The Commercial ACS steep spiral maneuver calls requires a pilot to fly a descending spiral with power set to idle and maintain a constant radius around a point. The maneuver is supposed to be flown at best glide speed Vg. You are allowed to fly up to a bank of 60 degrees to maintain the radius around the point. You need to complete three 360 degree turns with no power and complete the maneuver at 1500 feet AGL
This maneuver is a piece of cake when flown with no wind; you just have to fly a constant bank and airspeed. However things get much harder when there is a wind. When you fly downwind your ground speed increases so you have to increase bank to maintain the radius and when you fly upwind you have to decrease bank to maintain your radius. The ACS specifies that the applicant has to maintain an airspeed of +- 10 knots, a rollout heading of +- 10 degrees and complete the maneuver at an altitude of no lower than 1500 feet AGL.
Best glide in my airplane is 80 MPH. The other day I had a 30 knot wind from the Southwest and tried flying this maneuver with the wind. On downwind I ended up having to bank the airplane to a 45 degree angle while trying to maintain best glide. When I did this the stall warning went off. When you do the math you can see why. Stall speed increases with bank angle. The calculation for the the new stall speed at a bank angle is the normal stall speed times the square-root of the load factor which for a 45 degree bank is 1.4. For my airplane the stall speed is 67 MPH so when you do the math, the new stall speed comes out to 79.27 MPH. So you can see why the stall warning went off.
Best glide is really related to an angle of attack and not airspeed. When you increase bank angle you need to increase angle of attack to prevent the airplane from going into a spiral dive. So shouldn't you increase airspeed when increasing bank angle to maintain the best glide angle of attack? If that is so, then you would violate the ACS standards and could fail your commercial check ride. I also feel that this maneuver is unsafe for high bank angles (high winds) as specified as it could cause a pilot to stall the airplane in a bank and risk a possible spin.
In my opinion, I believe the maneuver should specify to maintain a constant rate of descent, allowing for changes in airspeed to maintain the best glide angle of attack.
Looking for answers from pilots and aerodynamicist on this question.