Incident Details
On July 7, 2017, at approximately 21:00 local time, a professional helicopter pilot was conducting a VFR flight from Łąck to Warsaw Okęcie Airport. While overflying the urban area of Warsaw, after passing the waypoint "ZULU", a red-filtered warning light labeled "BAT DISCH" (battery discharge) illuminated in the cockpit. The pilot decided to perform a precautionary landing on the roof of the TV Polsat building at Aleja Stanów Zjednoczonych, which he considered the most suitable location as he had participated in its construction as a future helipad.
After the Landing
After touchdown, the pilot reduced rotor speed to idle and switched off the air conditioning system. The "BAT DISCH" light then extinguished. Concluding that the warning was no longer active, the pilot decided to resume the flight to Warsaw Okęcie Airport. The remainder of the flight proceeded without further anomalies.
Reporting and Investigation
Upon landing at the destination, the pilot did not report the event to authorities, reasoning that he would only report if the situation recurred. Since no similar occurrences happened during subsequent flights, he maintained that decision. The helicopter remained in continuous operation throughout this period.
The investigation determined that the cause of the incident was the illumination of the "BAT DISCH" warning light, which led to a precautionary landing on an unapproved landing site (the Polsat building, not certified by the Civil Aviation Office – ULC). No safety recommendations were issued by the Polish State Commission on Aircraft Accident Investigation (PKBWL). However, the Commission reminded of the legal obligation to report aviation events within 72 hours.
Preventive actions included discussing the event with the aviation personnel employed at TV Polsat.