De Havilland BC DHBC-6 Twin Otter

The De Havilland BC DHBC-6 Twin Otter is a twin-engined STOL utility aircraft built by De Havilland British Columbia; it is a licence-built version of the De Havilland Canada DHC-6 Twin Otter, to which it is identical.

Design & development
The DHBC-6 Twin Otter was identical in all respects to the DHC version, but was sold exclusively on the BC market, as the terms of the licence forbade sales outside of BC.

Operational history
See also: DHBC-6 Twin Otter operators

Of 91 DHBC Twin Otters built, most remain in service - only seven have been retired, and five lost in accidents.

Only one BC-built Twin Otter has ever been registered outside of BC: Imperial Oil of BC bought two, of which one was registered in Canada.

Operators
Operators who took delivery of aircraft new from the factory are marked with a star (★).

Current

 * British Columbia
 * ★ BC Ambulance Service: 4
 * ★ BC Coast Guard: 4
 * ★ BC Government Air Service: 3
 * Corilair: 6
 * ★ Harbour Air: 12
 * Island Express Air: 5 (+1 retired)
 * ★ Kootenay Airways: 9 (+4 retired)
 * ★ North Cariboo Air: 5
 * Northern Thunderbird Air: 6
 * ★ Pacific Coastal Airlines: 5
 * ★ Royal Mail of BC: 8
 * Seair: 2
 * Utari Air: 4
 * ★ Vancouver Island Air: 8 (+4 retired)


 * Canada
 * ★ Imperial Oil: 1

Former

 * British Columbia
 * ★ Alberni Airways: 2
 * ★ Atlin Airways: 3
 * ★ Awyr Cymru Newydd: 8
 * ★ Haida Air: 3
 * Hawkair: 4
 * ★ Imperial Oil: 1
 * ★ Island International Airways: 6
 * ★ North Peace Airlines: 4
 * ★ Northern Air: 3
 * ★ Omineca Airlines: 2
 * ★ Pacific Western Airlines: 7
 * ★ Sunshine Coast Air: 3
 * ★ Thunderbird Airways: 4

Accidents & incidents

 * 14 January 1977 Northern Air VB-NTB (c/n C972/1968), operating as Flight NO 603 from Prince George to Terrace, crashed into a hill on approach to Runway 32 during a snowstorm. All nine passengers and three crew aboard were killed.


 * 17 September 1994 Corilair VB-COE (c/n C1041/1969), operating a charter flight from the Fish Egg Inlet logging camp to Pruth Bay located 16 nmi away, crashed on takeoff. As the aircraft climbed through 100 feet the flaps were retracted, when a violent pitch-up was experienced. The aicraft stalled, crashing into the water 100 feet offshore and sinking immediately; of the two crew and two passengers aboard, only the co-pilot survived. Investigation revealed that the elevator control cable failed at station 376 due to corrosion, causing the pilot to lose control of the aircraft; the corrosion had not been detected during the aircraft's last cable inspection.


 * 1 November 2000 Harbour Air DHBC-6 Twin Otter VB-HRG (C1565/1977), operating as Flight H3 151 from Vancouver–Coal Harbour to Victoria Inner Harbour, suffered a loss of power in one engine on take-off and crashed. Shortly after take-off for the 35-minute scheduled flight, at an altitude of around 80 feet the no. 2 engine failed. The aircraft struck the water about 25 seconds later in a nose-down, right wing-low attitude, and the right hand float and wing detached from the fuselage. Both pilots and the fifteen passengers managed to clamber up onto the float and the wing until rescue boats, including the SeaBus harbour ferry, arrived to evacuate the survivors. The investigation revealed that a planetary gear in the propeller gearbox of no. 2 engine disintegrated, causing the drive shaft to disconnect from the propeller, which resulted in the loss of propulsion from the engine. The gear failure was found to have been caused by the fracturing of the oil strainer screen sending wire fragments and debris into the gear bearing sleeve. Investigators also concluded that although the airspeed was above V MC, the aircraft became uncontrollable due to power on the remaining engine not being reduced to relieve the asymmetric thrust until impact was imminent.


 * 17 March 2012: Kootenay Airways Twin Otter VB-CYT (c/n C1094/1970), operating as Flight KY 266 from Cranbrook to Blue River, was damaged in a landing accident. Because Blue River Airport - an aerodrome used primarily for general aviation - does not have a published instrument approach procedure, approaches must be made under visual flight rules. Deteriorating weather, along with the lack of approach aids and runway markings, hampered the pilot's ability to establish the aircraft onto a stable final approach prior to crossing the threshold; the company's standard operating procedures for stabilized approaches were not followed, and an unstabilized approach was allowed to continue resulting in the pilot's inability to position the aircraft over the centre of the runway as it settled to land. The left main gear entered the deeper snow at the edge of the runway, causing the aircraft to veer into the snowbank. There were only minor injuries amongst the two crew and eight passengers, and the aircraft was repaired and returned to service.


 * 23 February 2018: Island Express Air Twin Otter VB-IXD (c/n C1316/1973), operating a non-scheduled charter flight from Abbotsford to San Bernardino, California, USA, crashed on takeoff. Weather conditions at Abbotsford at the time of departure consisted of a temperature of -2°C in moderate to heavy snowfall with winds of approximately 10 knots. Prior to the departure, the fuel tanks were filled to capacity and the pilot and passengers boarded the aircraft inside the operator's heated hangar. The aircraft was towed out of the hangar without being treated with anti-ice fluid, and taxied for the departure on Runway 07. Due to an inbound arrival at Abbotsford, the aircraft's departure was delayed. Once cleared for takeoff, the aircraft had been exposed to snow and freezing conditions for approximately 13 minutes. Approximately 4 to 5 seconds after takeoff, the pilot selected the landing gear control to the up position. As the gear retracted, the aircraft rolled approximately 30° to the left. To correct the uncommanded left bank, the pilot applied right aileron, and the aircraft returned to a near wings-level attitude. In order to make an immediate off-field emergency landing, the pilot retarded the power levers and then applied forward pressure on the control column to land the aircraft. The aircraft struck terrain between Runway 07 and Taxiway C. The aircraft slid across the snow-covered ground for approximately 760 feet before coming to rest in a raspberry patch located on the airport property. Four passengers and the pilot sustained serious injuries as a result of the accident which destroyed the aircraft.