History of the Flight
The pilot departed Cayenne-Félix Éboué airport at 12:58 local time with a cargo of foodstuffs, bound for Maripasoula aerodrome. After about 50 minutes of flight at a mean cruise altitude of 3,100 ft, the pilot began the descent to Maripasoula. He leveled off at approximately 850 ft and entered the right-hand downwind leg for runway 07. The pilot positioned the power lever to achieve 20 PSI, activated the booster pump, and began extending the flaps (four turns of the handle). He then made a left-hand turn to increase distance from the runway before starting the final descent. He began the final descent at around 800 ft and executed a large continuous 180° turn to align with the runway axis. At the start of the final approach, at about 520 ft, the indicated airspeed (IAS) was approximately 61 kt.
On short final, the pilot extended the flaps to nearly full deployment and verified their position. Speed progressively decreased, and a few seconds later, the pitch attitude increased to around 12°. The IAS dropped to 53 kt and continued to a minimum of 46 kt. The pitch attitude oscillated, reaching a maximum of 14° before suddenly decreasing. The pilot lost control of the aeroplane, which collided with the ground and came to rest on the left side of runway 07.
Wreckage and Site Information
The wreckage was located 20 m left of the runway 07 centreline and about 160 m from the threshold. The cargo, weighing 1,069 kg after the accident, had shifted due to impact, preventing precise load distribution determination. The left fuel tank gauge indicated less than 90 l; the right tank was empty due to a leak after the right wing was partially torn off. The cockpit trim indicator was found in position 2 (slightly nose-up). Flap position corresponded to approximately ten turns of the handle (maximum eleven and a half). Flight controls were continuous and functional on all three axes. The propeller examination indicated engine torque (moderate to high power, no feathering) at impact.
Weight and Balance
The cargo weighed 1,060 kg before loading, consistent with post-accident measurements. The pilot provided a weight and balance sheet after the accident, showing an aft centre of gravity within limits and weight slightly below maximum landing weight. However, the actual centre of gravity could not be determined due to cargo shift. Based on various hypotheses, Pilatus stated the aeroplane was close to weight and balance limits (aft centre of gravity, maximum landing weight) at landing.
Meteorological Information
Météo-France reported easterly wind of 3 to 5 kt with gusts up to 10 kt, few clouds, no precipitation, temperature 30°C, and sea-level pressure 1013 hPa between 13:00 and 14:00. Maripasoula does not have METAR or TAF reports.
Aircraft Information
HB-FDU was a Pilatus PC-6/B2-H4 single-engine aeroplane with a maximum cabin load of 1,000 kg behind the front seats. Maximum take-off weight was 2,800 kg, maximum landing weight 2,660 kg. Stall speed in landing configuration (VS0) was 52 kt at maximum take-off weight and zero bank. The flap system was mechanical; take-off position required eight turns (28° deflection), full deployment eleven and a half turns (39°). The engine was a Pratt & Whitney PT6A-27 with a Hartzell four-blade propeller. Engine and propeller controls included a power lever, propeller lever, and an idle control with three positions: HIGH IDLE, LOW IDLE, and CUT-OFF. The idle control was found in LOW IDLE after the accident; its position during final approach could not be determined.
The aeroplane had about 11,690 flight hours and 10,937 cycles. The propeller had been installed during the last maintenance inspection; a 30-minute check flight before the accident revealed no anomalies. Maintenance documents and propeller photos showed no issues.
Normal before-landing procedure in the flight manual requires setting idle control to HIGH IDLE, extending flaps as required, trimming for 68 kt, and preselecting torque for a 3° glide slope. Some PC-6 operators reported that using flaps in take-off position with approach speed around 75 kt on longer runways reduces manoeuvring difficulty. Pilatus stated the aircraft can be landed with full flaps.
Pilatus indicated that flap deployment increases drag and nose-up torque, which with an aft centre of gravity may increase pitch attitude. The increased drag combined with high mass may have contributed to deceleration, and pilot recovery via power adjustment may have been slowed.
Aerodrome Information
Maripasoula aerodrome is near the Suriname border; the border is less than 800 m from the threshold of runway 07, requiring a short final to avoid overflying Suriname.
Pilot Information
The 48-year-old pilot held a commercial pilot licence (CPL(A)) since 2010 and a PC-6 SET rating since 2023. He had about 4,000 total flight hours, including 400 on the PC-6. He flew 45 PC-6 hours in the three months before the accident, with the last flight over a month prior. He held a valid class 1 medical certificate.
The pilot stated the client had been waiting weeks for the cargo.