Crew Experienced Temporary Difficulty With Aircraft Control At Mont-Joli Airport, Quebec
According to a Transportation Safety Board of Canada (TSB) investigation report (A16Q0020), a combination of moderate turbulence and wind shear contributed to the temporary difficulty with aircraft control effectiveness encountered by the flight crew while on approach at Mont-Joli Airport, Quebec, in February 2016. There were no injuries and no damage to the aircraft.
On 3 February 2016, a Jazz Aviation LP de Havilland DHC-8-102 was operating as flight JZA8964 from Montréal/Pierre Elliott Trudeau International Airport, Quebec, to Mont-Joli Airport, Quebec, with 24 passengers and three crew members on board. After being cleared for an approach, and while descending through 2480 feet above sea level with the landing gear down, the flight encountered moderate turbulence. This resulted in an abrupt increase in airspeed, which exceeded the maximum permissible airspeed with the landing gear extended. The pilot disconnected the autopilot and immediately levelled off the aircraft to reduce the airspeed. The pilot then experienced a temporary difficulty with aircraft control, but was able to maintain the approach profile and carry out the landing with no further difficulty.
The investigation determined that the airspeed increased abruptly when the aircraft encountered significant increased performance shear while flying out of a low-level jet with the autopilot engaged in vertical speed mode. A low-level jet is a narrow zone of strong winds in the lower levels of the atmosphere. The combination of turbulence and shear contributed to the temporary difficulty with aircraft control on approach.
After landing, the pilot reported the occurrence to the company but it was only reported to the TSB six days later. If reportable occurrences are not reported to the TSB in a timely manner, perishable information may be lost, which could preclude the identification and communication of safety deficiencies to advance transportation safety.
(Source: TSB news release. Image from file)
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