Accident to the Jodel - D140 - C registered F-HJLB on 17/12/2021 at Superdevoluy mountain airstrip (Hautes-Alpes)

Cat. 3 investigation report: report concerning an occurrence with limited consequences, based on one or more statements not independently validated by the BEA.

This is a courtesy translation by the BEA of the Final Report on the Safety Investigation published in March 2022. As accurate as the translation may be, the original text in French is the work of reference.

Note: the following information is principally based on statements made by the pilot in instruction, the instructor, the second student and on the video from the mountain airstrip webcam. This information has not been independently validated by the BEA.

1 - HISTORY OF THE FLIGHT

The instructor carried out a dual command flight from Alpe d'Huez mountain airstrip, with one pilot in instruction and a second in the rear seat, with a view to obtaining the mountain “ski” rating. The pilot at the controls landed on Superdévoluy mountain airstrip and was unable to turn around on the platform. He stopped the engine, the three occupants got out and moved the plane by hand. The second pilot got into the left seat  and took off with the instructor in the right seat to perform two runway circuits, while the first student stayed on the ground and filmed the take-off.
After the first landing, the pilot made a right-hand turn on the airstrip, with the engine operating and in the take-off configuration. Just before the end of the turn, when the plane was offset to the left of the runway centreline, the pilot applied full power to take off. The aeroplane slid a few meters off the runway, heading for a post located several meters from the left edge of the runway. The instructor took the controls but was unable to avoid the collision. The left wing of the aeroplane struck the post. The instructor continued the take-off, performed an adapted runway circuit and, after some checks, returned to land.

2 - ADDITIONAL INFORMATION
2.1 Material damage

After the landing, the occupants found that the leading edge of the left wing had been substantially damaged by the collision with the post.

2.2 Mountain airstrip information

Dévoluy mountain airstrip has a runway oriented 03/21[1]. Landings are carried out on runway 21 and take-offs on runway 03. According to the occupants of the aeroplane, the left side of the runway has a slight downward slope in the direction of take-off. The runway was covered with packed snow, which the instructor said was cold and not sticky.
At the top of the runway (on the left during the take-off), there is a windsock and a post, secured with chains, holding a webcam, a weather station and an anemometer[2]. At the time of the accident, there were no aircraft or vehicles parked at the top of the airstrip.

2.3 Pilot information

The 46-year-old instructor held a mountain instructor rating obtained in 2019. He reported having logged approximately 8,180 flight hours in total, of which 822 hours were on type and 83 hours in the previous three months, including 27 hours on type. During the summer, he had landed several times on the mountain airstrip on wheels. His last landing on skis was in April 2021. He explained that he belatedly perceived that the aeroplane had excess speed during the turn, which increased the turn radius.
The 68-year-old pilot in instruction, held a private pilot license for aeroplanes and a mountain wheel rating. He declared having logged about 310 flight hours in total, of which 175 hours were on type and six hours in the previous three months, all on type. In addition, he had logged approximately 285 landings on wheels and approximately 130 landings on skis, including 19 on a Jodel D140. He indicated that he had difficulty performing the turnaround and hesitated continuing the turn. He explained that the instructor thought it would pass. He added that because of the slight bank, the aeroplane began to slide and enter the slope after the turnaround.

2.4 Meteorological information

The instructor and pilot-in-training reported that the weather conditions were ideal for this flight: no wind, no turbulence, CAVOK, temperature near 0°C. The video footage taken by the second student at the time of take-off showed no wind and visibility greater than 10 km.

2.5 Ground handling of the aeroplane

The CEPADUES guide entitled Le vol en montagne expliqué au pilote (Moutain flight explained to pilots) (3rd edition) specifies that when manoeuvring on level ground on packed snow, only moderate engine power is required to slide and the rear ski remains effective to steer the aeroplane. Manoeuvring on the ground on skis is similar to that on wheels but with a larger turn radius and without braking.
When airstrips are narrow, it is recommended to turn towards the uphill side to maintain propeller traction and reduce the turn radius.
On snow-covered airstrips, the guide recommends that the pilot adopts large safety margins with respect to other aircraft and surrounding obstacles, and to stop and move the aeroplane by hand if the turn is difficult.