There Is a Parachutist in Front of You
On the 15th of June 2023, a light aircraft crashed into the runway at Aversi private airfield in Denmark. The aircraft, registered in Germany as D-EPRR, was a Cessna TU206G Stationair, a six-seater single-engine aircraft which had been converted to a turboprop (with a Rolls Royce 250 turboshaft) by Soloy Aviation Solutions. Later, it was converted again by Turbine Conversion Ltd to have a five-blade MT-Propeller with a Pratt & Whitney PT6 engine.
In the right seat was a flight examiner with 22,500 hours, of which 390 hours were on type. The student was a commercial pilot for piston-engined aircraft with 950 flight hours. He was also an experienced parachutist. That day, the pilot was flying with the examiner for a VFR skill test to obtain a class rating for the Cessna Single Engine Turbine.
A PT6 takes much longer to spool up than a piston engine and a big part of the conversion to a turbine engine involves getting used to the significant lag when increasing the engine power.
The pair started the day with a navigation flight from Holbæk (EKHB) to Aversi private airfield, during which they completed the first part of the skill test. They refuelled the aircraft and the flight examiner briefed the pilot on the next part of the skill test which they would carry out on the grass strip, including a forced landing (simulating landing after an engine failure) and an aborted landing/go around at low altitude. They planned to then fly to Kalundborg.
The pilot took off for a circuit at 1,000 feet. At the end of the downwind leg, the textbook point to pull the power for a glide landing, the pilot stepped through the emergency checklist for an engine failure. The flight examiner reduced the engine power to simulate a stopped engine, including feathering the propeller, which stops the propeller from windmilling and reduces the drag.
The pilot continued, establishing the Cessna on short final with low engine power. The examiner was impressed with how well the pilot was managing the engine-out landing and decided that this would be a good opportunity to abort the approach for a go around at low altitude.
He waited until they were about 30 feet above the ground, checking that the airspeed was still reasonable, before making the call out.
Der er en faldskærmsspringer foran dig på banen, du skal gå rundt.
“There is a parachutist in front of you on the runway, you must go around.”
There was no parachutist. There was no one on the runway. This was a technique that the examiner had used before on the skill tests, giving a plausible reason for aborting a landing at low-level, such as “There is an aircraft lining up in front of you, you must go around.” The pilot was an experienced parachutist, which may have been what brought this particular scenario to mind.
Part of the point of the test is creating a startle effect: it’s one thing to set up for a landing that you know you are going to abort, ready to put the power on and pull away. It’s another to deal with an unfolding emergency.
The pilot was, in fact, startled. Somehow he understood that there was a parachutist in the air, which, to be fair, is a logical place for a parachutist to be. He reacted to the situation, a parachutist creating a situation, rather than the command to go around. Possibly he was also thinking about the fact that the power was low and the propeller feathered. The report does not comment on whether the pilot understood that the parachutist was imaginary.
He decided that the best course of action was to fly under the imaginary parachutist. He pulled the throttle from low power to idle and lowered the nose.
Reducing the power from low to idle changed the propeller blade angle, which caused the propeller to act as an airbrake.
The six-seater Cessna with a large turboprop installation is a heavy beast and they began to sink rapidly. The examiner and the pilot both tried to arrest the unexpectedly steep descent by pulling back on the control wheel, pulling the nose into the air, but they didn’t have the power or airspeed to pull this off. The Cessna fell the remaining fifteen feet onto the runway.
The nose landing gear collapsed on impact and was pushed up through the wheel well. The propeller struck the ground, bending and breaking the blades. The aircraft skidded forward and then came to a halt.
From the final report (in Danish)
Conclusions
The student pilot misunderstood an instruction to abort the landing and retarded the throttle to idle, which led to an increased rate of descent.
The low flight altitude made it impossible for the flight instructor to prevent a hard landing on the runway in time, whereby the aircraft was involved in an accident.
I’ve worked from a machine translation of the report but the phrasing is clear enough to conclude that the misunderstanding wasn’t specific to Danish. The phrase used was på banen, meaning on the runway, but the pilot somehow understood it as i luften, in the air. The investigation concluded that the problem was much more the front loading of the parachutist, faldskærmsspringer combined with foran dig, in front of you/ahead of you. This initial information could be interpreted as an airborne parachutist hazard; parachutists do not normally stand on runways. Once the pilot had this mental model of an upcoming hazard, he reacted without correctly parsing the rest of the statement (on the runway, go around).
It is for this reason that the ICAO and Eurocontrol (European Organisation for the Safety of Air Navigation) recommend that when calling for the landing to be aborted, that instruction should be given first, followed by the reason. For Air Traffic Control, the instruction is to only give the reason if time allows. It is the least important piece of information being imparted at that moment.
The report barely touches on this, but I think the fact that the pilot was converting from piston engines to turbine is a strong contributing cause. The slow-reacting turbine engine adds clear risk to the scenario shifting from landing under low power to a low-altitude go around. The instructor would not be able to quickly correct the amount of engine power available to them.
The report says that the instructor could have mitigated the risk by covering the throttle before calling for a go around at low altitude to stop the pilot from reducing the power further. However, this seems an odd point: if the pilot had understood correctly, he would have pushed the throttle forward, so that the engine would spool up and add power as they were climbing away. I can’t see why the instructor would have guarded the throttle.
The instructor said later that the pilot probably could have landed the aircraft safely if it had been a piston engine.
Radiotelephony skills are not always taken as seriously as they could be and when in the air, variations are frequently used. I thought this was an interesting reminder that not adhering to those principles can have unexpected effects.
“…that instruction should be given first, followed by the reason.”
Conversely, conditional instructions/clearances should always be given as condition then clearance. E.g., “after the short-finals Cessna, cross runway 35”. That’s in case the transmission gets cut off or stepped on.
It’s a rule I’ve been surprised to hear controllers, including ones I knew to be very experienced, break on a number of occasions.