History of the Flight
On 13 August 2020, an Approved Training Organization (ATO) scheduled a one-hour familiarisation flight for a candidate considering helicopter training on a Robinson R44 II. The pilot arrived at Warsaw-Modlin Aerodrome (EPMO) and began preparations, including refueling with 30 liters of AVGAS 100 LL (total fuel 113 liters). A pre-flight inspection revealed no faults. The candidate arrived around 10:30 hrs and was given a tour of the facilities.
The helicopter took off at 11:15 UTC from EPMO to a flight zone located between the India and Hotel waypoints north of the aerodrome. In that area, the pilot performed a low-height flight and demonstrated an off-field landing. He then flew a circuit to the EPMO Final Approach and Take-Off Area (FATO), descending to hover height without touchdown. After re-establishing communication with EPMO Tower, he was cleared to continue south in the Uniform waypoint zone, over the mouth of the Narew River where it meets the Vistula River. The pilot flew westward; after crossing a bridge over the Vistula, he began a descent. According to the pilot, when he attempted to stop descending at approximately 500 ft AGL, the collective became blocked, and the helicopter collided with the water surface of the Vistula River.
Injuries and Damage
The persons on board were seriously injured. The helicopter was destroyed. The pilot and candidate were rescued from the water by a Police river patrol and taken ashore, then transported to hospitals for medical treatment.
Cause
The investigation determined the cause of the accident was an incorrect estimation of flight height during descent above the river's surface. A contributing factor was performing flight below permissible height.