A hydrogen A320 APU and Airbus's paused project

Lufthansa Technik researchers published in Frontiers in Mechanical Engineering, on 26 October 2026, a thermodynamic analysis of retrofitting the A320 auxiliary power unit, the APS3200, to burn hydrogen. Flow is about 0.016 kg/s, against 0.0412 kg/s of kerosene. The model is zero-dimensional, excludes NOx and, the authors say, still needs experimental validation.

For new aircraft, the timeline has shifted. On 7 February 2025, Airbus said its ZEROe hydrogen aircraft, targeted for around 2035, is expected later, citing slower technology progress and the hydrogen ecosystem challenge, according to electrive.

If the new aircraft takes longer, today's fleet flies longer and its equipment gains value as a test bed. Retrofitting an APU uses a component already in service.

The study is at the modelling stage, with no emissions measurement or injector testing. Experimental validation will show whether the fleet in service can take part in the transition.