
Transforming the way the Air Force uses energy is a key focus of the Air Force Research Laboratory’s Advanced Power Technology Office as it seeks to enable the use of alternative energy and energy efficient technologies.

A new, hybrid electric and battery powered mobile dock system for aircraft depot maintenance is one way that the APTO team is refining capabilities for Air Force teams, developing a clean, efficient energy saving system in the process.

“Traditional lift platforms are either diesel or battery powered. The battery powered lifts have limited range; the batteries are typically depleted over the course of a shift, and they have a lengthy recharge time. This system includes a direct methanol fuel cell for onboard battery charging,” said Eric Griesenbrock, the APTO Installation Energy Working Group Lead. “It’s an electric, battery powered mobile dock but it has a fuel cell that continuously charges the battery—it’s like a ‘Prius’ for maintainers.”

Lift platforms and hard stands play a key role in the maintenance of Air Force platforms, enabling maintainers to safely access panels and components of an aircraft during routine maintenance at a hangar. Existing lift platforms are typically battery powered, with a limited range and lengthy recharge time, or they are diesel fueled, which is costly and limits indoor operations with the hangar doors closed.

Hard stands—similar to scaffolding—require maintainers to construct and relocate as they move around an aircraft to complete maintenance duties. Setting up and moving the hard stands can add a week to the time it takes to get an aircraft ready to begin the maintenance process.

Taking cues from commercial industry giants such as Walmart which uses fuel cell powered systems to operate indoors at distribution centers, the APTO team retrofitted commercial lift platforms with direct methanol fuel cells, aircraft maintenance platforms and safety devices and controls.

The result is a new mobile lift platform that is able to move and shift as maintainers move around an aircraft, eliminating the time required of traditional hard stands. Direct methanol fuel cells provide on-board battery charging, thereby enabling around-the-clock maintenance operations.

“This is a key enabler of systems sustainment,” said Griesenbrock. “Typical maintenance cycles for large aircraft can range from about 100 days up to a year in length for the C-5. Shaving off a day or week by improving equipment can save maintenance time and increase operational readiness for an aircraft.”

Another benefit of the new mobile platform is the integration of ‘clean’ technology which enables maintenance teams to operate the system with hangar doors closed. The enclosed methanol fuel cells for onboard battery charging meet Occupational Safety and Health Administration air, noise, heat and vibration requirements for indoor operations—a direct benefit over diesel fuel operation. Methanol tanks can be refueled in a matter of minutes, similar to a gasoline tank, thereby enabling a quick refueling time.

The new platforms are currently augmenting existing lift platforms and hard stands as part of a six month demonstration to validate their efficiency and effectiveness at Warner Robins Air Logistics Complex where the 402d Aircraft Maintenance Group is testing the system at the C-5 maintenance hangar. The demonstration will conclude in July, and so far the APTO team has received positive feedback about the systems capabilities.

“We (APTO) were asked to help improve maintenance productivity for Air Force depots. This new mobile dock is an example of how the technologies APTO investigates have the potential to improve maintenance not only for the C-5, but across Air Force platforms,” said Griesenbrock.