Spinning Normal Category Aircraft – What’s the Risk?

 
Author: Paul “BJ” Ransbury, Chief Executive Officer
Aviation Performance Solutions
www.apstraining.com
Former Part 141 Chief Flight Instructor
6 X Master CFI-Aerobatic / CFI / CFII / MEI / AGI
Former Airbus A320 Pilot, F/A-18 Hornet Fighter Pilot
Former Cirrus Standardized Instructor
Fighter Weapons Instructor
ICAS Certified Air Show Performer

TABLE OF CONTENTS:

• Statistics on “Stall Spin” Knowledge and Recovery
• Spin Training Versus Stall Training
• A Spin is Just a Turning Stall, Right?
• Stall Recovery
• Role of the CFI in Relation to “Stall Spin” Training
• Comments from Other Aerobatic Master CFIs
• Importance of Stall Recoveries in Other Aircraft
• Conclusion

Dear Readers,

The Certified Flight Instructor (CFI) plays a critical role in ensuring every pilot being instructed and evaluated by them is ultimately safe and safety conscious. As CFIs, our assessment of a pilot’s proficiency status comprehends a wide spectrum, including flight preparation, aeronautical knowledge, recency of experience, regulatory awareness and compliance, system management, stick and rudder skill, aeronautical decision-making, and mental attitude. In General Aviation, the CFI commonly represents the measuring stick by which most pilots compare their piloting capability to the ideal. This is a tremendous responsibility that CFIs should not take lightly.

Having said those high-sounding words, does that mean every CFI knows everything all the time? No, and they are not expected to. However, they must be firmly grounded in all Practical Test Standards (PTS) skills and knowledge requirements and familiar with how to find information on any topic within their professional domain.

In this article, I would like to address one specific aspect of a CFI’s range of safety-evaluation responsibilities – Regulatory Compliance. Specifically, we will investigate why performing spin training in a normal category single-engine certified aircraft is an unsafe practice. Additionally, we’ll highlight some of the reasoning behind established regulations related to “stall spin” awareness.

Hangar Talk:
Aside from aircraft certification requirements that normal category single-engine aircraft be fully recoverable within a one-turn spin, what really is the risk of doing spins in them?

Spin Training Regulations

Pilots well versed in AC 61-67C or who have recently read the placards posted in plain view in their normal or utility category aircraft may wonder why this topic is coming up.

COCKPIT PLACARDS

Normal Category:

“No acrobatic maneuvers, including spins, approved.”

Utility Category Not Meeting Acrobatic Certification:

“Spins Prohibited”

(Note: Not all utility category aircraft are spins-approved)

So what’s the issue? If the posted placards and published maneuvering limitations of the normal category aircraft say, don’t do spins, then don’t do them, right? Right. That is 100% correct. You’ve passed this short regulatory compliance exam. Simply put, don’t intentionally spin airplanes that aren’t approved for spins. If you agree and intend to action that reality, then you can stop reading here. If you didn’t pass or feel that’s optional then please keep reading and keep in mind that this article is intended to inform as well as offer food for thought in relation to your actions and teachings related to both stall and spin training.

Statistics on “STALL Spin” Knowledge and Recovery

Over the years, many diligent efforts have been made to ascertain the average instructor’s knowledge level related to “stall spin” dynamics, regulations, and recoveries. The results of a few are listed below. If you fall into a statistic indicating a possible shortcoming in “stall spin” knowledge, resist the temptation to feel reassured that many others are in the same situation. When it comes to “stall spin” awareness, “comfort in groups” or “but I know other people who do the same thing I do”, is not an answer you should be contented with. Regrettably, we are all a product of our training and opinions. To a certain extent, how we were trained is not our fault – however, when it comes to safety and regulatory compliance, “not knowing” or “being unaware” of the rules and regulations is not an acceptable explanation for violating them unintentionally or otherwise. Neither the FAA nor insurance companies have much tolerance during an accident investigation in the area of published safe flying regulations and practices.

1976 General Aviation Pilot Stall Awareness Training Study*

A survey of 75 CFIs attending a Flight Instructor Refresher Clinic revealed that only 30% of the instructors present would not spin a Normal-category aircraft despite intentional spins being prohibited in Normal-category airplanes.

