Six of the seven Maryland State Police Helicopters are in operation as of Friday afternoon after four were grounded last week.
Officials expected the seventh in Cumberland operating by the weekend.
Last week, Maryland State Police helicopters were grounded Sunday for inspection after cracks in the paint on the tail rotor were discovered. According to Maryland State Police spokesperson Greg Shipley, the helicopters were grounded out of an abundance of caution so inspectors could check whether the cracks affected the tail rotors.
This is the second time in a month inspectors spotted a crack in the paint on a tail rotor blade.
"Anything that could affect the integrity of that aircraft is a concern of our aviation command and that's why when the first crack in the paint was noted there was a concern and a follow-up with the manufacturer. Then when the second paint crack appeared, again the system wide inspection was done ," Shipley said.
Maryland State Police have 10 helicopters in their fleet. Seven are assigned to sections across the state while three are rotated for inspection and maintenance
Each aircraft has four tail rotor blades. Twelve blades had been sent back to the manufacturer for further inspection.
Several years ago, Maryland State Police replaced their fleet with 10 AgustaWestland AW139 helicopters.
There may be a history of tail rotor problems with the AW139. In 2011, the same model helicopter was involved in a fatal crash in Brazil.
Several emergency airworthiness directives were issued after the incident regarding the inspection of tail rotor blades.