Incident Overview
On 17 July 2007 at 18:30 UTC, a Cessna 152 (registration CS-AYU) landed on runway 35 of Aeródromo Municipal de Cascais (LPCS) without radio communications, passing over another aircraft that was in the takeoff position. The pilot and the sole passenger subsequently left the aircraft at the end of the runway.
Flight and Emergency Response
While flying at 1,000 feet over Cascais Bay, an electrical fire erupted and smoke began emanating from the radio panel. The pilot shut down all electrical systems, including the battery, and opened the windows to evacuate smoke. He then returned directly to the aerodrome for landing. Without functional radios, he proceeded straight to the final approach for runway 35 and landed, receiving no light signals from the control tower.
Investigation Findings
After landing, the pilot taxied to the turning area at the end of the runway and stopped, then exited the aircraft with the passenger. Firefighters arrived but found the fire already extinguished. Maintenance personnel discovered a burned voltage regulator, which had caused a voltage spike and subsequent short circuit, leading to the in-flight fire. The radio system was inspected, and the regulator and affected units were replaced. Electrical insulation and equipment functionality were tested, and the aircraft was declared airworthy.
Analysis and Recommendations
The investigation determined that the pilot correctly executed emergency procedures for an onboard fire and made a sound decision to land at the nearest aerodrome due to the loss of electrical power and instrument indications. However, the pilot did not follow standard procedures for radio communication failure near a controlled aerodrome, endangering flight safety by interfering with other traffic. Additionally, the aerodrome, which experiences high traffic levels including many training flights, lacked published local procedures for loss of radio communications. As a result, a recommendation was issued to NAV Portugal and the Aeródromo Municipal de Cascais to develop and implement such procedures in accordance with ICAO Annex 2, Appendix 1, Chapter 4.