French investigators have underlined the importance of rigorous training for operations at altiports – airports in mountainous terrain – after a Pilatus PC-12 collided with the steep runway slope at Courchevel.
The airport has been the scene of a number of accidents in recent years, including a similar strike by another PC-12 from the same company, EAPC, in 2017.
French investigation authority BEA says the occurrences demonstrate the extent to which altiport approaches demand specific skills, including use of visual cues, flightpath and power management, and precision piloting.
“For a pilot unaccustomed to flying in mountainous environments, several flights in varied conditions are necessary to acquire these skills,” it states.
BEA points out that, while French regulations define training topics to obtain altiport authorisation, the exact content, duration and quantity of landing practice is determined by instructors.
Instructor assessment of the pilot’s abilities and experience before training commences is “therefore essential”, it adds.
The PC-12 had been inbound from Brussels Charleroi to pick up seven passengers on 17 February last year.
Its crew of two pilots, the only occupants, planned a 5% approach path – approximately equivalent to a 3° descent – to runway 22.
Courchevel presents a challenging approach, because the short runway features a steep upward slope of 18.6% at the threshold.
After checking the runway condition and windsocks, the crew aligned the aircraft with the approach at 7,000ft and 2.4nm from the threshold, which has an altitude of 6,371ft.
But the descent, initiated at 1.6nm, was late and this forced the captain to adopt a steeper glidepath than the 5% intended. The PC-12, travelling at 85kt, descended at 700ft/min and dipped beneath the 5% glidepath at 0.75nm.
Although the descent rate was reduced to 300ft/min, the aircraft sank to 6,354ft – beneath the threshold altitude.
“At no time on final approach should the aircraft pass below the runway threshold altitude,” states BEA.
The captain increased the aircraft’s attitude while reducing engine power, and both the main and nose landing-gear collided with the slope. Its left-hand main gear fractured and the aircraft bounced several times, veering gradually to the left. The left wing-tip hit a snowdrift at the runway edge, separating the wing at the root, and spinning the aircraft by 180°.
Propeller blades also broke off during the impact and were thrown “several dozen metres”, says BEA.
The inquiry says the captain had “limited experience” with mountain and altiport flying from Courchevel.
Given this lack of experience, it adds, the duration of the pilot’s practical training for access authorisation to the airport “seems low”.
EAPC has since restricted operation to altiports to captains who have acquired a specific mountain qualification, and introduced additional training for those who hold such qualifications. It has also taken a number of other measures to reduce operational risk.
