On the fifteenth of June 2023, a lightweight plane crashed into the runway at Aversi non-public airfield in Denmark. The plane, registered in Germany as D-EPRR, was a Cessna TU206G Stationair, a six-seater single-engine plane which had been transformed to a turboprop (with a Rolls Royce 250 turboshaft) by Soloy Aviation Options. Later, it was transformed once more by Turbine Conversion Ltd to have a five-blade MT-Propeller with a Pratt & Whitney PT6 engine.
In the correct seat was a flight examiner with 22,500 hours, of which 390 hours have been on kind. The coed was a business pilot for piston-engined plane with 950 flight hours. He was additionally an skilled parachutist. That day, the pilot was flying with the examiner for a VFR talent check to acquire a category score for the Cessna Single Engine Turbine.
A PT6 takes for much longer to spool up than a piston engine and an enormous a part of the conversion to a turbine engine includes getting used to the numerous lag when rising the engine energy.
The pair began the day with a navigation flight from Holbæk (EKHB) to Aversi non-public airfield, throughout which they accomplished the primary a part of the talent check. They refuelled the plane and the flight examiner briefed the pilot on the following a part of the talent check which they’d perform on the grass strip, together with a pressured touchdown (simulating touchdown after an engine failure) and an aborted touchdown/go round at low altitude. They deliberate to then fly to Kalundborg.
The pilot took off for a circuit at 1,000 toes. On the finish of the downwind leg, the textbook level to drag the ability for a glide touchdown, the pilot stepped by way of the emergency guidelines for an engine failure. The flight examiner decreased the engine energy to simulate a stopped engine, together with feathering the propeller, which stops the propeller from windmilling and reduces the drag.
The pilot continued, establishing the Cessna on quick remaining with low engine energy. The examiner was impressed with how nicely the pilot was managing the engine-out touchdown and determined that this could be a very good alternative to abort the method for a go round at low altitude.
He waited till they have been about 30 toes above the bottom, checking that the airspeed was nonetheless cheap, earlier than making the decision out.
Der er en faldskærmsspringer foran dig på banen, du skal gå rundt.
“There’s a parachutist in entrance of you on the runway, you have to go round.”
There was no parachutist. There was nobody on the runway. This was a way that the examiner had used earlier than on the talent assessments, giving a believable motive for aborting a touchdown at low-level, similar to “There may be an plane lining up in entrance of you, you have to go round.” The pilot was an skilled parachutist, which can have been what introduced this specific state of affairs to thoughts.
A part of the purpose of the check is making a startle impact: it’s one factor to arrange for a touchdown that you already know you’re going to abort, able to put the ability on and draw back. It’s one other to take care of an unfolding emergency.
The pilot was, the truth is, startled. One way or the other he understood that there was a parachutist within the air, which, to be truthful, is a logical place for a parachutist to be. He reacted to the state of affairs, a parachutist making a state of affairs, slightly than the command to go round. Probably he was additionally desirous about the truth that the ability was low and the propeller feathered. The report doesn’t touch upon whether or not the pilot understood that the parachutist was imaginary.
He determined that the perfect plan of action was to fly below the imaginary parachutist. He pulled the throttle from low energy to idle and lowered the nostril.
Lowering the ability from low to idle modified the propeller blade angle, which precipitated the propeller to behave as an airbrake.
The six-seater Cessna with a big turboprop set up is a heavy beast and so they started to sink quickly. The examiner and the pilot each tried to arrest the unexpectedly steep descent by pulling again on the management wheel, pulling the nostril into the air, however they didn’t have the ability or airspeed to drag this off. The Cessna fell the remaining fifteen toes onto the runway.
The nostril touchdown gear collapsed on impression and was pushed up by way of the wheel nicely. The propeller struck the bottom, bending and breaking the blades. The plane skidded ahead after which got here to a halt.
From the ultimate report (in Danish)
Conclusions
The coed pilot misunderstood an instruction to abort the touchdown and retarded the throttle to idle, which led to an elevated charge of descent.
The low flight altitude made it not possible for the flight teacher to stop a tough touchdown on the runway in time, whereby the plane was concerned in an accident.
I’ve labored from a machine translation of the report however the phrasing is obvious sufficient to conclude that the misunderstanding wasn’t particular to Danish. The phrase used was på banen, that means on the runway, however the pilot in some way understood it as i luften, within the air. The investigation concluded that the issue was far more the entrance loading of the parachutist, faldskærmsspringer mixed with foran dig, in entrance of you/forward of you. This preliminary data may very well be interpreted as an airborne parachutist hazard; parachutists don’t usually stand on runways. As soon as the pilot had this psychological mannequin of an upcoming hazard, he reacted with out appropriately parsing the remainder of the assertion (on the runway, go round).
It is because of this that the ICAO and Eurocontrol (European Organisation for the Security of Air Navigation) suggest that when calling for the touchdown to be aborted, that instruction ought to be given first, adopted by the explanation. For Air Site visitors Management, the instruction is to solely give the explanation if time permits. It’s the least essential piece of knowledge being imparted at that second.
The report barely touches on this, however I feel the truth that the pilot was changing from piston engines to turbine is a robust contributing trigger. The slow-reacting turbine engine provides clear danger to the state of affairs shifting from touchdown below low energy to a low-altitude go round. The teacher wouldn’t be capable to shortly appropriate the quantity of engine energy accessible to them.
The report says that the trainer might have mitigated the chance by masking the throttle earlier than calling for a go round at low altitude to cease the pilot from lowering the ability additional. Nevertheless, this appears an odd level: if the pilot had understood appropriately, he would have pushed the throttle ahead, in order that the engine would spool up and add energy as they have been climbing away. I can’t see why the trainer would have guarded the throttle.
The teacher mentioned later that the pilot most likely might have landed the plane safely if it had been a piston engine.
Radiotelephony abilities are usually not all the time taken as severely as they may very well be and when within the air, variations are ceaselessly used. I believed this was an attention-grabbing reminder that not adhering to these ideas can have surprising results.
