**1. Introduction**

Aircraft maintenance can be described as activities performed to maintain an aircraft in a serviceable and airworthy condition. 'Maintenance' includes activities involving component or aircraft repair, inspection, overhauling, troubleshooting, and modifications [1–3]. Aircraft maintenance is a critical task that is essential for warranting aviation safety in relation to the life-cycle of an aircraft [4–6]. Even though maintenance is regarded as one of aviation's many high-risk areas due to its direct impact on aviation safety, it still has a considerable contribution in aircraft maintenance accident and incident occurrences [7–10]. Hobbs and Williamson [11] and Floyd [12] highlight the importance of understanding maintenance errors along with promoting a culture of identifying, reporting, and learning from maintenance errors for improving work quality and safety.

PeriyarSelvam, et al. [13] reports that maintenance costs typically make up between 10% and 20% of aircraft operational costs. The Airline Maintenance Cost Executive Commentary is published by International Air Transport Association's Maintenance Cost Technical Group, contains annual data acquired from airlines around the world. These data are based on the airline's maintenance cost data. Data collected from 54 airlines for 2018 shows that the airlines spent USD 69 billion on aircraft maintenance, repair, and overhaul. This represented approximately 9% of the total airline operational costs [14].

The general aim of this work is to help improve safety in scheduled commercial air transport; this will be achieved by understanding how accidents with maintenance contributions are unique in contrast to all other scheduled commercial air transport accidents. The knowledge gained from understanding these features of accidents with maintenance contributions will hopefully prevent further accidents, and hence, save lives and reduce the cost (both direct and indirect) to the aviation industry. The research questions addressed by this work include:


In response to these research questions, the following research hypotheses were proposed:

