Precipice of War

Precipice of War is a Railroad quest in Fallout 4.

Bugs
Another way to fix it (Not certain) is to walk around and/or back and fourth below the Vertibird, this may cause it to crash.
 * Shooting the attacking Vertibird with a weapon that can cripple an enemy's legs thanks to its unique affix will cause the Vertibird to become indestructible - its health can be depleted but it won't crash, thus preventing the mission from progressing to the next stage. Make sure to bring a powerful backup weapon if your primary gear features this affix.