Overview
On 5 June 2023, at approximately 15:20 local time (10:20 UTC), a Viking Air DHC-6-300 Twin Otter floatplane, registered as 8Q-ISI and operated by Island Aviation Services Ltd., impacted a swell during take-off from Brennia Kottefaru water aerodrome (KTH) at Kottefaru Island, Raa Atoll, Maldives. The aircraft, carrying 3 crew and 13 passengers, sustained damage to the left float and left wingtip. No injuries were reported among occupants.
History of the Flight
The aircraft, operating as flight Q2-2401, had earlier departed from Velana International Airport (MLE) and landed at KTH at 11:40 local time. After passengers and baggage were offloaded, the aircraft was taxied to a buoy in the lagoon and tied up. The crew disembarked to the resort and were provided rest facilities.
For the return flight scheduled at 15:30, a Flight Dispatch Release was issued. The crew boarded the aircraft at the buoy and taxied to a platform within the lagoon, where baggage was loaded and passengers boarded. The First Officer (FO) was designated Pilot Flying (PF), and the Pilot-in-Command (PIC) was Pilot Monitoring (PM).
Incident Sequence
The crew attempted take-off in a westerly direction from within the house reef. Water conditions were rough with heavy winds and high swells. The crew initially planned to take off parallel to the swells but could not due to rough water and swells from multiple directions. After discussion, the PIC confirmed a take-off line regularly used, which required initiating the run near the northern side of the service jetty and heading northwest past the arrival jetty.
During the take-off run, just past the fairway (boat entrance) of the reef, a high swell struck the aircraft, hurling it approximately 10 feet into the air. At that point, the aircraft speed was below take-off speed, and the aircraft began to bank left and descend. The PF lost control. The PIC stated he took over controls, applying right rudder, engaging ailerons, and reducing right engine power to idle (without shutting off fuel). Despite these actions, the aircraft banked left and came down outside the lagoon, about 100 meters from the take-off line, in extremely rough water. The aircraft landed on its left float first and then came to a stop.
Aftermath
After the initial take-off attempt, a second attempt was planned with the PIC as PF, but it was discontinued due to high swells and aircraft weight. Following the rejected take-off, the crew noticed an illuminated 'Doors Unlocked' caution light. The cabin crew exited onto the left float and adjusted the aft baggage compartment door handle, which turned the caution light off.
Damage
The left float and left wingtip were found damaged. No fire occurred.
Investigation
The serious incident was reported to the Accident Investigation Coordinating Committee (AICC) at 17:06 hours on the same day, and an investigation was initiated. The investigation focused on prevailing weather conditions, aircraft handling during the take-off attempt, and crew qualifications and experience.