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B190, Blue River BC Canada, 2012
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|On 17 March 2012, the Captain of a Beech 1900C operating a revenue passenger flight lost control of the aircraft during landing on the 18metre wide runway at destination after an unstabilised day visual approach and the aircraft veered off it into deep snow. The Investigation found that the Operator had not specified any stable approach criteria and was not required to do so. It was also noted that VFR minima had been violated and, noting a fatal accident at the same aerodrome five months previously, concluded that the Operators risk assessment and risk management processes were systemically deficient.|
|Actual or Potential
|Human Factors, Runway Excursion|
|Operator||Northern Thunderbird Air|
|Type of Flight||Public Transport (Passenger)|
|Origin||Vancouver International Airport|
|Intended Destination||Blue River Airport|
|Take off Commenced||Yes|
|Location - Airport|
|Airport||Blue River Airport|
|Tag(s)||Approach not stabilised,|
Inadequate Aircraft Operator Procedures,
Ineffective Regulatory Oversight,
Inadequate Airport Procedures
Plan Continuation Bias,
Procedural non compliance,
Ineffective Monitoring - PIC as PF
Off side of Runway
|Damage or injury||Yes|
|Causal Factor Group(s)|
On 17 March 2012, a Beech 1900C (C-GCMZ) being operated by Northern Thunderbird Air, on a passenger charter flight from Vancouver to Blue River positioned in increasingly marginal Visual Flight Rules (VFR) conditions to a visual daylight approach at destination. Immediately after touchdown off the runway centreline, the left MLG entered an area of deep snow and the aircraft veered into a snow bank, sustaining substantial damage. The occupants were not injured and there was no fire.
An Investigation was carried out by the Canadian TSB. Recorded data relevant to the Investigation was recovered from the Cockpit Voice Recorder (CVR). The aircraft was not fitted with an Flight Data Recorder (FDR) and was not required to be.
It was established that the aircraft had departed Vancouver Instrument Flight Rules (IFR) on what was a weekly charter flight after obtaining weather information which indicated that it would be possible to reach the destination aerodrome, which had no instrument approach procedures or navigation aids and had to be approached under VFR, at the ETA. With the First Officer as PF, the plan, as usual, was to approach the destination at or above lowest useable IFR altitude to see if a visual approach could be made. However, enough fuel was carried to be able to bypass Blue River, make an IFR approach into Valemount and then fly under VFR back to Blue River and still have enough fuel remaining to then divert to the nominated destination alternate.
Overhead the destination, it was not possible to descend VFR and so the aircraft continued to Valemount, let down to VFR and then set course for the 60nm back to Blue River, where the single runway aerodrome was situated at an elevation of 2240 feet asl. A speed of approximately 175 knots was maintained and the aircraft descended as necessary in order to remain in ground contact. The weather slowly worsened and it was necessary to descend to as low as 1100 feet agl in order to maintain visual contact with the ground in the Blue River Valley.
When approximately 4 nm from the aerodrome - and just 85 seconds before touchdown occurred, the Captain took over as PF anticipating a straight-in approach to runway 09. Visual acquisition of the unmarked, unlit and lightly snow-covered 1520 metre-long runway proved difficult (see diagram below) and only after the Captain had turned left away from what was almost the extended centreline did the First Officer sight the runway and call accordingly. Both pilots then rushed to complete the landing checks. The Captain continued to manoeuvre the aircraft in the expectation of a landing and he did not acknowledge that he had the runway in sight. The aircraft was only fully configured for landing 25 seconds prior to touchdown. The aircraft crossed the runway extended centreline near the threshold before making a sharp turn back towards and over the runway followed by a turn the other way to touch down left of the centreline just over 600 metres beyond the threshold. Immediately after touchdown, the aircraft veered left into the snow bank.
Neither the pilots nor their only passenger were injured. The aircraft was substantially damaged. Both propellers were damaged when the blade tips came in contact with the snow banks and the outer sections of several blades were detached. The NLG partially collapsed and most of the landing gear bay doors were damaged or destroyed. The outboard section of the right wing, the flaps and the engine nacelles were damaged, but there was only superficial damage to the fuselage. It was noted that the impact forces had not been enough for the ELT to be activated.
It was found that both pilots were experienced on the aircraft type and familiar with the destination but that the First Officer had not previously had experience of the low level VFR route from Valemount to Blue River. The Captain had an unspecified 'management position' with the Operator.
It was noted that the last weather observation prior to the accident taken 30 minutes earlier had recorded visibility as 2 sm, obscured ceilings at 2500 feet agl in light snow, wind from the north at 6 knots and a temperature of -1°C. A special observation immediately after the accident recorded the visibility reduced to 1 ½ sm in light snow and "the ceiling at 1200 feet agl obscured in snow". It was noted that the State VFR weather limitation in this area is based on the altitude of the aircraft - at or above 1000 feet agl, the aircraft must remain at least 500 feet below and 2000 feet horizontally from cloud with an in-flight visibility of at least 1 sm. Below 1000 feet agl, the aircraft must remain clear of cloud with an in-flight visibility of not less than 2 sm. The Operator had further increased the minimum in-flight visibility for all VFR flights to 5 sm because of the perceived greater risk of VFR flight in mountainous terrain such as around Blue River.
