Canadian North B733 at Fort McMurray on Aug 4th 2014, aligned with taxiway for landing, near collision with taxiing aircraft

Last Update: November 4, 2015 / 19:49:07 GMT/Zulu time

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Incident Facts

Date of incident
Aug 4, 2014

Classification
Report

Cause
Near collision

Airline
Canadian North

Flight number
5T-9131

Departure
Winnipeg, Canada

Destination
Fort McMurray, Canada

Aircraft Registration
C-GICN

Aircraft Type
Boeing 737-300

ICAO Type Designator
B733

The crew of a Canadian North Boeing 737-300, registration C-GICN performing flight 5T-9131 from Winnipeg,MB to Fort McMurray,AB (Canada), briefed for a visual approach to Fort McMurray's runway 25. Following an uneventful descent the crew acquired visual contact with the airport but inadvertently aligned with taxiway J, parallel to the runway, for final approach.

A Jazz de Havilland Dash 8-400, registration C-GGDU performing flight QK-8391 from Fort McMurray,AB to Edmonton,AB (Canada), was taxiing along taxiway J for departure from runway 25.

Abeam of the threshold runway 25 the crew of Boeing 737 initiated a go around and climbed over the Dash 8, the separation reduced to 230 feet vertical and 46 feet horizontal.

The Canadian TSB released their final report concluding the probable causes of the serious incident involving the risk of collision were:

Findings as to causes and contributing factors

- A visual approach was conducted in weather conditions below visual flight rules limits, which resulted in the flight crew experiencing visual illusions and inadvertently identifying Taxiway J as Runway 25.

- Perceptual confusion occurred during the routine task of identifying the runway. The position of the taxiway south of Runway 25 and its squared-off end, which resembles the end of a runway, contributed to the flight crew identifying Taxiway J as Runway 25.

- The controller had assessed the visibility as higher than reported by the automatic weather observation system and, therefore, did not turn on the approach lighting. This contributed to the flight crew not identifying Runway 25.

- The flight crew did not adhere to standard operating procedures, which required the monitoring of all available cues during the approach and landing. With both flight crew members looking out the window during the late stages of the approach, the instability of the approach was not identified, and a go-around was not conducted.

Findings as to risk

- If crews do not rigorously adhere to procedures that facilitate the monitoring of all available cues during the approach and landing, there is an increased likelihood of over-reliance on visual cues in the late stages of the approach, which increases the risks associated with visual illusions and unstable approaches.

- If standards do not provide detailed guidance on the geometry to be used in taxiway-end design, taxiways with squared-off ends risk looking like runways, which can contribute to perceptual confusion in flight crews.

- If occurrences are not reported as per the Transportation Safety Board Regulations, there is a risk that data (e.g., cockpit voice recorder data) may be lost, and, with it, the opportunity to identify safety deficiencies.

ATIS reported the visibility was 4 statute miles and there were scattered clouds at 4100 feet AGL. Standard Procedures by Canadian North required that crews brief for an instrument approach if the visibility is less than 5 statute miles. While descending through FL290 the crew was advised that current ATIS had changed, the ATIS now reported 2.5 statute miles visibility due to haze, which was caused by wild fires. The crew advised they were setting up for an ILS/DME approach to runway 25. The aircraft was vectored to intercept the localizer of runway 25 and was subsequently handed off to tower, the aircraft was descending through 4000 feet at that time.

The captain (ATPL, more than 10,000 hours total, 500 hours on type) was pilot flying, the first officer (3800 hours total, 600 hours on type) was pilot monitoring.

Tower instructed the aircraft to reduce speed to minimum safe, a Cessna was on a half mile final to runway 25. The pilot of Canadair CRJ complained at that time about needing to land into the sun stating that it was very difficult to see the airport environment and runway in that haze while looking into the sun. The controller responded that the tower manual, with calm winds, instructed to use runway 25, the comment by the pilot would be considered however.

The 737 levelled off at 3000 feet, the autopilot in control of the aircraft tracking the localizer and the approach mode armed.

At that time the Jazz Dash received taxi instructions to taxi along taxiway J to holding point runway 25.

According to tower manual the approach lights for runway 25 should be select on at intensity 4 during day light operations whenever the visibility is below 3 statute miles. The approach lights however were turned off, the runway threshold, edge and end lighting was active.

The Boeing crew, the aircraft still on autopilot, acquired visual contact with what they believed was the runway environment and used the control wheel steering to align the aircraft with what they had identified to be the runway, which in fact was taxiway J.

