Hennessey 4

Hennessey 4 was a digital volume at CTU Los Angeles. It stored data related to airport facilities.

Day 5
During the hostage crisis at Ontario Airport during Day 5, Curtis Manning spotted terrorist Ivan Erwich walking inside Hangar BB. He called Edgar Stiles at CTU to have schematics of the hangar. Edgar verified with Chloe O'Brian which volume held the data on airport facilities and confirmed it was Hennessey 4. He then sent the data to Manning.

Background information and notes

 * In technology, a volume refers to a storage area which could be a disk drive or a partition within one.