Twist locks fall from the bottom corner fittings of containers with some relative regularity. Most of us know that. That's just one reason why no one should be anywhere near a box/can as it's going overhead.
Twist locks typically fall out, because they were not put in correctly or because the nominal physical dimensions of the twist lock or the internal aspects of the corner fitting have been eroded.
The International standard that deals with the handling of intermodal containers requires 800 square millimeters (1.24 square inches) of surface contact area between the internal flange of the corner fitting and the fully actuated twist lock head.
For those of you who keep track of events when twist locks fall out of container corner fittings, it would be interesting to know which ones (which make/model) fall out more frequently.
I know that may be a "heavy lift" for most members, but some of you may have that type of knowledge.
LONGSHORE WORKER FATALLY INJURED IN FALLING TWIST LOCK ACCIDENT ABOARD CONTAINER SHIP [PANAMA CITY, FLORIDA – 06 OCTOBER 2019]
Longshore Safety - Ron Signorino