*4.3. MxFACS Level 2—System*/*Component Failures*

All 11 accident reports were further coded to identify the top-level system/componen<sup>t</sup> a ffected. This is shown in Table 7.


**Table 7.** Level 2 System/Component Failures.

A new coding of "other" was also created in level 2 and added to the taxonomy to categorise other maintenance-error-related events that did not match any of the themes. Level 2 (System/Component Failures) shows that engine, aircraft structure and "other" were directly a ffected by maintenance issues.

The UK Civil Aviation Authority [32] identified Air Transport Association (ATA) Specification 100 Chapter 32 "Landing Gear" as the second most a ffected system out of the top six events related to maintenance error. However, no landing gear system was identified as being a ffected by maintenance error in the last decade. This may be caused by the limited attention being given to maintenance errors in Nigeria. This can be improved upon by the AIB targeting maintenance, airworthiness and human factors causal and contributory factors when carrying out investigations. It also highlights why NCAA should include maintenance-related causal and contributory factors in data analysis. It may also be due to adequate inspection and testing carried out on such a visible area as the landing gear.

The accidents were further coded in accordance with MxFACS level 3 to identify the nature of aircraft maintenance errors that contribute to accidents in Nigeria.