1993 Transportation Research: Re-Examination of Stall/Spin Prevention Training*

Questionnaires were distributed in CFIs at 43 flight schools in Tennessee, Mississippi, California, and Utah and to instructors who attended seven FAA safety seminars and three Flight Instructor Refresher clinics. In total, 513 civilian flight instructors and 28 designated examiners participated. Five aviation professionals processed the surveys – all flight instructors with a college education in aerodynamics. NASA research, journal literature, and the textbook “Aerodynamics for Naval Aviators” were used as references. The results of surveying these Certified Flight Instructors and Designated Examiners are listed below:

• 94% relied primarily on popular literature for “stall spin” information (i.e. aviation magazines)
• 96% additionally relied heavily on their own instructors
• 95% failed to ever receive training in either spin dynamics or the likely conditions preceding an inadvertent spin
• 94% did not understand spin certification requirements nor the limitations imposed as a result
• 98% indicated that their formal spin training consisted of no ground instruction and a mere two spins – one in each direction

Despite the above statistics, all these instructors readily received logbook endorsements certifying they were competent to teach spins. The same study revealed the following general conclusions:

• Marginal understanding by surveyed CFIs in the following subjects:
  • stall aerodynamics
  • effects of control deflection on the stall
  • airfoil stall development, planform effects on stall behavior, and spanwise flow effects
  • stall warning signs and secondary effects of flight controls, and
  • roll control at high angles of attack
• Unsatisfactory understanding of these critical items:
  • pro- and anti-spin forces
  • autorotation
  • spin phases and spin modes
  • effects of the controls on spin motion and recovery, and
  • common student errors and the effects on aircraft motion

In the same survey, these instructors and examiners self-assessed their understanding of “stall spin” dynamics as “Excellent.” The survey results clearly indicate that those charged with teaching and testing new pilots possess a marginal understanding of “stall spin” phenomena.

2005 Stall/Spin Study by Embry-Riddle Aeronautical University*

An internet-based questionnaire evaluated 468 flight instructors on spin training, spin experience, and their individual “stall spin” knowledge. The conclusions are as follows:

• Spin Experience
  • 56% had received 1 hour or less of ground instruction before receiving spin endorsements
  • 36% performed 4 or fewer spin entries before receiving their spin endorsement
  • 59% had hands-on spin experience in only 1 or 2 different models of airplanes
  • 38% had not practiced spins since becoming an instructor
• “stall spin” Knowledge
  • 47% incorrectly believed the slip/skid ball would help identify the opposite rudder in a disorienting spin
  • 44% did not understand that spin direction would be in the same direction as yaw at the stall

* Reference: The Light Airplane Pilot’s Guide to Stall/Spin Awareness, Chapter 7: Who’s Spinning In

Spin Training Versus Stall Training

The thought process for some pilots, and even Certified Flight Instructors, who decide to push beyond approved stall training and into the regime of spin training lies within their interpretation of the normal category spin certification description. Assuming the aircraft in question does not fall under the classification of being Spin Resistant or meets the Equivalent Level of Safety (ELOS) criteria to meet certification, those familiar with certification requirements are aware that a normal category single-engine aircraft is spin-tested to be recoverable from up to a one-turn or 3-second spin (whichever takes longer). As stated clearly in AC 61-67C Chapter 4 (below), this is not permission or authorization for any pilot or CFI to perform intentional spins in those aircraft.

Sample CFI Question: So what’s the big deal? If the aircraft is recoverable from a one-turn spin, then why, as a CFI, can’t I do one-turn spins with my students? After all, the aircraft is certified to be recoverable, and I really think it’s important for my students to be current on spin recovery. We don’t have access to an aerobatic aircraft locally, and traveling to find one is expensive and inconvenient.

Although this instructor’s interest (above) in providing spin awareness training to himself and his students is admirable, he or she really needs to understand the intent of requiring the normal category aircraft to be recoverable from a one-turn spin. The reasoning is discussed in the AC 61-67C Chapter 4, Para 400a (above). The intent of the one-turn spin recovery certification is solely “to provide a margin of safety when recovery from a stall is delayed.” This is not referring to spin training and the delay from the stall during training should not be intentional. This margin of safety is there for both students AND instructors.

