Key strategies to prevent aerodynamic stalls in low altitudes
Aerodynamic stalls are a critical concept in aviation and are of extreme importance in ensuring the safe operation of aircraft. An aerodynamic stall occurs when an aircraft's wing or other lifting surfaces exceed their critical angle of attack, causing a sudden loss of lift and a disruption in the flow of air over the wing. This can result in a loss of control and potential aircraft accidents if not managed properly.
In November 2021, a Britten Norman BN-2A airplane (N866JA) was substantially damaged when it was involved in an accident on Beaver Island, Michigan. The pilot and three passengers were killed, and one passenger received serious injuries. The airplane departed the Charlevoix Municipal Airport (CVX) with the pilot and 4 passengers on board. After departing CVX, the airplane turned north and proceeded directly toward the Welke Airport (6Y8).
The en route portion of the flight was conducted about 1500 ft MSL. At this point, the airplane began descending and was maneuvered toward a straight-in approach to runway 35 at 6Y8. The Automatic Dependent Surveillance-Broadcast (ADS-B) data ended about 0.24 nm south of the accident site. The airplane impacted the ground about 110 ft east of the extended centerline of runway 35, and 320 ft south of the runway threshold. The turf runway was 3.500 ft long and had a displaced threshold just beyond its intersection with paved runway 9/27. Impact signatures indicated that the airplane struck the ground in a left-wing low, nose-low attitude. The front of the fuselage was crushed upward and aft.
The National Transportation Safety Board determines the probable cause(s) of this accident to be the pilot's exceedance of the airplane's critical angle of attack during the final approach, which resulted in an aerodynamic stall and loss of control at an altitude too low to recover.
Preventing aerodynamic stalls at low altitudes is crucial for the safety of an aircraft, especially during takeoff and landing when an aircraft is closest to the ground. Here are some key strategies and precautions to help prevent aerodynamic stalls at low altitudes:
Proper Training
Ensuring that pilots receive thorough training on stall recognition and recovery techniques is essential. Pilots should be trained to recognize the early warning signs of an impending stall, such as the stick shaker or stall warning horn, and respond appropriately to recover from the stall.
Aircraft Configuration
Maintain the aircraft in the appropriate configuration for the phase of flight. This includes setting the flaps and landing gear as recommended for takeoff or landing. Using the correct configuration helps maintain lift and control authority.
Airspeed Management
Pay close attention to airspeed. Stalls are often associated with a low airspeed or an excessive angle of attack. Pilots should adhere to recommended airspeeds for each phase of flight and avoid flying too slowly, especially in low-altitude situations.
Avoid Sharp Turns
Avoid making sharp or abrupt turns, especially at low altitudes. High-bank angles and excessive G-forces can increase the risk of an aerodynamic stall. Use coordinated turns and avoid over-aggressive maneuvers.
Windshear Awareness
Be aware of windshear conditions, which can rapidly change airspeed and direction at low altitudes, particularly during takeoff and landing. Modern aircraft are equipped with windshear detection systems to help pilots react appropriately.
Terrain Awareness
Maintain situational awareness of the terrain and obstacles in the vicinity, especially during the approach and landing phases. Terrain awareness systems (TAWS) can provide valuable alerts to prevent controlled flight into terrain (CFIT) accidents.
Stall Warning Systems
Ensure that stall warning systems are functioning correctly and respond promptly to stall warnings. These systems are designed to provide an early warning to pilots that they are approaching a stall condition.
Crew Coordination
Effective communication and coordination between the flight crew members are essential. Both the pilot flying (PF) and pilot not flying (PNF) should be vigilant in monitoring airspeed and aircraft attitude.
Go-Around Procedures
If conditions deteriorate or if a safe landing cannot be assured, pilots should be prepared to execute a go-around or missed approach procedure, which involves applying full power, retracting flaps to the appropriate setting, and climbing away from the runway to reset the approach.
Weather Considerations
Pay attention to weather conditions, including turbulence, icing, and visibility, which can increase the risk of stalls. Adjust the flight plan and approach accordingly to account for adverse weather conditions.
Risk Management
Use sound judgment and risk assessment when making decisions. If conditions are marginal or uncertain, it may be safer to delay or divert the flight rather than attempt a risky maneuver at low altitude.
Preventing aerodynamic stalls at low altitudes is a fundamental aspect of aviation safety. A combination of proper training, adherence to procedures, and situational awareness can help ensure that an aircraft operates safely during critical phases of flight near the ground.