### Introduction
Stalls are normally to be avoided during routine flight. But we practice them so we can be aware of the signs of impending stall, know how to safely recover (a stall recovery is quite similar to a go-around), and understand the aerodynamics that are at work. In [[PPL2.1 Slow Flight and Power-Off Stalls|lesson 2.1]] we covered one type of stall, the "power-off stall." Now we're talking about a "power-on stall", which is a stall while climbing under power. Both types of stalls need to be demonstrated on your checkride.
Additionally we'll be talking about spins. You are not required to demonstrate a spin, and we won't actually practice them, but it's important to understand flight situations where unintentional spins may occur, and the procedure for recovery.
**Pre-Lesson Reading/Homework:** [[~ PPL Pre-Lesson Reading]]
**Builds On:** [[PPL2.1 Slow Flight and Power-Off Stalls]]
**Schedule:** Ground 1.0 hr, Flight 2.0 hr
Practice on multiple flights
### Lesson Elements
#### Power On Stall Maneuver
1. Procedure
1. Simulates stall during climb after takeoff
2. [[CHAPS]]
3. Enter slow flight in takeoff configuration
4. At [[Vr]], add >65% power
5. Pitch up slowly for full stall, establish gentle turn if requested
6. Verbally acknowledge stall horn
7. Continue holding pitch to full stall
8. Recover: pitch down to normal climb attitude, full power. Climb [[Vy]].
9. If a wing drops, pick up the wing with rudder
2. Common errors:
1. Not maintaining rudder coordination, causing wing to drop during stall, entering spin!
2. Delay in stall recovery, causing excessive altitude loss or spin entry
3. Secondary stall due to aggressive pitch up during recovery
> [!maneuver]- 3D Visualizer: Power-On Stall
> <iframe src="https://maneuvers.cfijack.com/?embed&m=power-on-stall" width="100%" height="520" style="border:0;border-radius:12px"></iframe>
> [!maneuver]- 3D Visualizer: Power-On Stall (Turning)
> <iframe src="https://maneuvers.cfijack.com/?embed&m=power-on-stall-turning" width="100%" height="520" style="border:0;border-radius:12px"></iframe>
#### Spins
1. Spin Recovery Procedure
1. Follow the [[POH]]!
2. [[PARE]]/[[PARENT]] - Power Off - Ailerons neutral - Rudder opposite rotation - Elevator stick/yoke forward briskly. Then, neutralize rudder and recover from dive.
3. What if we enter a spin today?
2. Aerodynamics of spins
1. Spins are stalls, but with one wing "more stalled" than the other, causing rapid autorotation and descent. The nose may be pointing near the ground, but angle of attack is high, airspeed is slow, and descent rate is moderate.
2. > [!tip] Spins happen when the plane is stalled and has a yawing moment
1. ![[Spin Autorotation.jpeg]]
2. ![[Spin Entry and Recovery.jpeg]]
3. At spin entry, trying to lift the down wing with aileron deepens the stall and accelerates stall entry!
4. Rudder effectiveness in a spin
5. Relationship to [[CG]] -- If CG is too far aft (e.g. aft of utility category limits) spin may not be recoverable!
6. An altitude loss of approximately 500 feet per each 3-second autorotation ("turn") can be expected in most small aircraft
3. What does it look like from the outside?
1. > [!youtube] Published by [Aaron's Airways](https://www.youtube.com/@aaronsairways)
4. What does it look like from the inside?
1. > [!youtube] Published by [@StephanEdelman](https://www.youtube.com/@StephanEdelman)
5. What aircraft are approved for spins?
1. Check [[POH]]. Some airplanes are approved for spins in utility category (e.g. C152, C172, Citabria) but many are not.
2. Normal category planes are tested to recover from 1-turn spin only. Any spin further than 1 turn may not be recoverable!
6. Parachutes
1. Typically parachutes required for bank > 60° or pitch > +/-30° ([[FAR 91.307 Parachutes]]), however...
2. Parachutes are NOT required for spin training. See [[Fitzpatrick - Spartan College 2018]]
7. > [!question] What is the difference between 'slip' and 'skid'? Which is more dangerous?
8. Situations where unintentional spins may occur
1. The classic: Skidding base-to-final turn^[King Air crashed in Brazil due to skidding the base-to-final turn: https://youtu.be/YZIzEtHzbNU]
2. Trying to stretch a power-off glide
3. Climb-out stall that develops into spin (lots of [[P-factor]] during takeoff/go-around climb)
4. Iced up airframe
9. Practicing Spins and Recoveries (optional)
1. Before departure
1. Confirm aircraft W&B in utility/acrobatic category approved for spins
2. Secure interior - no loose objects
2. Discuss nervousness/anxiety about spins. They can be anxiety-inducing, but are very safe and controlled if procedure is followed!
3. Select altitude to recover above 3000', typically 4500' or above
4. Check traffic with clearing turns
5. Configure and perform power-off stall (no flaps), stick full aft
1. For stalling a Cessna 172S, consider RPM of 1500 RPM
2. Additional tips in [[Teaching Spins in a Cessna 172]]
6. As stall breaks, add full rudder in desired direction of spin
7. Hold full aft elevator and full rudder for desired number of turns in spin
8. Recover with [[POH]] (often [[PARE]]) procedure as described above
9. Pull up from dive and add power to regain altitude as necessary
10. Common errors
1. Failure to configure aircraft properly (e.g. spinning with flaps down, since recover may exceed flap limit speed)
2. Failure to hold full stall, resulting in a steep spiral and high airspeed
3. Improper use of controls during recovery, especially neutral ailerons (instinct is to lift the low wing with ailerons)
4. Disorientation, and "freezing" during the spin
5. Recovering from dive too abruptly, causing secondary stall
6. Spinning an airplane not approved for spins, or out of utility limits. This could be fatal!
> [!maneuver]- 3D Visualizer: Spins
> <iframe src="https://maneuvers.cfijack.com/?embed&m=spins" width="100%" height="520" style="border:0;border-radius:12px"></iframe>
### Completion Standards
Learner must be able to demonstrate power-on stalls, to ACS standards. The client must be able to assess and avoid situations where unintentional spins may occur, and must be able to explain (and optionally demonstrate) procedures to recover from unintentional spins.
> [!success]- Tolerances (Partial) from [[Private Pilot ACS|ACS]]
> Recovery no lower than 1500' AGL, heading ±10° before stall, or specified bank angle ±10° (and <20°), acknowledge cues of impending stall and recover promptly with proper procedure.
### Resources
- [[Private Pilot ACS]] Sections VII.C and VII.D
- [[POH]]
- [[AC 61-67]]
- [[General Aviation Pilot Stall Awareness Training Study]]
### Required Homework
None
### Recommended Homework
- [ ] Chair fly power-on stalls
- [ ] Chair fly spin recovery
*Return to [[~ PPL Lesson Plan Outline|Table of Contents]]^*