According to statistics released by GAMA, the entire segment was down more than 15 percent from a year ago, with turbine helicopters down 11.3 percent.
The FAA is investigating an incident in which a Boston MedFlight pilot briefly fell asleep at the controls of a helicopter while transporting a patient.
Since the first engineered materials arrest system was installed in 1999, there have been 15 incidents where an aircraft has rolled onto one in an overrun.