As for helicopters, U.S.-registered twin-turbine helicopter accidents nearly tripled, from five in the first nine months of 2011 to 14 this year. Accidents involving U.S.-registered single-turbine helicopters climbed slightly to 39 this year, versus 36 in the same period in 2011.

Non-U.S.-registered helicopters, however, were involved in significantly fewer accidents – down from 27 in the first nine months of 2011 to 13 this year. Single-engine helicopters were involved 81 accidents, down from 93 in the first three quarters of 2011.

Breiling says engine failures – particularly in the single-engine helicopters – are still accounting for a relatively high number of the accidents. This is especially true as the fleet internationally continues to grow, he says.