Planning for a Safe Takeoff

Don't Trust Your Airplane

by John Kounis

A first-time student peers suspiciously at an airplane older than he is. “Are you sure it will fly?” he asks. It does fly. And it continues to fly. After many successful flights, the former student, now pilot, believes the airplane will fly. Every step of the preflight reinforces his belief. By the time he advances the throttle and accelerates for takeoff, he is convinced the airplane will fly.

Like the above pilot, many of us take for granted that our airplanes will fly. That is when we are least prepared for an aborted takeoff, or worse, an engine failure after takeoff. If we approach every flight with the trepidation of a first-time student, we will anticipate problems and be prepared to take immediate action.

Anticipate Emergencies

How do you prepare for an engine failure? Envision it. In simulator experiments, the mere mention of the words “engine failure” prior to flight significantly improved the pilot’s reaction time.

During an emergency is the wrong time to decide your course of action. The decision may take only 10 seconds, but those seconds are crucial. Anticipating an emergency before takeoff will greatly increase your safety. For this reason, you should add three items to your pre-takeoff checklist: abort point, engine failure procedure, and turn-around altitude.

Abort Point

Establish the point where you will abort if takeoff is not going as planned. Visualize this point in reference to available landmarks: a windsock, fence post, oil stain, etc. Should anything unexpected occur (such as slow acceleration, loud noise, excess vibration) at this point, abort the takeoff. Such a conservative attitude may result in an extra abort or two during your flying career, but could save your life someday.

On long runways, set the abort point where you expect to lift off. If problems occur before that point or you reach it and are not yet airborne, you can abort successfully. On shorter runways, establish the point where it is still possible to stop in the remaining runway. For example, on a 1,600-foot runway with an anticipated 1,200-foot takeoff roll, a good abort point would be at 800 feet. If the takeoff isn’t going well after 800 feet, you still have 800 feet to stop.

You must also adjust the point based on your braking and acceleration ability. A weak aircraft on a paved runway may accelerate poorly, yet have effective braking. You could then abort 3/4 down the runway and still stop in the remaining 1/4. Conversely, if you have a powerful aircraft on an icy runway, you could accelerate for 1/4 of the runway, then need the remaining 3/4 to stop due to ineffective braking.

At the abort point, how do you know the aircraft will fly? Will you attain flying speed before the end of the runway? Aircraft on hard surfaces have relatively constant acceleration. Assuming constant acceleration, a good rule-of-thumb is that you’ll attain 70% of flying speed halfway through your takeoff roll. (Since speed is proportional to the square of distance, one over the square root of 2 is roughly 70%.)

For example, if normal liftoff is 50 KIAS, you should have a minimum of 35 KIAS at the halfway point. Prudence dictates adding a safety margin to this minimum speed (e.g., 40 KIAS). These calculations are easier to make before takeoff, not while charging down the runway.

Keep in mind that the drag of a soft surface may inhibit acceleration, so increase your minimum speed accordingly (e.g., 80% or 90% of liftoff speed).

Engine Failure Procedure

Prior to takeoff, decide what you will do if the engine fails immediately after takeoff. Will you land straight ahead, make a slight left turn to avoid a grove of trees, or dive under power lines and land in a field?

In some cases, the options are poor. The only choice at one airport was to fly into a 100-ft. long Del Taco parking lot. It wasn’t a good option, but it was the best option. If you consider your options before takeoff, you will execute the safest option immediately, rather than delay in indecision.

Turn-around Altitude

Most light aircraft require about 500 feet to return to a runway they just departed. You should know what the turn-around altitude is: remember it or jot it down prior to takeoff. Passing 2,625 feet after departing from an airstrip at 2,189 feet is the wrong time to calculate if you can turn around.

To determine how much altitude you need, take your aircraft to altitude and configure it for takeoff—gear down, flaps, full power, etc. Then reduce power rapidly to idle and make a teardrop turn. A 180-degree turn will not result in a turn back to the runway. You will be pointing the opposite direction, but offset from centerline. You must turn about 225 degrees, then 45 degrees back, making a teardrop. Note the altitude loss during the turn. Then remember that you were expecting the engine failure this time. In a real emergency, it will take you a few seconds to react, so increase your anticipated altitude loss accordingly.

Your turn-around altitude will be field elevation plus the anticipated altitude loss of a teardrop turn.

Execute the Takeoff

Once you have reviewed the abort point, engine failure procedures, and turn-around altitude, you’re ready for takeoff! Do not be in the mindset that you will fly. Rather, agree to takeoff only if everything is going well at the abort point. Once you pass this point, think about your engine failure procedure and be ready to execute it immediately. Now is when your aircraft is most vulnerable—after takeoff, but before you can return to the runway.

As you climb, keep thinking about the turn-around altitude. Once you pass it, the riskiest part of the flight is over. You can now return to the runway or find another suitable landing area in case of engine failure. En route to your destination, make safety a habit by constantly reviewing your options in case of an emergency. Someday, those few thoughts may save your life.