1. PUSH – Reduce Angle of Attack: Aggressively unload the aircraft through a purposeful “Push” straightforward on the control column to reduce the wing’s angle of attack to below critical AOA to eliminate this critical aerodynamic spin-risk component*. The amount of elevator movement and control pressure may vary from a simple release of control column pressure to a distinct push of 20-30 lbs or more in a nose-high autopilot trimmed power-on stall condition in a transport category aircraft. In a stall where the wings are close to level (less than 45 degrees), the angle of attack should only be reduced enough to get out of the stall, yet not so much to unnecessarily induce a significant amount of altitude loss.
2. POWER – Make a Power Selection: The power is typically selected to full thrust. There are exceptions to this general guidance based on aircraft design and configuration. Exceptions to applying full power (or full thrust) in a stall situation include situations such as Vmc (a failed engine) stall in a multi-engine aircraft, high-powered single-engine propeller aircraft where the manufacturer cautions the torque rolling effect as being excessive in slow-speed high-AOA flight conditions, and in large jet aircraft where the manufacturer may require the reduction of power in the stall recovery because of excessive nose-up moments at full power in low-speed high-AOA situations when the engines are mounted under the wing.
3. RUDDER – Cancel Yaw with Rudder: Apply a firm single application of rudder to cancel yaw to attain coordinated flight. Remember, if the aircraft is in a stall, the turn coordinator ball is unreliable. Visually arrest the yaw/roll couple to eliminate this critical aerodynamic spin-risk component*. It is important to emphasize that the rudder is NOT used to roll the aircraft unless judiciously and properly combined with aileron input in the “ROLL” step (next). This recommended stall recovery DOES NOT advocate the “Step on the Sky” technique as it unnecessarily uncoordinates the aircraft, significantly increases drag, may overstress the rudder assembly (especially when above Va and/or the rudder is cycled), and has marginal secondary roll response in comparison the proper use of aileron as detailed in the next step.
4. ROLL—Re-orient the Lift Vector to the Nearest Horizon: Using the aileron, the lift vector must be rolled to the nearest horizon immediately. In an overbanked scenario (above 45 degrees), the roll must be accomplished while keeping the aircraft unloaded at a low angle of attack under positive G. Up to full control deflection must be initiated to achieve the desired wings-level flight attitude in minimum time.
5. CLIMB – Initiate an Immediate Climb: With the lift vector oriented in a wings-level flight attitude, the pilot should initiate an aggressive pull on the control column to attain a climbing Vy pitch attitude. Pilots must necessarily manage AOA-onset to avoid the secondary stall below Va and manage G-onset to avoid exceeding the aircraft’s limit-load above Va.

* NOTE: Two critical aerodynamic factors must be present for an aircraft to enter a spin: 1) AOA above critical (see PUSH above), and 2) Continuous yaw (see RUDDER above). Without both of these components present simultaneously, an aircraft can not spin. A proper stall recovery must aggressively resolve both factors.

Role of the CFI in Relation to “STALL Spin” Training

In short, the role of the CFI out in the field is to instruct spin-awareness and avoidance through thorough academic examination of the student’s aeronautical knowledge and regulatory-compliant stall training in accordance with AC 61-67C. Additionally, the CFI should educate each student on the risk of incorrect stall recovery and the importance of maneuvering each aircraft flown within its approved operating envelope.

In all that we do as pilots and instructors, insisting on a margin of safety must always be integrated into practical operations and personal training. Venturing into the regime of spin training by implementing intentional spins with a normal category aircraft is in violation of the aircraft’s approved operating limitations. This practice puts the instructor and all aboard in a scenario with very little or no margin of safety.

Become a Referral Expert:

At a minimum, encourage your students and other pilots you influence to participate in a spin training course in approved aircraft given by expert instructors. A list of established schools can be found on the IAC website. Remember that spin training is part of the story but not all-inclusive regarding the all-attitude, all-envelope flight environment. The best recommendation you can provide is to seek out an Upset Prevention and Recovery Training (UPRT) course founded on thorough “stall spin” awareness academics, upset recovery, a wide variety of stall recovery, spin recovery, and, if recommending an instrument rated pilot, instrument recovery training. A comprehensive UPRT course will additionally include integrated aerobatic training with a strong focus on developing recovery skills in a crisis and extensive flight envelope awareness. An aerobatics course alone is not at all the same as, or equivalent to, a properly delivered UPRT program. Before sending students to any particular provider, be sure to call them to discuss their instructor’s experience level, aircraft used, depth of instruction, and demonstrated results.

