What happened
On September 4, 2022, a de Havillost DHC-3 (Otter), registration N725TH, crashed into Mutiny Bay near Freeland, Washington. The aircraft, operated by West Isle Air dba Friday Harbor Seaplanes, was performing a scheduled passenger flight under Part 135 regulations. The flight began at Friday Harbor Seaplane Base (W33) with the intention of reaching Will Rogers Wiley Post Memorial Seaplane Base (W36).
On the day of the accident, the pilot was scheduled for three roundtrip legs. While the first leg was completed without incident, the accident occurred during the second leg of the day. ADS-B tracking data indicates that after departing Friday Harbor, the aircraft flew a southerly course at altitudes between 600 and 1,000 feet above mean sea level. At approximately 15:08, the aircraft's flight path changed significantly. Performance calculations show the plane pitched up by roughly 8° before undergoing an abrupt 58° pitch down.
Witnesses and video evidence corroborated that the aircraft was in level flight before entering a slight climb and then pitching downward. Some observers described the aircraft as spinning or spiraling during the descent. The aircraft maintained a steep, near-vertical descent until it struck the water. The crash resulted in 10 fatalities, including the pilot and nine passengers. The aircraft subsequently sank in the bay.
Findings
Data analysis indicates that the aircraft experienced a sudden and extreme change in pitch shortly before impact. While witnesses noted the plane appeared to be rotating or spiraling, one observer noted that the sound of the engine and propeller remained consistent, with no audible change in pitch detected during the descent.