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Teaching and Learning Flying - Flight Instructor, Single-Engine Airplane

Spins


DEFINITION

    A spin is an aggravated stall with autorotation occurring as the airplane follows a corkscrew path downward.

SAFETY FACTORS

  • To enhance safety is primary objective of spin training
  • Specific safety-related objectives:
    • To develop the student's skill in recognizing when a spin condition exists and taking prompt action to prevent a fully developed spin
    • To develop the flight instructor's knowledge and skill in recognition of and recovery from spin situations that might be encountered in poorly executed maneuvers during student training flights
  • Airplanes approved for the spin maneuver based on airworthiness
    • category and type certificate
    • FAR 23.221 covers spin certification
    • Normal category single engine airplane
      • "One-turn spin" (recover from one turn or 3-second spin, the longer, in not more than one additional turn after recovery control application), or
      • Spin-resistant requirement
      • One turn spin is an incipient spin, not a developed spin
      • Avoid spins in normal category airplanes
    • Utility category
      • Must meet either normal or acrobatic requirements
    • Acrobatic category
      • Must recover from any point in spin in not more than 1½ additional turns after normal recovery application of controls after a spin test of 6 turns or 3 seconds, the longer, (and one turn or 3 seconds, the longer, with flaps extended)
    • Avoid spins unless specifically approved for that airplane
    • Airplane placarded against spins may be uncontrollable in a spin
  • Relationship of various factors such as configuration, weight, center of gravity, and control application to spins
    • Flaps down may delay or preclude recovery in some airplanes
    • Maximum positive load factor may be exceeded during flaps-down pullout from dive (2 to 3 G's may be experienced during pullout)
    • Piper Tomahawk PA-38-112 is approved for spins in the utility category with flaps fully retracted (max pos load factor 4.4G flaps up, 2.0G flaps down)
    • More weight means more inertia during spin, so greater aerodynamic force and/or more time needed to stop the spin
    • Aft CG tends to delay recovery; CG aft of limit may result in flat, unrecoverable spin
    • Maintaining coordinated flight makes spins unlikely
  • Flight situations where unintentional spins may occur
    • Any uncoordinated stall
    • Distractions may lead to uncoordinated stalls
      • Skidding turn from base to final
      • Emergency landing situation
  • How to recognize and recover from imminent, unintentional spin
    • Airplane stalling or close to stall and roll or yaw is occurring, spin is imminent
    • Practicing stalls helps develop skill in promptly and appropriately reacting to imminent spins
    • Recover from imminent spin
      • Close throttle
      • Apply opposite rudder against the roll or yaw
      • Control wheel forward
  • Minimum entry altitude for intentional spins
      PA-38-112 Piper Tomahawk
      • Allow full recovery above 4,000 feet AGL to provide adequate safety margin (POH PA-38-112)
      • A one-turn spin and recovery requires 1,000 to 1,500 feet
      • 6-turn spin and recovery requires 2,500 to 3.000 feet
      • Entry should be above 6,000 to 7,000 feet AGL

TOLERANCES

  • Demonstrate instructional knowledge of the elements of spins
    • Aerodynamics of spins
    • Approval of airplanes for spins
    • Relationship of various factors (configuration, weight, CG, coordination) to spins
    • Flight situations where unintentional spins may occur
    • Recognition and recovery from imminent unintentional spins
    • Intentional spin entry technique and minimum entry altitude
    • Control technique to maintain a stabilized spin
    • Orientation during a spin
    • Recovery technique and minimum recovery altitude for intentional spins
    • Anxiety factors associated with spin instruction
  • Exhibit instructional knowledge of common errors related to spins
    • Failure to establish proper configuration prior to spin entry
    • Failure to achieve and maintain a full stall during spin entry
    • Failure to close throttle when a spin entry is achieved
    • Failure to recognize the indications of an imminent, unintentional spin
    • Improper use of flight controls during spin entry, rotation, or recovery
    • Disorientation during a spin
    • Failure to distinguish between a high speed spiral and a spin
    • Excessive speed or accelerated stall during recovery
    • Failure to recover with minimum loss of altitude
    • Hazards of attempting to spin an airplane not approved for spins
  • Demonstrate and simultaneously explain a spin (one turn) from an instructional standpoint
  • Analyze and correct simulated common errors related to spins

