In "Endgame", it is supposed to extract General Shepherd from the river outside Site Hotel Bravo; however, it gets shot down by Captain Price. All of its occupants, including Shepherd, are killed, either by the crash or by John "Soap" MacTavish. One of the soldiers from the chopper is seen crawling on the ground next to the Pave Low, and another is seen lying on the ground trying to shoot Soap; however, his G18 is out of ammo.
If it is possible to catch up to the Pave Low before it takes off; the player can go through it, revealing that it is not a solid object.
The crashed Pave Low is the same as the one in "Wolverines!". Only the destroyed ground in front of it got removed.
While lying on the ground as Soap after the boat went over the waterfall the Pave Low can be heard crashing.
If the player goes through the Pave Low, they will see the pilots have the character models of Volker and Pelayo from Call of Duty 4: Modern Warfare, who makes several appearances with their character models, but when the player is on the ground after crashing down the waterfall, there will be two Shadow Company soldiers with piloting gear on, not Pelayo nor Volker.
Warhorse 5-1 is mentioned in the Modern Warfare 3 reveal trailer during the scene with the AC-130.