1970 Piper PA-30 Collision at Geneva-Cointrin Airport (HB-LDE)

Accident Overview and Investigation Approval On 13 August 1970 at 2000 local time, a Piper PA-30 “Twin-Comanche B” registered HB-LDE collided with a parked Piper PA-30 “Twin-Comanche” registered G-ATYR at Geneva-Cointrin Airport. The Swiss Federal Commission of Inquiry into Aircraft Accidents approved its investigation report of 15 October 1970, with one amendment, by circulation on 15 February 1971. The aircraft was operated by Aeroleasing SA of Geneva-Aéroport and had been built by Piper Aircraft Corp. in 1966, factory number 30-1121. ## Sequence of Events After landing on runway 23, the sole occupant taxied toward the light-aircraft parking area beside the large hangar. The pilot kept the engines at 1400 rpm, which required light braking to maintain normal taxi speed. On the parking platform, the pilot turned left past a row of parked aircraft. A vacant space was available beside the last aircraft in the row, G-ATYR. To align with that space, the pilot made a sharp 180-degree left turn, increasing right-engine rpm considerably and applying the left brake to reduce the turning radius. The left brake did not respond. The aircraft continued its turn, and the pilot cut the ignition but could not avoid striking G-ATYR. ## Damage and Findings The pilot was not injured. HB-LDE sustained dented and torn leading-edge skin on the right wing over about 80 cm, with estimated damage of about Fr. 12,000. G-ATYR, owned and operated by Executive Flying Service Ltd. of Southend-on-Sea, Essex, England, had serious damage to its left wing near the aileron, a fuselage bend leftward at the rudder, and a damaged elevator, with estimated damage of about Fr. 26,000. ## Technical Observations Before the aircraft was moved, the investigator found that the left brake pedal offered no resistance to the end of its travel; after several applications, the pedal travel was reduced. Brake fluid in the reservoir was sufficient. A slight brake-fluid leak was later found at the bleed fitting of the left wheel brake cylinder. The brake segments were heavily worn and partially crumbled. They were part number 752 342, originally installed by Piper on this type up to serial number 30-846; Piper later installed harder, more wear-resistant metal segments, part number 752 335. The manufacturer approved both segment types for replacement. The brake disc thickness was within tolerances. The brakes had been checked and the segments changed on 2 November 1969; 46 flight hours and 123 landings had been made since. ## Discussion and Conclusion The pilot held a first-class commercial pilot licence issued by the Federal Office of Civil Aviation on 2 April 1970, with multi-engine piston and night extensions, and had 1,110 total hours, including 496 on the Piper PA-30. The aircraft had been regularly maintained by authorized enterprises. The investigation concluded that the collision was attributable to excessive taxi speed and failure of the left-wheel brake during the final phase of the parking maneuver.