Brindabella Airlines has withdrawn four of its 10 aircraft from service to ensure they are working properly. All the planes were twin-propeller Jetstream 41s, which carry up to 30 passengers.
Several flights have been cancelled as a result, including Monday's Canberra-to-Newcastle service at midday as well as some Sydney-to-Orange and Sydney-to-Narrabri services.
The airline's chief commercial officer, James Blake, said on Sunday the planes would return to operation this week.