Tragedy of Free-Falling Plane Caused by Forgotten Small Component

NTSB Investigation Reveals Missing Lock Ring in DHC-3 Otter Crash

The de Havilland DHC-3 Otter, operated by Friday Harbor Seaplanes (West Isle Air), departed from Friday Harbor Seaplane Base at 14:50 local time on September 4, 2022, heading for Renton, Washington. According to NTSB records, the flight was operating normally at a cruising altitude between 600 and 1,000 feet with speeds ranging from 115 to 135 knot under clear skies and moderate turbulence. Approximately 18 minutes into the flight, witnesses and security footage recorded the aircraft pitching up about 8° before entering an extreme, near-vertical dive at a 58° angle, ultimately striking Mutiny Bay and sinking 200 feet.

Investigators discovered that a clamp nut had completely separated from the horizontal stabilizer actuator tube because a crucial lock ring designed to hold it in place was absent. Laboratory testing conducted during the probe confirmed that a red moisture seal installed by the director of maintenance in April 2022 to prevent corrosion had increased rotational friction between the clamp nut and the eye bolt. The NTSB could not definitively establish whether the ring fractured during flight or was simply omitted by maintenance personnel during the prior component overhaul.

Korean Air Flight KE189 Rapid Descent and Passenger Injuries

In a separate commercial aviation event, a Korean Air Boeing 737 Max 8 operating flight KE189 from Incheon to Taichung, Taiwan, suffered a cabin pressure system malfunction on June 22, 2024, according to reports from Bisnis.com and The Straits Times. Flightradar24 tracking data indicated the aircraft descended 26.900 feet over a 15-minute window after a pressure warning triggered roughly 50 minutes after departure. The plane safely returned to Incheon International Airport about three hours after its initial takeoff.

South Korea’s Ministry of Land, Infrastructure and Transport reported that 15 passengers experienced hyperventilating or ear drum pain during the descent, with 13 individuals transported to hospitals upon landing. Passengers described severe panic onboard as oxygen masks deployed, children cried, and families struggled with the sudden cabin altitude changes. Korean Air subsequently scheduled the continuation of the flight for the following morning using a different aircraft and issued formal apologies to affected travelers.

Frequently Asked Questions

What caused the de Havilland DHC-3 Otter crash in September 2022?

According to the NTSB, the crash was caused by the separation of a clamp nut from the horizontal stabilizer actuator because a retaining lock ring was missing, leading to an uncontrolled downward dive.

How many passengers were injured in the Korean Air KE189 incident?

According to South Korea’s Ministry of Land, Infrastructure and Transport, 15 passengers reported hyperventilation or ear drum pain, and 13 passengers were taken to hospitals after the aircraft landed back at Incheon International Airport.

Did the Korean Air flight complete its journey?

Yes. According to Korean Air, the flight was rescheduled and departed the next morning using a different aircraft, approximately 19 hours after the initial departure time.