Summary of Failure Conditions Recorded in Selected Helicopters Operated by Army Air Corps

Abstract

This paper has been drawn up for the Air Operations Group and the Technical Maintenance Group of the 56th Air Force Base in Inowrocław (Poland). Its primary purpose is to compare the frequency of failure conditions and their impact on the safety of flights performed on Mi-24 and W-3PL helicopters. Special attention has been paid to the values of flight parameters recorded and any anomalies identified. The data were analyzed using the "Objective Record Analysis" software, with two aspects taken into consideration. The first aspect – failure conditions which do not affect flight safety, i.e. when the crew exceeded the permissible flight parameters for a given exercise, an interference took place, a calculation error occurred in the system or the equipment became uncalibrated. A total of 534 failure states were singled out, with 18% of them caused by the human factor. The remaining 82% occurred due to interference and errors in the recording system or due to an incorrect flight parameter recording process (with this factor remaining beyond the control of the flight crew or maintenance personnel). The second aspect focused on failure conditions having an impact on flight safety, i.e. when the crew exceeded the aircraft's operating envelope or damage to the aircraft's systems and components occurred. 1,075 states have been recorded, with safety violations caused by exceeding the aircraft’s operating limits accounting for 5% of them. Damage to aircraft systems and components was the root cause of the 95% of the failures (with emergency landings required in 6 cases). It was shown that 80% of the failure conditions studied occurred on the Mi-24, with the number of missions performed on this particular type being nearly twice as high as on the W-3PL. Analysis of the years to which the available data was related (2012-2016) has led to the conclusion that the number of flights performed and the number of failure conditions was on an increase. However, the share of failure conditions in the total number of flights decreased. Authors 1 and 2 serve in the 56th Air Force Base and were granted permission to access and publish the data presented in this paper.