If the manufacturer does not specifically approve an airplane for spins, intentional spins are not authorized by the CFRs or by this post. The official sources for determining whether the spin maneuver is approved are:
- Type Certificate Data Sheets or the Aircraft Specifications
- The limitation section of the FAA-approved AFM/ POH. The limitation section may provide additional specific requirements for spin authorization, such as limiting gross weight, CG range, and amount of fuel.
- On a placard located in clear view of the pilot in the airplane (e.g., “NO ACROBATIC MANEUVERS INCLUDING SPINS APPROVED”). In airplanes placarded against spins, there is no assurance that recovery from a fully developed spin is possible.
Unfortunately, accident records show occurrences in which pilots intentionally ignored spin restrictions. Despite the installation of placards prohibiting intentional spins in these airplanes, some pilots and even some flight instructors attempt to justify the maneuver, rationalizing that the spin restriction results from a “technicality” in the airworthiness standards. They believe that if the airplane was spin tested during its certification process, no problem should result from demonstrating or practicing spins.
Such pilots overlook the fact that certification of a normal category airplane only requires the airplane to recover from a one-turn spin in not more than one additional turn or three seconds, whichever takes longer. In other words, the airplane may never be in a fully developed spin. Therefore, in airplanes placarded against spins, there is absolutely no assurance that recovery from a fully developed spin is possible under any circumstances. The pilot of an airplane placarded against intentional spins should assume that the airplane could become uncontrollable in a spin.
Weight and Balance Requirements Related to Spins
In airplanes that are approved for spins, compliance with weight and balance requirements is important for safe performance and recovery from the spin maneuver. Pilots must be aware that even minor weight or balance changes can affect the airplane’s spin recovery characteristics. Such changes can either degrade or enhance the spin maneuver and/or recovery characteristics. For example, the addition of weight in the aft baggage compartment, or additional fuel, may still permit the airplane to be operated within CG, but could seriously affect the spin and recovery characteristics.
An airplane that may be difficult to spin intentionally in the utility category (restricted aft CG and reduced weight) could have less resistance to spin entry in the normal category (less restricted aft CG and increased weight). This situation arises from the airplane’s ability to generate a higher AOA. An airplane that is approved for spins in the utility category but loaded in accordance with the normal category may not recover from a spin that is allowed to progress beyond one turn.
Common errors in the performance of intentional spins are:
- Failure to apply full rudder pressure (to the stops) in the desired spin direction during spin entry
- Failure to apply and maintain full up-elevator pressure during spin entry, resulting in a spiral
- Failure to achieve a fully-stalled condition prior to spin entry
- Failure to apply full rudder (to the stops) briskly against the spin during recovery
- Failure to apply sufficient forward-elevator during recovery
- Waiting for rotation to stop before applying forward elevator
- Failure to neutralize the rudder after rotation stops, possibly resulting in a secondary spin
- Slow and overly cautious control movements during recovery
- Excessive back elevator pressure after rotation stops, possibly resulting in secondary stall
- Insufficient back elevator pressure during recovery resulting in excessive airspeed