Grumman G-164B CS-ASN Accident at Barrosinha, Portugal

Overview and Flight History On 9 July 2009, at 10:25 local time, a Grumman G-164B biplane, registration CS-ASN, operated by AGROAR – Trabalhos Aéreos Lda., landed at the Barrosinha airfield near Alcácer do Sal, Portugal. The aircraft was returning to the runway to reload agricultural product after a work flight. During the flight, the pilot selected the parking brake to the “on” position, which locked the main landing-gear wheels. ## Accident Sequence At the start of the landing, when the main wheels touched the runway, the aircraft showed a tendency for the nose to drop. This behavior alerted the pilot to the parking brake being in the “on” position. The pilot immediately attempted to release the brakes by pressing the pedals, but the attempt was unsuccessful. The aircraft then overturned and came to rest inverted. The pilot exited the aircraft uninjured. ## Aircraft and Operator The aircraft was a single-engine, taildragger biplane manufactured by Grumman American Aviation, with a maximum takeoff mass of 3,184 kg and capacity for one crew member. It was powered by a Pratt & Whitney R-1340-AN1 engine and fitted with a Hamilton Standard 12D40-401 propeller. The airframe serial number was 812B, and the aircraft had 5,908 total flight hours. The operator, based at Évora Municipal Aerodrome, held an Air Work Operator Certificate (COTA) and a JAR-145 maintenance certificate. ## Damage and Survival The aircraft sustained visible damage to the vertical fin, propeller, upper surfaces of the wings, the right wing front spar, the right upper wingtip, and structural components. No third-party damage was recorded. The pilot was the only person on board and suffered no injuries. The safety belts and the robustness of the cockpit contributed to the pilot’s safe egress. No fire occurred. ## Investigation Findings The investigation established that the pilot held the required licenses and qualifications, and the aircraft was maintained in accordance with applicable regulations. The pilot had activated the parking brake in flight, and it remained in the “on” position at the time of landing. The propeller blades struck the gravel runway and were damaged, reducing their thrust capability and preventing the pilot from discontinuing the landing. The accident was caused by the main landing-gear wheels being locked at the moment of landing, with the inadvertent activation of the parking brake in flight identified as a contributory factor. No safety recommendations were issued.