Several years back when I was working as an A&P for a cargo outfit. We picked up a 727-200 with a fresh "C" check and cargo mod and ferried it over to Guam and start up an operation.
After being on the island for a month or so and this aircraft making several trips to the smaller islands to pick up cargo (fresh fish) the crew departed PTRO enroute back to PGUM.
Just after liftoff and upon gear retraction, the RT MLG wouldn't lock in the up position. After flying around a bit, trying to T/S the problem. The weather at PTRO went below min's (NBD APPR).
The crew elected to continue on to PGUM with the one leg down and after a while they found out that the fuel burn was too excessive to continue on and elected to try for PTYA which was hovering around mins too.
They landed safely at PTYA and had an A&P look the gear over and he signed it off "no fault found" and they gassed up continued on to PGUM.
After liftoff at PTYA, same thing happened again and the crew just left the gear in the UP pos and continued home.
When it arrived, I looked the gear over really well with special attention to the UPLOCK assy.
And sure enough, a piece of phenolic block was jammed up in the lock assy, between it and the spring bungee, keeping the uplock actuator from rotating the hook over and holding the gear up.
Needless to say, we wanted to kick some serious arse at that repair station.