Aircraft System Failures - Electrical System

The condition of the electrical system of an aircraft is vital in providing both safety and reliability for the pilot during flight. The electrical system can be extremely extensive depending on both the size and the design of each aircraft. Some larger aircraft can have up to miles of wire strung throughout its body connecting all of the aircrafts systems together. 

https://electrical-engineering-portal.com/wp-content/uploads/2017/01/aircraft-electrical-system-guide.jpg

The electrical components in some aircraft can be responsible for the majority of the vital systems like the landing gear, flight controls, and engine, to some of the less essential systems like radios, navigation, and lights. Although fairly uncommon, electrical failures can and will happen on all aircraft. 

Some of the most common types of electrical failures can include short circuits, blown fuses, battery discharging, or even smaller components like sensors and alternators simply quitting. These failures are usually derived from normal wear and tear during flight and taxiing, as well as the constant movement of components required for flight and mission requirements. This can often times cause wire chafing leading to shorts, or strain on wires causing a break or de-pinning in connectors. Weather and environmental conditions also play a large role in the worsening condition and failure of electrical components, leading to brittle wires and wire decay.

https://www.devicetech.com/wp-content/uploads/Spring-Fast-wire-chafe-example-1.jpg

One specific issue to address is the rubbing of wire shielding producing chafing, breaking, and eventually a short. As previously stated, wire rubbing is common, especially in aircraft that perform many strenuous maneuvers like stunt planes and fighter jets. These common forceful flight control movements will eventually start to rub wires on surfaces creating heat and friction strong enough to rub holes right through the shielding exposing bare wire (a recipe for disaster). When this now bare wiring touches any conductive material, boom, you have a short. These shorts will often times cause the system it is connected to to fail, or it could even start a fire. 

https://cdn.boldmethod.com/images/learn-to-fly/systems/how-to-survive-an-electrical-fire-in-flight/chafing-small.jpg

When a system goes down and you want to identify if it is a short, what is the solution? Firstly it is important to identify if there is a fire. If there is no fire the next step, depending on the location of the wires that power that system, is to either inspect the visual condition of them, or to start shooting wires that power that system to identify if any of the wiring is showing zero ohms indicating there is a break or damage somewhere along the wire. Now that the shorted wire has been identified, the solution is to replace that wire or wire section. When the wire is replaced, an operational check of the system that originally stopped functioning properly is required to diagnose the problem is fixed. 

References:

ERAU SpecialVFR. (2016, September 9). Aircraft Systems - 08 - Electrical System. YouTube.com.            https://www.youtube.com/watch?v=d5sXmNplQHw&list=PLzW-Ub1FWeZzdOHQhNK0U0Ci1a-VRH8IO&index=40 

Causes of Aircraft Electrical Failures. (1991, August). IEEE Aerospace and Electronic Systems Magazine. IEEExplore. https://ieeexplore.ieee.org/abstract/document/90949/authors#authors