Widerøe Flight 744
Encyclopedia
Widerøe Flight 744, also known as the Namsos Accident , was a controlled flight into terrain
of a de Havilland Canada DHC-6-300 Twin Otter during approach to Namsos Airport, Høknesøra
in Norway
. The incident occurred on 27 October 1993 at 19:16:48 and killed six of the nineteen people on board, including the crew of two. No technical problems were found on the aircraft, and the accident report commented on a number of procedural errors committed by the two pilots during descent.
was 43 years old, had held a pilot's license
since 1974 and had been employed in Widerøe since 1985. He had held a C certificate since 4 January 1993, and had been a pilot in command since 20 January. He had flown 4,835 hours and landed 13 times at Namsos Airport in the last 12 months. The first officer was 34 years old, had training from the United States, starting in 1981, which had been converted to a C certificate in 1988. He had 6,354 hours of flight, of which 1,356 was in a Twin Otter. He had been a pilot in command for 3,441 hours prior to working for Widerøe, where he had been employed since 1990. He had landed 27 times the last 12 months at Namsos Airport.
The first officer was using a medication against back pains which was not permitted while flying. However, these had been prescribed by a physician who had training in aviation medicine. No traces of the substance were found in the pilot's body after the accident. The aircraft had a maximum take-off weight of 5675 kilograms (12,511.2 lb), while the aircraft took off with 5460 kilograms (12,037.2 lb). Prior to departure, the ground handling agent, Scandinavian Airlines System
had calculated the passenger load and mean aerodynamic chord
of the passengers. When correcting this after observing the seating of the passengers, the pilot in command had made a calculation mistake, whereby he though passengers did not need to move around, while they actually would have to meet the limits of the distribution of weight.
The crew had started duty at Bodø Airport
at 13:30 (UTC+1
) and were to make a round trip to Trondheim Airport, with intermediate stops at Sandnessjøen Airport, Mosjøen Airport, Brønnøysund Airport, Brønnøy
, Rørvik Airport as Flight 711. On the way down, the flight canceled stopping at Mosjøen due to the bad weather and the aircraft landed at Trondheim Airport at 17:52. The return flight was to operate as Flight 744 from Trondheim via Namsos to Rørvik, where the plane and crew were to overnight. At Trondheim, 17 passengers boarded along with 136 kilograms (299.8 lb) of cargo. Estimated flight time to Namsos was 35 minutes. The aircraft left Trondheim Airport at 18:37 after which it ascended to cruising height at 5000 feet (1,524 m). At 18:53, the QNH
was confirmed by Namsos to be 1017 hPa
. This gave a height reading of 4950 feet (1,508.8 m) and 4900 feet (1,493.5 m), respectively, for the pilot in command and first officer. There was 25 knots (13.6 m/s) wind from 250°, with gusts up to 36 knots (19.6 m/s).
The pilot in command then decided on the descent plan, involving an initial descent to 4000 feet (1,219.2 m), then down to 3000 feet (914.4 m), before making a swing towards localizer 255. Then the aircraft should descend to 2100 feet (640.1 m) and head towards Namsos beacon inbound. After that, minimum height was set to 2100 feet (640.1 m). At 19:01, the aerodrome flight information service
(AFIS) announced new weather data: the wind had changed to 260° at 25 knots (13.6 m/s), with gusts up to 40 knots (21.8 m/s). As the crew planned to use Runway 26, this would give wind directly against the craft, so the crew decided to add some height to the descent. At 19:05, the first officer stated that the descent checklist was completed, and the pilot in command started the approach checklist. At this time, both height indicators showed 5000 feet (1,524 m). At 19:07, the aircraft was turned to 050°.
At 19:10, the aircraft reached the center line and the aircraft was confirmed by Namsos AFIS at 255°. By 19:14, the aircraft had descended to 2100 feet (640.1 m) and at 19:15:13, it passed Namsos beacon. At 19:15:30, the first officer confirmed visual contact with the field. At 19:16:35, the pilot in command stated a height of 500 feet (152.4 m), confirmed by the first officer. Four second later, the pilot in command stated: "we should not descend any further". At 19:16:48, the aircraft hit a hill 6.15 kilometres (3.8 mi) from the airport, at Berg in Overhalla. A distress radiobeacon signal was received by Namsos and a search and rescue
operation was started immediately. Both pilots, plus four passengers were killed, while the remaining thirteen passengers were injured. The aircraft first hit some trees, located 119 metres (390.4 ft) above mean sea level
. The aircraft was written off after the accident. The instrument landing system
at Namsos Airport was tested by the Norwegian Aviation Authority
on 28 October and 4 November, without finding any faults with the system.
