Accident Sequence
On 22 April 1997 at 19:17 local time, a Yakovlev JAK-52, registered LY-AIX, experienced an accident at Alytus aerodrome, Lithuania. The aircraft was operated by the Alytus Aero Club and piloted by a Finnish citizen. That day, the club was conducting circuit and area flights with a group of Finnish pilots. An instructor pilot (pilot B) performed five control flights and authorized pilot A to fly solo. The aircraft had previously been flown by pilot C from 18:35 to 18:57, who after landing completed all post-flight actions, including closing the air system valve.
Pilot A started the engine at 19:09 and took off at 19:14 for a solo circuit flight. The flight proceeded normally, and before the third turn, pilot A reported ready to land and received clearance. The landing was performed on three points—without raising the nose wheel. After touchdown, the nose landing gear strut began to retract rearward (toward the retracted position). Approximately 35 meters from the touchdown point, the propeller began contacting the ground, and 10 meters further, the engine touched down. The aircraft continued to plow through the ground with the engine for another 35 meters before stopping. The total ground roll from touchdown to full stop was 80 meters.
Aircraft and Pilot Information
The aircraft was a Jakovlev 52 (JAK-52), registration LY-AIX, serial number 866802. It was manufactured in Romania on 30 July 1986 and underwent a repair on 9 March 1989 at Shakhty Aviation Repair Plant (Russia). Total time since new was 499 hours 46 minutes, with 2,130 landings. Since the last repair, the aircraft had flown 69 hours 59 minutes with 301 landings. The engine was a M-14P, serial number KH 622010, manufactured by Voronezh Aviation Plant, Ukraine, with a total time of 506 hours 46 minutes (overhaul life 730 hours). The aircraft used AVGAS 100LL fuel (80 liters) and MS-20 oil. Weight and balance were within limits. The aircraft had undergone a special 50-hour check after deconservation on 17 April 1997 and was test-flown on 21 April 1997.
The pilot was born in 1953, held a Finnish private pilot license issued in 1995, with endorsements for day VFR and as pilot-in-command of aircraft up to 2,000 kg MTOW. Total flight time was 1,500 hours, with 50 hours on type (0 hours 31 minutes in the previous 90 days). The pilot was wearing lap and shoulder harnesses; no seat or harness damage was noted.
Meteorological Conditions
Weather was simple visual meteorological conditions: cumulus clouds at 3 oktas (1,500 m), wind 300°/1-2 kt, visibility 10 km, QNH 736 mmHg (981 hPa). Weather had no influence on the outcome.
Injuries and Damage
No persons were injured. The aircraft sustained substantial damage: one propeller blade completely broken, the other half-broken; deformed engine mount, exhaust pipes, lower cowling; broken nose gear traverse mounting bracket and frame; deformed oil and header tanks; fuel filter and fire valve block; and other components. The landing gear retraction/extend system, including locking and signaling, functioned normally during post-accident tests despite partial nose gear damage.
Investigation Findings
The investigation commission could not determine an objective and undisputed cause for the nose landing gear retraction after landing. Examination of the accident site and aircraft revealed that the nose gear strut had retracted rearward. After the accident, when the aircraft was evacuated by raising the nose, the nose gear strut forcefully extended and locked in the down position, and the air system valve was found open. However, the commission could not conclusively establish when the valve was opened—before the flight or after the accident. The pilot reported that the landing gear was down and three green lights were illuminated before landing. Nevertheless, tire marks at the touchdown point indicated that the nose wheel touched down first, contrary to the pilot's statement of a main-wheel-first landing. The commission's analysis hypothesized that the gear retraction may have been caused by the flight being conducted with the air system valve closed, but this was not confirmed as a definitive cause.
Probable cause: The investigation was unable to determine an objective and incontrovertible reason for the nose gear retraction after landing.