The March 2021 crash of a Beechcraft Bonanza A36 in Pembroke Pines, Florida, resurfaced

debate about the “turnback,” or the “impossible turn”, an engine-out course reversal shortly

after takeoff to land in the opposite direction on the departing runway.

Initial NTSB reports indicate the pilot of the Bonanza attempted a turnback with disastrous

results.

Opponents of the turnback argue that it’s impossible in some aircraft, and near impossible

in the rest.

Even with a glide ratio that makes a turnback technically possible, they say, the difficulty

of the maneuver, close proximity to the ground, a startle factor, and the stress of life-or-death

consequences all conspire against a successful outcome.

Proponents argue that turnbacks are a viable option for some pilots, in some aircraft,

under some circumstances.

As for the FAA, they caution that CFIs should train single-engine pilots not to attempt

a turnback unless altitude, best glide performance and pilot skill allow for a safe return.

In April, the AOPA Air Safety Institute flew test profiles in several aircraft to determine

the feasibility of the so-called “impossible turn.”

We flew turnback profiles at Martinsburg, West Virginia’s 8,800-foot-long, 150-foot-wide

runway.

Our lineup included me in my 150-horsepower, 1993 Piper PA–18 Super Cub with full gas;

Editor-at-Large Dave Hirschman flew solo in his Van’s RV–4 fully fueled; AOPA Director

of Flight Operations Luz Beattie alone in a fully fueled 1978 Cessna 172N; and Hirschman

and AOPA Vice President of Flight Operations Dave Roy in a 1971 Beechcraft Bonanza A36

with a 300-horsepower Continental IO-550, full gas, and 40 pounds of baggage.

Prior to the exercise, we all climbed to altitude and practiced stalls, including stalls in

45 degrees of bank, to calibrate the actual stall speeds at play during our turnback exercise.

We then established our minimum required turnback altitudes using a technique inspired by airline

pilot and CFI Brian Schiff.

We set a climb profile, cut the power to idle, and began an idle power, 45-degree-bank turn

at best glide for 360 degrees, noting the altitude lost.

The idea behind using a 360 degree turn is that practicing at 180 degrees is not enough.

The 180 degrees will get you turned around, but abeam the runway.

In reality, it takes more turn to get back over to the runway and aligned with the runway

centerline.

With stall numbers and expected turnback altitude requirements freshly established, we each

flew three profiles in near-perfect conditions: cool, sunny morning, light winds, and low

density altitude, on a simulated 4,000-foot-long runway.

The plan was to climb between VX and VY with full power to the predetermined altitude,

cut power to idle, delay three seconds to simulate a startle period, then push to best

glide while entering a 45-degree-bank turn back to the runway.

I went first in the Super Cub.

The

Super Cub returned to a simulated 4,000-foot-long runway in all three turnback attempts, one

at 500 feet AGL and two at 300 feet AGL.

In fact, I estimate I could have returned back to a 2,000-foot-long runway in the Super

Cub.

Next up - Dave Hirschman in his RV-4.

Hirschman initiated turnbacks at 1,000 feet AGL.

He made it back, barely, two out of three times.

The third time would have resulted in a landing short of the runway.

Hirschman’s performance may have been impacted by his three-blade, constant-speed propeller

that created far more drag at high-RPM setting than a fixed-pitch prop would.

Luz Beattie made her turnbacks at 1,000 feet AGL, 800 feet AGL, and 600 feet AGL.

She comfortably returned to the runway each time.

Both Beattie and I may have benefited from some idle thrust, with engines still running,

but experts such as Catherine Cavagnaro advised us that the light thrust we might have received

at idle power was somewhat offset by the drag from the moving propeller, so the advantages

of an engine at idle are believed to be minimal.

The last airplane to try the turnback profile was the Bonanza.

And those results were perhaps the most startling.

Turning back at 1,000 feet AGL and varying speeds from best glide (110 knots) to 95 knots

(to reduce the turn radius), and propeller settings from high to low RPM, Dave Roy and

Hirschman didn’t come close to making it back to the runway

in any attempt.

Even in an optimum glide configuration with landing gear and flaps up, the Bonanza would

have come down well short of a simulated 4,000-foot-long runway.

Our takeaway is that turning back is a viable option for certain aircraft, in the right

conditions, flown by proficient pilots who have trained for the maneuver.

It's not a good option for aircraft with high climb speed and high best glide speed, as

we learned with the Bonanza.

These speeds combine to take you farther from the runway on departure, and result in more

offset in the turnback, leaving you longer distance to glide.

Pilots flying aircraft with these characteristics should eliminate turnbacks as an option for

engine failure after takeoff.

Variables like wind, temperature, density altitude, runway length, and technique could

affect these results, but not enough to change our overall recommendations.

Please don’t try to fly this exercise solo in an attempt to prove us wrong or confirm

our results.

We’ve lost pilots training in these maneuvers due to the high potential for an uncoordinated

stall and spin in the turnback.

Fly with a CFI, at altitude first, and determine your strategy in the event of an engine failure

on takeoff.