britoca | Boeing 747 Contrails - Onboard View @britoca | Uploaded May 2011 | Updated October 2024, 2 hours ago.
Couldn't find an HD onboard contrail video so here's mine

May 3rd, 2011 - Flying over the northern Pacific (NRT-SFO) on an United 747-400 at 12km (40 000') altitude I noticed the contrail forming behind engine #2. Engine #1 is also forming a contrail but it's a bit harder to see.

video could be a bit clearer, but that's all I could get, hope you enjoy