Originally Posted by
JimEli
What makes you think its a structural issue?
As explained to me years ago, aircraft long line external cargo weight limits were determined by the airframe structural load path from the external load to the primary lifting structure. Not all airframes have a direct structural link to the primary lift structure which limit the amount of weight on the hook. There is also the reverse where some aircraft have a lower internal weight limit vs a higher external hook weight limit. In those cases the airframe structural limit can be the landing gear, floor loading limits, CG envelop issues, etc. As to the cargo hooks, it's been my experience that hook mfg'r tend to design/produce hooks to fit groups of aircraft models rather than one hook type for each model. Unless they get a specific OEM contract. So comparing a hook wt. limit to an aircraft external weight limit may not be an accurate comparison.