The Crashed Vertibird can be found in a crater east of the Old Nuclear Test Site and south of Matthews Animal Husbandry Farm. The crater is almost always guarded by several sentry bots and Mister Gutsies. Be aware that sometimes these enmies can differ, occasionally the guardians are Feral Ghouls.
Points of Interest
The Vertibird is confirmed to belong to the Navarro Outpost.
The unique energy weapon Tesla-Beaton Prototype is located here, scattered among a few skeletal remains just outside the front window of the Vertibird, along with some other basic pieces ammunition such as Energy Cells, Missiles and Flamer Fuel. You can also loot the corpses of the sentry bots and Mister Gutsies for more of the same.
On rare occasions you will be assisted by an unknown NCR Ranger when fighting the robots here. It is not now where this Ranger comes from, however.
It is advised to take with you energy weapons that makes use of the EMP effect, as this can be particularly effective on robots. However, do note that the hardened sentry bots seem to have a higher EMP resistance than normal. If you can, make it past the robots and collect the Tesla-Beaton Prototype (But also make sure you have Electron Charge Packs in your inventory; this is what the TBP uses as ammunition). This weapon is particularly effective with dealing with the robots, most of which should go down after only a couple of shots.
It is likely that the charred remains surrounding the Vertibird are that of Enclave Soldiers and Pilots.