4.2.7. Engines

The ICAO ADREP taxonomies use multiple categories to differentiate the most common engine types used on aircraft. However, the ICAO official accidents code engines as reciprocating (piston), turboprop, and jet (which captures turbofan and turbojet engines). From Figure 7a, the most common engine in accidents (both maintenance and all) is jet. For the number of engines, Figure 7b, a twin engine aircraft is typically involved in accidents. This is because twin engine aircraft are the most common. For both engine type and engine count, there was no statistically significant difference between all accidents and those with maintenance contributions.

**Figure 7.** Distribution of aircraft engines for accidents with maintenance contributions: (**a**) the type of engine; (**b**) the number of engines.
