Maryland State Police have grounded much of its fleet of helicopters, after finding cracks in the paint of blades on the choppers' tail rotors.
The news comes just weeks after unscheduled maintenance issues forced a similar grounding of the choppers.
In 2014, Maryland State Police completed the shift to the new AW139 helicopters. The move was in part prompted by the fatal crash of a state trooper chopper in 2008. State Police bought 10 AW139s, made in Philadelphia at a cost of about $12 million each.
AW139 helicopters have had a history of tail rotor problems. After a fatal crash in Brazil in 2011, emergency airworthiness directives were issued, alerting users to the possibility of tail rotor problems.
State Police say they ordered an inspection of tail rotors on all 10 MSP helicopters after cracks were found in the paint of rotor blades on two choppers.
The first crack was found Jan. 9 during a routine heavy inspection of one chopper. Police addressed the problem with the manufacturer and the blade was sanded down, repainted and re-installed, police said. No cracks were found in the blade itself, police said.
On Sunday, similar cracks found in the paint of rotors on a second chopper, which prompted the inspection of all choppers.
Engineers from the manufacturer have traveled from Philadelphia to Maryland to help with inspections on all 40 blades (4 on each chopper).
Police have released the results so far:
- 17 blades passed complete inspection
- 5 blades passed initial inspection; await final inspection
- 12 blades to be further inspected by manufacturer
One chopper was already in Philadelphia for pre-scheduled maintenance and will be inspected there.
State Police normally have seven choppers in service at any given time, with one to three out as backup or for scheduled maintenance. Three choppers are currently in service, with a fourth expected back in service Wednesday afternoon, with another due back Thursday.
There has been no interruption of Medevac services.
Of six calls since Sunday, U.S. Park Police handled four, Delaware State Police handled one and Maryland State Police handled one.