3h - Spirals, Descents, Unusual Attitude Recovery, Spins (optional)
Required for Solo: 61.87(i)(15)
Lesson Objective
The student will learn typical modes of entry into, and methods of recovery from, unusual attitudes including spins and spiral dives. The student will also learn the concept and limitations of the "benign spiral" descent mode. As an optional task for post-solo (and for rated pilots), spins may be demonstrated and practiced if requirements are met.
Regulatory Requirement
Student Pilot Candidates: (Maneuvers and procedures for pre-solo flight training in a glider)§61.87(i)(15)
Content
Instructor demonstration:
• Overbanking tendency into spiral dive entry
• Spiral dive entry from spin or departure (from controlled flight) conditions
• Initial slow-speed aft-stick-limited spiral dive
• Transition to high-speed g-limited spiral dive
• Spiral dive recovery procedure
• Nose-high slow airspeed recovery procedure
• Initiation of benign spiral descent mode
• Nose-low steep bank unusual attitude recovery
• Nose-high low-speed unusual attitude recovery
• Initiation of benign spiral descent mode
Completion Standards
• How spiral dives might develop from a nose-low overbanking turn, or following a spin recovery
• The differences between spiral dives and spins
• The recovery technique from a spiral dive, and hazards of incorrect techniques
• How spins might develop, and the general recovery technique from a spin
• The recovery technique from a nose-high low-airspeed unusual attitude
• The benefits and limitations of a benign spiral descent mode
• Recovery from a nose-low steeply banked attitude, including spiral dive (relax aft stick pressure, roll wings level, stick smoothly aft until nose above horizon)
• Recovery from a nose-high low-airspeed unusual attitude (neutral elevator and ailerons, rudder to minimize yaw, roll wings level after nose falls to horizon)
• Initiation of an intentional benign spiral descent mode (full spoilers, trim slightly aft, hands off stick, feet off rudders)
Prerequisite Study
- Glider Flying Handbook (2024), Chapter 8, page 8-110 "Spiral Dives" and "Spins"
- Soaring Safety Foundation, Flight Safety Videos,
- "Stall/Spin" (2)
- "Spiral Dive"
- Please read the pop-up "Instructor Guides" links for each section
Recommended Study
- Airplane Flying Handbook, Chapter 5, "Maintaining Aircraft Control: Upset Prevention and Recovery"
- Pilot's Handbook of Aeronautical Knowledge, Chapter 5, page 5-20, "Spiral Instability"
- Skylines, June 2005 "Stay Safe in Wave", article about benign spirals
- SSA Video: Spiral Dive
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Optional Spin Task
To demonstrate and practice spins, only the club ASK-21 N321K with spin kit attachment may be used. Spins may be demonstrated and practiced after solo but before a checkride, if desired, or this task may be flown at any time by rated pilots (with instructor).
Spin Sortie Preparation and Special Instructions
• Study N321K POH, including TN4B with two attachments, for spin description, entry and recovery procedure, restrictions, and spin kit details
• Ensure aileron and elevator seals are taped and air-tight
• Briefing on spin entry and recovery procedures required before flight
• Weigh-in on day of flight at the airfield, as dressed for flight
• Compute CG and number of spin kit disks to achieve 73% aft CG (16”) without exceeding MAGW
• Install spin kit bolt, disks, nut, and pin before flight
• Remove spin kit bolt, disks, nut, and pin after flight
• Recommend at least a 4000’ AGL tow (5000’ AGL preferred) to allow for multiple spins, if practical
• Typical altitude loss per turn in a spin is 200’, up to 250’
• Typical altitude loss during recovery is less than 300’ from initiation of recovery through return to normal flight attitude
• Minimum altitude to initiate spin recovery is 2500’ AGL (know the elevation of the ground below!)
• Minimum planned altitude to complete spin recovery is 2000’ AGL
Content
Instructor demonstration:
• CG calculation and spin kit installation
• Spin entry and recovery (if needed, 1-turn spin recommended)
Student practice:
• Slow flight
• Stall from slow flight (note stall speed, needed for normal spin entry)
• Spin entry and recovery (2-turn spin recommended)
Completion Standards
The student must be able to explain:
• How aft CG affects the susceptibility of the glider to enter, sustain, and recover from spins
• The importance of keeping spoilers closed and locked during dive recovery
• How to calculate the CG and desired number of spin kit weights
• The recovery technique from a spin, and hazards of incorrect techniques
The student must be able to perform:
• Recovery from a normally entered spin
Prerequisite Study
All study items listed above, plus:
• Skyline Soaring POH for ASK-21 N321K including TN4b spin kit details, procedures, restrictions
• Skyline Soaring cockpit cards for ASK-21 N321K
• Skyline Soaring weight and balance worksheet and/or spreadsheet for ASK-21 N321K
Recommended Study
• AOPA search on spin topics
• FAA Advisory Circular on Spin Training
• FAA Airplane Handbook, Spin Awareness
• Spinning, by Kai Gertsen
• Avoiding the Spin