The number of business jet accidents increased even as traffic numbers remain steady, but the turboprop safety record has dramatically improved this year, according to the latest statistics released by business aviation safety expert Robert E. Breiling Associates, Inc.

Through the first nine months, the number of accidents involving U.S.-registered business jets increased by four to 15, including five fatal accidents that involved 19 fatalities. During the same period in 2011, the U.S. business jet fleet accounted for 11 accidents, none of which were fatal (the statistics do not include the April 2011 crash of the Gulfstream G650 test aircraft, because it was operating on an experimental certificate).

The fatal accidents this year included two U.S.-registered Gulfstream G-IVs that crashed in the Congo and France, combining for seven fatalities. Others involved three different models of Cessna Citations – the 750, 550 and 501 – two of which crashed in North Carolina and the third in France.

Non-U.S.-registered business jets, meanwhile, were involved in six accidents, two of which were fatal, resulting in five fatalities. This is an improvement over the eight accidents, including three fatal and 12 fatalities, in the first nine months of 2011.

While the non-U.S. accident record improved this year, international accidents have accounted for a disproportionate number of the total. Business jets in Europe, for instance, represent about 16% of the worldwide fleet and 15% of the hours flown, but more than 22% of the total fleet accidents. U.S. business jets represents 63% of the worldwide fleet, but have accounted for just 34% of the accidents, according to Breiling data that tracks accidents over the past five full years.

“Landing continues to be the primary phase where the accidents are happening,” says Breiling Associates’ Robert Breiling. Runway overshoots remain a problem for business jets, he says, adding that it is “particularly high” in smaller jets. He says a number land fast and touch down long. While smaller jets typically can operate on shorter runways, the overwhelming majority of runway overshoots – 78% – are occurring on runways that are 5,000 ft. or longer.

While no one reason accounts for the overshoots, Breiling points to less experienced pilots who may be flying smaller jets, along with that a number of the aircraft can be operated single-pilot. “If something goes wrong, you really have your hands full,” he says.

As for business turboprops, the U.S. fleet marked a dramatic improvement in the safety record. U.S.-registered turboprops were involved in 18 accidents, including three fatal accidents and eight fatalities in the first nine months. This compares with 36 fatal accidents, including nine fatal accidents and 19 fatalities.

Nearly all types of U.S. turboprop operations were involved in fewer accidents in the first nine months. The number of accidents involving owner-flown turboprops marked the largest decline from 15 accidents in the first three quarters of 2011 to seven this year.

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.