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Man vs. Machine: testing Pilot-directed Airdrop in a C-17

By Staff Sgt. William A. O’Brien | Joint Base Charleston Public Affairs | July 27, 2018

JOINT BASE CHARLESTON, S.C. — Test directors from the Air Mobility Command Test and Evaluation Squadron at Joint Base McGuire-Dix-Lakehurst, New Jersey, conducted a capability evaluation of C-17 Globemaster III Pilot-Directed Airdrop tactics, techniques and procedures here July 9-20, supported by aircrews from Joint Base Charleston, South Carolina and Joint Base Lewis-McCord, Washington.

The test measured the capability of an aircrew member to conduct an airdrop using visual cues in situations where the aircraft is operating with a degraded or complete loss of primary navigation computer operations.

“The C-17 is designed as a two-person cockpit and for visual airdrop, they’re adding in a third person,” said Capt. Tiffany Szumila, one of two AMCTES PDA test directors. “The third person is the right additional crew member, or RACM, who is essentially becoming a navigator of sorts by using route study on the ground to identify visual points of certain distances that match up to a predefined time, based on a ground speed, in order to do a visual navigation to that point.”

During standard airdrop operations, if the aircraft computers are not functioning properly, the aircrew decides if they are going to take another pass and try to reboot the system, or return without completing the airdrop. This is determined by the threat level assigned to the mission.  However, with PDA, if the system were not working, the RACM would replace the functions of the computer and assist the pilots in getting over the drop zone and successfully dropping the cargo.

“All the timing cues we normally get from the mission computer are then solely the responsibility of the RACM,” said Capt. Nikolaus Krause, pilot from the 8th Airlift Squadron at JBLM. “From a minute out, that is all on the RACM to make sure the timing of the drop is happening and when it gets really critical is within five seconds, because if we’re even a second late, that's 85 yards off target for just that one second.”

The test evaluated two aspects of PDA: the accuracy of each drop, and the perceived workload of the pilot acting as the RACM.  The test team collected data based on where the RACM called for the drop in comparison to where the computer would have otherwise specified.  The metrics are based on actual aircraft position over the ground, removing post-release variables such as wind effects.

“The goal for the past two weeks has just been to see how accurate we can be within a predetermined boundary from the desired release point,” said Krause. “We're more concerned with how accurate we are in relation to our predetermined release point than we are necessarily with the material that’s dropped.”

To determine that accuracy, the test directors received printouts showing how closely the drops would have been to the drop point.  Over the next few weeks, the team will evaluate the data and report on the effectiveness of PDA, supporting AMC leaders in making a final fielding decision. 

A crucial aspect to any new tactic or procedure is the additional workload placed on the crewmembers and potential interference with other mission-essential tasks.  During the test, each pilot rated their workload on a 1 to 10 scale.  With the data from every pilot in every crew position, test directors are able to determine task distribution in the cockpit, especially with the addition of the new RACM crew position and duties.  Through comparison with pilot and co-pilot ratings over the test period, the test directors will evaluate the crew resource management, a critical facet of crew aircraft, and provide feedback to assist with optimizing the new tactics.

“After every airdrop, we ask them [test participants] what they perceive the workload to be.  Those are relative numbers and change by the person, but what we're trying to understand is how busy do they feel,” said Maj. William Carter, AMCTES PDA test director. “Do they feel like they can't do anything else if they’re doing this?  Do they have enough situational awareness to take care of all the other tasks they need to do while operating the aircraft and doing the airdrop mission?”

With all the tests now complete, the AMCTES team will publish a formal report on their findings helping to enhance the combat capability of the AMC fleet.