What happened
On September 19, 2020, an Aero AT-3, registration SP-RWF, was scheduled for a flight departing from Warsaw Babice (EPBC) with a route via EPLLEPPT and returning to EPBC. After retrieving the aircraft from hangar number 4 at 12:40 UTC and performing necessary checks, the pilot taxied to the holding point for runway 28L. Due to heavy airport traffic, the pilot waited approximately 10 minutes before receiving takeoff clearance.
The takeoff was executed at 13:45 UTC. Shortly after liftoff, at an altitude between 200 and 250 feet AGL, the pilot observed a sudden drop in engine RPM from the standard takeoff setting of 5400 RPM down to a range of 3500–4000 RPM. This reduction in power was accompanied by light vibrations throughout the airframe. The engine parameters and vibrations returned to normal after approximately two seconds.
Following the event, the pilot reported the situation to Babice Radio. The pilot continued the climb to an altitude of approximately 1200 ft (QNF) before initiating a turn back to the airfield. The aircraft landed on runway 10R with a crosswind at 13:48 UTC without further incident.
The investigation
The PKBWL examined the final report submitted by the aircraft operator regarding the engine fluctuations and the subsequent flight maneuvers.