Is there information available about an aircraft incident from New York to LHR in 2004?
Here it is: British Airways flight diverted to Bangor.


  At about 8 p.m. British Airways Flight 112, traveling from John F. Kennedy International Airport in New York City to Heathrow Airport in London, diverted to Bangor after smoke was discovered in the cockpit.


Story was published on June 10th, 2004. Article says Wednesday night, so it should have happened on June 9th.

Both the AAIB and the NTSB don't have any reports. It must have been a minor issue. Just a BA 777 on the same day, fuel leak on departing Heathrow.