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 three lost in an 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: 6
 * ★ 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.