Stall Training

Introduction

Flight instructors must provide stall training as outlined in Exercise 12 of the Flight Instructor Guide (TP 975) and the Flight Training Manual. Emphasize that techniques and procedures for each aircraft may differ and that pilots should be aware of the flight characteristics of each aircraft flown. As an instructor you need to know how your training aircraft behave in order to provide an effective and safe demonstration. Strict adherence to the AFM/POH is necessary to ensure safety.

The following air exercises describe procedures that complement the Flight Instructor Guide and provide additional guidance in the training of stalls and incipient spins. To encourage the use of scenarios based on practical flight situations, some examples are provided but are not considered to be a comprehensive list. Refer to the matrix in Appendix 1 Stall Scenario Conditions, in this document, to help select the conditions for developing various scenarios. The intent of this matrix is to provide a variety of options. Instructors are not expected to teach every variation. Select a few that work well with the type of aircraft you fly.

Many aircraft manufacturers prohibit the use of flaps when practising intentional spins. If an inadvertent spin is entered during advanced stall practice, follow the manufacturers recommendations or, in the absence of these recommendations, retract the flaps at the first opportunity after initial recovery action has been taken.

Departure Stalls

Instructor and Student Practice

At a safe altitude,

  1. Demonstrate coordinated and uncoordinated power-on stalls straight ahead and in turns.

  2. Demonstrate with departure flap settings. Emphasize how these stalls could occur during takeoff. Point out the possibility of a spin developing from these types of stalls.

Stalls During Overshoots

At a safe altitude,

  1. Trim the aircraft for a power-off descent and demonstrate a full-flap, gear extended, power-off stall, then recover with power and attempt to climb with flaps extended. If a higher than normal climb pitch attitude is held, a secondary stall will occur. (In some aeroplanes, a stall will occur if a normal climb pitch attitude is held.)

  2. Demonstrate a full-flap, gear extended, power-off stall, then recover and retract the flaps rapidly as a higher than normal climb pitch attitude is held. A secondary stall or settling with a loss of altitude may result.

  3. Elevator Trim Stall. Place the aeroplane in a landing approach configuration, in a trimmed descent. After the descent is established, initiate a go-around by adding full power, holding only light elevator and right rudder pressure. Allow the nose to pitch up and torque to yaw the aeroplane left. Emphasize the importance of correct attitude control, application of control pressures, and proper trim during overshoots. Demonstrate the same exercise with the flaps retracted.

Scenarios

A reduced power setting can be used to simulate high density altitude.

During departure or overshoot

Steep climb or steep climbing turn

  • avoiding obstacles
  • avoiding birds or other aircraft
  • showing off
  • caught in a downdraft (windshear)
  • wing contamination
  • distraction resulting in airspeed decay

Using information from actual aviation accident reports can help lend realism to scenario development. For example,

"Location: 1,100 FT grass strip with 75 feet high pine trees at departure end of the runway. The departing C-150 was observed by witnesses to become airborne approximately 200 feet from the end of the strip and approximately 500 feet from a line of pine trees off the departure end of the strip. The a/c entered a steep climbing right turn then rolled to the left and descended in a steep nose down attitude until it collided with the ground. 2 fatal"

Using this example refer to the Stall Scenario Conditions Appendix 1. Starting at the left column of the matrix select

Departure stall,

  1. medium power,
  2. 0° flaps,
  3. gear n/a,
  4. coordinated medium turn,
  5. climbing attitude.

This one scenario can be modified by changing any of the 5 conditions in the matrix. Many other scenarios can be developed from the matrix by using aircraft accident reports and personal experience. Avoid using only one or two scenarios in your training. Students should be exposed to as wide a variety of situations as possible.

Arrival Stalls

Instructor and Student Practice

At a safe altitude,

  1. Demonstrate coordinated power-off or reduced power stalls straight ahead and in turns. Demonstrate with various flap settings. Emphasize how these stalls could occur during approach. Emphasize the possibility of a spin developing from these types of stalls.

  2. Cross-controlled Stalls in Descending Turns. Demonstrate stalls at medium and low power settings while simulating turns from base to final. Demonstrate the stalls from a properly co-ordinated turn, a slipping turn, and a skidding turn. Explain the difference between slipping and skidding turns. Explain the position of the ball on the turn co-ordinator (or turn and bank indicator) in each turn and the aircraft behaviour in each of the stalls.

Note:  In some aircraft types a skidding descending turn stall will result in the inside wing stalling first and a sudden and aggressive incipient spin developing. Training aircraft that exhibit docile spin characteristics may not produce a convincing demonstration of this manoeuvre. Try different configurations with your aircraft to find the most effective demonstration.

Scenarios

Arriving at an airport or off-airport landing area.

  • turning to correct for an overshoot of the extended runway centreline
  • turning to avoid obstacles, birds, other aircraft
  • attempting to stretch a glide to the runway by raising the nose and not applying power
  • illusions in strong wind conditions
  • distraction resulting in airspeed decay

Again, using information from actual aviation accident reports can help lend realism to scenario development. For example,

"Location: 1 mile east of the aerodrome. Weather conditions: VFR, winds NW at 15 KT, moderate turbulence. The Piper Cub J-3 overshot the extended centreline for runway 26 while turning final. Witnesses observed the a/c turning from the south to the west at a moderate bank angle. Prior to completion of the turn the a/c bank attitude increased rapidly and the nose dropped to a nearly vertical attitude. The wreckage impact was consistent with an a/c in a spin condition. 1 fatal"

This accident is consistent with an attempt to "cheat" when overshooting a turn to final by input of rudder to increase the rate of turn and opposite aileron to maintain a normal bank angle. If the aircraft is allowed to stall at this point, the inside wing will stall first and a spin will develop.

