All About Aircraft Disconnects


All About Aircraft Disconnects

Aircraft maintenance and safety is of utmost importance, and that goes without saying. With the huge size of the aircraft, we can imagine the number of cables and plugs installed to help in the efficient working of the vehicle. And, any compromise in the maintenance means huge hazards because the vehicle moves not on road, but in the air. Imagine one mistake and the tremendous accidents that can happen!

A single aircraft can have hundreds of miles of cables within for performance! And, the wisest decision is to have cable assemblies rather than cables so that it becomes easy to handle, manage, maintain, repair, and replace the cables when required. Miracle Aerospace is one of the best aircraft cable assembly manufacturers in India who is engaged with providing products to various fighter jets, light transport aircraft, versatile helicopters, cockpit harnesses, radar refurbishing projects, and Indian army and missile launcher harnesses.

We now know how so many hundreds of cables and cable assemblies are present within an aircraft. But, now we will speak about the various segments they are divided into. First of all, you must understand that a single aircraft is broken into many different sections like forward section, aft section, cockpit, wings, engine, landing gear, etc. Each of this section connects to the other. But, instead of having wires connecting all these sections, connectors are placed in the firewalls or bulkheads of the aircraft to provide connecting points. This is because having long miles of continuous cables and assemblies can be a big issue.

When there is a quick maintenance or repair required, it would require the removal of all the wires in a section, or the entire aircraft! You can imagine it as replacing all the wires within your entire home/office when only a single wire of a single appliance becomes defective. And obviously, nobody can afford that. This is why disconnects are important. In fact, the more disconnects within the aircraft, the easier it is to replace the equipment and cables within.

These cables, cable assemblies, and connectors all form the Electrical Wiring Interconnect System (EWIS) of the aircraft. The EWIS design should be a robust one, and must also be resistant to EMI, environmental hazards, maintenance hazards, and common mode failures. All this criteria is met when wires are routed in the airframe. But, what when a disconnect is required? Competing for weight and bulkhead space, along with structural considerations, means disconnects are congested with many types of signals from a multitude of systems. Thus, here are some guidelines for an effective EWIS system.

  • Power carrying conductors should be routed through different disconnects than data or other low-level signals; and similar signals must be routed together in power circuits.
  • Data signals with similar EMI and RFI sensitivity must be kept in the same disconnect. And, signals known to have a sensitivity to EMI or RFI coupling should be run in separate connectors, or must be shielded/grounded in the disconnect pinout as much as possible.
  • Redundant signals should be kept separated. To reduce the number of disconnects, the use of connectors containing more than one contact size within the same connector will be increased.
  • Redundant signals that can’t be routed through separate disconnects should be kept as far from each other in the connector as possible, so that there is lesser effect of an overcurrent on more than one of the signals.