After several maintenance adjustments of the right propeller and flight idle fuel flow, the aircraft was test flown and released for flight. Several pilots continued to note discrepancies concerning the right propeller system. Adjustments were made and the aircraft was again released for flight. At Mayaguez, the crew made a short, steep approach to the runway. On very short final, witnesses said they heard sounds resembling a propeller in reverse thrust. The aircraft made an extreme yaw to the right, followed by a left bank, then a right bank. The aircraft impacted right wing first. The post-accident investigation revealed that the right propeller had been in the beta range. The right engine flight idle fuel flow was excessively high. Exam of the maintenance program showed deficiencies in the management, supervision, and handling of pilot-reported problems. The investigation also found the FAA management of the bilateral type certification of the C-212-CC ineffective. (For further information see NTSB/AAR-88/07.)