Divers were today searching for clues to a mid-air crash between a light aircraft and a sightseeing helicopter carrying tourists over New York’s Hudson River in which nine people died.

Investigators probing a deadly train crash near the Washington-Maryland border are looking more closely at a stretch of track near the wreck site after finding abnormalities yesterday in equipment that senses trains and transmits speed commands.

A small plane slammed into a 40-storey apartment building in New York, killing two people in a crash that rained flaming debris onto the pavements and briefly raised fears of another terrorist attack.

The lone US air traffic controller on duty the morning Comair Flight 5191 crashed had cleared the jet for takeoff, then turned his back to do some “administrative duties” as the aircraft veered down the wrong runway, a federal investigator said in Kentucky.

Investigators in Kentucky, probing a weekend plane crash in which 49 people were killed, were today trying to determine why the commuter aircraft used a runway that was too short for take-off.