Synopsis
On 26 October 1988 at 0821 UTC, a Learjet 31, registration N311DF, departed Zurich-Kloten for a demonstration flight with a potential customer. The responsible pilot, a professional pilot with instructor endorsement for the type, occupied the right seat. The customer, who was not type-rated and had limited jet experience, flew from the left seat. Two employees of the manufacturer were also on board. The flight included an intermediate landing at La Chaux-de-Fonds/Les Eplatures. Weather was good, with calm wind and a dry runway. At 0900 UTC, during the landing on runway 24, the aircraft touched down hard approximately 50 meters after the threshold, near the centerline, with a high rate of descent, resulting in substantial damage. No injuries were reported.
Flight History
The demonstration tour was arranged by the manufacturer's international sales office. The customer, who owned a Cessna Citation I Eagle and a Cheyenne II XL, had requested performance data for the Learjet 31 at the Les Eplatures aerodrome. The aircraft had been ferried from Wichita to Zurich on 24-25 October. On the evening of 25 October, the captain and sales manager discussed the next day's itinerary. The captain had studied each airfield, but information on Les Eplatures was limited. On 26 October, the crew met at the airport around 0700 UTC. The captain briefed the customer on systems and performance for 45 minutes. The customer expressed reluctance about flying the approach due to his lack of experience, but was encouraged by the captain. The flight departed Zurich at 0821 UTC, climbed to FL 510, and performed maneuvers before descending toward Les Eplatures.
Accident
The approach to Les Eplatures was flown by the customer under direction from the instructor. The aerodrome had no instrument approach aids. The approach path had a 4° glide slope due to obstacles, and the runway had an uphill slope. As the aircraft crossed the threshold, it had a high rate of descent and a pronounced nose-high attitude. The instructor reduced engine power just before touchdown. The aircraft contacted the runway hard, causing significant structural damage. The landing occurred on the centerline, 50 meters past the threshold of runway 24.
Probable Cause
The accident was due to an abnormally high rate of descent resulting from a combination of a very nose-high attitude and a reduction of engine power just before touchdown.
Contributing Factors
The investigation identified several contributing factors:
- The aircraft was flown by a pilot not qualified on the type, with limited jet experience.
- The available runway length was at the limit of the aircraft's performance.
- The approach was steep (4°) due to obstacles.
- The terrain configuration and the uphill slope of the runway.
- The instructor's preoccupation with the demanding approach, which was outside his usual operating conditions.
- A lack of coordination between crew members in the final phase of flight.