Updated: Dec 8, 2020
Steep Spirals Lesson by wifiCFI
To determine that the applicant exhibits satisfactory knowledge, risk management, and skills associated with steep spirals.
The applicant demonstrates understanding of:
Purpose of steep spirals.
Maintaining a constant radius around a point.
Effects of wind on ground track and relation to a ground reference point.
The applicant demonstrates the ability to identify, assess and mitigate risks, encompassing:
Failure to divide attention between airplane control and orientation.
Collision hazards, to include aircraft, terrain, obstacles and wires.
Low altitude maneuvering/stall/spin.
Distractions, loss of situational awareness, and/or improper task management.
Failure to maintain coordinated flight.
Effects of wind.
Airframe and/or airspeed limitations.
Steep Spirals (AFH C9)
The objective of the steep spiral is to provide a flight maneuver for rapidly dissipating substantial amounts of altitude while remaining over a selected spot.
This maneuver is especially effective for emergency descents or landings.
A steep spiral is a gliding turn where the pilot maintains a constant radius around a surface-based reference point while rapidly descending, similar to the turns around a point maneuver.
Sufficient altitude must be gained prior to practicing the maneuver so that at least three 360° turns are completed.
The maneuver should not be allowed to continue below 1,500 feet above ground level (AGL) unless an actual emergency exists.
Flying the Maneuver
The steep spiral is initiated by properly clearing the airspace for air traffic and hazards.
In general, the throttle is closed to idle, carburetor heat is applied if equipped, and gliding speed is established.
Once the proper airspeed is attained, the pitch should be lowered and the airplane rolled to the desired bank angle as the reference point is reached.
The steepest bank should not exceed 60°.
The gliding spiral should be a turn of constant radius while maintaining the airplane’s position to the reference.
This can only be accomplished by proper correction for wind drift by steepening the bank on downwind headings and shallowing the bank on upwind headings, just as in the maneuver, turns around a point.
During the steep spiral, the pilot must continually correct for any changes in wind direction and velocity to maintain a constant radius.
During practice of the maneuver, the pilot should execute three turns and roll out toward a definite object or on a specific heading.
During rollout, the smooth and accurate application of the flight controls allow the airplane to recover to a wing’s level glide with no change in airspeed.
Recovering to normal cruise flight would proceed after the establishment of a wing’s level glide.
Operating the engine at idle speed for any prolonged period during the glide may result in excessive engine cooling, spark plug fouling, or carburetor ice.
To assist in avoiding these issues, the throttle should be periodically advanced to normal cruise power and sustained for a few seconds.
If equipped, monitoring cylinder head temperatures provides a pilot with additional information on engine cooling.
When advancing the throttle, the pitch attitude must be adjusted to maintain a constant airspeed and, preferably, this should be done when headed into the wind.
Maintaining a constant airspeed throughout the maneuver is an important skill for a pilot to develop.
This is necessary because the airspeed tends to fluctuate as the bank angle is changed throughout the maneuver.
Not clearing the area
Inadequate pitch control on entry or rollout
Not correcting the bank angle to compensate for wind
Poor flight control coordination
Ineffective use of trim
Inadequate airspeed control
Performing by reference to the flight instrument rather than visual references
Not scanning for other traffic during the maneuver
Not completing the turn on designated heading or reference
Commercial Pilot ACS Standards
Clear the area.
Select an altitude sufficient to continue through a series of at least three 360° turns.
Establish and maintain a steep spiral, not to exceed 60° angle of bank, to maintain a constant radius about a suitable ground reference point.
Apply wind drift correction to track a constant radius circle around selected reference point with bank not to exceed 60° at steepest point in turn.
Divide attention between airplane control and ground track, while maintaining coordinated flight.
Maintain the specified airspeed, ±10 knots, rolls out toward object or specified heading, ±10°.
FAA Sources Used for This Lesson
Commercial Pilot Airmen Certification Standards
Airplane Flying Handbook (AFH) Chapter 9