A team of researchers studied the most frequently occurring types of maintenance problems. The top eight in order of occurrence are:
1.Incorrect installation of components
2.The fitting of wrong parts
3.Electrical wiring discrepancies (including cross-connection)
4.Loose objects (tools, etc.) left in aircraft
5.Inadequate lubrication
6.Cowlings, access panels, and fairings not secured
7.Fuel/oil caps and refuel panels not secured
8.Landing gear ground lock pins not removed before departure