The charity's two helicopters will now be able to respond to emergencies in darkness using night vision imaging systems.
The Airbus H145s will fly from 6am-12pm during the week and from 6am-10pm at weekends, with crews wearing night vision goggles.
The Yorkshire Air Ambulance's director of aviation Captain Andy Lister said:
“This really is a great step forward in the operational developments of the YAA. Our pilots and crews have worked extremely hard over the last few months to undertake and learn the processes involved in NVIS flying. It is a complex process for our operational team to have embarked on, however I am pleased to report that we now have a fully capable NVIS team at the YAA. I am very proud of them all, and know we are moving forward together to provide the best possible service for the people of Yorkshire.”
The flights will begin with immediate effect as the nights start to draw in.
The helicopters are based in Thirsk and Wakefield.