### What is a spiral dive? Exactly what it sounds like: an upset or undesired aircraft state originating from a steep bank and subsequent nose-low attitude, resulting in a tight descending spiral flight path with rapidly increasing airspeed, and rapid loss of altitude Recall the forces involved in turns. As the bank angle increases, the vertical component of lift decreases, and the horizontal component of lift increases; [[Overbanking Tendency]] will also increase. Normally, the pilot establishes and maintains a steep bank angle intentionally to improve turning performance ([[Radius of Turn]] and [[Rate of Turn]]), and maintains the required vertical component of lift by increasing total lift, by increasing angle of attack with elevator back pressure. If the pilot fails to sufficiently increase elevator back pressure, or enters a steeply banked attitude unintentionally, the loss of vertical component of lift will result in a rapidly decreasing pitch attitude, and a spiral dive. If a spiral dive has developed, increasing elevator back pressure will mostly increase horizontal component of lift; tightening the spiral, and increasing airspeed, [[Load Factor]] and altitude loss. ### Causes - Failure to correct for loss of vertical component of lift and increased need for elevator back pressure during steeply banked turns - Failure to prevent **spiral instability** (or graveyard spiral) ### Recognition - Aircraft attitude: steep bank with extreme nose-low pitch attitude - Aircraft performance: rapidly increasing airspeed, rapid loss of altitude - Pilot sensations: increased load factor, increased flight control forces ### Hazards - Pilot disorientation - Loss of aircraft control - Overspeeding aircraft - Over-stressing aircraft during improper recovery ### Recovery - Stop the turn with coordinated aileron and rudder; THEN - **Smoothly** increase pitch to exit the dive ### Common Errors - Failure to recognize a developing spiral dive - Improper sequence of flight controls to recover - Rough, abrupt, or excessive use of flight controls during recovery - Failure to distinguish a spiral dive from a **spin** ### Completion Standards - This maneuver is only included in the CFI-G PTS - While not included in other practical tests, any applicant should: demonstrate knowledge of conditions that cause spiral dives, recognition of spiral dives, hazards associated with spiral dives, and the correct recovery procedure for exiting a spiral dive ### References - FAA, *Glider Flying Handbook - Bob Wander, *Learning to Fly Gliders* - FAA, *Practical Test Standards for Glider Category*