Ms Geller says the men were taking infrared photographs for an aerial photography company. They were on their way to Manassas from Philadelphia, but rerouted to Dulles when they ran low on fuel.
Ms Geller says the pilot was taken to the hospital with serious injuries. A woman who was in the apartment was taken to the hospital with non-life-threatening injuries.
The Red Cross is helping nine adults, seven children and pets who had to leave the building.