Spin Awareness

An aggravated stall that produces autorotation — the airplane follows a downward corkscrew path, rotating about its vertical axis under different lift and drag forces on each wing while descending under gravity, rolling, yawing, and pitching in a spiral (AFH ch. 5). In all spins, at least one wing is stalled.

Stall plus yaw. A spin occurs when at least one wing exceeds the critical AOA with a sideslip or yaw acting on the airplane at or beyond the stall (AFH ch. 5). Take either ingredient away and there is no spin — which is why the AFH's prevention rule is maintain directional control and do not allow the nose to yaw before stall recovery is initiated.

• Adverse yaw from aileron deflection
• Engine and propeller effects — P-factor, torque, spiraling slipstream, gyroscopic precession
• Wind shear, including wake turbulence (AFH ch. 5)

And when the yaw is pilot-induced by incorrect rudder use, you may not realize the critical AOA has been exceeded until the airplane yaws out of control toward the lowering wing.

In the direction of rudder application — regardless of which wingtip is raised (AFH ch. 5). This is the answer that separates a commercial applicant from a private one: the bottom rudder in a skidding base-to-final overshoot, not the bank, sets the rotation direction.

Entry, incipient, developed, and recovery (AFH ch. 5).

• Entry — the pilot, intentionally or accidentally, supplies the stall and the yaw
• Incipient — from the stall and start of rotation until the spin fully develops; two to four turns in most airplanes, with aerodynamic and inertial forces not yet in balance
• Developed — rotation rate, airspeed, and vertical speed stabilized in a nearly vertical flightpath; forces in equilibrium
• Recovery — rotation ceases and AOA drops below critical; may take as little as a quarter turn or up to several turns

Because the two inputs work together and the sequence is deliberate: the forward elevator decreases AOA and drives the airplane toward unstalled flight while the rudder kills the rotation, and the AFH explicitly says do not wait for the rotation to stop before applying it (AFH ch. 5). Waiting is a listed common error.

The first turn loses approximately 1,000 feet; each subsequent turn loses about half that (AFH ch. 5). Intentional spins should begin high enough to complete recovery at or above 1,500 ft AGL. Do that arithmetic against traffic-pattern altitude and the reason a base-to-final spin is unsurvivable becomes obvious.

Use the turn indicator — the symbolic airplane deflects in the direction of rotation. Do not use the slip/skid ball: its indication depends on where the instrument is mounted, not on the spin. A ball mounted on the left side of the airplane always moves left, even in a right spin (AFH ch. 5). Airspeed helps too — in a spin the airplane is stalled, so indicated airspeed is low and constant; if the airspeed is increasing, you are no longer in a spin.

Spin: stalled, low and constant airspeed, low G, autorotating. Spiral dive: not stalled, very tight circles in a nearly vertical attitude, with airspeed and G-load increasing rapidly (AFH ch. 5).

Some training airplanes will not enter the developed phase and may instead transition unexpectedly from the incipient phase into a spiral dive. Applying spin recovery to a spiral dive — full rudder and forward elevator at an already accelerating airspeed — is a structural problem. Recognize by the airspeed trend.

91.303: no aerobatic flight over a congested area or an open air assembly; within the lateral boundaries of the surface areas of Class B, C, D, or E airspace designated for an airport; within 4 NM of the center line of any Federal airway; below 1,500 ft AGL; or when flight visibility is less than 3 SM. Aerobatic flight is an intentional maneuver involving an abrupt change in attitude, an abnormal attitude, or abnormal acceleration, not necessary for normal flight.

91.307(c): approved parachutes for each occupant if you carry any person other than a crewmember and exceed 60° of bank or a 30° nose-up or nose-down attitude. 91.307(d) excepts flight tests for a certificate or rating, and spins and other maneuvers required by the regulations when given by a certificated flight instructor or an ATP instructing under 61.67.

The AFH's pre-spin review list (AFH ch. 5):

• The AFM/POH limitations section, placards, or type certification data to determine whether the airplane is approved for spins
• Weight and balance limitations
• Recommended entry and recovery procedures
• The current 14 CFR part 91 parachute requirements (91.307)

Plus a thorough preflight with attention to loose or excess items that could shift the CG or jam controls, and to slack control cables — particularly rudder and elevator — which could prevent full anti-spin deflection and delay or preclude recovery.

And prior to any intentional spin, clear the flight area above and below the airplane for other traffic — the AFH notes this task may occur while slowing the airplane for the entry (AFH ch. 5). "Above and below" is the part applicants forget: the maneuver is a vertical one, and you are about to descend through roughly 1,000 ft on the first turn alone.