Comments from Other Aerobatic Master CFIs

Rich Stowell, MCFI-A, 2006 National CFI of the Year

Author: Emergency Maneuver Training: Controlling Your Airplane in a Crisis
Author: The Light Airplane Pilot’s Guide to Stall/Spin Awareness

When asked to comment on the subject of this article Rich submitted the following excerpt from his most recent book:
The Light Airplane Pilot’s Guide to Stall/Spin Awareness

Chapter 23: Taking Charge of Your Education – Risk Management

… “Strive to give yourself as great a margin of safety as possible when flying, too. For example, one frequently asked question is: can a Normal category airplane be spun?? Yet another is: can a Normal category airplane be rolled?? The truthful answer to both is yes, of course the airplane can be. But the real question is should it be spun, or rolled, or anything else if the airplane isn’t approved for it?? It’s not about what happens if everything goes according to plan, but what happens if something goes wrong. In the case of spins, the difference in the margin of safety is one turn in the Normal category versus up to six turns in the Acrobatic category; unproven spin recovery capability beyond one turn versus proven recovery capability. From a structural standpoint, the Normal category airplane is limited to +3.8 g’s before metal might start to bend, whereas the Acrobatic category airplane might have a +6.0 g limit. Thus a botched maneuver in a Normal category airplane (perhaps resulting from an unapproved roll) risks structural problems much sooner compared to the Acrobatic category airplane.

“Eating into our margin of safety increases risk; conversely, as our margin of safety increases, risk decreases. It is of little value to have plenty of altitude and possess the skills to apply the correct recovery inputs if we’re going to intentionally spin airplanes not approved for spins. It is likewise also of little value to spin a spins-approved airplane with insufficient altitude for recovery, or given enough altitude and a recoverable airplane, to lack the necessary recovery skills. Our margin of safety is tied to the Trinity: altitude, airplane capability, piloting skills. Acknowledging this and acting to achieve a balance among these elements will improve the safety of each flight operation.”

Rich adds: “There is ZERO margin for error when spinning a Normal category airplane. Plus, the experience may be instilling a false sense of security in pilots doing it. What’s to stop someone who adopts that mindset from loading up a Cessna 182 with four people and baggage for a cross country, and along the way saying, ‘hey, watch this!’”

Importance of Stall Recoveries in Other Aircraft

As a CFI, we must always be cognizant of the various Laws of Learning during the instruction and evaluation of other pilots. For example, the Law of Primacy often creates the most lasting impression, as first impressions are persistent. Additionally, following the Law of Recency, pilots tend to do things the way they’ve done them recently. Wrapping it up with one more, pilots in the long term tend to do things in accordance with the Law of Exercise that what we do most often is usually the best learned. Having said that, think about the students you are teaching.

What are they learning about “stall spin” training first, most recently, and most often? Can what you teach be looked up in an official aviation training publication of some kind? If not, it should be.

The nice thing about stall training in accordance with AC 61-67C is that the general recovery principles remain consistent across the spectrum of fixed-wing aircraft, including GA, large, business jet, and airline category machines. General philosophy: reduce the angle of attack, make a power decision, cancel yaw with rudder, re-orient the lift vector towards the sky, and initiate a climb. In each and every aircraft you fly, every CFI or authorized instructor must emphasize recognition, avoidance, and, if necessary, immediate stall recovery. Note the repeated emphasis on “immediate”.

So what about the pilot moving up from the single-engine GA aircraft where they make the potentially fatal thought, “You know, I really need to be sure I’m safe from spinning my new Cessna 421, so I think I’m going to go do some one-turn spin recoveries”. Is that a thought that could occur?

Although very wrong and potentially deadly, that type of thinking does happen. Too often. Why would their thinking change if they erroneously learned Spins-Prohibited equals One-Turn Spins-Approved? Having trained thousands of pilots in an unusual attitude and spin recovery training, you’d be surprised how many pilots make a similar initial call to our office saying, “I’m concerned about safety when flying my family around, so I think it’s really important that I learn how to recovery from spins in my Beech Baron (or a similar light twin). I used to do one-turn spins with my instructor in my Piper Arrow, but I’d like to have an instructor with me in my new aircraft before I try it on my own”.

