Someone is flying drone surveillance aircraft around Empire City. One of them has come down near you and Moya asks you to investigate. Run to the wreckage on the pier and press 
to transmit the codes to Moya. She'll then pinpoint four other UAVs that are still in the air.
Take out the drones[edit]
The shipping crane over the wreckage of the downed UAV makes a great first platform to take down one of the drones still in the air. Climb to the top and shoot at anything that comes close. When one goes down, a single objective marker will show on your map. Get there as quickly as possible, approach the wreckage and press to collect the flight recorder. If the UAV goes down in the water or you don't get to the UAV in a certain time limit (which is never displayed), the wreckage disappears and another UAV appears in the sky in the same flight path.
Repeat this performance for the other three UAVs. You'll need to find a tall building roughly in the flight path of each UAV, shoot it down (use Precision to make sure you get a good, clean shot) and chase down the wreckage. Once you have all four flight recorders, you have to find a satellite uplink to send the data to Moya.
You're directed to a satellite on top of the tall round tower in the north central part of the Warren. Of course, the place is now crawling with Dust Men. Find a tall building on the perimeter and take out the Dust Men on the tower, then glide across and climb to the satellite.