Three places (AFH ch. 5):

• The Type Certificate Data Sheet or aircraft specifications
• The limitations section of the FAA-approved AFM/POH, including any limiting gross weight, CG range, or fuel quantity
• A placard in clear view of the pilot — for example, "NO ACROBATIC MANEUVERS INCLUDING SPINS APPROVED"

If the manufacturer does not specifically approve the airplane for spins, intentional spins are not authorized.

Because of what that test actually required. Certification of normal category single-engine airplanes under 14 CFR part 23, section 23.221(a) — still applicable to airplanes certificated under it — required only recovery from a one-turn spin or a three-second spin, whichever takes longer, in not more than one additional turn after the first recovery control input, or compliance with the optional spin-resistant requirements. Many of these airplanes were never required to recover from a fully developed spin (AFH ch. 5). Section 23.2150 governs spin characteristics going forward. In an airplane placarded against spins there is absolutely no assurance that recovery from a fully developed spin is possible — assume it could become uncontrollable.

Even minor weight or balance changes can affect spin recovery characteristics, degrading or enhancing them (AFH ch. 5). Weight added in the aft baggage compartment or extra fuel may keep you legally within CG and still seriously change the spin and recovery. The AFH's key case: an airplane hard to spin in the utility category (restricted aft CG, reduced weight) can have less resistance to spin entry in the normal category (less restricted aft CG, higher weight), because it can generate a higher AOA — and an airplane approved for spins in utility but loaded to normal category may not recover from a spin allowed to progress beyond one turn.

No. They tend to be more reluctant to spin than older designs, but it is not impossible for them to spin — mishandling the controls in turns, stalls, and uncoordinated slow flight can put even the most reluctant airplane into an accidental spin (AFH ch. 5). Spin resistance is a margin, not an exemption, and it evaporates with aft loading, ice, or a hard uncoordinated pull.

• Skidding base-to-final overshoot — bank, back pressure, and bottom rudder; the cross-control stall gives very little warning, the nose may pitch down, the bank may change suddenly, and the airplane may continue rolling toward inverted, which is usually the beginning of a spin (AFH ch. 5). The correct answer to an overshoot is a go-around; stay reluctant to exceed 30° of bank that low, and never skid the turn
• Departure stall with yaw — full power, high AOA, insufficient right rudder, a wing drops
• Accelerated stall at an unexpected attitude with the ball out (Task VII.D)
• The impossible turn — an engine failure after takeoff answered with a steep, uncoordinated turn back toward the runway — if the nose is not lowered sufficiently during the turn, "an accelerated stall and fatal crash may occur" (AFH ch. 18)

All four are low-altitude events, and the first turn alone costs about 1,000 ft (AFH ch. 5). Prevention is the only real recovery below pattern altitude.

The published 1G stall speed the warning is built around is valid only under specific conditions (AFH ch. 5):

• Unaccelerated 1G flight
• Coordinated flight with the ball centered
• One weight
• One CG

A spin entry violates the coordination condition by definition, so the airspeed on the dial is not the margin you think it is. In a power-off 1G stall the buffet cue is weak anyway, and the real indicators may be full-up elevator and a high descent rate (AFH ch. 5). An AOA indicator helps but has its own limits (AFH ch. 5):

• Calibration
• Unheated probes
• Indicator type
• Flap setting
• Wing contamination

Coordination — the ball and the rudder — is the protection no warning device provides.

• Turbulence and wind shear inject both AOA changes and yaw, including wake turbulence, without pilot input (AFH ch. 5)
• High density altitude reduces climb performance, tempting the nose-high, low-airspeed departure that starts the chain, and lengthens every recovery
• Distraction and disorientation — the AFH's spiral-dive discussion notes pilots typically get there during an inadvertent IMC encounter by relying on kinesthetic sensations rather than the instruments; the same fixation is what lets an unnoticed yaw develop at the stall

The commercial-level answer is task prioritization: fly the airplane coordinated first, then handle the distraction.

From the AFH's list (AFH ch. 5):

• Failure to apply full rudder to the stops, briskly, against the rotation
• Slow and overly cautious control movements
• Failure to apply sufficient forward elevator, or waiting for rotation to stop before applying it
• Failure to neutralize the rudder after rotation stops — a possible secondary spin
• Excessive back pressure after rotation stops, causing a secondary stall; or insufficient back pressure, causing excessive airspeed in the pullout