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Stalls and Spins

To Spin or Not to Spin, Part 2

ADAPTED BY PHYLLIS A. DUNCAN, EDITOR (From FAA Aviation News, July/August 1992)

I n Part 1 of this article in the May/June issue, we discussed the theories behind stall/spin recognition and avoidance. In Part 2 we talk about some concrete training examples that will help to enhance stall awareness and spin prevention. After you finish this installment, test your knowledge with the Stall/Spin Quiz on the inside back cover. - Editor

In-flight spin training is not required for any pilot certificate other than the CFI in airplanes or gliders, but recent changes to FAR §§ 61.97, 61.105, and 61 .125 require ground instruction in "stall awareness, spin entry, spins, and spin recovery techniques" for all pilots who seek airplane or glider category ratings. Flight instructors should be thoroughly familiar with the stall/spin phenomena and should be comfortable discussing situations that lead to stall/spin accidents with their students. As a CFI you could decide, with your student's consent, to go beyond mere discussion of stall/spin awareness and provide your students with some practical spin experience under your guidance.

Spin discussion

When you get to the point of discussing stalls and spins, there are a number of points to be covered in order to meet the new requirements of FAR Part 61. Specifically, you should pose and answer the following questions:

  • When will an aircraft wing always stall?
  • Will an airplane spin without having first entered a stall?
  • Is it possible to stall an aircraft at any speed? In any attitude?
  • Does the spin follow the stall as the night follows day? If not, why not?
  • Assuming a wing is stalled, what will help to enhance stall awareness pilot action is required to recover from the stall?
  • How does a spin differ from a steep spiral? How does the recovery technique for the former differ from that for the latter?
  • What is the sequence of control actions necessary to effect recovery from a fully developed spin in most general aviation aircraft?
  • Where do most stall/spin accidents occur and how can they be prevented?

The answers to all except the last question can be found in Part 1 of this article (May/June 1992), which, like Part 2, was based on information from FAA's Flight Training Handbook (AC 61-21A) and other commercial flight training sources. You will find the answer to the last question, and some information you may find useful in avoiding the stall/spin accident, in the following in-flight demonstration scenarios - all of which should be conducted at a safe altitude with a certificated instructor proficient in spin training on board and in an aircraft properly certificated for spins. Use prescribed recovery techniques immediately, either for an imminent or full stall, if you elect to stop there, or for a spin. (See Part 1 of this article for stall and spin recovery.) Also, use clearing turns as often as necessary to "clear" the airspace below you before practicing either stalls or spins.

In-flight spin training

Flight instructor candidates in airplanes or gliders must have in-flight spin training to prepare themselves for their responsibilities as an instructor. Commercial applicants, even though in-flight spin training is not required, may be highly receptive to adding this maneuver to their repertoire of chandelles and steep spirals. However, approach in-flight spin training with all primary students very cautiously. In-flight spin training might be better introduced late in the primary student's training, once students have soloed and developed sufficient confidence in their ability to handle the airplane. A pre-solo "Student may be too "eager to please" an instructor to voice any misgivings about suggested in-flight spin training. And. unless the instructor is proficient and demonstrates the spin and its recovery properly, the very abruptness and sometimes violent rotation of the aircraft in a spin could leave an indelible mark on a student pilot's psyche.

Once you as an instructor and your student agree upon in-flight spin training, stay with the time-honored instructional approach: first demonstrate and then allow the student to practice under your guidance. If you are a pilot seeking spin training, have the instructor (who is spin proficient, of course) demonstrate the following scenarios then allow you supervised practice.

Short-field takeoff

Departing from a short runway or a runway with obstructions means the pilot must operate the aircraft at the limits of its takeoff performance capabilities. The Right Training Handbook states:

"To depart such an area safely, the pilot must exercise positive and precise control of aircraft attitude and airspeed ..."

The Handbook goes on to describe short field takeoff and climbout technique. But the message is implicit in the phrasing about precise control of attitude and airspeed. To get the point across about the need for precision in a short-field takeoff, demonstrate the following situation.

