Aircraft Engine Turbo Trouble

What do you do on a flight far from home if the engines not running right but no one can fix it?

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Airplane ownership is not for the faint of heart. In addition to the responsibilities coming with the financial commitment to acquire, operate and maintain an aircraft, theres the decision-making and judgement calls one must make, even before the first flight of the day. These decisions become especially difficult when paired against possible consequences of missing an important business meeting or failing to fulfill a personal commitment, to name but two.

And, since an airplane is designed to go places, the ownership burden often becomes more complicated when, at a distant airport, a mechanical problem rears its ugly head. In such a situation, prudence often requires contracting with a facility or person whose skill and dedication isnt known to you. Frequently, conflicting schedules means a maintenance facility cant find the time to perform a detailed diagnosis of a transient airplanes troubles before the pilot is scheduled to leave. One result is attempting to fly an airplane with known deficiencies.

Its easy to climb on a soapbox and declare, as does the FAA, no airplane should ever leave the ground unless everything in and on it is in working order. But the real world doesnt work that way (neither, it should be noted, does the FAA). The reality is people fly airplanes with certain equipment inoperative or malfunctioning. Most of the time, nothing happens, especially if the equipment-deicing boots, as an example, or navigation lights-isnt needed during the flight. Sometimes, of course, it gets exciting. Somewhere between the two extremes, pilots often try to nurse home an ailing airplane, where the mechanics, pricing, parts availability and downtime, if not known quantities, at least are more manageable. Depending on the mechanical problem, that course of action may be a sound one. One of the keys, though, is knowing what the problem is.

Background

On April 22, 2006, at about 1252 Central time, a Mooney M20K was destroyed during a forced landing following a reported loss of engine power. The airplane had just departed the Golden Triangle Regional Airport (GTR), near Columbus, Miss. The solo commercial pilot and owner sustained fatal injuries. Visual conditions prevailed for the planned IFR flight to Omaha, Neb.

The pilot arrived at GTR on April 16, 2006. During his stay in Mississippi, he asked a mechanic to examine his airplane, complaining it wasnt making sufficient power. The mechanic conducted a visual inspection, which revealed no obvious anomalies. An engine runup was not performed. Meanwhile, the pilot contacted a shop in Omaha, stating he observed a lack of turbocharger boost at altitude while on his trip to GTR. He requested the shop to “look into” the turbocharger problem upon his return. The pilot added that he would do a ground run before his departure from GTR.

A review of the airport security camera tapes reveals the accident airplanes engine was started about 1232, with takeoff at 1247.

Investigation

The airplane was first observed on radar shortly after takeoff, at 300 feet msl. The airplane climbed at an airspeed of approximately 90 knots until reaching 1000 feet agl. The airplane then descended to 900 feet agl before a right turn was initiated back towards GTR. The airplane continued to descend at an airspeed of between 80 and 90 knots until below 200 feet msl when radar contact was lost.

The main wreckage came to rest in tall grass at the northeast corner of a freshly planted cornfield, approximately 4054 feet north of the departure end of GTRs Runway 36. There was no post-impact fire; all major components were accounted for at the accident site. After turning around and before impact, the pilot elected to fly back to GTR across a four-lane highway and an open field in an attempt to reach the airport.

A complete teardown of the Teledyne Continental Motors TSIO-360-GB engine was performed by Continental. Overall and except for obvious damage suffered in the crash, the engine was in good operating condition. Its magnetos made spark, the cylinders did not display wear and the oil filter did not contain metal. In particular, the turbocharger revealed no visible damage to the turbine, center or compressor housings. No exhaust leak signatures were noted. No other anomalies were found with the turbocharger.

The wastegate was examined by its manufacturer, revealing no apparent leaks, failed internal components or anomalies that would have prevented normal operation before impact. In fact, nothing, including contaminated fuel, could be identified as a reason for engine failure.

Probable Cause

The National Transportation Safety Board determines the probable cause(s) of this accident to include: “The loss of engine power for undetermined reasons. A contributing factor was the pilots improper decision to forgo suitable forced landing opportunities in an attempt to return to the airport.”

Its tough to second-guess this pilots decision to depart for home in an airplane with a known mechanical problem. On one hand, a local mechanic couldnt find anything wrong with the engine. After the fact, including a complete teardown and inspection, neither could its manufacturer. The pilot even discussed the problem with his back-home shop, apparently following its recommendations and with the intent to have them look at it upon his return.

In hindsight, grounding the airplane and asking for a more thorough inspection might have found the problem. But wed judge that outcome unlikely, given what we know about the post-crash investigation and about getting maintenance done away from home.

The NTSB faulted the pilot not for flying the airplane but for overflying a four-lane highway and an open field in his attempt to reach the airport. In some ways, his actions are understandable: It was his personal airplane; putting it down off-airport risked damage. In reality, though, it wasnt his any longer: Once the engine failed, it belonged to the insurance company. They were just letting him land it.

If we waited until everything on the airplane is working perfectly, wed have huge maintenance bills and limited use of it. This pilot did what many of us would have done-attempt to fly the ailing airplane home where it can receive proper attention. Most of the time, that plan works. This time, it didnt. On the other hand, if hed tried to land on the highway, we might not be writing about him.

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