FlightFollowerTwin Otter Ditches in the Pacific After Fuel Starvation
A long ferry flight to Hawaii
On the morning of May 20, 2023, a de Havilland DHC-6-400 Twin Otter, registration N153QS, left Charles M. Schulz–Sonoma County Airport in Santa Rosa, California, bound for Honolulu. It was a ferry flight, not a passenger service, and the aircraft had been set up specifically for the long ocean crossing. Its amphibious floats had been taken off, and a ferry fuel system had been installed in the cabin.
Refuelling the day before was a significant job. The fixed-base operator at Santa Rosa put in 1,189 gallons. The aircraft's two main tanks were filled first, then two forward ferry bladder tanks, then a third, smaller bladder.
Plenty of fuel, but not usable
About four hours out over the Pacific, the crew called air traffic control to report a problem transferring fuel and said they were thinking about turning back. They soon declared an emergency, and the numbers they gave explain why. They estimated about 10 hours of fuel was still on board, but only around 2 hours of it could actually reach the engines.
Satellite tracking shows the Twin Otter reversing course to the northeast, toward Santa Rosa, roughly 356 miles from the California coast. By the time it was about 132 miles out, it had descended to about 4,000 feet. The controller told the crew a Coast Guard helicopter would head to their last known position to meet them, and the pilot thanked him. It was the last transmission from the aircraft.
The final minutes
In the final minutes of track data, the altitude falls from about 3,600 feet to around 240 feet. The last recorded position was about 33 miles off the coast, near Half Moon Bay. The aircraft hit the water at about 1:54 p.m. local time and sank, and the Coast Guard arrived within minutes. The fuselage was found upside down with the wings and both engines torn away. The pilot and the one passenger were killed.
The official finding
In its final report (WPR23LA192), the NTSB found that the ferry fuel tank system failed to transfer fuel, for reasons that could not be determined. That failure led to fuel starvation and the ditching.
Why this case matters
This accident was not caused by running out of fuel in the usual sense. When the crew turned back, most of their fuel was still on board. The problem was that a temporary system bolted in for a single long flight became the only path to that fuel, and when it stopped working the aircraft had just a couple of hours of range left, hundreds of miles from land.
Ferry flights like this depend on an auxiliary tank system and on the crew being able to confirm it is working early, while turning back is still easy. By the time the problem was clear, the Twin Otter was already four hours into a crossing that its accessible fuel could no longer cover.
Research and reconstruction
Flight Follower Editorial Team
This reconstruction was researched from official investigation records where they exist, the original air traffic control recording, and contemporary reporting. The aircraft movement, timeline and written account were assembled independently by Flight Follower. Where an investigation is open or no probable cause has been published, the account says so rather than offering one.
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- Incident date
- 20 May 2023
- Aircraft / registration
- DHC-6 Twin Otter 400 — N153QS
- Investigation status
- NTSB Final Report WPR23LA192