Each year, approximately two million commercial flights depart or arrive in Canada and ten million in the United States, report Statistics Canada Transportation Division and the Bureau of Transportation Statistics respectively. Without reliable lighting systems to facilitate aircraft movements, flights can be delayed or cancelled, causing an onerous ripple effect for travelers, businesses, and airlines alike. Worst case, an incursion can occur at an active runway intersection with a potential for fatal results. Liberty Airport Systems, an Ontario, Canada-based equipment manufacturer, provides some interesting uses of wireless communication as a runway lighting backup to a primary fiber optic network.
We all do it. Gaze out oblong windows from seats in their upright positions; feel the deceleration of the plane as it floats down the glide slope of the approach; watch our smooth descent toward two retreating columns of light defining the runway ahead. It is part of the experience of flying and much of one’s personal safety rests on the reliability of the airfield lighting systems that serve as the pilots’ visual aids during take-off and landing.
Airfield Lighting Control System Architecture
Lighting infrastructure on the airfield includes runway and taxiway edge lights, threshold lighting, airfield guidance signs, and apron areas where aircraft are loaded and refueled.
Power is distributed to the lighting circuits by underground cables from electrical vaults installed at selected locations on the site. These vaults contain the power distribution equipment for the lighting circuits, and are controlled by an Airfield Lighting Control & Monitoring System (ALCMS).
Liberty Airport Systems holds over 30 years experience designing airfield lighting power and control systems, including those for George Bush Intercontinental Airport in Houston and Toronto International Airport.
“If a network communication problem means a major airport cannot control the approach and runway lighting, the airport may be forced to delay or divert the flights” says Liberty president Allan Fletcher. “That’s a big deal; that’s why we use robust industrial grade products and multiple levels of redundancy in our control system products.”
While Liberty’s power and control system solutions are application-specific, the core hardware and software products employed in their system design remain constant.
At the heart of each ALCMS system are Rockwell Automation® ControlLogix® Programmable Automation Controllers (PACs). Lighting circuit status is served to a FactoryTalk® View Supervisory Control and Data Acquisition (SCADA) operator console located in the Air Traffic Control Tower, providing Federal Aviation Administration (FAA) controllers with a touch screen interface from which they control the various lighting circuits on the airfield.
FactoryTalk View is part of a unified suite of monitoring and control solutions designed to span stand-alone machine-level applications up through supervisory-level Human Machine Interface (HMI) applications across a network. This suite offers a common development environment and application reuse such that system engineers can improve productivity while helping clients to reduce maintenance costs and improve airfield safety overall.
Fiber optic cable is used as the primary communications medium. In many cases, a secondary parallel fiber network is installed as a backup. However, reliable, fiber-based communications can have shortcomings. Field conditions may be such that:
- Airside construction can compromise communications and thus operations.
- Communications duct banks lay under concrete slab runway and taxiways, which are very costly to install and maintain.
- Redundant fiber networks normally run parallel to the primary line, and thus are subject to common risks, especially when a duct bank is compromised by a negligent back hoe operator.
Independent Wireless Redundancy
INFORMATION TECHNOLOGY 2004 In this special section, AIRPORT BUSINESS takes a look at information technology products and services available to airports and airport-based businesses. More...