Aftermath: Turnback

One bad decision leads to another.

Aftermath Artwork

Aftermath Artwork

A Mooney M20J with two aboard, flown by a 300-hour private pilot, began its takeoff roll on Runway 19 at Kansas City Charles B. Wheeler Downtown Airport (MKC) at intersection Kilo, with 5,313 feet of runway remaining. The pilot retracted the landing gear immediately after liftoff and began a climb, whereupon the engine lost power. The pilot declared an emergency as the airplane settled to an estimated 10 feet above the surface with the gear still retracted. The engine then returned to life; the pilot told the tower "I'm OK," and he resumed climbing. Twenty seconds later, when the airplane was at an estimated 300 to 400 feet above the end of the runway, the pilot radioed, "We do have a problem." The local controller, who had no way to know that the engine had quit, cleared the pilot to land on Runway 21.

The airplane stalled out of a gliding right turn and crashed in a field a quarter-mile southwest of the departure end of the runway. Both occupants died.

National Transportation Safety Board investigators found no mechanical problem in the engine to account for the power loss, but there was a mix of avgas and water in the fuel distributor. The reasonable assumption was therefore that fuel contamination had been the culprit. The probable cause was determined to be "the pilot's improper decision to attempt continued flight after a momentary loss of engine power with usable runway remaining. Contributing to the accident were the pilot's premature retraction of the landing gear, the loss of engine power due to fuel system water contamination, and the pilot's failure to detect the fuel contamination during the preflight inspection."

The original accident report, published in October 2014, supplied strong support for the water contamination hypothesis in the form of the statement that nearly 1¼ inches of rain had fallen in the three days since the Mooney had arrived at MKC from Ohio. The report also included a statement by a flight instructor that the tank caps on Mooneys (which are a mil-spec type, no different from those used on many other types of airplanes) are prone to leak. It took the sharper eyes of the lawyers for the firm that had recently replaced the seals on the airplane's tank caps to notice that the heavy rainfall in question had taken place in 2014, not 2013, and that, incidentally, the "Quality Controlled Local Climatological Data" tables supplied by the NTSB to document the heavy August rainfall were actually those for the month of September, not August. In fact, there had been a "trace" of rain on the day the Mooney arrived and none at all since then.

Nevertheless, there was water in the injection system, the engine had quit, and there was no mechanical reason for it to have done so; therefore, rain or no rain, the likely cause of the power interruption was water in the fuel. If it didn't get there while the airplane was parked, it must either have already been in the tank or have been added when the pilot bought fuel at MKC. No water was found in the FBO's fuel tank or pump, however, and no other aircraft fueled that day reported any contamination.

Fuel pickups are not placed at the lowest points in tanks; a small part of the tank below the pickup, known as the "sump," contains some inaccessible fuel and whatever else, including water, might get in. In principle, draining the sumps before flight until no contaminants emerge should provide assurance that nothing but fuel can get to the pickup. The integral fuel tanks in the Mooney's wings do not have internal baffles, and so it is not likely that water could pool somewhere and then shake down to the fuel pickup because of turning or acceleration.

The finding of probable cause is not explicit about the pilot's draining or not draining his sumps, but it implies that he had not, since if he had he would presumably have found the water and removed it. The instructor who checked him out in the Mooney when he bought it the previous December, however, described him as an "adept" pilot who was thorough and did not rush or skip checklist items. The accident report included a comment by a witness, an airplane mechanic, that the run-up had been "short ... less than a minute" with just a "quick" magneto check — an observation that seems to have been included to suggest that the pilot was hasty. The instructor, however, commented that plugs were prone to foul on the ground, particularly while running on a single mag during the checks, and that he had suggested to the pilot that he lean the mixture while taxiing. So it was possible that the "quick" mag check was due not to haste but to a reasoned policy on the pilot's part.

Apart from the question of why the engine failed and whether the pilot's actions had anything to do with it, the accident raises several issues of technique.

The first is the decision to make an intersection takeoff. Despite the clichés about the uselessness of runway behind you, an intersection takeoff with more than a mile of runway ahead of you is so common that it can hardly be criticized — especially since it seems, in this case, to have had nothing to do with the outcome.

The second is the pilot's retracting the landing gear immediately after the wheels left the ground. No instructor teaches that practice in a single. Everyone recommends leaving the gear down until a landing on the runway is no longer possible, unless in certain rare situations, for instance if the maximum climb rate is needed from the very moment the plane is airborne. But it is not clear what, if anything, early gear retraction had to do with what happened next.

That was the decision not to abort the takeoff after the first power loss. In the NTSB's view the primary cause of the accident was the pilot's "improper" decision to continue the takeoff. Most pilots, I think, would unhesitatingly abort a takeoff at any sign of irregular engine operation. Perhaps this pilot was influenced by his knowledge that the gear was up, so he could not immediately put the airplane back on the runway anyway, and by the powerful, confidence-inspiring surge of power when the engine sprang back to life. Whatever his reason, the decision to continue flying, when he still had ample space in which to put down the gear and land, was a fateful one.

The last issue was the decision to turn back to the runway after the second power loss. In my opinion, that decision, which the NTSB does not criticize or even mention, was defensible. It is almost invariably said, when turnbacks are discussed, that the wiser course is to land straight ahead. Far too many airplanes have stalled while attempting to get back to a runway from a low altitude. But each case is special. If landing straight ahead is impossible and there is a chance of safety in a turn, people will turn. In this case, with 300 or 400 feet of altitude, the Mooney was actually in a position to make a 180-degree turn and a forced landing, if not on the runway then on a strip of grassy land parallel to it or even in the adjacent river. Straight ahead, on the other hand, was a built-up area in which a survivable landing, without risk to people on the ground, would be unlikely.

As often happens, after a series of bad decisions the coup de grâce comes from faulty flying technique. In his haste to turn, the pilot stalled the airplane, and that was that.

This was a classic case in which an angle-of-attack indicator might have saved the day. By removing the complexities of speed, bank angle and G load, it would have reduced to a single easily followed cue the difficult, but still possible, task of turning back to safety.

This article is based on the NTSB's report of the accident and is intended to bring the issues raised to our readers' attention. It is not intended to judge or to reach any definitive conclusions about the ability or capacity of any person, living or dead, or any aircraft or accessory.

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