Flight History
On Monday, 18 July 2005 at 17:47 local time, a student pilot on his second solo flight took off from runway 21 at Salamanca Airport in a Socata TB-10, registration EC-FSP. The takeoff run was normal with all engine parameters normal. The aircraft rotated at about 70 knots and climbed at 80 knots. At an altitude of 2,800 to 2,900 feet above mean sea level (airport elevation 2,595 feet), the pilot detected a smell of smoke and initiated a right turn. Requesting authorization to enter the downwind leg, he noted a gradual loss of thrust when at 3,200 to 3,400 feet in the crosswind, which quickly progressed to a total loss of power. The pilot declared an emergency and headed for a nearby field, performing an emergency landing in a recently harvested wheat field.
The aircraft traveled about 120 meters over the field before coming to a stop after the nose landing gear collapsed and the propeller hit the ground. The pilot, who had inhaled some fumes entering the cockpit, was not injured but was taken to a medical center for examination, which revealed no problems.
Aircraft and Damage
The aircraft, operated by Adventia, was a single-engine Aerospatiale Socata TB-10 (serial number 1561) with a Lycoming O-360-A1AD engine. The student pilot, aged 19, held a Student Pilot license and had 31:50 total flight hours, all on the type.
Major damage was observed to the nose landing gear, propeller, and forward lower fuselage. The left lower side of the engine cowling was perforated due to fire or heat, creating a hole about 30 cm long. Smoke traces were found in the fuselage, and a bundle of electrical wires had melted. The engine firewall was deformed.
Exhaust System Findings
Inspection of the engine compartment revealed that the clamp of the left front exhaust pipe was loose and the pipe had detached from its normal position in the muffler. The pipe end had rotated, directing hot exhaust gases against the interior of the engine cowling. Additional exhaust flow from the muffler entrance affected another forward zone of the cowling.
One propeller blade was undamaged, indicating the engine was not rotating when the other blade, bent rearward, struck the ground. After the accident, the power, propeller, and mixture levers were found full forward in the cockpit. The cabin air cooling and demisting levers were fully open, and the external air scoop on the pilot side was found open.
The TB-10's exhaust system consists of four manifold pipes channeling exhaust to a single pipe through a muffler. The detached pipe was the forward left cylinder exhaust manifold, secured by a single-screw stainless steel clamp. There had been a history of exhaust pipe detachments in TB-10 aircraft, leading to Airworthiness Directive AD 92-206(A)R3 requiring compliance with Socata Service Bulletin SB 10-073 Amendment 2, which specified seal replacement and torque values for the upper mounting flange. Maintenance records showed the aircraft had complied with SB 10-073 in June 1994. The clamp in question was last disassembled and reassembled on June 14, 2005 during an engine change, and re-tightened on July 13, 2005 during a 50-hour inspection after being found loose. The accident occurred on July 18, 2005, after 64 additional flight hours.
The manufacturer stated they were not aware of any other exhaust manifold detachments after compliance with SB 10-073 Amendment 2, except one case in a French TB-9 in November 2000, cause unknown. The thermal protection blanket on the cowling was perforated during the accident; the manufacturer was not aware of previous cowling perforation from exhaust after manifold detachment.