The US’s Federal Aviation Administration (FAA) has proposed a civil penalty issued to ERA Helicopters for flying a modified helicopter on passenger service without performing the necessary test flights.

According to the FAA, ERA replaced a log damper, a part in the rotor system, on one of its helicopters in February 2009. Following the replacement, the company operated the helicopter on 23 passenger-carrying flights without performing tests and checks to verify that the work had been completed properly.

The FAA will assess the $260,000 penalty given to ERA.

ERA will need to respond to FAA’s enforcement letter within 30 days of receipt.