Part 135 operators registered under the Air Charter Safety Foundation’s Industry Audit Standard (IAS) have a safety record exceeding that of all of Part 135 and fractional operations, according to the foundation. A recent review conducted by aviation safety firm Robert E. Breiling Associates revealed that registered IAS operators logged an accident rate of 0.162 per 100,000 hours over the past five years versus 0.54 per 100,000 flight hours for Part 135 and fractional operators combined. IAS-registered operators flew 616,777 hours between 2009 and 2013.