No step

By JEB BURNSIDE.

One of aviation’s endearing characteristics involves the abundant myths surrounding aircraft operation: Do this, that or some other thing and your airplane will carry more, fly faster on less fuel and land on a dime. Such myths are great hangar-flying fodder, but most of them fall down when confronted with the real world.

One such myth involves “the step,” the mystical and mysterious airplane attitude that, when established only by virtue of a pilot’s superior skill and experience, allows a higher cruise speed.

It can be second only to “lean of peak EGT will cook your engine” or “never spin a Tomahawk” as a solemn truism whispered from pilot to pilot.

Similar aviation myths are handed down to less-experienced pilots like old headsets. And, like many myths, they may have some basis in fact. But a close examination and a quick demonstration flight can dispel many of them, and give you something else to talk about at your next hangar-flying session. So it is with “the step.”

What is “the step,” anyway?

A Good Attitude

A definition of “the step” might be some specific airplane attitude allowing for the highest airspeed in level flight. Tradition has it that to “get on the step,” we maintain climb power through our target cruise altitude to, say, a couple hundred feet above it. Then, while still maintaining climb power, we gently push the nose over, slowly descending back to the target altitude.

Once there, we set cruise power while the airplane maintains its slightly nose-low attitude, one supposedly minimizing drag and maximizing speed. We then sit back and enjoy the extra few knots, content in our superior airmanship as we motor past others not so enlightened or skillful. That’s the mythical “step.”

While this procedure isn’t a bad one — it allows us to accelerate to cruising speed more quickly than might otherwise be the case — there’s no magic to it. And you can prove it on a quick test flight in, say, a Skyhawk.

First, get on “the step” as described above. Use an intermediate altitude of, say, 5,500 feet msl. Set cruise power and adjust pitch trim for level flight. Engage altitude hold if so equipped. Wait 10 minutes and write down the indicated airspeed.

Next, descend a couple thousand feet, say to 3,500, add climb power and level off at 5,500 as you reach it. Set cruise power and adjust pitch trim for level flight. Your airspeed initially will be lower than cruise, but it slowly will increase. Wait another 10 minutes.

Again, write down the indicated airspeed. Presuming everything remains the same — aircraft weight, pitch trim, air density, power setting, etc. — the two airspeeds you’ve written down also will be the same.

Myth Math

I mentioned above that all good aviation myths may have some basis in fact, and “the step” doesn’t disappoint. Supposedly, the myth has its origins in flying’s earlier days — as with all good aviation stories — when airplanes were relatively underpowered and aerodynamically inefficient.

Those early airplanes often had to cruise at an altitude near their service ceiling. Using a standard level-off technique, they’d stagger along in a slightly nose-high attitude and took a long time to accelerate to cruise speed, if they ever reached it at all. But by climbing above the desired altitude and then descending back to it, their crews could coax them to cruise speed more quickly. Thus was borne the myth of “the step.”

It may also have something to do with seaplane operations, which were a solution when a large, smooth body of water offered a much longer “runway” than the land-based infrastructure of the day. With a seaplane, “getting on the step” refers to a balancing the airplane on a specific portion of the floats or hull, where hydrodynamic drag is minimized.

Conveniently, there’s also Aerodynamics 101 to help us refute this myth. The increased drag from maintaining a nose-up attitude after a standard level-off retards acceleration to cruise speed. Deflecting the pitch control to maintain altitude at the lower speed slows us down even more. An airplane’s ability to accelerate to cruise speed involves additional math about the power available in excess of what’s required for level flight.

The ideal for cruise flight would be zero-degree pitch-control deflection, minimizing drag and maximizing airspeed for a given power setting. That’s achievable, but requires paying some attention to the airplane’s centers of gravity and lift. More math. Less myth.

Kung Fu Flying

Recognizing all this, it makes perfect sense to climb slightly above a target altitude and then descend back to it while accelerating to cruise speed. But such a technique doesn’t expose some mystical, mythical aerodynamic kung fu built into your airplane, conjured only by your superior knowledge and skill. It’s just good airmanship.

Some caveats apply, of course. For one, altitude deviations can be a serious matter, and it would be a very bad idea to exceed an expected or cleared altitude by 300 feet, especially when IFR. In everyday cross-country flying, climbing only 50 to 100 feet above a target cruise altitude should be more than enough when flown gently and the airplane is given time to accelerate. Altitude-hold capabilities greatly help us maintain maximum cruise speed when they’re available.

At the end of the day, a given airplane’s ability to accelerate to its cruise speed after a traditional level-off depends greatly on available power. One with plenty of power available in excess of that required to maintain level flight, e.g., climb, obviously will accelerate more quickly. An airplane near its service ceiling may need some help.

All a pilot is doing by descending an airplane back down to its cruise altitude — “getting on the step” — is providing some help. It’s as simple as that.

(But that part about not spinning Tomahawks? True story…)