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Last updated: 1 December 2021
Status:Final
Date:Wednesday 13 December 2017
Time:18:12
Type:Silhouette image of generic AT43 model; specific model in this crash may look slightly different
ATR 42-320
Operator:West Wind Aviation
Registration: C-GWEA
MSN: 240
First flight: 1991-03-08 (26 years 10 months)
Total airframe hrs:26481
Cycles:32051
Engines: 2 Pratt & Whitney Canada PW121
Crew:Fatalities: 0 / Occupants: 3
Passengers:Fatalities: 1 / Occupants: 22
Total:Fatalities: 1 / Occupants: 25
Aircraft damage: Destroyed
Aircraft fate: Written off (damaged beyond repair)
Location:1,5 km (0.9 mls) W of Fond-du-Lac Airport, SK (ZFD) (   Canada)
Phase: Initial climb (ICL)
Nature:Domestic Scheduled Passenger
Departure airport:Fond-du-Lac Airport, SK (ZFD/CZFD), Canada
Destination airport:Stony Rapids Airport, SK (YSF/CYSF), Canada
Flightnumber:WEW280
Narrative:
A West Wind Aviation ATR 42-300 collided with trees and terrain shortly after takeoff from Fond-du-Lac Airport (CZFD), Canada. The aircraft was destroyed. Six passengers and one crew member sustained serious injuries. Eighteen other aircraft occupants were also injured. One of the passengers, a 19-year old male, died of his injuries on December 25.
The aircraft arrived at Fond-du-Lac Airport at 17:25 local time. During the descent, the aircraft encountered icing conditions and the anti-icing and de-icing systems were activated. When the de-icing and anti-icing systems were turned off, residual ice remained on portions of the aircraft.
At Fond-du-Lac Airport new passengers boarded and cargo was loaded on the aircraft.
The operator, West Wind Aviation, had some de-icing equipment in the terminal building at the airport, consisting of two ladders, a hand-held spray bottle with electric blanket and wand, and a container of de-icing fluid. However, the aircraft was not de-iced before takeoff, and the takeoff was commenced with ice contamination on the aircraft.
The aircraft took off from runway 28 at 18:11, bound for Stony Rapids.
At 18:12, shortly after takeoff, the aircraft collided with trees and terrain less than a mile west of the end of runway 28. The wreckage path through trees and across terrain was at least 800 feet long. The aircraft came to rest with the forward cabin and cockpit rotated 90° to the right, and the remainder of the fuselage rotated about 35° to the right.

Probable Cause:

