The Lot Event yesterday got me thinking...

- How often to Landing Gears fail (very rarely apparently)
- Are there any Planes with Backup Devices?

I always considered a failing Landing Gear a major Risk, particularly on the big Boeings (like above) that have the engines considerably lower than the rest of the frame (considering they could break and subsequently turn the aircraft).

Then, in my mind - it was all rather simple. Never looking for proof, I assumed they would have some kind of crank lever they could use in order to manually wind down and lock the landing gear (even if it would probably take half an hour or an hour of cranking) in case of a hydraulic / landing gear failure.
Apparently this is not the case on a 767...

Are there other aircraft that have this (or another) backup, or are pilots just meant to be able to land aircraft w/o landing gear?

Is such a failure even considered in an aircraft's design phase (to make sure the engines and wings are stable enough), or is that a "unforeseen - well good luck!" moment?