OBJECTIVES

  • To develop the student's skill in recognizing when a spin condition exists and taking prompt action to prevent a fully developed spin
  • To develop the flight instructor's knowledge and skill in recognition of and recovery from spin situations that might be encountered in poorly executed maneuvers during student training flights

PROCEDURES

  • Discuss lesson objectives, elements, completion standards
  • Demonstrate spin entry, spin and recovery in flight
  • Entry technique and minimum entry altitude for intentional spins PA-38-112 Piper Tomahawk
    • Allow full recovery above 4,000 feet AGL to provide adequate safety margin (POH PA-38-112)
    • A one-turn spin and recovery requires 1,000 to 1,500 feet
    • 6-turn spin and recovery requires 2,500 to 3.000 feet
    • Entry should be above 6,000 to 7,000 feet AGL
    • Pre-spin check
      • No baggage
      • Loose items: out or secure
      • Belts firm
      • Harness tight
      • Check: full rudder operation
      • Check: full control wheel
      • Seats secure
    • Spin entry
      • Climb to > 6,000 to 7,000 feet AGL
      • Lights on , CLEAR area
      • During clearing turn
      • Check flaps up
      • Trim to power-off glide at 75 KIAS
      • Reduce speed 1 kt/sec to stall
      • Full aft control wheel
      • Full rudder in direction of spin and
      • Maintain
      • (Aileron neutral)
  • Control technique to maintain a stabilized spin
    • Maintain full aft control wheel and full pro-spin rudder
    • Neutral ailerons
  • Orientation during a spin
    • Use outside ground references (road or railroad) and count turns around reference
    • Miniature airplane in TC indicates direction of spin
    • Other instruments no help in orientation (ball in TC on left side of airplane moves to left due to centrifugal force regardless of direction of spin)
  • Recovery technique and minimum recovery altitude for intentional spins
    • Regulations require recovery above 1,500 feet AGL
    • PA-38-112 POH recommends recovery above 4,000 feet AGL
    • Spin recovery (PA-38-112)
      • Apply and maintain full rudder opposite the direction of spin
      • As rudder hits stop, move control wheel full forward and be ready to relax forward pressure as the stall is broken
      • As rotation stops, centralize rudder and smoothly recover form dive
      • Power off and ailerons neutral throughout entry and recovery
      • Recovery may take 1½ turns with proper technique
      • Initial normal response to correct recovery application may by steeper nose-down attitude and increase in rotation rate
      • Centralize rudder as soon as spin stops, before airspeed reaches VA = 103 KIAS
      • If engine stops and does not restart with prop windmilling, set up 75 KIAS glide and restart with starter motor
  • Coach student practice of spin entries, spins and spin recoveries
  • Critique student performance

COMMON ERRORS

  • Failure to establish proper configuration prior to spin entry
    • Read back instructions
    • Flaps up, Tomahawk
  • Failure to achieve and maintain a full stall during spin entry
      If back elevator pressure is relaxed as the spin starts, the airplane will slip into a spiral dive, indicated by increasing airspeed
  • Failure to close throttle when a spin entry is achieved
    • PA-38-112: enter spin from power-off glide
    • Power on in a developed spin usually results in flatter spin and recovery delay
  • Failure to recognize the indications of an imminent, unintentional spin
      Airplane approaching stall and rolling or yawing is set up for a spin
  • Improper use of flight controls during spin entry, rotation, or recovery
    • At entry, apply full rudder in direction of spin; ailerons neutral
    • In spin, control wheel full aft, rudder full into spin, ailerons neutral
    • To recover, maintain full opposite rudder, then control wheel full forward to break stall; neutralize rudder as rotation stops and smoothly recovery from dive
  • Disorientation during a spin
    • Count turns by outside references
    • Direction indicated by needle or miniature airplane in TC
  • Failure to distinguish between a high speed spiral and a spin
    • Spiral indicated by increasing airspeed
    • Spin features almost constant, low airspeed
  • Excessive speed or accelerated stall during recovery
  • Failure to recover with minimum loss of altitude
    • Brisk , positive control applications minimize altitude loss
    • PA-38-112: move control wheel forward as rudder hits stop; relax this forward control wheel pressure as stall is broken
    • Neutralize rudder as rotation stops
  • Hazards of attempting to spin an airplane not approved for spins

Greg Gordon MD, CFII
Updated: