wired upAPEX Insight: In the slim-margins airline business, increasing aircraft payload or improving fuel efficiency can come down to the wire.

Passengers are likely to be unaware of the complexity of the aircraft systems that are hidden from view. After all, their onboard interactions are limited to aircraft seats, flight attendants and in-flight entertainment systems.

Like a human nervous system, an aircraft’s wiring carries signals and information critical to the safe operation of the airplane. Carlisle IT, W.L. Gore and AeroFlite are a few of the companies that design and manufacture “the nerves.” Connecting everything from the fly-by-wire flight control systems to the coffeemaker in the galley requires miles of wires, thousands of connectors and tens of thousands of support brackets that have to be cut, bundled, tested and installed.

A narrow-body airliner such as the Boeing 737NG has as much as 40 miles of wiring. The wide-body Boeing 747 has 150 miles of wires, but the “Queen of the Skies” is topped by the double-decker Airbus A380, which has over 320 miles of cables. And like every component intended for aerospace application, wires, cables and connectors undergo stringent testing to meet safety and operational standards.

Wires, cables and connectors undergo stringent testing to meet safety and operational standards.

Keeping an aircraft’s weight within its design specification is often a challenge for airframers, and a pound saved in wiring is a pound that can be used for increasing payload and decreasing fuel consumption. New manufacturing techniques and materials are leading the way to lighter and more capable wires.

The Airbus A350 benefits from Draka Fileca’s Star Quad KL24 high-transmission rate data cable, which weighs 25 percent less than earlier types of comparable cables. And even though the 787 reflects Boeing’s “more electric” design and engineering philosophy, the Dreamliner has 20 miles less wiring than the aircraft it replaces, the 767.

As airlines install more advanced IFE systems and satellite connectivity solutions, faster, lighter and more capable aircraft wiring and connectors will be needed. Onboard systems now require gigabit bandwidths to meet the growing demands of the connected passenger and, as a result, fiber optic cables are being installed. After all, the passenger in 26C wants to finish binge-watching her favorite show.

“Wired Up” was originally published in the 7.2 April/May issue of APEX Experience magazine.

Howard has been passionate about aviation since he was a little kid, and is a pilot who loves to fly gliders and just about anything else with wings. He's a frequent contributor to aviation magazines and blogs.