Because of construction works on runway 35, the threshold at Porto was displaced by 760 m, and which was also NOTAMed as such. Prior to departure from Madrid-Barajas Airport (MAD), Spain, the crew did not receive this NOTAM. Flight RG1336 took off at 15:16. The flight was uneventful and the crew contacted Porto Approach at 16:14. The controller issued descent instructions in preparation for a landing on runway 35. The controller did not mention the displaced threshold. The flight was cleared to land at 16:25. Three minutes later the controller realized that the flight was approaching the closed part of the runway. He radioed “Overshoot please”. But the flight crew did not react and continued their landing on runway 35. The Saab undershot the displaced threshold, ran 200 m and crossed a trench, which caused the undercarriage to be sheared off. CAUSES (translated from original Portuguese report): The Commission of Investigation determined that the probable causes for the accident were: – The fact that the crew did not know of the NOTAM’s published by Porto airport that reported the temporary threshold of runway 35, due to work on the runway. – The existence of two markings on the runway 35 threshold, which may have confused the crew; Contributory factors: – Lack of concentration of the crew during the flight; – The controller did not effectively alert the aircraft about the ongoing work; – The controller, in a warning to the crew, used incorrect phraseology.