We will soon have an Australian edition of Rich Stowell’s excellent book Stall/Spin Awareness – every pilot, especially flight instructors should read the relevant sections. Spin flight instructors should read it from cover to cover and use it as their “bible”.
Two documents listed in that book’s bibliography are:
- NASA TN D-6575 SUMMARY OF SPIN TECHNOLOGY AS RELATED TO LIGHT I GENERAL-AVIATION AIRPLANES by James Bowman
- Spin CHARACTERISTICS of CESSNA MODELS
I recommend that you read both of those. The NASA report summarises the key points from their research, The Cessna document is obviously dedicated to Cessna airplanes but has some gems such as this:
One would expect CASA’s Flight Instructor Manual to be worth listing as a reference however ATSB Investigation AO-2017-096 of 22/5/2019 found otherwise.
While the ATSB assessed that the instructor’s incipient spin recovery knowledge was consistent with established guidelines and did not contribute to the accident, the investigation identified incorrect incipient spin recovery guidance provided by CASA.
The CASA publication Flight Instructor Manual, provides the following guidance for incipient spin recovery:
RECOVERY FROM THE INCIPIENT STAGE
As soon as the aeroplane has stalled and commenced to yaw take the appropriate recovery action. Increase power, apply sufficient rudder to prevent further yaw and ease the control column forward sufficiently to un-stall the aeroplane. Point out that if power is to materially assist recovery action it must be applied before the nose of the aeroplane has pitched too far below the horizon otherwise its use will only increase the loss of height.
Increasing engine power prior to an application of sufficient rudder to prevent further yaw and applying sufficient nose-down elevator un-stall the wings as described is inconsistent with established guidelines and manufacturer guidance.
The United States Federal Aviation Administration publication Airplane Flying Handbook, Chapter 5: Maintaining Aircraft Control: Upset Prevention and Recovery Training provides the following guidance, consistent with established guidelines, regarding spin recovery:
To accomplish spin recovery, always follow the manufacturer’s recommended procedures. In the absence of the manufacturer’s recommended spin recovery procedures and techniques, use the spin recovery procedures in the spin recovery template. If the flaps and/or retractable landing gear are extended prior to the spin, they should be retracted as soon as practicable after spin entry.
Spin recovery template:
1. Reduce the Power (Throttle) to Idle
2. Position the Ailerons to Neutral
3. Apply Full Opposite Rudder against the Rotation
4. Apply Positive, Brisk, and Straight Forward Elevator (Forward of Neutral)
5. Neutralize the Rudder After Spin Rotation Stops
6. Apply Back Elevator Pressure to Return to Level Flight.
The handbook also provides further guidance regarding power use during spin recovery:
Reduce the Power (Throttle) to Idle. Power aggravates spin characteristics. It can result in a flatter spin attitude and usually increases the rate of rotation.
CASA advised the ATSB that this matter will be referred to Safety Education for review and correction as required.”
When that report was issued “CASA has advised the ATSB that they have taken the following safety action …..” i.e. they reviewed the above text but took no action so they must believe it to be correct.
Knowledge of the “standard” spin recovery procedure is required for all pilots per CASA’s Part 61 Manual of Standards yet I still encounter pilots who describe a dangerously incorrect method. Recently, two flight instructor candidates were failed because they briefed the examiner on such a technique.
CASA has published their AC 61-16 Spin avoidance and stall recovery training, which is good.
CASA has seemingly withdrawn CAAP 155-1, Aerobatics as it was outdated with the new Part 61 and 91 regulations. It also contained some dangerous misinformation. My recommendation is that it be replaced by two advisory circulars. One on aerobatics for recreational pilots and another on spinning focussed on flight instructors.
There are many descriptions of a spin in these references but let’s go to the FAA AC 23-8C FLIGHT TEST GUIDE FOR CERTIFICATION OF PART 23 AIRPLANES for the definitive one:
“A spin is a sustained autorotation at angles-of-attack above stall. The rotary motions of the spin may have oscillations in pitch, roll, and yaw superimposed upon them. The fully developed spin is attained when the trajectory has become vertical and the spin characteristics are approximately repeatable from turn to turn. Some airplanes can autorotate for several turns, repeating the body motions at some interval, and never stabilize. Most airplanes will not attain a fully developed spin in one turn.”
AC23-8C also describes spin recovery:
“Recoveries should consist of throttle reduced to idle, ailerons neutralized, full opposite rudder, followed by forward elevator control as required to get the wing out of stall and recover to level flight.
For acrobatic category spins, the manufacturer may establish additional recovery procedures, provided they show compliance for those procedures with this section.”
So, if the aeroplane is autorotating then it is a spin and the spin recovery method in the Flight Manual must be used. After all, for a type not approved for spinning, it has only been tested for up to one turn in a spin, so still in the incipient phase, and the flight manual is very clear on what to do if it starts to spin.
That “standard” spin recovery technique referred to in the CASA MOS must be that described in AC23-8C above which is the same as in the FAA’s Airplane Flying Handbook.
FAA AC 61-67C – Stall and Spin Awareness Training includes this excellent advice:
“…. to provide a margin of safety when recovery from a stall is delayed, normal category airplanes are tested during certification and must be able to recover from a one turn spin or a 3-second spin, whichever takes longer, in not more than one additional turn with the controls used in the manner normally used for recovery … The pilot of an airplane placarded against intentional spins should assume that the airplane may become uncontrollable in a spin.” That description of “controls used in the manner normally used for recovery” is specified in the Flight Manual.