Both aircraft fell into the Potomac River on Wednesday night, killing 67 people.
US officials say warnings were sent to a military helicopter and passenger jet in the seconds before they collided over Washington DC.
Both aircraft fell into the Potomac River on Wednesday night, killing 67 people.
Investigators hope to have an initial report on the mid-air collision within 30 days.
The bodies of 42 people have been recovered - with 38 of them identified.
Asim Raza's niece Asra was among them:
