Helio H-391B N4431U accident near Monroe, Michigan, August 18, 2025
Helio H-391B, registration N4431U, was involved in an accident near Monroe, Michigan on August 18, 2025. The NTSB lists the highest injury level as none. Case CEN25LA325 is completed.
ADS-B receivers recorded 29 minutes of the flight, reaching a maximum of 2,400 ft. The last recorded position was at 16:33 UTC, at 1,000 ft and 51 knots, descending at 704 feet per minute, about 2 km from Monroe/Custer Arpt (KTTF).
The nearest weather report, from KTTF (2 km away), showed wind 100° at 6 knots, visibility 6 miles or more, ceiling 3,600 ft (VFR conditions).
This page reconstructs the flight from public ADS-B data for information only. The NTSB report is the authority on what happened and why.
Key facts
- Date
- August 18, 2025
- Location
- Monroe, Michigan
- Aircraft
- Helio H-391B
- Registration
- N4431U
- Injuries
- None
- NTSB case
- CEN25LA325 (Completed)
- Nearest airport
- Monroe/Custer Arpt (KTTF)
- Recorded flight
- 29 min, max 2,400 ft
- Last recorded position
- 16:33 UTC, 1,000 ft, 51 kt
3D flight replay
Replay the recorded flight in 3D with the weather, light and terrain at the time, flight instruments reconstructed from the aircraft's ADS-B transmissions, and automatically detected events.
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Sources: NTSB case CEN25LA325; ADS-B flight data from adsb.lol (ODbL); weather from NOAA / Iowa Environmental Mesonet and Open-Meteo.