Flight recorder

Marked One is trying to find the crashed helicopter that was carrying Fly. A black box from the helicopter No. 124 that crashed into the roof of the CNPP-2 will be necessary to retrieve for Voronin, and Fly's artifact should be somewhere nearby.
== Walkthrough ==
Warning: This NS quest is notoriously janky. You have to follow the exact directions in this article to advance it. In particular, you must enter CNPP-2 by using the Monolith teleportation device, because the trigger that spawns the flight recorder is located on the otherwise inaccessible roof that is only reachable with this teleport.
=== Flight recorder ===
The helicopter is located on the roof of the 4th reactor unit, near the CNPP chimney. Next to the helicopter, you can find the large spherical flight recorder (20kg):
Pick the flight recorder up. Strelok will shoot off a message to Fang. Fang advises you not to turn around just yet, and to investigate the helicopters in CNPP-2 yourself before the military gets their hands on the recorder.
=== Second helicopter ===
Descend onto the building under the Sarcophagus to the next crashed helicopter.
There will be a letter next to one of the corpses. Open the note by double-clicking it in your inventory, and read it:
"To Cpt. Zimin: 
Why the hell we had to fly over the station... All three helis got caught into a blowout. One tried to do emergency landing onto CNPP roof, another one grazed the chimney with its main rotor and left hanging there. We've got lucky: we landed, but into a wrong place... The radiation readings are off the scale here. Our only chance to get out of there is to drop down to the reservoir below from a rotor blade... But we don't have any time..."
There will be a conspicuous box on the tanks below the helicopter to the south. You have to walk along the blade according to the pilot's letter, and the picture above, to activate the teleport specific to this mission.
Drop down from the helicopter blade to the tanks below, and look for the green box on it. Inside it, you'll find a photograph of the helicopter crashed into the chimney (you can look at it by double-clicking it). Turn east and you can see the massive chimney and the helicopter stuck in it in the distance. Unsurprisingly, this is your target. Head into the newly-formed teleport on the nearby tank.
=== Third helicopter ===
The teleport transports you into the cabin of the tower crane near the huge chimney. Two extra stashes spawn on the crane, the locations are shown on the video below (timecode 6:00):
Head to the front of the crane towards the chimney. You're able to walk inside the crane boom (underneath the girders) without falling. You'll have to walk through the anomaly that induces the double vision. After that, 4 Monolithians spawn on the ground below. From the end of the boom, jump down to the first walkway on the chimney below. Make sure to touch the spot pointed at the picture.
As soon as you land, a new teleport will spawn on the other side of the walkway, and two turrets blocking your way to it from both sides. The ladder is nonfunctional, so head into the teleport.
The teleport transports you onto another walkway above. Beware of two more turrets there. Under the helicopter, you'll find the backpack with the artifact named Water Bloom. Grab it. After approaching the backpack, another teleport will spawn on the opposite side of the walkway; it will take you down to the ground level of CNPP-2.
=== Finishing the quest ===
Bring the black box back to Voronin in the Bar.
== After the quest ==
After giving the flight recorder to Voronin, Strelok will exchange messages with Fly's grandfather, and he will send a helicopter into the Undiscovered Land to return the girl onto the mainland. Head over there, to the stalker camp, and speak to Fly. The helicopter will arrive soon after that, picking Fly up. Before leaving, the pilot will drop off a "gift box" with ammunition for you.
Talk to Fang once again. Suddenly, the helicopter with the girl will be taken down over the [ central swamp] above the Fiery Cave. Strelok will exchange some messages with Fang. Head to the swamp to find Fly's corpse and a wounded soldier. Heal him and ask what happened. The soldier will say that stalkers shoot the helicopter from the south. He gives you two photos of the suspect group and their leader; look at the photos in your inventory - of course it's Skygazer.
Strelok will message Black Doctor, asking him to help Fly in exchange to the artifact. He will reply that to be able to revive people he will need you to go to the Generators and help the scientists in bringing back one of the generators online. (this will lead to Generator startup).
Judging by the photo of the ambushers, they were near the [ hidden cave in the northwest]. Head there to take out the ambushers. You won't find anyone; Strelok messages Fang about that.
==Notes==
* There's no need for long-range turret combat tools since they will spawn directly next to you behind cover. Lean precisely to get an angle on them and take them out with a shotgun (or anything you like).
* The Photos taken by a helicopter pilot item can be given to Kolmogor in a cyclic in exchange for Unique gloves.
* The Pilot's letter item can be given to Informant in a cyclic in exchange for the AWP "Antikiller".
* Strangely enough, Fly's corpse can give coordinates to a rookie-level stash when looted.
==Bugs==