By Ken Ibold
After a while, flight instructors and other flying gurus start to sound monotonous in some respects. Follow the airplanes POH and fly the airplane are two of the biggies.
Knowing and following the operating handbook can help keep you out of trouble in the first place. But if something does go wrong, the adrenaline of an emergency can make it a bit more likely that youll forget a basic step in the emergency plan or overcontrol the airplane to the point of losing control.
It isnt just rookie pilots who forget these two basic truisms, however. Time and again pilots who successfully deal with an emergency relate their initial shock and inability to respond properly, followed by the realization that flying the airplane has to take primary importance over navigation, communication and even troubleshooting.
General aviation accidents are noteworthy in their frequent lack of sufficient clues to determine why events transpired as they did. There usually arent qualified witnesses close enough to the scene to give credible evidence. Theres no black box that records an ill-fated pilots last actions. Investigators are left with a jigsaw puzzle of smoking wreckage that is often reluctant to give up its secrets.
Often there is enough evidence to create suspicions, but not enough to get a conviction. In that case, the quest for answers doesnt end with the final NTSB report, it begins.
Such is the case with a 2001 crash of a Piper Chieftain – an accident in which the NTSB report leads to as many questions as it answers. While the specific events of this case may to some extent be open to speculation and debate, it serves as a good illustration of how seemingly small uncertainties or transgressions can have serious consequences.
The pilot was flying from a maintenance base in Reading, Pa., to the airplanes home base in Ferndale, N.Y., after maintenance on the airplane, which was used in a Part 135 charter operation. The airplane was in for adjustment of the left engine manifold air pressure, alignment of the breather tubes in each engine and a new fuel drain tube for the left engine. Additionally, the shop took off the left elevator to install rivets at one of the hinges and the right elevator to dress an area where a bolt had caught on the spar.
The pilots delivery of the airplane was his first solo in a PA-31-350, but he was hardly wet behind the ears, reporting 1,385 multiengine hours and 1,150 hours as a flight instruction. He had been in training to take a Part 135 checkride and was signed off for solo flight in preparation for that ride. The 20 hours of training hed had had gotten good reviews from the charter outfits training captain, who described him as smooth, conscientious and capable.
At no time did I observe the control or safe operation of the aircraft to be in doubt, he told investigators. [The accident pilot] was familiar with the POH of this aircraft and was fluent in emergency procedures. He had a calm presence in the cockpit and was also a person of humor and wit.
When the airplane arrived at the maintenance shop, a technician uncowled the left engine and discovered clean oil pooled at the bottom. The pilot told him he had spilled the oil prior to taking off from Ferndale, and the mechanic agreed thats what it looked like. Unfortunately, it was a harbinger of things to come.
After the work was done, the pilot arrived at the airport in the morning and ordered the airplane fueled with 80 gallons of avgas. An employee who dealt with the pilot at the office noted he was very nervous, kind of spacey, and his hands were shaking a bit – a description that paints a decidedly different picture than the one given by the training captain.
Fast forward to the pilots preparation to depart. The pilot entered the maintenance hangar and asked one of the mechanics for a funnel to add oil to an engine. The mechanic loaned him one, then watched as the pilot added three quarts of oil to the left engine – an engine that had just been in maintenance. Several employees asked among themselves why the pilot added oil, but no one asked the pilot himself.
Adding that much oil could have been a sign that the pilot was unfamiliar with a basic characteristic of the airplane – a fact covered in the POH the training pilot said the accident pilot knew well. The oil dipstick is calibrated on each side for each engine, due to the location of the dipstick and the sump. Use one side of the stick to note the quantity if you pull it out of the left engine and the other side if you pull it out of the right engine.
The two sides of the dipstick are offset, with the full mark on the side for the right engine farther from the tip of the dipstick than on the right. In other words, if the left engine is full of oil, it will read full on the left engine side of the dipstick but nearly two quarts low on the right engine side of the dipstick.
Operating the engine with the oil sump overfilled would have blown oil out of the engine breather tube, which could put oil on the exhaust pipes as well as make a general mess, but reps from Lycoming and Piper said it should not represent an operational hazard.
