I had one in LAX when I had just started flying for work. We came in on approach for what seemed forever and just as we were about to set down we heard the wail of the 767 engines and back up we went quick quickly as well. The pilot came on and said an aircraft had strayed across the runway. Personally, I think the guy took too long to put the a/c down but that's really a moot point.

My old boss earned the nickname "Bad Luck John" He was a top level with DL and had been on a/c that 1) blew an engine on takeoff 2) collapsed nose gear landing and 3) I belive the third one was one engine that died during flight. He told me about these as we were waiting for a YVR-YYC flight together and the a/c had gone mechanical and they actually told us at the gate they had to replace an engine! This was back in 99 and I think it was a DC-9 to boot. My boss asked if they had taken it up for a spin and they replied that they had tested it on the ground. He wasn't too pleased about getting on that bird.