Jet Experiences Sudden Stall and Inverted Roll while in Autopilot Mode

Jet Experiences Sudden Stall and Inverted Roll while in Autopilot Mode

In the realm of aviation, the correct selection of autopilot modes can significantly impact the safety, efficiency, and comfort of flights. When climbing or descending, choosing modes that manage the desired vertical profile is key.

One such mode is the Vertical Speed (VS) mode, which allows you to set a specific climb or descent rate, such as 500 feet per minute. This mode offers precise control over vertical speed during climbs and descents, helping to maintain passenger comfort and ensure compliance with air traffic control instructions or terrain clearance.

Another useful mode is Flight Path Angle (FPA) mode, which commands the aircraft to maintain a constant angle of climb or descent relative to the horizon, providing smooth and fuel-efficient vertical transitions. Not all autopilots support FPA mode, but for those that do, it can be a valuable tool.

At the end of climbs or descents, Altitude Hold or Altitude Capture modes are used to stabilise the aircraft at a target altitude.

The choice of autopilot mode is crucial as it ensures the aircraft climbs or descends at the appropriate rate and angle for safety, avoiding excessive speeds or insufficient altitude separation from obstacles or other traffic. Correct mode selection also improves fuel efficiency by optimising the aircraft’s vertical profile according to its performance characteristics. It helps in maintaining situational awareness and compliance with ATC clearances, especially when following specific vertical constraints in the flight plan.

However, it's important to be aware of the potential risks in V/S Mode climbs. In 2013, a Citation Jet (CJ2+) experienced an inadvertent stall over central England while the autopilot was in V/S Mode. The pilot, who was using a portable electronic device (PED) at the time, was not injured, but the aircraft's wings were substantially damaged.

This incident underscores the importance of monitoring descent airspeeds to avoid exceeding Vne/Vmo and Va, or turbulence penetration speeds. SPS autopilots, which can automatically adjust the vertical rate to prevent a stall, can serve as a backup to prevent incidents like the one involving the Citation jet.

For pilots looking to improve their instrument flying skills, Boldmethod offers an Instrument Procedures course. Subscribing to Boldmethod's email service provides real-world flying tips and information directly to the user's inbox each week.

In summary, the best autopilot modes for climbs and descents depend on the aircraft and avionics system but generally revolve around vertical speed control or flight path angle modes for smooth and controlled altitude changes. Selecting the appropriate mode ensures safety, comfort, and efficient operation. When selecting climb and descent modes while using an autopilot, it's crucial to consider the specific circumstances and potential risks.

[1] FAA's Advanced Avionics Handbook [3] Boldmethod's Instrument Procedures course [5] U.K. Air Accidents Investigation Branch (AAIB) report [6] Flight Safety Foundation article

1. In aviation, the correct selection of autopilot modes not only enhances flight safety but also promotes efficiency and passenger comfort.
2. When flying a Cessna or any other aircraft, choosing the right autopilot mode is vital to ensure the aircraft maintains a suitable vertical profile.
3. FAA regulations mandate compliance with air traffic control instructions and adherence to specific vertical constraints in the flight plan.
4. To maintain a constant angle of climb or descent relative to the horizon, some aircraft offer the Flight Path Angle (FPA) mode in their avionics system.
5. During climbs and descents, it's important to monitor airspeeds to prevent exceeding Vne/Vmo and Va, or penetrating turbulence.
6. The aviation industry has witnessed numerous incidents, such as the 2013 Citation Jet stall over central England, that underscore the importance of careful autopilot mode selection and airspeed monitoring.
7. To prevent incidents like stalls, some avionics systems include Safety Pilot Stall (SPS) autopilots that automatically adjust the aircraft's vertical rate to avoid stall conditions.
8. For pilots seeking to enhance their instrument flying skills, training programs like Boldmethod's Instrument Procedures course provide valuable insights and real-world flying tips.
9. By subscribing to services like Boldmethod's email service, pilots can gain direct access to practical information and tips to sharpen their flying skills.
10. In the dynamic and ever-evolving aviation financing landscape, investments in aviation technology and training contribute to enhanced safety and efficiency in the transportation sector.

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