Lesson 30 - Stalls
September 05, 2023
The focus for today’s lesson was to make sure that we go over all the solo requirements, as per FAA. Federal Aviation Administration has a whole list to cover pre-solo flight training requirements
FAR/AIM - Part 61.87 Solo Requirements for student pilot
(d) Maneuvers and procedures for pre-solo flight training in a single-engine airplane.
A student pilot who is receiving training for a single-engine airplane rating or privileges must receive and log flight training for the following maneuvers and procedures:
Proper flight preparation procedures, including preflight planning and preparation, powerplant operation, and aircraft systems;
Taxiing or surface operations, including runups;
Takeoffs and landings, including normal and crosswind;
Straight and level flight, and turns in both directions;
Climbs and climbing turns;
Airport traffic patterns, including entry and departure procedures;
Collision avoidance, windshear avoidance, and wake turbulence avoidance;
Descents, with and without turns, using high and low drag configurations;
Flight at various airspeeds from cruise to slow flight;
Stall entries from various flight attitudes and power combinations with recovery initiated at the first indication of a stall, and recovery from a full stall;
Emergency procedures and equipment malfunctions;
Ground reference maneuvers;
Approaches to a landing area with simulated engine malfunctions;
Slips to a landing;
Go-arounds.
All except one was covered in all prerios lessons. The only one remaining was stalls.
Stall happens when airplane's lift component is suddenly reduced to zero, and that happens when critical angle of attack is exceeded. Stall can happen at any phase of the flight: Take-off, Landing and In-Flight. Stall occurences during take-off and landing are most significant because during those two phases, you do not have enough altitude to break the stall and recover. Most of the accidents happen during these two phases of flight, and hence being stall-aware is very important for every pilot.
What is critical angle of attack?
Critical Angle Of Attack (AOA) is defined as the angle between the chord of the wing and the relative wind. It is reached when the maximum LIFT component is reached, and after that the airplane will loose the LIFT component and airplane will stall.
The aircraft will always stall at Critical AOA, so it is always about relative airflow above the wings. That means, in a stronger and gusty headwind and crosswind, the airplane will stall at much higher airspeed than otherwise.
Power-ON Stall
Power on stall maneuver introduces pilot to a stall that might happen right after the take-off. Imagine (actually don't imagine, as it is not a pretty picture) that the pilot rotates the nose in pitch-up attitude during take-off, but exessively, relative to the headwind. As the critical angle of attack exceeds, the plane’s lift component is no longer generated, and plane stalls. At this point, the only way to break the stall is to push the nose forward and reduce the angle of attack. While breaking the stall, pilot should also be aware of the Secondary Stall. If the recovery from initial stall is incomplete, and critical angle of attack exceeds again, the plane enters the secondary stall. Secondary stalls are generally more aggressive and violent.
Power-OFF Stall
Power-off stall maneuver introduces pilot to a stall that might happen on the approach to landing. The physics behind the stall is still the same as power-on stall, but the setting is different. In power-on stall , you don't have any more throttle input available (since during take-off you have all the power), whereas in power- off configuration, you have throttle idle, since you are on approach to land. The recovery fundamentals are same - reduce the critical angle of attack relative to the wind. In power- off configuration, you have pitch and power at your disposal to achieve it, so you have to push the nost down and add power as needed to reduce the angle of attack.
Alright, so I have to demonstrate these stall maneuvers during my checkride. Stalls are anything but fun and I have always seen Drew's aversion towards stalls demonstration. We climbed up to 4000 feet and Drew started power-off stall demonstration. He levelled the flight, and slowly started to pitch the nose up. Airspeed started to drop and soon enough, as it got in the flaps range. He put 10 degrees of flaps in, then 20, then 30, and with each incremental flaps, airspeed started to drop. Nose was still pitched up.
As airspeed dropped lower and lower, at some point stall horn started to blow. He still maintained pitched-up attitude, and the horn sound grew louder and louder, and then at one moment, it felt as if the seat started to shake. That's stalling the plane till the buffet. He immediately pushed the nose down, put full power in and watched the airspeed increase. He slowly then took the flaps up in increments and recovered to the straight and level flight. Maneuver complete.
I repeated the same maneuver after him.
This is perhaps the most important lesson so far. Soon I will be flying solo, and I am not going to have my buffer, my CFI, next to me on the controls. I can only imagine what must be going on in his mind not being able to prevent something bad from happening. But that's what happens, when kids grow up, they have to be responsible and accountable for their actions and be prepared to face the consequences.
In this case since the consequence is potentially death, Drew has been equipping me with all the tools and techniques necessary to avoid the stall in the first place. Altitude and airspeed are my best friends and as long as I have them with me, I am in better position to recover. Another reflex I have to train on is as soon as I hear the stall horn, push the nose forward so that the angle of attack is reduced, and lift is generated.
No pressure G - you got this !