A Check: This check is carried out every 400 - 600 flight hours or 200 - 300 movements depending on the type of aircraft. This examination requires about 150-180 working hours and is generally carried out in the hangar for at least 10 hours
B Check: This check is carried out every 6-8 months. Inspections require 160-180 hours of work, depending on the type of aircraft, and generally finish within 1-3 days in the hangar
C Check: This check is carried out approximately every 20-24 months the time needed for this examination is between 1-2 weeks and requires up to 6000 working hours
D Check: This check requires up to 50000 working hours and 2 months to complete.