How thankful we are when these pilots call as they’ve taken the first step on the road to safety and education. It is calls like these that affirm the importance of “stall spin” awareness and recovery training by approved, highly qualified experts.

Twin-engine airplanes are not evaluated for spin recoverability during certification testing. The only requirement, as stated in the Flight Test Guide AC 23-8A, is that twin-engine airplanes can not display an “undue tendency” to spin from an unaccelerated, wings-level stall with the critical engine failed. It is common practice during stalls in multi-engine aircraft in this configuration to select power to idle in the recovery.

For example, in response to several flat spin accidents in the Beech Baron, the US Army spin-tested the airplane in 1974. One of the most noteworthy published findings was that it took less than one second for the airplane to spin following a single-engine stall. Immediate recovery action was needed to avoid spinning. In 1998 and 2002, the Raytheon Aircraft Company published a safety communique reporting the results of 229 spins in Baron Models 58 and 58P. With the windmilling left engine idle with max continuous power on the right engine throughout the stall, entry to beyond 270 degrees of rotation, the spin was unrecoverable, requiring the spin chute deployment. Part of Raytheon’s published recommendations was:

“During single-engine operation (actual or simulated), at the first indication of approach to stall (the stall warning horn, buffeting, or both) stall recovery must be initiated immediately … if this instruction is not followed, a stall will occur, and a dangerous spin is likely to occur”

Conclusion

The simple answer is that intentional spins in Normal-category aircraft are not approved. As a professional CFI, this statement alone should keep us from ever considering doing an intentional spin in a normal aircraft category or recommending that others do it. The fact that a normal category aircraft is certified to be recoverable from a one-turn (or 3-second) spin is most definitely not an authorization to violate the “Spins Prohibited” maneuvering limitation of these aircraft. The one-turn spin recoverability only adds a margin of safety in regulatory-compliant stall recovery training.

Following the same philosophy, it should be obvious that training to prepare pilots to effectively recover from a one-turn spin (the absolute maximum certified limit of recoverability in a normal category aircraft) should ONLY be done in aircraft with a margin of error. Spins-approved Utility category and Aerobatic category aircraft within their spins-approved certified weight and balance limits are the only aircraft that should be used for spin training of any kind. There is a reason why CFIs, Designated Examiners, and FAA Examiners do not evaluate CFI candidates in their ability to recover from spins in a Normal category aircraft.

The reason: Intentional spins are prohibited.

For CFIs still not convinced to stop spin training in Normal category aircraft, let’s step it up a notch on behalf of your future students and passengers who don’t know better …

First, I strongly urge you to stop this practice. Second, despite the fact that the regulations tell you not to do it, it is a prohibited maneuver. I’m telling you not to do it, every reputable CFI spin instructor is telling you not to do it, every Master CFI-Aerobatic is telling you not to do it, the FAA and Designated Pilot Examiners won’t do it …, but there are still some among you who will still say, “I am going to do it.”

Consider this: However you justify doing what you’re doing when spinning a normal category aircraft, be certain to use some other reason than being in the name of flight safety. You are free to risk your own life by violating regulations and may have even found that you’ve been successful in the past based on your skill and familiarity with your specific aircraft.

Regulations and approved maneuver limitations comprehend information and safety practices that may not be readily apparent to all pilots or CFIs. The only way to ensure your safety is to know and comply with the limitations published for your aircraft.

Final Question: Can you spin a Normal category aircraft?

As Master Flight Instructor Rich Stowell explains nicely (above), Yes. But you can not do it legally, not for more than one turn, not without zero margin of error and not without counting on flawless spin recovery techniques. Following the practice of offering spin training in a normal category aircraft puts yourself, and those with you, at grave risk both during your intentional spin in violation of regulation and even more so when your student or fellow CFI is out by himself or with friends, practicing one-turn spin recovery based on your recommendation to do so.

Maybe your spin recovery technique is perfect but what about others you teach to do the same, is their technique perfect? I can tell you personally from training thousands of pilots in spin avoidance and recovery that their technique is not perfect (far from it); neither is yours nor is mine.

In closing, we all need a margin of safety in “stall spin” avoidance and recovery training, so be sure you have one. Emphasize immediate recovery in all stall training and ensure you and all pilots you influence seek quality spin training in a spins-approved aircraft provided by qualified spin instructors. Fly safe and be prepared.