Incident Overview
On September 8, 2016, at Warsaw Chopin Airport (EPWA), an Embraer 190-100 (registration OH-LKM) operated by Finnair as flight AY 744 from Warsaw to Helsinki was being pushed back from stand 22. The pushback was performed using a Schopf F 206 tow tractor (side number 1218) and a towbar assigned for that aircraft type.
Circumstances
After the tow tractor and aircraft reached taxiway M at approximately 19:00 local time, the headset operator began the procedure to disconnect the towbar from the tractor and release the aircraft for taxi. At that point, the locking pin securing the towbar to the tractor could not be removed. The tractor operator left the cab to assist the headset operator in disconnecting the towbar. After several attempts, the pin was successfully removed, causing the towbar to fall onto the apron, thereby disconnecting the assembly.
While leaving the vehicle, the tractor operator had not engaged the handbrake. Due to the slope of the terrain and the lack of a fixed resistance, the tow tractor began to roll uncontrolled after disconnection. The moving tractor struck the forward section (nose) of the aircraft with the edge of its cab roof, resulting in a cracked radome.
Both operators involved held valid qualifications and tested negative for alcohol or other intoxicating substances. Weather conditions at the time were not a contributing factor to the incident.
Cause
The investigation determined that the cause of the incident was non-compliance with applicable procedures.
Actions Taken
No safety recommendations were issued by the investigating entity. The operator had not taken any preventive actions at the time of the report.