Announcement comes after fatal collision between military helicopter and American Airlines jet on 29 January

Federal investigators looking for the cause of the collision between a passenger jet and a US army helicopter that killed 67 people near Washington DC in late January recommended a ban on some helicopter flights Tuesday to improve safety.

The recommendation came after a military helicopter collided with an American Airlines jet as it approached Ronald Reagan national airport over the Potomac River on 29 January. Among the victims were 28 members of the figure-skating community.