The Big Picture

Situational awareness is a frequent buzzword in the world of aviation. From a maintenance perspective it deals with self-preservation. Knowing what is going on around us is a great way to avoid incidents or worse yet, accidents involving bodily...


Synthetic vision employs databases containing detailed information on terrain, obstacle, geo-political boundaries, and relative vertical navigation information. A typical SVS application uses the stored data on board the aircraft in unison with navigation information including GPS and inertial reference systems through a processor which provides position information to an image generator and on to the flight deck display. A highway in the sky (HITS) is then used to depict the projected path of the aircraft in perspective view. Pilots acquire instantaneous understanding of the current as well as the future state of the aircraft with respect to the terrain, towers, buildings, and other environment features.

The first FAA certified application of a synthetic vision system was part of the Gulfstream PlaneView flight deck introduced in 2009. This form of the synthetic vision — primary flight display (SV-PFD) replaces the traditional blue-over-brown artificial horizon with the computer-generated terrain overlay with typical PFD symbols. Since then, many newer glass cockpit systems offer synthetic terrain presentations.

Enhanced vision systems incorporate a unique imaging capability, inspired by the forward-looking infrared (FLIR) technology. An infrared sensor that operates in the shortwave infrared (SWIR) spectrum is designed to depict anything producing heat such as runway lights, animals, or even other aircraft. The externally mounted thermal detector sends a video image to the flight deck displays, giving the pilots an accurate look at their surroundings even in low visibility.

Even at night, EVS increases visibility of runway markings, taxiways, adjacent highways, and the surrounding landscape. This feature does drastically reduce the margin for error and for controlled flight into terrain (CFIT) which is considered the No. 1 danger in aviation today.

Laptop as a new maintenance tool

New technology does provide new opportunities for maintenance technicians. The age where analog information comprised of variable voltage, frequency, and phase has been superseded by digital data and discrete signals in and out. Use of a volt, ohm meter (VOM), and test lamp and while they still hold importance are loosing ground to the laptop computer and oscilloscope. Understanding the principles of troubleshooting digital data buses and video systems are now paramount.

The nature of our trade is rapidly changing. In years past the guys “upstairs” in the avionics shop would deal with flight deck indication dilemmas and we were trained on instrument removal procedures. Today the training element, while still necessary, is being superseded by a genuine need for education on new technology.

Thorough understandings of system switching and certification requirements are essential for accurate diagnostics and dispatch decisions. Adaptability of a minimum equipment list (MEL) to a digital flight deck is not without challenge. Often when a fault message is presented an underlying cause may be the culprit. Maintenance diagnostic systems do incorporate different design philosophies where some can sense ON/OFF along with understanding valid logic functions it may not always be intuitive enough to provide accurate diagnosis without applying a significant amount of brain power.

Situational consciousness in aviation maintenance will always be an important part of what we do but with equipment used in the flight decks of today it’s creating an entirely new awareness. 

 

Jim Sparks has been in aviation for 30 years and is a licensed A&P. He is the manager of aviation maintenance for a private company. He can be reached at sparks-jim@sbcglobal.net.

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