Descending through 690 feet AGL tower advised the 737 crew, that the Cessna had cleared the runway and cleared the 737 to land, the 737 was 1.4 dots to the left of the localizer and 1.7 dots above the glide path.

Autopilot and autothrust were turned off, the aircraft descended to 1.4 dots below the glidepath, the GPWS issues a glide slope aural caution, the localizer deviation had increased to 1.9 dots.

The 737 queried whether the runway was clear, tower affirmed.

When the 737 descending through 85 feet AGL the Jazz crew broadcasted that the 737 was lined with the taxiway, 4 seconds later the 737 crew initiated a go around at 46 feet AGL and 2800 feet before the Dash. The 737 overflew the Dash 8 230 feet above the Dash.

The TSB wrote: "At the time of the occurrence, the position of the sun was at an elevation of 21.42° and azimuth of 268.65° True, which was nearly aligned with the orientation of Runway 25 (270° True)."

The TSB analysed: "One of the key tasks involved in transitioning from an approach to a landing is visually identifying the runway or runway environment. The potential for confusion exists where an object with the approximate size and shape of the runway is identified in the expected location of the runway. This confusion has been known to result in a taxiway parallel to the intended runway being misidentified as the runway."

With respect to environmental factors the TSB continued analysis: "In this occurrence, the flight crew encountered lower visibility than they had anticipated. Their ability to identify the runway environment was compromised by haze from forest fire smoke, compounded by the aircraft’s approach into the setting sun. Once the taxiway had been identified as the runway, both pilots focussed their attention outside the aircraft, and cues that could have alerted the crew to their error were not assimilated. Such actions have been observed in previous instances of aircraft landing on taxiways and are consistent with errors of perceptual confusion: once an object is believed to have been identified, little cognitive effort is invested in confirming that it is the correct item. A visual approach was conducted in weather conditions below visual flight rules (VFR) limits, which resulted in the flight crew experiencing visual illusions and inadvertently identifying Taxiway J as Runway 25."

With respect to airport geometry the TSB analysed: "Taxiway J had been in service for approximately 4 months prior to the occurrence. Although both crew members had flown into Fort McMurray (CYMM) since the new taxiway had been built, they both had significantly more experience at the airport prior to the construction of the new taxiway and were more familiar with the airport when the runway was the southernmost strip of asphalt."

With respect to the controller's decision to not turn on the approach lights the TSB analysed:

Several factors resulted in the controller not turning on the approach lighting as required by NAV CANADA’s Air Traffic Control Manual of Operations (ATC MANOPS) for the visibility that prevailed. The controller estimated the visibility to be greater than that reported by the automatic weather observation system (AWOS). The visual cues that supported the controller’s assessment that visibility was greater than 3 statute miles (sm) included:

- cloud ceiling of 3900 feet above ground level (agl);

- viewing the approach end of the runway facing away from the sun, which resulted in the perception of better-than-actual visibility; and

- using a ridgeline that is not identified on the 13-year-old Environment Canada visibility chart, given its lack of markers between 1 and 4 sm.

The controller had assessed the visibility as higher than reported and, therefore, did not turn on the approach lighting. This contributed to the flight crew not identifying Runway 25."

The TSB analysed that the approach was never stable below 1000 feet, the crew however did not identify the necessity to go around. The TSB wrote: "The approach was not stable at 1000 feet agl and below, and the flight crew never identified the need to initiate a go-around. The aircraft was initially high on the glide slope and continued past 1000 feet agl with a significant rate of descent. The aircraft was lined up with Taxiway J, which was half the width of the runway; this led to the perception of being high on approach. In the absence of additional references, the flight crew continued below the glide slope in an attempt to recreate the expected visual scene. ... Canadian North Inc. standard operating procedures (SOPs) require the PM to call excessive deviations in sink rate or approach profile in both visual and instrument conditions. In this occurrence, the focus of both crew members was outside the cockpit during the late stages of the approach and, therefore, these deviations were not noted by the PM. ... The flight crew did not adhere to standard procedures, which required the monitoring of all available cues during the approach and landing. With both flight crew members looking out the window during the late stages of the approach, the instability of the approach was not identified and a go-around was not conducted."
Incident Facts

Date of incident
Aug 4, 2014

Classification
Report

Cause
Near collision

Airline
Canadian North

Flight number
5T-9131

Departure
Winnipeg, Canada

Destination
Fort McMurray, Canada

Aircraft Registration
C-GICN

Aircraft Type
Boeing 737-300

ICAO Type Designator
B733

This article is published under license from Avherald.com. © of text by Avherald.com.
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