Simulate a takeoff at a safe altitude with gear and flaps in the takeoff configuration, continuously increase the pitch attitude as might be done in an attempt to clear obstacles (entry is similar to a departure-type stall). This demonstration is most effective if rudder coordination is improper when the aircraft stalls. For example, to make a right turn in a steep climb. a pilot may use insufficient right rudder and excessive right aileron. This produces a slipping turn to the right (ball indicator to the far right) with the result that, if a departure stall occurs. the airplane spins rapidly to the left "over the top."

The tendency of the airplane to enter a spin from a left climbing turn is less pronounced since, with no rudder pressure applied by the pilot. the left yawing moment is approximately correct. resulting in a (more or less) coordinated turn, and the spin may not develop as rapidly after the stall break.

In any event, this demonstration makes the point that a departure stall is especially critical, not only because of the low altitude involved, but also because of the tendency for the airplane to enter a spin rapidly at a critically low altitude.

Engine failure on takeoff or initial climb

If the airplane's engine fails on initial climbout before attaining a safe maneuvering altitude, it is usually inadvisable to turn back to the runway. For whatever reason, pilots are often lured by a false sense of security to try and land where they took off from after an engine failure even though landing straight ahead may be the only viable option. Consider the problems involved in turning back at a low altitude and with little or no power available. If there was wind on takeoff, the pilot must make a downwind turn to return to the runway. This may increase the groundspeed of the aircraft and thus allows little time to plan the approach. All the while the aircraft is losing precious altitude, which further hurries the pilot and makes mistakes more likely. In turning back to a runway, the likelihood of slipping or skidding, cross-controlled turns increases (see following). Also, the increase in groundspeed may cause the pilot to attempt to slow down prematurely. Low and slow and in a bank may set the airplane up for an out-of-control cartwheel instead of a landing. All this can be avoided by lowering the nose to establish best glide speed after an engine failure and landing straight ahead under control. If you do not believe us, try this.

At a safe altitude establish a climb at best angle-of-climb airspeed. Note the altitude then reduce the power to idle. If you do not reduce the pitch attitude immediately, a high sink rate develops.

Next, lower the nose to obtain best glide speed, execute a 1800 turn, and note the total loss of altitude. What will happen is that you will likely descend below the altitude you established as your "runway." You can recover now, or if this is not convincing enough, you can carry the scenario to its inevitable conclusion, provided there is sufficient altitude left, then recover.

Cross-controlled turns to final approach

If you learned crosswind landings by the "wing-low" method (aileron into the wind to counteract drift and opposite rudder to track the centerline), then most of your landings involve crossed controls, i.e., aileron in one direction and rudder in the other. Cross-controlling becomes a precursor of stall/spin accident most often in poorly conducted turns from base to final on a landing approach. These improperly coordinated turns to final, and their resultant stalls and spins close to the ground, are where most stall/spin accidents occur. Usually, they result from a skidding turn to final when the pilot realizes the airplane is too low to make the runway or a slipping turn to final after an overshoot.

