2012 04 aborted takeoffs

Vintage Instructor THE

BY Steve Krog, CFI

Aborted takeoffs

I

t was a beautiful late fall afternoon. My friend Bob was anxiously preparing to make the very first test flight in his newly restored J3C-65 Cub. The restoration had taken several years, but prior to that effort, the Cub had been stored in a barn for more than 30 years. All control cables had been replaced and were checked one final time. The engine and engine accessories had been overhauled several years earlier but had been “pickled” until being installed on the restored Cub. Engine test runs were conducted including a full power static check. Everything seemed to check out normal.

After doing one final magneto and carb heat check, Bob taxied into position, smoothly applied full power, and headed down the 3,000-foot hard-surface Runway 29.

The tail came off the ground; the engine sounded strong and ran smoothly. Just as the main wheels lifted off the surface, the engine was suddenly quiet. Instantly, Bob dropped the nose, executed a wheel landing, and rolled to the end of the runway. A perfectly executed aborted takeoff, and no harm was done to either the plane or the pilot!

Magnetos were again checked, fuel lines were disconnected, and fuel flow was checked. The carburetor fuel screen was checked for restriction and contamination, as was the gascolator. Fuel was drained and collected from the carb fuel bowl, again looking for any sign of contamination. All systems were pronounced fit, and a full-power static run was again done. Everyone thought it must have been a fluke thing. With no hint of the problem repeating itself, Bob once again taxied to the very end of Runway 29 for another try.

After aligning with the runway, full power was applied and the Cub again lifted off. This time the Cub managed to get to about 20 feet in the air before the engine went completely silent. Bob repeated his actions, lowering the nose, touching down in a wheel-landing configuration, and rolling to a stop at runway’s end. Two engine failures and two aborted takeoffs were enough. It was time to examine all systems in much more detail.

Some of us may fly for our entire career and never experience a “real time” aborted takeoff or a forced landing. Others have experienced them in several different airplanes.

When was the last time you executed an aborted takeoff?

34 APRIL 2012

With rare exception, your response is probably, “Not since my checkride!” And that could have been anywhere from one to 40 years ago.

All of my students, past and present, as well as many individuals with whom I conduct flight reviews, think that I am, at times, rather devious. Every time I see a throttle knob pushed to full power without a hand on the knob, I have a tendency to quickly pull it, either back to idle or to an approximate 50 percent power setting, and then ask, “What are you going to do?” It’s not something I do to scare the individual, but rather it is an exercise to get them to think.

I require aborted takeoff training of all students with whom I fly. Someday any one of them may experience one in a real-time situation. A little practice may well help them instantly recognize the situation and take immediate corrective action. I think of aborted takeoff training much like spin training. Unless you’ve experienced it a time or two, how will you instantly recognize the situation and what will you do in response?

A search of the FAA accident reports collected over the past several years indicates the most common error committed in an aborted takeoff is loss of directional control.

Pilots encountering this situation for the first time become baffled by the loss of power and forget to fly the airplane back onto the runway.

The airplane, already in a nose-high, low-airspeed configuration, stalls in a second or two if no corrective action is taken. It then drops onto the runway and bounces. At this point the pilot is usually just along for the ride as no action was taken to keep the airplane on the ground and aligned with the runway. Add to that situation a good crosswind, and it’s easy to see why these incidents end up as “loss of directional control” followed by a ride through the drainage ditch paralleling the runway. When the dust settles, gear and wingtip damage usually result, along with possible prop damage.

In that case, the landing following the aborted takeoff results in a very expensive, time-consuming repair along with a badly bruised ego. Sadly, the damage could probably have been prevented had the pilot had some experience with aborted takeoff training.

While sitting in a nice big easy chair reading this article, ask yourself, “What would I have done had Bob’s situation

happened to me?” With time to think through the situation, it really isn’t difficult. But now, visualize this scenario. You have just finished a large stack of pancakes and four or five link sausages, talked to at least two dozen fellow pilots, and you’re now ready to head home.

The fly-in breakfast was held at a small grass-strip airport with airplanes parked right up to the edge on both sides of the runway, and there are some very large trees that you’ll need to clear at the far end. Add to this a steady crosswind. You are number three for takeoff, and there are four more airplanes behind you just as anxious as you are to get going. Your mind is thinking through everything except an aborted takeoff at this point.

Having to abort a takeoff is not a common occurrence, but it is something that should be a part of your mental checklist every time you align your airplane with the runway centerline.

What situations might you encounter requiring an aborted takeoff? Certainly either a silent or very roughrunning engine is cause for abandoning the takeoff. But there are times when a deer or other wildlife may be on the runway. I once had to abort a takeoff early one morning in South Dakota when a herd of antelope decided to occupy the runway ahead of me just as I added full power.

Ground vehicles and other aircraft inadvertently moving onto the runway is another potential for an aborted takeoff, especially at the smaller airports from which we fly, but it can happen anywhere. This situation has been defined by the FAA as a runway incursion.

I was once a passenger on a fully loaded Boeing 747 taking off from Kennedy Airport in New York. Just as the pilot began rotation and the nose came off the ground, the engines went to full reverse. Everything in the cabin began to shake, overhead bins opened, and luggage was flying everywhere. My wife grabbed my arm and asked what was happening. I remember the incident vividly to this day.

I told her to prepare for a swim as the only place for this airplane to go was in the water. The very seasoned captain brought the 747 to a halt well before colliding with another aircraft that had taxied partway onto our runway.

Eight hours later we were safely aboard a second aircraft and again on our way. I found out later the 747 had blown 14 tires, required a mandatory inspection of all engine mounts, and needed a complete change of brakes.

The steps that I have my students follow include: Lower the nose: It is vital that you prevent a stall.

Then level, flare, and follow through as you would a normal landing.

Move the throttle to idle: In case the engine would cough or catch for an instant. A quick burst of power for a second or two would add a great deal of confusion and possible loss of control of the airplane. You are committed to landing the airplane. Do everything in your power to make it happen with no additional surprises.

Maintain directional control: Keep flying the airplane until it comes to a complete stop. There is no sense in damaging the airplane after you are back on the ground.

After “surprising” the student with one or two simulated aborted takeoffs, it becomes second nature to anticipate experiencing another whenever they fly with me.

Anticipation followed by practice creates a positive habit.

One additional exercise I like to do with students when working in the traffic pattern is this: Every 10-15 seconds I’ll ask what they would do and where would they go if the engine were to quit this instant: •While on climb-out •On crosswind •While turning downwind •At midpoint on downwind •While turning to base leg This is also a good exercise for anyone. It is quite easy to become complacent, especially when flying from the same airport. Take a moment or two the next time you go for a flight and ask yourself these same questions while in the pattern. It may prevent a nonevent from becoming an incident or even an accident!

Bob’s Test Flight Conclusion After removing and disassembling the carburetor, it was found that the needle and jet were incorrect. It was meant for a carburetor in conjunction with a mechanical fuel pump. The head pressure for a gravity-fed system was not great enough to allow proper fuel flow. When the correct needle and jet were installed, no further problems were encountered.

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VINTAGE AIRPLANE 35