An aircrew performs preflight checks before flying a mission July 18, 2018, to test the ability to perform a Pilot-Directed Airdrop in a C-17 Globemaster III. For the tests, the aircrew included an additional crewmember who was responsible for initiating the airdrop instead of the onboard computer. the purpose of the test mission was to conclude the effectiveness of having an aircrew conduct an airdrop using visual cues in situations where the aircraft is operating with a degraded or complete loss of primary navigation computer guidance.