Slow Flight and Stalls

Question 1

What causes a spin?

Answer 1

A full stall plus a yaw acting on the plane at, or beyond, the point of the stall - i.e. a stall plus a yaw.

Question 2

What can cause the plane to yaw?

Answer 2

Uncoordination (too much rudder, or not enough - so a skid or a slip), turbulence/wind shear, torque, p-factor, slipstream, gyroscopic precession, improper aileron usage, adverse yaw (a slip), asymmetrical thrust.

Question 3

You’re in a climbing right turn and the plane stalls. You step on the left rudder at the point of the stall. Which direction will the plane spin?

Answer 3

In the direction of the yaw, which in this case will be to the left as you just applied left rudder.

Question 4

In a spin, are both wings stalled or just one?

Answer 4

Both.

Question 5

Are the wings producing any lift in a stall and/or spin?

Answer 5

Yes, in both a stall and a spin the wings are producing lift, just not nearly enough to maintain level flight.

Question 6

You’re spinning to the left, which wing has the greater angle of attack? Which wing is producing more drag?

Answer 6

The lower/inside wing is at the higher AOA and is creating more drag; it is more stalled, it has more exceeded the critical AOA.

Question 7

What happens to this spin if you add left aileron, so aileron in the direction of the spin?

Answer 7

Tightens/speeds up the spin and points the nose down, tends to transition into a spiral, causing rapidly increasing loads.

Question 8

What happens to this spin if you use right aileron, so opposite the direction of the spin?

Answer 8

The spin flattens, i.e. the nose rises and recovery becomes more difficult.

Question 9

To cause a spin to the right, would you step on the left or right rudder?

Answer 9

Right. The plane spins in the direction of the yaw, and right rudder causes a yaw to the right.

Question 10

During a spin is the plane corkscrewing downward around its own vertical axis, or an outside independent spin axis?

Answer 10

The plane follows a downward corkscrew path around an independent spin axis.

Question 11

What happens to the relationship between the plane’s vertical axis and the spin axis during a flat spin?

Answer 11

The axes move closer together.

Question 12

What does the ASI show once established in a spin?

Answer 12

Stabilized at an airspeed around the stall speed, usually a little below.

Question 13

What’s the difference between a spin and a spiral?

Answer 13

In a spin the wings are stalled. In a spiral the wings are not stalled - the plane is just flying in a spiral dive toward the earth.

Question 14

Define a spin.

Answer 14

A spin is an aggravated stall that typically occurs from a full stall occurring with the airplane in a yawed state and results in the airplane following a downward corkscrew path, i.e. “autorotation.” The airplane is basically descending due to gravity, rolling, yawing, and pitching in a spiral path.

Question 15

Aerodynamically, what causes the plane to enter the downward corkscrew formation of a
spin?

Answer 15

Both wings have exceeded their critical AOA’s, but not equally. With gravity pulling the stalled plane downward, the lower wing is more stalled and therefore at a higher AOA, creating more drag; whereas the outboard/raised wing is less stalled, at a lower AOA, and therefore creating less drag and more lift.

Question 16

You’re in a spin in IMC, how can you determine the direction of the spin?

Answer 16

The miniature airplane/rate-of-turn indicator. It will be banked in the direction of the spin .

Question 17

What about the ball/inclinometer, could you use that to determine the direction of the spin in IMC? Why or why not?

Answer 17

No, the FAA resources say that the ball is unreliable.

Question 18

Why wouldn’t you want to rely on the AI or the HI to determine spin direction to recover from a spin?

Answer 18

Their gyros tumble.

Question 19

You’re in a spin in IMC, what tells you that you’ve transitioned from a spin into a spiral?

Answer 19

ASI will start increasing, as you are no longer stalled.

Question 20

What are the stages of a spin?

Answer 20

Entry, Incipient, Fully Developed, Recovery

Question 21

What characterizes both the Incipient and Fully Developed stages?

Answer 21

Incipient: first 2-4 turns where aerodynamic and inertial forces have not yet reached a balance. Fully Developed: Plane is in equilibrium. Rate of rotation, rate of descent, and airspeed are all stabilized in a near-vertical downward flightpath.

Question 22

What is the generic spin recovery procedure for a SE airplane? (Every 172 model POH/AFM details its own spin recovery nuances that should be followed; however, all closely resemble this generic recovery procedure listed in the AFH and AC61-67(c).)

Answer 22

P.A.R.E. To be performed sequentially: Power (throttle) idle, ailerons neutral, rudder full opposite the direction of the spin, elevator briskly fwd (sufficiently to break the stall). Neutralize the rudder once the spinning stops and gradually apply back pressure in order to return to level flight.

Question 23

Explain the WHYS behind each spin recovery step.

Answer 23

● Throttle idle: this reduces the left turning/yaw tendencies, slows the rate of rotation and rate of descent, and decreases airflow over the elevator in order to reduce negative lift (a down force on the tail) and help lower the nose to break the critical AOA, i.e. recover from the stall.
● Ailerons neutral: using aileron control opposite the spin direction flattens the spin by increasing the AOA on the lower wing, thus deepening that wing’s stalled condition; because of the flatter (more nose-up) spin attitude, lowering the nose to break the critical AOA becomes more difficult. As for using same-direction aileron, this causes the plane to roll into a steeper (more nose-down) spin attitude, increasing the rate of rotation, increasing airspeed, potentially causing excess loads on the aircraft and delaying recovery.
● Rudder full opposite (then held in that position): considered by the AFH to be the most important control for spin recovery, this input resists the spin direction and yaws the plane out of the spin, i.e. stops the rotation.
● Elevator briskly forward: this reduces the AOA below the critical AOA, thereby reattaching smooth airflow over the tops of the wings and breaking the stall. If the plane isn’t stalled, it’s not spinning.

