This pressurization is what allows rockets holding huge weights of liquid in thin tanks to not buckle and collapse on the launch pad even with similar wall-thickness to diameter ratios as the soda cans.

More on topic - make sure the tug operators are looking for even small dents in towbar tubing. They won't affect the ability to pull but will greatly reduce the ability to stop.