A steep spiral is a power-off gliding turn flown at a constant radius around a point on the ground, through at least three 360° turns, to lose a lot of altitude while staying over one spot, as you might over a chosen field after an engine failure. The commercial ACS (FAA-S-ACS-7B, Area V, Task B) caps the bank at 60°, requires the specified airspeed within 10 knots and a rollout within 10° of a chosen object or heading, and the maneuver must end no lower than 1,500 feet AGL.
Part of our Flight Maneuvers guide. This page is educational and is not a substitute for instruction from a certificated flight instructor.
What a steep spiral is for
The FAA’s Airplane Flying Handbook (FAA-H-8083-3C) states the objective plainly: rapidly dissipating substantial amounts of altitude while remaining over a selected spot, a skill that may be useful during an emergency landing. It is a gliding turn that holds a constant radius around a surface reference point, much like turns around a point from your private pilot ground reference maneuvers, except that the airplane is descending quickly the whole time.
It is not the same as an emergency descent. The AFH notes that although the two are similar, the reasons for using them may differ and the airspeed and configuration are usually different. An emergency descent is about getting down as rapidly as possible, in the configuration the manufacturer recommends; the steep spiral is a precise glide that stays over one spot with constant wind correction.
How to fly a steep spiral
- Plan your altitude. You need room for at least three full turns and a rollout at or above 1,500 feet AGL. Altitude lost per turn varies with the airplane and the bank you use, so measure it in your airplane during practice and start high enough to finish above the floor.
- Clear the area and pick a reference. Make clearing turns and choose a prominent point on the ground. As the AFH says for turns around a point, make sure you can keep it in sight throughout, even with a wing lowered in a steep bank.
- Set up the glide. Close the throttle to idle, apply carburetor heat if your airplane has it, and let the airplane slow to gliding speed. The ACS grades you on holding the specified airspeed within 10 knots, so settle beforehand which gliding speed you will fly.
- Roll in at the reference point. Once you reach the proper airspeed, lower the nose to hold it and roll to the bank you need as you reach the reference point. Your distance from the point sets the radius, and the steepest bank anywhere in the circle must not exceed 60°. Entering on a downwind heading, as the AFH recommends for turns around a point, puts the steepest bank first; if it is already too steep, exit and reposition farther from the point.
- Fly the circle. Correct for wind continuously (next section), hold the airspeed and stay coordinated while you keep scanning for traffic.
- Roll out on target. After at least three turns, roll out toward a definite object or onto a specific heading, into a wings-level glide with no change in airspeed, then return to normal cruise.
Wind correction: steepest downwind, shallowest upwind
A constant bank in wind does not produce a constant-radius circle over the ground. The AFH’s fix is the same as in turns around a point: steepen the bank on downwind headings, where groundspeed is highest, and shallow it on upwind headings, where groundspeed is lowest. On the crosswind sides the bank is in between and the nose is angled into the wind. Because the wind can change during a long descent, keep correcting for changes in direction and velocity all the way down.
Airspeed is the other half of the job. The AFH points out that airspeed tends to fluctuate as the bank changes, so anticipate pitch corrections as you steepen and shallow the bank rather than chasing the airspeed indicator afterward. Steep banks also raise the stall speed, and the ACS lists airframe and airspeed limitations among this task’s risks, so a precise, coordinated glide matters as much as the ground track.
Clearing the engine on the way down
A long glide at idle brings problems of its own. The AFH warns that prolonged idle may cause excessive engine cooling, spark plug fouling or carburetor ice. To prevent them, periodically advance the throttle and hold it for a few seconds, adjusting pitch to keep the airspeed constant, preferably while headed into the wind. If your airplane has a cylinder head temperature gauge, monitor it.
Note your altitude loss per turn. The AFH points out that knowing how much altitude each revolution costs helps you decide when to roll out in a real emergency, so that you are neither too high nor too low to make a safe approach. For extra challenge it suggests rolling out on a heading perpendicular to the wind or directly into it, a skill that would be particularly useful in an actual emergency.
ACS standards for the steep spiral
The steep spiral is Task B in Area of Operation V of the Commercial Pilot for Airplane Category ACS, FAA-S-ACS-7B, the current edition. The skill elements are:
- 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° of bank, at a constant radius about a suitable ground reference point.
- Apply wind-drift correction to track a constant-radius circle around the reference point, with bank not exceeding 60° at the steepest point.
- Divide attention between airplane control, traffic avoidance and the ground track while maintaining coordinated flight.
- Maintain the specified airspeed within 10 knots, roll out toward an object or specified heading within 10°, and complete the maneuver no lower than 1,500 feet AGL.
The knowledge elements are the maneuver’s relationship to emergency landing procedures, maintaining a constant radius about a point, and the effect of wind on ground track. Risk elements include low-altitude maneuvering, uncoordinated flight, wind, and airframe or airspeed limitations. For an initial commercial certificate with a single-engine land or sea rating, the ACS has the examiner select either steep turns or the steep spiral, so train both. Multiengine applicants fly only steep turns.
What you'll need
The handbook, standards and test prep for your commercial certificate, from PilotMall.com.
Common steep spiral errors
From the AFH’s list:
- Not clearing the area, or not scanning for traffic during the maneuver.
- Inadequate pitch control on entry or rollout, and inadequate airspeed control.
- Not correcting the bank angle for wind, so the circle drifts.
- Poor flight control coordination and ineffective use of trim.
- Becoming disoriented.
- Flying by reference to the instruments rather than visual references.
- Not completing the turn on the designated heading or reference.
How it connects to engine-out landings
The steep spiral is the glide-path cousin of the power-off 180 accuracy landing. For a real engine failure, the AFH describes using any combination of gliding maneuvers, from wings-level glides to spirals, to arrive at the key position at a normal traffic pattern altitude over your chosen landing area, then flying a normal power-off approach from there. Practicing the two together turns the spiral into a practical emergency skill. The rest of Area V is chandelles, lazy eights and eights on pylons; see our commercial pilot requirements for the full certificate picture.
Frequently asked questions
What is a steep spiral?
A steep spiral is a gliding turn, flown with the throttle at idle, that keeps a constant radius around a point on the ground for at least three 360° turns. Its purpose is to lose a lot of altitude quickly while staying over a selected spot, which can be useful in an emergency landing.
What are the ACS standards for a steep spiral?
FAA-S-ACS-7B requires at least three 360° turns at a constant radius with wind-drift correction, bank not exceeding 60°, the specified airspeed within 10 knots, a rollout within 10° of the chosen object or heading, and completion no lower than 1,500 feet AGL.
What is the maximum bank angle in a steep spiral?
60°. Because you vary the bank to correct for wind, the steepest point comes on the downwind headings, so that is where you must watch the bank most closely.
How many turns are in a steep spiral?
At least three 360° turns, according to both the ACS and the Airplane Flying Handbook. Start high enough that you can complete them and still roll out no lower than 1,500 feet AGL.
Why do you clear the engine during a steep spiral?
A long glide at idle can cause excessive engine cooling, spark plug fouling or carburetor ice. The Airplane Flying Handbook recommends periodically advancing the throttle for a few seconds while adjusting pitch to hold airspeed.
Is the steep spiral on every commercial checkride?
Not necessarily. For an initial commercial certificate with a single-engine land or sea rating, the examiner chooses steep turns or the steep spiral, so be ready for both. Multiengine applicants fly steep turns only.