I had a main gear failure to lock down on a C1K going into Bardufoss in the early 70's, went into the hold at 10000', depressurised, carried out the wind down drill, still no engagement of the pins in the travelling block, undid the rear viewing window and noticed a brake hose trapped between the two, wound it up a bit and pushed the hose out of the way. Wound it down into downlock, landed safely. All that effort at altitude was knackering, would I have seen the problem with side guidance and a full pallet load?