History of the Flight
On 15 March 2009, at approximately 11:25 UTC, a Tecnam P-92 Echo ultralight aircraft, registration CS-UJX, operated by Aero Clube de Alverca do Ribatejo, was preparing for a training flight at Lezíria airstrip in Porto Alto, Vila Franca de Xira. The sole pilot on board aligned the aircraft on runway 28 while still on the apron, intending to perform a short takeoff ("maximum performance" takeoff). He applied full brakes and set the engine to maximum takeoff power.
Before releasing the brakes, the aircraft suddenly yawed left, exited the runway at a 90-degree angle, and accelerated toward the hangar, approximately 30 meters away. The pilot did not have time to react before the aircraft struck the closed hangar doors, causing the engine to stop and the aircraft to come to rest. The pilot shut down all systems and exited the cockpit unaided.
Injuries and Damage
The pilot, the sole occupant, sustained no injuries. The aircraft suffered severe damage to the propeller, engine, wings, fuselage, and landing gear, calling into question its repairability. The hangar doors were torn from their mounting structure and suffered significant damage.
Pilot Information
The 52-year-old Portuguese male pilot was a member of the aero club and held a valid pilot license with instructor/examiner qualifications. His total flight experience was 868 hours and 40 minutes, with 10 hours and 30 minutes in the previous 90 days.
Aircraft Information
The aircraft was a Tecnam P-92 Echo ultralight, class MEA-G3, with a maximum takeoff mass of 358 kg. It was equipped with a Rotax 912 UL engine. The airframe had accumulated 799 hours and 35 minutes at the time of the last inspection on 11 March 2009.
Braking System
The standard P-92 braking system consisted of a hydraulic oil reservoir, a piston, disc brakes on each main wheel, and a parking brake valve. Brake application was via a lever and torsion bar between the seats, applying equal pressure to both wheels without differential braking. Later models introduced differential braking using individual pistons actuated by pedal pressure.
Aircraft CS-UJX had been modified to allow differential braking via the rudder pedals. The original lever (item 5) was removed, and the parking brake system was altered. The modification was already installed when the aero club acquired the aircraft second-hand; no records of the modification were held by the operator. Attempts to contact the previous owner were unsuccessful as he had died. The manufacturer's representative could not provide information on the modification.
Meteorological Information
Weather at the time of the accident was good for flying: visibility unrestricted, clear skies, and light wind (METAR: 151100Z 03006KT CAVOK 17/11 Q1020).
Wreckage and Impact
The wreckage came to rest at the point of impact. No parts separated during the collision. The left main landing gear became detached but remained near the aircraft. Inside the cockpit, fracture of the right pedal was visible. Damage to the wing, engine/propeller, and fuselage was consistent with a frontal impact with a stationary obstacle.
Tests and Research
Investigation revealed that the right pedal torsion bar had fractured. The aircraft had been modified for differential braking, but no certification or records of the modification were available. The fracture led to loss of braking effectiveness on the right side.
Probable Cause
The primary cause was the fracture of the right pedal torsion bar, which resulted in loss of braking effectiveness on that side. Contributing factors included the execution of a short takeoff with full brakes and maximum engine power, which placed abnormal stress on the right pedal structure, which failed due to material weakness.