Piper PA-44-180 F-GIDF Incident at Perpignan Airport

Incident Overview and Flight Details On 9 December 2004, a Piper PA-44-180 with registration F-GIDF was operating an instruction flight for a multi-engine piston qualification at Perpignan Airport. The aircraft was operated by Ecole Aéro-Pyrénées and carried an instructor and a student. During a demonstration of a steep bank turn, the instructor reported that the pitch control became soft. The aircraft entered a slight nose-down attitude at 125 kt. The instructor informed the student and the control tower, and the student moved to the rear seat to adjust the aircraft's center of gravity. ## Aircraft Handling and Landing The instructor stabilized the aircraft in level flight at approximately 2,600 ft and 140 kt, using the trim and power settings to manage the descent. The aircraft was configured for a long final approach to runway 33. During the final approach, the aircraft oscillated in pitch when the propellers were advanced to full low pitch, but it stabilized. The aircraft landed in a three-point configuration without bouncing. ## Investigation Findings After landing, the terminal of the pitch control cable was found broken. The aircraft had 212 flight hours since its last major overhaul, during which the cables had been visually inspected according to the manufacturer's maintenance manual, with no anomalies noted. Laboratory examination of the broken terminal revealed that it failed at a fillet near the adjustment flat of the threaded terminal. No fatigue crack indicators, deformation, or external corrosion pits were observed at the break. However, micrographic analysis showed a network of branched, intergranular, and transgranular cracks originating from the break. Chlorine was detected inside some of these cracks. ## Cause and Safety Actions The investigation concluded that the terminal broke due to local embrittlement of the material caused by internal corrosion, which was likely favored by the aircraft's operation in a maritime environment near Perpignan. The corrosion had developed inside the metal without significant external marks. The aircraft was subject to a mandatory Piper Service Bulletin (SB 1048) for lubricating stainless steel cables to protect against corrosion, which had been applied. However, the maintenance personnel were not aware of previous similar incidents and did not perform a sufficiently rigorous inspection to identify the visible external corrosion marks that should have led to the terminal's replacement. Following the incident, the French DGAC issued a recommendation bulletin (BR 2005/14) for detailed visual inspections of control cable terminals on affected aircraft, and the maintenance organization integrated these procedures into its maintenance programs.