Loss of Control
The pilot taxied to runway 36 and was cleared for takeoff and a right turn on course. Two minutes later, he radioed, Tower, I gotta return. I got an engine problem.
The controller asked him if he needed assistance, and the pilot responded he did not. The controller cleared him to make left traffic to runway 36 and advised him that the winds were from 330 to 030 at 7 knots. The controller told the pilot he was cleared to use runway 31 as well.
The airplane turned toward a left downwind and leveled off at 1,050 feet agl and a groundspeed of 156 knots. The radar track shows the airplane then descended 300 feet and picked up nearly 20 knots in the next 14 seconds. The airplane then crashed, killing the pilot.
A witness who was formerly a crash/rescue worker at the airport said he was at his house a quarter mile from the departure end of runway 36 when he heard the airplane depart. He said one of the engines sounded strange, as if it was not making full power, but it was not sputtering. The airplane was about 200 feet agl and puffs of white smoke were coming from the left engine.
The witness said the airplane turned toward the airport. It then entered a snap roll real hard to the right followed by a nose dive below the tree line.
A second witness said the airplane was flying very fast when it went into a left-hand wingover and dove toward the ground. A third witness said the airplane just didnt sound right, describing it as a giant saw in a saw mill that sounded like it was running out of gas.
A fourth witness, an engine mechanic, said he heard one engine running and the other engine making a popping sound that was like an engine not getting enough gas rather than one with an ignition problem.
The wreckage in this case was not particularly illuminating. There was no evidence of pre-impact engine malfunction on either engine, no hint of pre-impact control discontinuity and the elevators and rudder were rigged and trimmed within specifications. The impact signatures on both propellers were consistent with a flat impact with the ground, with some leading edge damage but primarily aft bending on the blades and hub.
The NTSB threw up its hands, blaming the crash on a loss of control for undetermined reasons. But there are some findings that are interesting, even if they had no bearing on the outcome here.
The pilots reported nervousness and apparent misinterpretation of the oil dipstick readings may indicate a high stress level, especially given the instructor pilots description of the accident pilot as cool. The president of the charter company said the accident pilot was engaged to be married, had a young child and two older children, and did not appear to be financially well off, supplementing his flying income with carpentry work. He had just taken this job, and given the stakes, may have felt he had to make it work.
Consider also the dynamics at play if the pilot, with low time in Chieftains, mistook smoke from an oil-overfill for an engine problem.
Witnesses in these kinds of events are notoriously unreliable, so talk of engine noises, snap rolls and wingovers may be misguided. However, interpreting the radar signature shows no sign the pilot stalled or dropped below the minimum controllable single-engine airspeed.
The fact that both sides of the elevator had been worked on may have given the airplane different pitch feel, particularly if a bolt was binding on the spar up to that point.
Consider, however, the results if the pilot got a bit behind the airplane with an uncertain engine. He did not secure and feather the engine, so apparently he was still troubleshooting the problem. As he turned toward the airport and flew downwind at 150 knots, he may have gotten a bit behind the airplane.
The handling of the PA-31 line is good, with some pitch sensitivity when operating at the forward or aft CG limits. That pitch sensitivity increases as the speed drops.
Recall the witness who described a right snap roll. A right snap roll could be entered by kicking full right rudder (as in to pick up a left wing that is low because the power is dropping?) at the same time as stalling the airplane with brisk aft elevator (as in overcontrolling an elevator that is no longer binding?).
Taken together, all of these elements paint a picture of a pilot that got a little behind at a critical juncture and perhaps was trying to consult an emergency checklist at the wrong time. Obviously the specifics will never be known.
But armchair quarterbacks have already figured out that, with 1,000 feet and 150 knots to work with, the pilot didnt need to feather the engine if, in fact, it was losing power. Reducing power on the good engine would have restored whatever control authority was lost if the left engine was losing power. Even cutting power to both engines and letting the props windmill would have left enough glide range to make the airport.
Without delving too deeply into speculation about an unknowable situation, this accident should remind you that those old saws about knowing the handbook and flying the airplane became clichs because they were conceived in wisdom.
Also With This Article
Click here to view “Piper PA-31-350 Profile.”