What happened
While operating as JZA8105 from Houston to Calgary, an Air Canada Jazz Bombardier CRJ7 and05, registration C-FBJZ, was cruising at flight level 400. Following instructions from Edmonton Centre to meter into Calgary, the pilot flying reduced power to slow the aircraft from 0.77M to 0.70M. During this period, the crew focused on calculating fuel reserves for a potential hold.
As the aircraft slowed, the airspeed dropped significantly. Despite the pilot advancing the thrust levers, the aircraft could not accelerate in level flight due to limited power availability at that altitude. The airspeed eventually fell to 0.61M, triggering the stick shaker and disengaging the autopilot. The crew responded by pushing the control yoke forward to initiate a descent, which allowed the airspeed to recover. A second stick shaker event occurred 11 seconds later due to a subsequent pitch-up maneuver. There were no injuries and no damage to the aircraft.
The investigation
The investigation examined the aircraft's performance, the crew's training, and the pilot's physiological state. Investigators found that the aircraft's weight and center of gravity were within limits and that weather conditions were not a factor.
Analysis of the crew's training revealed that the conversion program from the CRJ200 to the CRJ705 did not adequately cover flight characteristics at high altitudes, specifically regarding the relationship between cruise speed and minimum drag speed (Vmd). Furthermore, the company's speed recovery training was limited to altitudes below 10,000 feet, leaving the crew unprepared for high-altitude recovery techniques.
Findings
- The crew was unaware that the chosen long-range cruise speed was below the minimum drag speed (Vmd) for their flight conditions.
- The captain's fatigue, resulting from insufficient sleep the night before, likely contributed to a loss of concentration and a failure to monitor the airspeed effectively.
- The aircraft lacked sufficient power to maintain level flight at the reduced speed at flight level 400.
- Training deficiencies in both the conversion course and company-specific speed recovery procedures prevented the crew from recognizing and reacting to the deteriorating airspeed appropriately.
Safety action
- Bombardier Aerospace issued a message to operators regarding Vmd limitations and planned to add Vmd tables to the Quick Reference Handbook.
- Air Canada Jazz implemented a new "High Altitude and High Speed Training" program and restricted operations to FL 350 until completion.
- The airline developed new reference charts for plotting Vmd and updated its operations manual to warn crews about speed maintenance.
- Transport Canada released an advisory circular providing guidance on stall recovery training and checking.