On April 17, 2017, about 1104 hours universal coordinated time, a Piper PA-31T, serial number 31T-8020091, Swiss registration HB-LTI, was destroyed during impact and a postimpact fire following a loss of control during initial climb from runway 17 at the Cascais Aerodrome (LPCS), Cascais, Portugal. The pilot, his three passengers, and an individual on the ground were fatally injured. The flight was originating at the time of the accident and was destined for Avignon-Provence Airport (LFMV), located near Avignon, France.The accident investigation is under the jurisdiction and control of the Gabinete de Prevenção e Investigação de Acidentes com Aeronaves (GPIAA). This report is for informational purposes and contains only information released by or obtained from the government of the Portugal. Further information pertaining to this accident may be obtained from: Gabinete de Prevenção e Investigação de Acidentes com Aeronaves (GPIAA) Praca Duque de Saldanha, 31 – 4ºAndar 1150 - 094 Lisboa Portugal Tel.: (351) 212739230 E-mail: geral@gpiaa.gov.pt Fax: (351) 212739260