Using this example refer to the Stall Scenario Conditions Appendix 1. Starting at the left column of the matrix select

Arrival stall,

  1. medium power,
  2. 0° flaps,
  3. gear n/a,
  4. uncoordinated medium skidding turn,
  5. descent attitude.

This one scenario can be modified by changing any of the 5 conditions in the matrix.

Engine Failure after Take-off (followed by an attempt to return to the runway)

This demonstration will show the student how much altitude the aeroplane loses when, following an engine failure after take-off, an attempt is made to return to the departure runway. In order to complete the manoeuvre, the aircraft must be turned to a reciprocal heading AND realigned with the runway. This requires much more than just 180 degrees of turn. For novice pilots, turning back is not an option. An evaluation of stall/spin accidents in Canada showed that the pilot is eight times more likely to be killed or seriously injured turning back than landing straight ahead. For expert pilots who know how much altitude is needed to complete the required manoeuvring, it can be an option but even experts should be looking for landing areas that require less manoeuvring and less risk. Perform this demonstration using either a medium or steep bank in the turn, giving emphasis to stall avoidance.

Instructor and Student Practice

At a safe altitude,

  1. In cruise configuration, establish the best rate of climb speed (Vy). Note your altitude.

  2. Reduce power smoothly to idle to simulate the engine failure.

  3. Lower the nose to maintain the best glide speed and make a 270° turn followed by a 90° turn in the opposite direction to roll out on the reciprocal of the original heading.

  4. Point out the altitude loss and emphasize how rapidly airspeed decreases following a power failure in a climb attitude.

  5. Demonstrate the manoeuvre again and allow the aeroplane to stall during the turn. (This is actually a variation of an approach stall.) Emphasize the possibility of a spin developing from these types of stalls.

Note:  It should be stressed that the successful return to the airport after an actual engine failure on take-off depends on a variety of factors including available landing surfaces, altitude AGL when failure occurs, weather, turbulence, aircraft type and pilot skill and stress level . Point out that the altitude loss incurred during the controlled demonstration will be significantly less than in a real life situation. It is recommended to conduct the demonstration from the cruise configuration to reduce wear on the engine.

Accelerated Stalls

Instructor and Student Practice

At a safe altitude, set the aircraft up at 80% of the appropriate manoeuvring speed (Va) for the weight of the aircraft.

  1. Demonstrate the difference in stall speed by approaching the stall in level, unaccelerated flight and noting the airspeed at which the stall warning activates. Then demonstrate a 60° bank level turn and note the speed at which the stall warning activates. Emphasize that the stall is a function of angle of attack, not airspeed. An aircraft can stall at any speed and any attitude. Emphasize that these stalls could occur during any phase of flight, where abrupt or excessive control movements produce an increased load factor on the aircraft, such as steep turns, pulling out of a dive or sudden changes in direction of flight. Emphasize the possibility of a spin developing from these types of stalls.

  2. Demonstrate a 45° bank turn and gradually decrease power, while trying to maintain altitude with increasing back pressure, until the stall occurs. Demonstrate a 45° bank turn at cruise or climb power and "tighten the turn" with rapid back pressure on the control column. Demonstrate an abrupt pull-up (at low speed).

Scenarios

Abrupt pull-up to avoid obstacles or after a recovery from a stall

Aggressive manoeuvring while "showing off"

Distraction resulting in airspeed decay during a turn

  • While sight seeing at low level.
  • Turning to look at landmarks, wildlife, people.
  • Turning to avoid obstacles, aircraft.

Here is an actual aviation accident report that can help you design a realistic scenario.

"The Cessna 210 with 3 persons onboard was observed to be flying at tree top level and manoeuvring in an abrupt manner. A video camera recovered from the wreckage recorded the final minutes of the flight. The pilot was manoeuvring to allow a passenger to video tape a moose when the stall warning horn activated and the aircraft stalled in a 45° left bank turn at an altitude of 50 feet AGL. 3 fatal"

Using this example refer to the Stall Scenario Conditions Appendix 1. Starting at the left column of the matrix select

Accelerated stall,

  1. high power,
  2. approach flaps,
  3. gear up,
  4. coordinated steep turn,
  5. level attitude.

This one scenario can be modified by changing any of the 5 conditions in the matrix.

Distractions

Improper airspeed management resulting in stalls is most likely to occur when the pilot is distracted by one or more other tasks, such as locating a checklist or attempting a restart after an engine failure; flying a traffic pattern on a windy day; reading a chart or making fuel and/or distance calculations; or attempting to retrieve items from the floor, back seat, or glove compartment.

Pilots at all skill levels should be aware of the increased risk of entering into an inadvertent stall, spin or spiral dive while performing tasks that are secondary to controlling the aircraft. Providing the student with normal tasks secondary to the control of the aircraft builds confidence and ability. A properly trimmed aeroplane is a key component of controlling the aircraft while handling distractions. The following list of deliberate distractions can challenge students and improve their skills.

1.  Have the student

  1. pick up a dropped pencil.
  2. determine a heading to an airport using a chart.
  3. reset the clock to Universal Co-ordinated Time.
  4. get something from the back seat.
  5. read the outside air temperature.
  6. call the Flight Service Station (FSS) for weather information.
  7. compute true airspeed with a flight computer.
  8. identify terrain or objects on the ground.
  9. identify a field suitable for forced landing.

2.  Ask the student to decrease the cruise airspeed by 10 knots and repeat #1.

3.  Have the student climb 200 feet and maintain altitude, then descend 200 feet and maintain altitude while performing a task in #1.

4.  Have the student reverse course after a series of S-turns and create a distraction.

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