. The aircraft was not equipped with ground proximity warning system
, nor was this required. There was no requirement for the aircraft to have a flight data recorder
and cockpit voice recorder
, but the airline had chosen to install the latter. Interviews with the surviving passengers show that none of them perceived that there was any problems with the flight until the sudden impact. One of the passengers of navigation profession could see parts of the cockpit from his seat, being able to confirm some of the navigational displays. Interviews with locals indicated that the aircraft followed a normal path.
The report from the Accident Investigation Board Norway pointed to several errors, both from the pilots, but also systematic failures from Widerøe and the Aviation Authority. In particular, the report commented on the lack of callouts during descent. The base turn procedure was also criticized, because the crew failed to time it correctly, ending up 14 NM from the airport. When the flying pilot canceled the instrument landing and changed to visual landing during darkness, he did not have sufficient visual references to the terrain. During this part of the approach, the aircraft's position was not controlled with any available navigational aids. This was in part due to both pilots focus on extra-cockpit activity after the non-flying pilot had identified the necessary sight to the airport. The crew were not aware of their distance from the terrain; the small margins from 500 feet (152.4 m) to 392 feet (119.5 m) were in part caused by pilots' unawareness. The cooperation between the crew did not follow the regulations of crew resource management
and seemed to have stopped after visual identification of the airfield. The airline was criticized for not having standardized an operative concept that the crew fully respected and followed.
Controlled flight into terrain
Controlled flight into terrain describes an accident in which an airworthy aircraft, under pilot control, is unintentionally flown into the ground, a mountain, water, or an obstacle. The term was coined by engineers at Boeing in the late 1970s...
of a de Havilland Canada DHC-6-300 Twin Otter during approach to Namsos Airport, Høknesøra
Namsos Airport, Høknesøra
Namsos Airport, Høknesøra is a regional airport located along the Namsen river, just outside of the town of Namsos in Nord-Trøndelag county, Norway. The airport is served with Dash 8 aircraft from Widerøe on public service obligation contracts with the Norwegian Ministry of Transport and...
in Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
. The incident occurred on 27 October 1993 at 19:16:48 and killed six of the nineteen people on board, including the crew of two. No technical problems were found on the aircraft, and the accident report commented on a number of procedural errors committed by the two pilots during descent.
Accident
Widerøe Flight 744 was a scheduled flight from Trondheim Airport, Værnes to Namsos Airport, Høknesøra operated with a de Havilland Canada DHC-6-300 Twin Otter. The aircraft had registration LN-BNM and serial number 408, and was delivered to Widerøe in 1974. The aircraft had flown 40,453 hours and had met all service requirements. The pilot in commandPilot in command
The pilot in command of an aircraft is the person aboard the aircraft who is ultimately responsible for its operation and safety during flight. This would be the "captain" in a typical two- or three-pilot flight crew, or "pilot" if there is only one certified and qualified pilot at the controls of...
was 43 years old, had held a pilot's license
Pilot licensing and certification
Pilot licensing or certification refers to permits to fly aircraft that are issued by the National Aviation Authority in each country, establishing that the holder has met a specific set of knowledge and experience requirements. This includes taking a flying test. The certified pilot can then...
since 1974 and had been employed in Widerøe since 1985. He had held a C certificate since 4 January 1993, and had been a pilot in command since 20 January. He had flown 4,835 hours and landed 13 times at Namsos Airport in the last 12 months. The first officer was 34 years old, had training from the United States, starting in 1981, which had been converted to a C certificate in 1988. He had 6,354 hours of flight, of which 1,356 was in a Twin Otter. He had been a pilot in command for 3,441 hours prior to working for Widerøe, where he had been employed since 1990. He had landed 27 times the last 12 months at Namsos Airport.
The first officer was using a medication against back pains which was not permitted while flying. However, these had been prescribed by a physician who had training in aviation medicine. No traces of the substance were found in the pilot's body after the accident. The aircraft had a maximum take-off weight of 5675 kilograms (12,511.2 lb), while the aircraft took off with 5460 kilograms (12,037.2 lb). Prior to departure, the ground handling agent, Scandinavian Airlines System
SAS Ground Services
SAS Ground Handling is Europe's third largest full-service provider of aircraft ground handling and airport related services. SAS Ground Handling is the largest ground handling company in Scandinavia....
had calculated the passenger load and mean aerodynamic chord
Chord (aircraft)
In aeronautics, chord refers to the imaginary straight line joining the trailing edge and the center of curvature of the leading edge of the cross-section of an airfoil...
of the passengers. When correcting this after observing the seating of the passengers, the pilot in command had made a calculation mistake, whereby he though passengers did not need to move around, while they actually would have to meet the limits of the distribution of weight.
The crew had started duty at Bodø Airport
Bodø Airport
Bodø Airport is civil airport in Bodø, Norway. Located just south of the city centre, on the westernmost tip of the peninsula Bodø lies on, it shares facilities with the military air force base Bodø Main Air Station. The airport has a single concrete, runway which runs in a roughly east-west...
at 13:30 (UTC+1
UTC+1
UTC+01:00 is an identifier for a time offset from UTC of +01:00. In ISO 8601 the associated time would be written as .This time is used in:*Central European Time*West Africa Time*Western European Summer Time**British Summer Time**Irish Standard Time...
) and were to make a round trip to Trondheim Airport, with intermediate stops at Sandnessjøen Airport, Mosjøen Airport, Brønnøysund Airport, Brønnøy
Brønnøysund Airport, Brønnøy
Brønnøysund Airport, Brønnøy is the airport serving the town of Brønnøysund in the Brønnøy municipality in Nordland, Norway. The airport is located southeast of the town centre and opened in 1968. Brønnøy is operated by Avinor...
, Rørvik Airport as Flight 711. On the way down, the flight canceled stopping at Mosjøen due to the bad weather and the aircraft landed at Trondheim Airport at 17:52. The return flight was to operate as Flight 744 from Trondheim via Namsos to Rørvik, where the plane and crew were to overnight. At Trondheim, 17 passengers boarded along with 136 kilograms (299.8 lb) of cargo. Estimated flight time to Namsos was 35 minutes. The aircraft left Trondheim Airport at 18:37 after which it ascended to cruising height at 5000 feet (1,524 m). At 18:53, the QNH
QNH
QNH is one of the many Q codes. It is defined as, "barometric pressure adjusted to sea level." It is a pressure setting used by pilots, air traffic control , and low frequency weather beacons to refer to the barometric setting which, when set on an aircraft's altimeter, will cause the altimeter to...
was confirmed by Namsos to be 1017 hPa
Pascal
Pascal or PASCAL may refer to:-People:* Pascal , a French given name* Pascal , a French and Italian surname* Adam Pascal , American actor and singer, best known for his role of Roger Davis in the Broadway musical Rent* Blaise Pascal , French mathematician and philosopher* Cleo Paskal, environmental...
. This gave a height reading of 4950 feet (1,508.8 m) and 4900 feet (1,493.5 m), respectively, for the pilot in command and first officer. There was 25 knots (13.6 m/s) wind from 250°, with gusts up to 36 knots (19.6 m/s).
The pilot in command then decided on the descent plan, involving an initial descent to 4000 feet (1,219.2 m), then down to 3000 feet (914.4 m), before making a swing towards localizer 255. Then the aircraft should descend to 2100 feet (640.1 m) and head towards Namsos beacon inbound. After that, minimum height was set to 2100 feet (640.1 m). At 19:01, the aerodrome flight information service
Flight Information Service
A flight information service is a form of air traffic service which is available to any aircraft within a flight information region , as agreed internationally by ICAO....
(AFIS) announced new weather data: the wind had changed to 260° at 25 knots (13.6 m/s), with gusts up to 40 knots (21.8 m/s). As the crew planned to use Runway 26, this would give wind directly against the craft, so the crew decided to add some height to the descent. At 19:05, the first officer stated that the descent checklist was completed, and the pilot in command started the approach checklist. At this time, both height indicators showed 5000 feet (1,524 m). At 19:07, the aircraft was turned to 050°.
