Lack of knowledge
Lack of knowledge (alternatively known as lack of KSA; hereinafter, the Factor) is the human factor that is characterized by a lack of KSA (knowledge, skills, and abilities), particularly gained through training and experience, in the task at hand. The Factor is one of the Dirty Dozen of Human Factors.
In aviation maintenance
According to the FAA AMT Handbook,
A lack of knowledge when performing aircraft maintenance can result in a faulty repair that can have catastrophic results. Differences in technology from aircraft to aircraft and updates to technology and procedures on a single aircraft also make it challenging to have the knowledge required to perform airworthy maintenance.
All maintenance must be performed to standards specified in approved instructions. These instructions are based on knowledge gained from the engineering and operation of the aircraft equipment. Technicians must be sure to use the latest applicable data and follow each step of the procedure as outlined. They must also be aware that differences exist in the design and maintenance procedures on different aircraft. It is important for technicians to obtain training on different types of aircraft. When in doubt, a technician with experience on the aircraft should be consulted. If one is not available, or the consulted technician is not familiar with the procedure, a manufacturer's technical representative should be contacted. It is better to delay a maintenance procedure than to do it incorrectly and cause an accident.
Mitigating the risk: (a) Only fix parts that you are trained to fix, (b) If you do not know how to fix something, ask for help from someone who does, (c) Ensure that the maintenance manual you are using is up to date. In a world of ever changing technology, maintainers must remain up to date on current equipment and how to fix it.