Tail Rotor Shaft Failure Risk: Rosaviatsiya Orders Urgent Inspection of All Ansat Helicopters

Rosaviatsiya has issued an airworthiness directive mandating an urgent inspection of the entire fleet of Ansat helicopters and their modifications, including ambulance versions. The reason is the discovery of corrosion damage to the tail rotor shaft, which could lead to its failure in flight.

The directive was prompted by an investigation into an incident that occurred on June 20 with an Ansat-U helicopter used in state aviation. According to preliminary data, the tail rotor shaft of the aircraft failed due to manufacturing defects. Despite the seriousness of the situation, information about the incident was not communicated to operators and was not covered in the media.

Since the shafts on civilian and state aviation Ansats have an identical design, the Kazan Helicopter Plant initiated unscheduled inspections of all aircraft. To this end, the company prepared a technical solution with an inspection map and additional control measures, based on which Rosaviatsiya issued the directive.

The document prescribes a visual inspection of the tail rotor shafts installed on helicopters and in storage within the next ten flight hours. If blistering of the paint coating or traces of corrosion are detected, the parts must be immediately removed from service and sent to Reduktor-PM for pipe replacement. In addition, regardless of their condition, all shafts of a certain series that have previously undergone overhaul without pipe replacement are subject to re-repair.

The directive also introduces mandatory additional visual inspection of tail rotor shafts every 50–60 flight hours or every three months.

According to preliminary information from industry sources, operators are already finding defects in the form of coating blisters and clusters of pinpoint damage on a number of helicopters during inspections.

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