Findings as to causes and contributing factors
1. When West Wind commenced operations into Fond-du-Lac Airport (CZFD) in 2014, no effective risk controls were in place to mitigate the potential hazard of ground icing at CZFD.
2. Although both the flight crew and the dispatcher were aware of the forecast ground icing, the decision was made to continue with the day’s planned route to several remote airports that had insufficient de-icing facilities.
3. Although the aircraft’s ice-protection systems were activated on the approach to CZFD, the aircraft’s de-icing boots were not designed to shed all of the ice that can accumulate, and the anti-icing systems did not prevent ice accumulation on unprotected surfaces. As a result, some residual ice began to accumulate on the aircraft.
4. Although the flight crew were aware of the ice, there were no handling anomalies noted on the approach. Consequently, the crew likely did not assess that the residual ice was severe enough to have a significant effect on aircraft performance. Subsequently, without any further discussion about the icing, the crew continued the approach and landed at CZFD.
5. Weather conditions on the ground were conducive to ice or frost formation, and this, combined with the nucleation sites provided by the residual mixed ice on the aircraft, resulted in the formation of additional ice or frost on the aircraft’s critical surfaces.
6. Because the available inspection equipment was inadequate, the first officer’s ice inspection consisted only of walking around the aircraft on a dimly lit apron, without a flashlight, and looking at the left wing from the top of the stairs at the left rear entry door (L2). As a result, the full extent of the residual ice and ongoing accretion was unknown to the flight crew.
7. Departing from remote airports, such as CZFD, with some amount of surface contamination on the aircraft’s critical surfaces, had become common practice, in part due to the inadequacy of de-icing equipment or services at these locations. The past success of these adaptations resulted in the unsafe practice becoming normalized and this normalization influenced the flight crew’s decision to depart.
8. Although the flight crew were aware of icing on the aircraft’s critical surfaces, they decided that the occurrence departure could be accomplished safely. Their decision to continue with the original plan to depart was influenced by continuation bias, as they perceived the initial and sustained cues that supported their plan as more compelling than the later cues that suggested another course of action.
9. As a result of the ice that remained on the aircraft following the approach and the additional ice that had accreted during the ground stop, the aircraft’s drag was increased by 58% and its lift was decreased by 25% during the takeoff.
10. During the takeoff, despite the degraded performance, the aircraft initially climbed; however, immediately after lift off, the aircraft began to roll to the left without any pilot input. This roll was as a result of asymmetric lift distribution due to uneven ice contamination on the aircraft.
11. Following the uncommanded roll, the captain reacted as if the aircraft was an uncontaminated ATR 42, with the expectation of normal handling qualities and dynamic response characteristics; however, due to the contamination, the aircraft had diminished roll damping resulting in unexpected handling qualities and dynamic response.
12. Although the investigation determined the ailerons had sufficient roll control authority to counteract the asymmetric lift, due to the unexpected handling qualities and dynamic response, the roll disturbance developed into an oscillation with growing magnitude and control in the roll axis was lost.
13. This loss of control in the roll axis, which corresponds with the known risks associated with taking off with ice contamination, ultimately led to the aircraft colliding with terrain.
14. The aircraft collided with the ground in relatively level pitch, with a bank angle of 30° left. As a result of the sudden vertical deceleration upon contact with the ground, the aircraft suffered significant damage, which varied in severity at different locations on the aircraft because of the impact angle and the variability in structural design.
15. The design standards for transport category aircraft in effect at the time the ATR 42 was certified did not specify minimum loads that a fuselage structure must be able to tolerate and remain survivable, or minimum loads for fuselage impact energy absorption. As a result, the ATR 42 was not designed with these crashworthy principles in mind.
16. On impact, the induced acceleration was not attenuated because the landing gear housing did not deform. This unattenuated acceleration resulted in a large inertial load from the wing, causing the wing support structure to fail and the wing to collapse into the cabin.
17. The reduced survivable space between the floor above the main landing gear and the collapsed upper fuselage caused crushing injuries, such as major head, body, and leg trauma, to passengers in the middle-forward left section of the aircraft. Of the 3 passengers in this area, 2 experienced serious life-changing injuries, and 1 passenger died.
18. The collapse of part of the floor structure compromised the restraint systems, limiting the protection afforded to the occupants when they were experiencing vertical, longitudinal, and lateral forces. This resulted in serious velocity-related injuries and impeded their ability to take post-impact survival actions in a timely manner.
19. Most passengers in this occurrence did not brace before impact. Because their torsos were unrestrained, they received injuries consistent with jackknifing and flailing, such as hitting the seat in front of them.
20. Given that regulations requiring the use of child-restraint systems have yet to be implemented, the aircraft was not equipped with these devices. As a result, the infant passenger was unrestrained and received flail and crushing injuries.
21. As a result of unapproved repairs, the flight attendant seat failed on impact, resulting in injuries that impeded her ability to perform evacuation and survival actions in a timely manner.

Accident investigation:
cover
Investigating agency: TSB Canada
Status: Investigation completed
Duration: 3 years and 11 months
Accident number: A17C0146
Download report: Final report

Classification:
Icing
Loss of control

Sources:
» CBC


Follow-up / safety actions
Transport Canada suspended West Wind Aviation’s Air Operator Certificate on December 22.
The department took this action because it identified deficiencies in the company’s Operational Control System during a post-accident inspection.
The AOC was reinistated on May 8, 2018 after a review of the company’s operations.

TSB issued 2 Safety Recommendations

Show all...

Photos

photo of ATR-42-320-C-GWEA
accident date: 13-12-2017
type: ATR 42-320
registration: C-GWEA
photo of ATR-42-320-C-GWEA
accident date: 13-12-2017
type: ATR 42-320
registration: C-GWEA
photo of ATR-42-320-C-GWEA
accident date: 13-12-2017
type: ATR 42-320
registration: C-GWEA
photo of ATR-42-320-
photo of ATR-42-320-
Seat map ATR 42-320
photo of ATR-42-320-C-GWEA
accident date: 13-12-2017
type: ATR 42-320
registration: C-GWEA
 

Aircraft history
date registration operator remarks
8 March 1991 F-WWEG ATR first flight
14 May 1991 XA-RUC Aviación del Noroeste delivered
1995 XA-RUC Aviación del Noroeste airline shut down; aircraft stored at Toluca
Dec 1996 N240JS Focus Aviation registered
9 March 1999 5Y-JNT Eagle Aviation registered
19 June 2001 N240JS Focus Aviation registered
15 Feb. 2002 N240JS Hurstfield Ltd
26 July 2002 ZS-OWU Hurstfield Ltd registered
Feb. 2003 5Y-BRB Aircraft Leasing Services (ALS) registered
28 April 2004 ZS-OVL Executive Turbine Aviation
15 May 2004 ZS-OVL Zambia Airways leased
Sep. 2004 ZS-OVL Executive Turbine Aviation
Oct. 2004 ZS-OVL Aircraft Africa Contracts
Feb. 2005 ZS-OVL United Nations leased
2 Jan. 2007 5Y-BUT Fly540 registered
18 June 2010 D2-FLA Fly540 registered
1 June 2012 C-GWEA West Wind Aviation registered

Map
This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Fond-du-Lac Airport, SK to Stony Rapids Airport, SK as the crow flies is 77 km (48 miles).
Accident location: Exact; deduced from official accident report.

This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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