A review of the Cockpit Voice Recorder (CVR) data showed that at no time did the First Officer call an unstable approach or prompt the Captain to make a go around even though Company Standard Operating Procedures (SOPs) had quite recently been amended to state that "for VFR and visual approaches, turns onto final should not be done below 500 feet agl" and included an explicit requirement for the PNF to call any deviations in respect of excessive sink rate or bank and any deviations from the vertical profile or extended runway centreline. They were also found to state that “the PNF shall vigilantly monitor the PF and heighten readiness to intervene in the case of PF incapacitation or risky deviations". However, the Investigation found that there was no requirement in the applicable Canadian Aviation Regulations for the Operator involved to define criteria which specified when an approach must be regarded as unstabilised.
It was concluded that until the aircraft had been about 5 nm from the runway, the flight had been able to continue in accordance with Company limitations but the visibility had then reduced below the specified minimum. At that point, the crew were supposed to have two options - remain VFR and turn around to fly back to where the weather was better or climb IFR to the nominated alternate. However, the Investigation considered that both options became problematic once poor weather had been encountered near the runway. The valley was narrow - at the altitude at which the aircraft was flying, it was in some places only 1 nm wide and at the speed the aircraft was flying, a 30° banked turn would require about 1.6 nm of horizontal distance so a successful course reversal would require a significant reduction in airspeed, an increase in altitude, a higher angle of bank, or a combination of all 3. On the other hand, climbing out IFR would mean doing so over an area not assessed for obstacle clearance with mountains extending 5000 feet above the initial altitude of the aircraft.
The runway conditions were considered. The 18m wide runway was only slightly wider than the 16.6 metre wingspan of the aircraft and the arrangements for keeping the runway useable and flattening the snow banks created at the runway edges at an aerodrome primarily used by helicopters were both informal and complex. The weather conditions prevailing at the time of the accident had produced "a low, dull lighting condition that made features of the runway surface difficult to define". Without runway edge markings, it was considered that "identifying the runway edge becomes more difficult as the aircraft moves down the runway beyond the threshold area (and) the only thing the pilots can see is a large monochromatic area with no clear definition of the runway edges".
An examination of Northern Thunderbird Air's arrangements for risk assessment in respect of its revenue passenger operations into Blue River and its system for the ongoing risk management of such operations found that they were inadequate in various systemic respects. It was also noted that the Operator had been involved in 2 significant occurrences relevant to the current Investigation. Five months earlier, the crew of a Company Beech King Air 100 had lost control of their aircraft and crashed on short final at Vancouver killing both pilots and seriously injuring the seven passengers after an unstabilised approach. And the previous month, there had been a precursor event where a Beech 1900C had made an approach to Blue River, landed slightly off the centreline in similar conditions and almost veered into a snow bank. The dull ambient light and lack of runway edge definition were determined by the Company to be the cause of that incident. It was considered generally that the ineffective action in response to the safety issues highlighted by both these occurrences served to emphasise the inadequacies of safety management at the Operator.
The Investigation formally concluded as follows in respect of Causes and Contributing Factors:
- Although the hazardous runway condition had been identified by the company's safety management system, the delay in action to mark the runway allowed this condition to persist.
- Up-to-date weather and runway condition information was not provided to the crew, nor was it requested by the crew.
- The pilot continued the approach below the visibility limits specified in the company's standard operating procedures.
- Deteriorating weather, as well as 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 unstabilised approach was allowed to continue.
- The pilot was unable to position the aircraft over the centre of the runway as it settled to land, and the left main landing gear entered the deeper snow at the runway edge, causing the aircraft to veer into the snow bank.
In respect of Risk, it concluded that:
- If a company's risk mitigation strategy is not implemented in a timely manner, hazards are allowed to persist, increasing the risk of an accident.
- If company standard operating procedures do not include criteria and procedures for stabilised approaches, or they are not followed, there is an increased risk of landing accidents.
- Operating on a snow-covered runway that does not have markings or devices to allow a pilot to easily identify the runway surface increases the risk of runway excursions.
- If the identified risks and mitigation strategies are not communicated to the people exposed to the risks, it is possible they will deem the risk as acceptable to management and continue operations.
In response to the Findings of the Investigation, Transport Canada indicated that in their view, "the issue of rejected approaches may be better addressed through guidance material on pilot decision making and crew resource management" than by means of "further prescriptive regulations" and advised that training standards in respect of Crew Resource Management and Pilot Decision Making (PDM) would be improved, including the inclusion of the TEM model in these standards.
The Final Report was authorised for release on 18 December 2013 and officially released on 07 February 2014. No Safety Recommendations were made.