Plane & Pilot
Tuesday, August 6, 2013

Engine Loss: How Will You React?


When an aircraft engine loses power, the pilot’s initial response can mean the difference between life or death


If you do decide to attempt a return, the challenge is to find the AGL altitude that works for you and the aircraft that ­you fly. The best method to determine that altitude is to experiment by selecting an altitude a few thousand feet above the ground as the "pseudo ground" level, and then attempt the return at increasingly higher altitudes until you identify an AGL altitude that allows a no-pressure return. That altitude is the "trigger altitude" below which you absolutely won't attempt a return in an emergency situation. It's generally bandied about that 800 feet AGL or higher is the minimum altitude, but that assumes the pilot is spring loaded to attempt the turnaround, and the aircraft is capable. In an actual emergency, spring loaded rarely happens. Usually, there are a few seconds of surprise and denial. One-thousand feet AGL or greater is a more realistic minimum. Remember, the sight picture out of the windshield is significantly different at 300 feet AGL than it is at 3,000 feet. Instinct, often instinct detecting imminent danger, comes into play near the ground as does mental paralysis from stress. So, higher is better.

Also, a 180-degree return isn't really a 180-degree turn. The turn will be more like a teardrop or a 225-degree turn in one direction and then 45 degrees back to align with the runway. The steepness of the bank and turn rate are your decision, and you should determine what works best by experimenting. Too slow a turn, and the altitude loss might preclude a successful return; too fast or steep, and the risk is a loss of control or significant altitude loss. To learn how to accomplish this maneuver, find an instructor who's comfortable teaching it and learn the right way.

The final gating factor is wind. With any kind of significant headwind component, you'll be closer to the airport when the engine fails. But the stronger the wind, the more you'll want to turn back into the wind to touch down, thus raising the risk factor and altitude requirement tremendously. Since the stronger the headwind, the slower the groundspeed, this again might be a situation where landing straight ahead will be the best choice.

But if you're going to turn back, unless the terrain is more accommodating in the other direction, make the initial turn into the wind if there's a crosswind, because that will keep the aircraft closer to the runway centerline.

Finally, a caveat. It's one thing to determine the altitude and learn an acceptable procedure, it's quite another to be both instantly prepared for the eventuality and current in your skills. Personally, I like having this procedure in my bag of tricks, but it's highly unlikely I'd ever attempt it at less than 1,500 to 2,000 feet AGL. The consequence of failing isn't worth the risk.

What To Do When It Happens
The aircraft's POH should provide the approved procedure for dealing with an engine failure immediately after takeoff. Sadly, many older aircraft's POH don't cover this emergency.

No matter what, there are a few things you must do to maximize the probabilities of a successful outcome. First and foremost, always fly the airplane. If you do nothing else, keeping the aircraft under control until it's stopped will maximize your chances. Second, immediately lower the nose and trim for the aircraft's best glide speed because that ensures the longest gliding distance. You should have that airspeed memorized—an emergency isn't the time to look it up. The best glide speed varies with the current aircraft weight. The book value is for gross weight. Worst case, use the book value, but on my Columbia 400, the best glide speed range varies from 108 KIAS at 3,600 pounds to 96 KIAS at 2,700 pounds. That's a bit over a knot per 100 pounds. Only the correct airspeed for the current aircraft weight will achieve the maximum gliding distance.



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