Incident Details
On 7 July 2001 at 1515 local time, a privately operated Yakovlev Yak-52, registration LY-ANS, executed a landing on runway 23 at Gullknapp flyplass, Arendal, Norway. The flight originated from Skien lufthavn Geiteryggen. The pilot, a 31-year-old male holding a Private Pilot License (PPL-A) with 661 total flight hours (14 hours on type in the preceding 90 days), reported a normal approach and landing. Crossing the runway threshold at 120 km/h, the aircraft touched down in a three-point attitude. The pilot applied hard pumping brake action. Shortly thereafter, all braking effect was lost, described by the pilot as "fading." He steered the aircraft using rudder toward the side of the runway, intending to reach the gravel shoulder for increased friction. The aircraft departed the paved surface at approximately 30 km/h. With no steering or braking remaining, it continued across the gravel shoulder and down a rocky slope before coming to a stop against rocks and flipping onto its back. The canopy was shattered, but the pilot was able to exit uninjured. He immediately contacted police via emergency number 113.
Aircraft Information
The Yak-52 (manufactured 1986, engine Aerostar V-M14P) is a Russian-designed trainer built under license in Romania. It was registered in Lithuania and was to be repaired there. The aircraft is equipped with a pneumatic brake system, common to Russian designs and similar to older British types such as the Spitfire and Vampire. A compressed air reservoir, charged during flight, supplies the brakes, landing gear, and flaps. Braking is applied via a handle on the control stick; with centered rudder pedals, pressure is distributed equally to both main wheels, while forward pedal deflection directs more pressure to one side.
Investigation Findings
Post-accident examination by the police included measurements, pilot interview, and photography. At the request of the Accident Investigation Board (HSL), a functional check of the brake system was performed, which operated normally. The aircraft sustained extensive structural damage to the propeller, nose gear leg, canopy, tailfin, and left wing tip. Runway 23 is asphalt, 500 m long by 15 m wide, with a landing distance available (LDA) of 470 m. The aircraft's calculated landing mass was approximately 1,150 kg. An amateur video of the landing showed three-point touchdown, a delay before braking began, and then vigorous braking with blue smoke from the main wheels, indicating heavy brake application. The measured braking skid marks began 212 m from the start of runway 23 and extended about 280 m to the asphalt edge, then continued 10 m on gravel and 10 m down the rocky slope, for a total rollout of about 290 m. The pilot stated he used the recommended technique of pump braking.
Probable Cause
The HSL determined that overheating of the brakes, caused by hard braking, resulted in brake failure. The pilot had identified "fading"/heat as the cause of the brake failure, and the HSL supported this assessment.