At 19:10, the aircraft reached the center line and the aircraft was confirmed by Namsos AFIS at 255°. By 19:14, the aircraft had descended to 2100 feet (640.1 m) and at 19:15:13, it passed Namsos beacon. At 19:15:30, the first officer confirmed visual contact with the field. At 19:16:35, the pilot in command stated a height of 500 feet (152.4 m), confirmed by the first officer. Four second later, the pilot in command stated: "we should not descend any further". At 19:16:48, the aircraft hit a hill 6.15 kilometres (3.8 mi) from the airport, at Berg in Overhalla. A distress radiobeacon signal was received by Namsos and a search and rescue
Search and rescue
Search and rescue is the search for and provision of aid to people who are in distress or imminent danger.The general field of search and rescue includes many specialty sub-fields, mostly based upon terrain considerations...
operation was started immediately. Both pilots, plus four passengers were killed, while the remaining thirteen passengers were injured. The aircraft first hit some trees, located 119 metres (390.4 ft) above mean sea level
Above mean sea level
The term above mean sea level refers to the elevation or altitude of any object, relative to the average sea level datum. AMSL is used extensively in radio by engineers to determine the coverage area a station will be able to reach...
. The aircraft was written off after the accident. The instrument landing system
Instrument Landing System
An instrument landing system is a ground-based instrument approach system that provides precision guidance to an aircraft approaching and landing on a runway, using a combination of radio signals and, in many cases, high-intensity lighting arrays to enable a safe landing during instrument...
at Namsos Airport was tested by the Norwegian Aviation Authority
Avinor
Avinor AS is a state owned limited company in that operates most of the civil airports in Norway. The Norwegian state, via the Norwegian Ministry of Transport and Communications controls 100 percent of the share capital. Avinor was created on 1 January 2003, by the privatization of the...
on 28 October and 4 November, without finding any faults with the system.
Cause
The weather in the area had wind up towards 30 knots (16.3 m/s), with clouds and heavy rain, and some reports of turbulenceTurbulence
In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic and stochastic property changes. This includes low momentum diffusion, high momentum convection, and rapid variation of pressure and velocity in space and time...
. The aircraft was not equipped with ground proximity warning system
Ground Proximity Warning System
A ground proximity warning system is a system designed to alert pilots if their aircraft is in immediate danger of flying into the ground or an obstacle. The United States Federal Aviation Administration defines GPWS as a type of terrain awareness warning system...
, nor was this required. There was no requirement for the aircraft to have a flight data recorder
Flight data recorder
A flight data recorder is an electronic device employed to record any instructions sent to any electronic systems on an aircraft. It is a device used to record specific aircraft performance parameters...
and cockpit voice recorder
Cockpit voice recorder
A cockpit voice recorder , often referred to as a "black box", is a flight recorder used to record the audio environment in the flight deck of an aircraft for the purpose of investigation of accidents and incidents...
, but the airline had chosen to install the latter. Interviews with the surviving passengers show that none of them perceived that there was any problems with the flight until the sudden impact. One of the passengers of navigation profession could see parts of the cockpit from his seat, being able to confirm some of the navigational displays. Interviews with locals indicated that the aircraft followed a normal path.
The report from the Accident Investigation Board Norway pointed to several errors, both from the pilots, but also systematic failures from Widerøe and the Aviation Authority. In particular, the report commented on the lack of callouts during descent. The base turn procedure was also criticized, because the crew failed to time it correctly, ending up 14 NM from the airport. When the flying pilot canceled the instrument landing and changed to visual landing during darkness, he did not have sufficient visual references to the terrain. During this part of the approach, the aircraft's position was not controlled with any available navigational aids. This was in part due to both pilots focus on extra-cockpit activity after the non-flying pilot had identified the necessary sight to the airport. The crew were not aware of their distance from the terrain; the small margins from 500 feet (152.4 m) to 392 feet (119.5 m) were in part caused by pilots' unawareness. The cooperation between the crew did not follow the regulations of crew resource management
Crew Resource Management
Crew resource management or Cockpit resource management is a procedure and training system in systems where human error can have devastating effects. Used primarily for improving air safety, CRM focuses on interpersonal communication, leadership, and decision making in the cockpit...
and seemed to have stopped after visual identification of the airfield. The airline was criticized for not having standardized an operative concept that the crew fully respected and followed.