Overview
On 10 January 2025, a Sikorsky S-61N helicopter registered as N703HG was involved in an accident at Sèdjè-Dénou, in the commune of Zè, Benin. The aircraft was operated by Construction Helicopters Inc., AFRICOM, with actual operation by CHI Aviation. The flight was a passenger transport and surveillance mission from Tourou Airport (Parakou) to Cotonou Bernardin Gantin Airport. On board were one pilot in command, one co-pilot, two technicians, and no passengers. No injuries were reported.
Sequence of Events
The helicopter departed Tourou Airport at approximately 07:56 local time. During the flight, a probable loss of hydraulic pressure occurred, leading to an emergency landing at Gnanhouizoumè, in the arrondissement of Damè-Wogon (commune of Bonou). Another Sikorsky S-61N (registration N761HG) departed from Tourou carrying mechanics to provide assistance. Repairs were performed, and tests were conducted on the aircraft before departure. The helicopter departed again at 15:26 local time, bound for Cotonou, accompanied by the second Sikorsky, which did not have sufficient fuel to return to Tourou.
Near Zè, in the vicinity of Sèdjè-Dénou, additional technical problems with the hydraulic flight controls, as reported by the crew, occurred, leading to the accident at approximately 15:40 local time. The crew performed emergency procedures and began searching for a landing site. During landing, the left landing gear sank into wet ground, causing the helicopter to tip onto its left side. The main rotor blades and tail rotor blades contacted the ground, resulting in substantial damage. All occupants escaped unharmed.
Damage
The aircraft sustained substantial damage from the impact of the main rotor blades and tail rotor blades with the ground. No other damage was reported.
Investigation Progress
The French Bureau Enquêtes-Accidents (BEA) is leading the investigation, with participation from the U.S. National Transportation Safety Board (NTSB), as the United States is the state of registration, design, and manufacture of the aircraft. A preliminary report was published in February 2025. The aircraft was not equipped with a Flight Data Recorder (FDR) or Cockpit Voice Recorder (CVR). The investigation has focused on the hydraulic system and the flight control servomotors, as key components for understanding the aircraft's behavior. Possible failure modes being assessed include wear, corrosion, mechanical fatigue, hydraulic fluid contamination, or internal failure. International cooperation has been initiated to conduct specialized analyses beyond local capabilities.
The BEA published this interim public statement on the first anniversary of the accident, in accordance with international and national regulations, to inform the public and stakeholders of the investigation's progress. The investigation continues, with further examinations of the hydraulic servomotors planned. Final conclusions and any safety recommendations have not yet been issued.