Lesson 3h - Spirals, Descents, Unusual Attitude Recovery, Spins (optional)

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

Completion Standards

Prerequisite Study

• Glider Flying Handbook (2013), Chapter 8, page 8-15 "Spiral Dives" and "Spins"
• Soaring Safety Foundation, Flight Safety Videos, "Stall/Spin" (2) and "Spiral Dive", including pop-up "Instructor Guides"

Recommended Study

• Airplane Flying Handbook, Chapter 4, "Maintaining Aircraft Control: Upset Prevention and Recovery"
• Pilot's Handbook of Aeronautical Knowledge, page 5-20, "Spiral Instability"
• Skylines, June 2005 "Stay Safe in Wave", article about benign spirals
• Benign Spirals forum reference to Knauff glider transition book
• Unload for Control forum reference to Rutan article
• 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 on spins
•  FAA Advisory Circular on Spin Training
•  FAA Airplane Handbook, Spin Awareness
•  Spinning, by Kai Gertsen