  • Skidding turn to final approach
    Turn from "base" to "final" at a safe altitude. (FM does NOT recommend use of flaps in cross-control demonstration because of the possibility of exceeding the aircraft's structural design limits in a cross-control stall.) The scenario is that the airplane is at too low an altitude on the turn from base to final, and, as a result, the pilot hesitates to use a properly coordinated turn and instead attempts to turn using excessive bottom or inside rudder to yaw the airplane onto final approach. The excess rudder causes the airplane to bank anyway and the nose to pitch down. At this point the pilot may be distracted by attention to ground references and could be counteracting the steepening bank with opposite aileron and further nose-up elevator to oppose the down-pitching tendency. The inside wing may suddenly drop, rolling the airplane inverted after an accelerated stall.
  • Slipping turn to final approach
    In this scenario the turn from base to final is started too late to avoid overshooting the simulated runway centerline. The pilot rolls rapidly into a steep bank with insufficient rudder pressure in the direction of the turn. The steep bank creates a tendency for the nose to pitch down and not only increases the sink rate but also the roll rate. If opposed with aft elevator control movement, the result may be an accelerated stall and a spin "over-the-top." Following these cross-control demonstrations, the instructor should emphasize the need for proper planning in the traffic pattern; for airspeed, altitude, and power control; and for properly coordinated, medium-banked turns. In a cross-control stall, the airplane may stall with little warning, thus allowing little or no time for recovery so close to the ground. Further, the instructor should emphasize that these kinds of errors are also likely to occur in the event of either an engine failure shortly after takeoff or a forced landing where the pilot is faced with a difficult situation and might attempt a rapid turn at low altitude while trying to extend a glide by using excessive up-elevator control.
  • Overtaking slower traffic
    We do not usually think of a stall/spin possibility when overtaking a slower aircraft. Again, this is usually a traffic-pattern occurrence where the pilot of a faster aircraft has not allowed sufficient spacing for a slower aircraft ahead. Paying attention to the aircraft ahead may divert attention from aircraft control. In a simulated traffic pattern at a safe altitude reduce power and increase pitch to maintain spacing behind simulated slower traffic. At all the points where the slower "aircraft" would reduce power and slow down, continue increasing the pitch attitude until the diversion of attention means you fail to notice instrument or other indications of a near-stall condition.
  • Power loss on final approach
    At a safe altitude simulate power loss on final approach in the landing configuration. Using only back pressure, try to prevent the aircraft from losing more than 1 00 feet of altitude during the next 20 seconds. You will find that you have to keep increasing the back pressure in an attempt to keep from losing altitude - i.e., you are trying to stretch a glide. This seldom works, especially when you have no power and little altitude available, and that increasing pitch attitude can result in a stall. Then you run out of airspeed and altitude at the same time - remember the precise control of attitude and airspeed we talked about earlier? A landing short of the runway under control is less embarrassing and less deadly than trying to extend a glide and causing a stall/spin with no room to recover.
  • Go-around with full nose-up trim
    This scenario is similar in some respects to the short-field takeoff situation and demonstrates how an improperly executed go-around can result in an inadvertent stall or spin. This situation is particularly dangerous when the pilot delays initiation of the go-around until obstacle clearance at the departure end of the runway becomes a factor. At a safe altitude, establish a properly trimmed descent to simulate a short-field approach at 1.2 Vso; then initiate a go-around by application of full power. Failure to counteract nose-up pitching with forward elevator pressure can result in an extremely nose-high pitch attitude and a stall or spin, especially if the aircraft is loaded at aft center of gravity.
  • Go-around with premature flap retraction
    This scenario illustrates the effect of flap retraction at a speed below the flaps-up stalling speed, such as you might encounter on a mishandled go-around, At a safe altitude simulate a go-around from the short-field approach speed of 1.2 Vso. Reduce speed in a simulated landing flare to just above stalling, apply full power, and retract the flaps rapidly. The result is usually a stall and then a full or partial spin, if you do not recover from the stall.
  • Left turning tendency on a go-around in a right crosswind
    This scenario demonstrates the aggravated left-turning tendency of an airplane on go-around. At altitude and with the proper approach speed and trim, establish a slipping approach to the right such as a pilot may use to compensate for a right crosswind on landing. This requires right aileron and left rudder. Then simulate the go-around by applying full power and establishing a climb pitch attitude, but do not neutralize the rudder. Carried to extreme, this control action can result in a rapid spin entry to the left, especially if the nose-up attitude is too high.

Whew! If you do all of these demonstrations in a single flight training session, you deserve more than a rest. As tiring and challenging as this sort of practice may be, reassure yourself with the knowledge that you have protected yourself from becoming a spin statistic. Awareness is the key.

If the thought of conducting or participating in these demonstrations frightens you, it should not. If conducted in a properly certificated airplane, with an appropriately trained and qualified instructor, and at a safe altitude, the spin is a routine aerobatic maneuver. There is little to fear - it can even be fun!

Editor's Note: Parts 1 and 2 of this article were adapted from "To Spin or Not to Spin" from the October 1991 issue of the AOPA Air Safety Foundation's (ASF) Flight Instructor Safety Report. ASF sends the safety report to its members who are certificated flight instructors. For further information on the AOPA Air Safety Foundation, contact them at 421 Aviation Way, Frederick, MD 21701; (301) 695-2171.