Originally Posted by
FlyinHawaiian
Yes; it happens. Given the amount of strain the device is under and number of times its used, it's not totally extraordinary for one to break. It's also interesting to note that tow bars often vary by type of aircraft.
As a few of us have noted, the tow-bars are designed to shear upon reaching a certain stress limit, which is supposed to be a lower stress limit than the stress that would cause damage to the nose-gear of the aircraft. However, each aircraft type has different weights and thus different stress levels which would result in damage, thus the tow-bar required would be based on the aircraft type.