Impossible Takeoff

When wanting an airplanes maximum performance, we need to load and configure it correctly.

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Ive done my share of flying to and from soft fields, in a variety of airplanes, including 150s, 172s and my current flivver, a Beech Debonair. The landing portion doesnt require a great deal of planning-presuming the runway isnt too short-and my primary training taught me well enough I never have a problem with the arrival.

The departure, however, is another thing entirely. The built-in deceleration a soft field provides on landing works against us on takeoff. Soft terrain, high grass and (my) imperfect technique all combine to lengthen the takeoff roll. I know this, again thanks to my training, and always pull out the AFM/POH or a soft-field takeoff checklist to review the procedures. Ideally, I do that-plus run a basic soft-field takeoff performance calculation-before even committing to go into such a landing area.

Obstacles are another problem we often have at soft fields, since the landing areas themselves-almost by definition-are rural and things like houses, telephone poles and trees abound. Many of these obstacles easily can exceed the proverbial 50 feet expectation found in the AFM/POH, and may be factors for both the landing and the takeoff. Practice makes some of this less dramatic. So does familiarity with the airplane and the field, and doing things by the book.

Regardless, one of the things we must consider is adhering to the AFM/POH and/or checklist recommendations for procedures and configuration. An example is deploying the recommended flap setting for a soft-field takeoff, which likely is different than for a “normal” takeoff from a paved runway.

In any case, I always want to be as light as possible for such a takeoff, even to the extent of refusing to top the tanks before arrival and accepting the need to make a fuel stop before reaching my destination. As were about to be reminded, trying to get out of even a well-maintained turf runway when were overgross and dont set the flaps per the manufacturers recommendations rarely works out.

Background

On June 26, 2009, at 0904 Central time, a Piper PA-32R-300 Lance was substantially damaged when it struck a tree and impacted terrain shortly after taking off from Gastons Airstrip in Lakeview, Ark. Visual conditions prevailed. The instrument-rated private pilot and two passengers were fatally injured. A fourth passenger was seriously injured, and a fifth passenger sustained minor injuries.

An employee of the fishing lodge operating the airstrip drove the pilot and his passengers to their airplane. The employee said the passengers “had luggage on their laps.” He thought the airplane was “overloaded” and the passengers “were tense, [but] maybe [it was] just the heat.” They also appeared to be “in a hurry to leave.” He said the engine “didnt sound right before takeoff,” and the airplane “didnt appear to lift very well.”

Witnesses observed the airplane take off and disappear into a shallow valley. When it reappeared, it was in a slight climb, the wings were “wig-wagging” and the airplane was “porpoising.” A witness who was fishing in a boat on the nearby White River said he heard the airplane take off and could see it through the trees. He could tell it “didnt have much altitude.” Another witness fishing on the river said the airplane “sounded like it was barely moving. The plane was approximately 100 feet off the ground. The plane veered to the right. The back of the plane hit a tree (sheared left wing).”

Investigation

The airplane left tire tracks in the tall grass, on a magnetic heading of 120 degrees, leading to a damaged barbed wire fence. Just beyond the fence was a large tree exhibiting marks consistent with propeller strikes. Most of the bark was missing. At the base of this tree were the airplanes left wing and left rear cargo door. Beyond the tree was the airplane wreckage.

The fuel selector was positioned on the left main tank. The landing gear handle was in the down position and the bellcrank was extended. The flap handle lay flat on the floor, and the actuator was in the up position. The elevator trim jackscrew revealed eight exposed threads, equating to a slightly nose-up stabilator trim setting.

Examination of the engine revealed oil in the crankcase. Thumb compression was obtained on all cylinders. The spark plugs were of normal coloration, and the fuel screen and servo and oil filter were clean. Both magnetos produced spark when turned by hand. All three propeller blades were bent aft midspan, and the tips were curled forward. There were 90-degree chordwise scratches on the cambered surfaces of all the blades.

Using the field elevation of 479 feet, temperature and dew point of 27 and 23 degrees C, respectively, and an altimeter setting of 29.91, density altitude was calculated to be 2367 feet. Weight and balance was computed, establishing the airplane was 188 pounds over its maximum gross takeoff weight.

The airplanes performance charts were consulted. For a turf runway, the computed flaps-up takeoff ground roll would be approximately 1870 feet, and the computed flaps-up takeoff distance over a 50-foot barrier would be approximately 3190 feet.

Using 25 deg. of flaps for takeoff, the computed takeoff ground roll and takeoff distance over a 50-foot barrier from a short grass runway would be 1331 feet and 1870 feet, respectively. The runway was 3200 feet long.

Probable Cause

The National Transportation Safety Board determined the probable cause(s) of this accident to include “The pilots poor judgment/decision making in attempting the no-flap takeoff, his failure to comply with weight and balance limitations, and his failure to calculate the airplanes performance under existing conditions.” This isnt a surprise. In fact, the only surprising thing is the pilot attempted the takeoff under those conditions in the first place.

Three basic things the pilot could have done to prevent this accident come to mind. First, he could have lightened the load by leaving behind some passengers, bags and/or fuel (and come back later for them). Second, he could have used a checklist to remind him to deploy flaps for the takeoff. Third, he could have waited for cooler weather and better performance.

Performance charts and weight/balance information is available to us for a reason. Refusing to understand or acknowledge the limitations and procedures they present will get us into trouble every single time.

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