PENN TWP — Officials from Pittsburgh-Butler Regional Airport want county residents to know that they may see two low-flying helicopters in areas in the county through the end of July.

The aircraft are doing contract work — surveying pipelines and power lines — for utility companies, said Ike Kelly, airport manager.

The helicopter surveying the pipelines will be flying 100 or 200 feet above the ground, Kelly said, and hovering on occasion as workers search for evidence of ground disturbance or discoloration.

The helicopter patrolling along power lines will have 10 large, circular saw blades suspended beneath the aircraft, Kelly said, and will be trimming tree limbs that are too close to the lines.

He said people need to keep clear of both helicopters while they perform their work. No daily schedule for the helicopters’ flights is available, but Kelly said both aircraft likely would be operating in northern and eastern Butler County through the end of July.