ALBUQUERQUE, N.M. (AP) — Sixteen months after a crash killed four first responders, New Mexico’s most populous county has resumed its law enforcement helicopter operations.

Bernalillo County Sheriff’s officials said the Metro 1 Air Support Unit took to the sky Tuesday after months of training for pilots and mechanics, with some deputies becoming tactical flight officers.

The A-Star B3 helicopter initially will fly law enforcement missions exclusively including air patrol, critical incident response and collaborative operations with the Albuquerque Police Department’s Air Unit.

Sheriff’s officials said Metro 3 — a fixed-wing Cessna T-41C — will transition to a non-response role and be used solely for training purposes.

They said a new helicopter known as Metro 4 will join the fleet in the coming months with the name Metro 2 being retired in honor of the fallen first responders that included the county’s undersheriff.

The Metro 2 helicopter went down in July 2022 while returning from a firefighting mission. The cause of the crash still is being investigated by the National Transportation Safety Board.

Following the fatal crash in the hills near the northern New Mexico community of Las Vegas, the sheriff’s office suspended helicopter operations.