Question 24

Per the AFH, approximately how many feet are lost in each 3 second turn in a spin?

Answer 24

500ft (this ratios to a 10,000 ft/min descent).

Question 25

What are the 3 types of spins listed in AC61-67c? Which is the most dangerous?

Answer 25

Incipient, fully developed, and flat. Flat spins are the most dangerous.

Question 26

What is a flat spin and why is it a particularly dangerous type of spin?

Answer 26

A flat spin is a spin with a nose-high/pitched-up attitude. It is dangerous because it is harder to get the nose down in order to break the stall during the recovery.

Question 27

What is Piper’s recommended PA-44-180 spin recovery procedure? (No spin tests have been conducted, and the PA-44-180 is not approved for spins, so this is a recommended procedure based on best available information.)

Answer 27

P.R.E.A. As soon as the spin is entered, and as near simultaneously and as forcefully as able: Power idle, rudder full opposite, elevator full forward, ailerons neutral. These controls should be held in this position until the rotation stops. Once the spinning has stopped, neutralize the rudder and slowly pull out of the dive.

Question 28

In ME aircraft, why is it imperative to input these controls as immediately as possible and as soon as spin development is recognized?

Answer 28

The longer you wait, the less recoverable the spin becomes. Light twins are not required to undergo spin testing and thus are not designed to be spin recoverable.

Question 29

What effect does an aft CG have on spin recovery? Why?

Answer 29

Makes it more difficult. The aft CG makes lowering the nose and breaking the critical AOA/stall more difficult. Conversely, with a fwd CG, not only does the nose naturally want to lower itself, there is also a longer arm between the CG and the control surfaces that are used to arrest the spin - i.e. the rudder and elevator - translating to more leverage.

Question 30

If you are in a spin with the flaps extended, when should you retract them? Why?

Answer 30

Leave the flaps extended until the spinning stops. Flaps help keep the nose pitched down. As soon as you’re out of the spin, retract the flaps immediately.

Question 31

Approximately how many Gs does an airplane experience in the fully developed phase of a spin? How about during the recovery phase?

Answer 31

1G during the spin, 2.5Gs during the recovery.

Question 32

Where and when are unintentional spins most likely to occur and why?

Answer 32

● The takeoff and landing environment where airspeeds are slower, distractions most prevalent, and task saturation more likely. Base-to-final turns, go arounds, and short field t/o’s and approaches require particular vigilance when it comes to spin avoidance.
● Delayed recoveries and bad technique while performing certain low-airspeed maneuvers such as stalls, slow flight, and especially one engine inoperative (OEI) maneuvers.

Question 33

How can you determine whether your aircraft is certified for intentional spins?

Answer 33

1) TCDS, 2) limitations section of the POH/AFM, 3) placard in the cockpit.

Question 34

The 172 is certified for intentional spins only when the CG falls within what category? What are this category’s load limits?

Answer 34

Utility. 4.4 to -1.76.

Question 35

Talk me through a left base-to-final turn resulting in a XC stall?

Answer 35

In a misguided attempt at turning faster (say, after overshooting final), pilots may apply too much rudder (beyond the necessary rudder to maintain coordination) IN THE DIRECTION OF THE TURN, in this case to the left. Because the plane is already in a left bank, the nose will point downward (remember, you’re only about 500ft AGL at this point…) causing the pilot to pitch back and attempt to remove the bank by using right aileron. At this point the plane is at a low airspeed, and the pilot has applied left rudder, right aileron, and back pressure . . . all the ingredients necessary for a spin to occur, with minimal altitude available for a recovery.

Question 36

Which direction will this plane spin?

Answer 36

To the left.

Question 37

What are some other flight situations conducive to cross-control stalls?

Answer 37

● Stalling during a fwd slip to land.
● Losing track of airspeed and stalling during a crosswind landing while using the wing low sideslip technique.
● Use of ailerons to counteract roll in a stalled condition.

Question 38

Is a spin an aerobatic maneuver? According to what?

Answer 38

No, not according to the FAA’s Finagin Legal Interpretation. It states: “Spin training typically is conducted under three scenarios: (1) to meet the requirements for the issuance of an initial CFI certificate; (2) in conjunction with unusual upset instruction; and (3) in conjunction with aerobatic flight instruction. The first two scenarios typically are not considered aerobatic flight maneuvers because spin training maneuvers, in these circumstances, do not require use of a parachute and are required by regulation for particular certificates and ratings to simulate recovery procedures. 14 CFR § 91.307(d). The FAA distinguishes spin training in these scenarios from intentional spin aerobatic flight maneuvers.”

Question 39

According to 91.303, aerobatic maneuvers are prohibited when, over any congested area of a city, town, or settlement; over an open air assembly of persons; within the lateral boundaries of the surface areas of Class B, Class C, Class D, or Class E airspace designated for an airport; within 4 nautical miles of the center line of any Federal airway; below an altitude of 1,500 feet above the surface; or when flight visibility is less than 3 statute miles. Do these prohibitions apply to spin training?

Answer 39

No, the Finagin Legal Interpretation goes on to say, “. . . provided no additional aerobatic flight maneuvers are performed, spin training to meet the requirements of a CFI certificate or associated with upset recovery training are not considered aerobatic maneuvers, and the requirements of § 91.303 do not apply.” Regardless, not abiding by 91.303 when performing spins would show abysmal ADM.

Question 40

During spin training for the 61.183(i) endorsement, are the student and IP required to wear parachutes? Why or why not?

Answer 40

No. According to 91.307(c), parachutes are not required when performing spins required by the regulations for a certificate or rating when the training is being conducted by a CFI.