Impact of Safety Management Systems on 14 CFR, Part 135 Safety Performance

Abstract

Safety Management Systems (SMS) are currently required at all U.S. scheduled air carriers operating under Title 14 of the Code of Federal Regulations (CFR), Part 121, but are not currently required for air carriers operating under 14 CFR, Part 135. Therefore, some Part 135 operators adopted SMS, and some did not. This study determined the impact of SMS on 14 CFR, Part 135 operator’s safety performance.

A simple random sample (SRS) of Part 135 operators was chosen, and then divided into two different categories including operators with, and without, an SMS. The safety performance of each group was measured by the aircraft accident and incident rate of the two groups. SMS databases from International Standard for Business Aircraft Operations (IS-BAO), Wyvern Consulting LLC (WYVERN), and ARGUS International, Inc (ARGUS) were used to determine which Part 135 operators had an SMS. Federal Aviation Administration (FAA) and National Transportation Safety Board (NTSB) databases were used to determine the accident and incident rate of each group.

A plus four confidence interval analysis was performed, and it was determined that the operators with an SMS did not have better safety performance than the operators without an SMS. The safety performance of the group with an SMS was then compared before and after SMS implementation. A significance test for comparing two proportions and a plus four confidence interval analysis were performed, and it was determined that the implementation of SMS did improve an operator’s safety performance.