SATA International flight RZO129, an Airbus A320-214, suffered a hard landing at PDL. The flight departed from Lisbon at 18:40 hours with the captain as Pilot Flying (PF) and co-pilot Pilot Not Flying (PNF). The descent to PDL started at 20:12 hours and the aircraft reached Initial Approaxh Fix (IAF) position at 20:30 hours. Shortly before passing the IAF, the PF engaged both Auto Pilots and performed a Runway 30 ILS straight in approach. Passing 875 ft (RA) both AP were disconnected and the approach continued manually, with FD engaged in LOC & G/S mode and A/THR engaged in SPEED mode. The approach was performed with the aircraft in normal configuration for landing. The approach speed was 141 kts, which has been selected and followed during the approach. At 20:35 hours, the aircraft made a hard touch down, bounced to a height of 12 ft AGL and came back to the ground in a severe hard landing condition. On the apron, the captain reported hard landing to the ground support engineer. Both analysed the DMU Load Report. However, they were not able to reach a coherent interpretation. As the event has occurred at night, the Engineering Department was closed and they could not get the necessary help to clarify the Load Report message. Both pilots and ground support engineer performed a visual inspection, looking for any damage to landing gear or associated parts and they did not detect any irregularity. The event was not even reported on the Technical Log book. The aircraft flew back to LIS without further problems. At Lisbon, the flight crew reported again, and verbally, to the ground engineer asking his assistance to decode de DMU message, also here without success. There was no decoding capability at that time in the night. Then, ground personnel decided to wait for the next shift delivering the message to the coming staff. Meanwhile, time elapsed was too long and CS-TKO was prepared for the next scheduled flight. Consequently, the aircraft left the airport without the message being decoded. In the following flights no irregularity was detected. During between flights, at the time when turn-around checks, neither pilots nor ground assistance engineers were able to find any inaccuracy. No reports of any hard landing suspicion were written on the aircraft Technical Log book. The aircraft performed six more sectors after the event before entering an ?A? type inspection. It was found that Wing Shroud Box Lower Panels, on both sides, showed some damage with some rivets on these panels popped out. ACCIDENT PROBABLE CAUSE: The GPIAA Investigation Team determine that the probable cause of this accident was a hard landing, of significant vertical acceleration (4.86g), due to aircraft loss of lift caused by Ground Spoilers extension in flight, during a bounce of great amplitude (12ft AGL). Contributing factors to this accident were: ? The flare inputs were not adequate to reduce the A/C vertical speed before touchdown, thus leading to the first hard landing; ? The thrust levers were not retarded before touchdown; ? During the 12ft high bounce the crew decided to continue landing and did not initiate a go around.