Story ID: 
Thales Pitches Head-worn HUD
By: Thierry Dubois
Caption: Equipment manufacturer targets small cockpits.
Word Count: 510
Thales is offering a new head-worn display system that it claims is particularly well suited to cockpits that are too cramped to allow installation of a conventional head-up display (HUD), such as on light business jets. Dubbed TopMax, the monocular glass can present the usual HUD information such as the flightpath vector.

“The field of view is unlimited because the display turns with the pilot’s head,” Richard Perrot, Thales’s avionics marketing director, told AIN. The pilot can choose to add input from enhanced vision (EVS) and synthetic vision (SVS) systems as well. Such images would be superimposed, however, as the head-worn system does not fuse the two separate sources.

The entire system weighs 700 grams (1.5 pounds), including the audio headset with active noise reduction. The electronic unit is the size of two iPhones, according to Perrot.

In addition to being lighter and smaller, TopMax is also much easier to install than a conventional HUD, according to Perrot. The head-tracking subsystem that determines the pilot’s line of vision uses optic and inertial cameras and it also monitors stickers on the overhead panel. In a conventional HUD, by contrast, the arm that holds the glass in front of the pilot is a complex component that must eliminate vibration and pass a 16g crash test.

Thales expects TopMax to offer the same performance as a traditional system on takeoff and landing, allowing minimums equivalent to Cat 1 ILS.

It also opens fresh possibilities. Thanks to head tracking, the synthetic vision of the terrain will appear without interruption. The system can display an electronic flight bag-lookalike when the pilot turns his head down and to the left. If the pilot selects an aircraft on the head-down Tcas, the corresponding symbol will appear on the head-worn display to help the pilot spot the real aircraft in the sky.

In a crosswind, the pilot can see the flightpath vector aligned with the runway although the aircraft is off axis. “This is the same for a curved approach,” Perrot added.

Thales capitalized on the head-tracking expertise it found in Visionix, a U.S.-based company the French firm acquired in 2012. It also drew on its experience in the military field, with the TopOwl (binocular) and Scorpion (monocular) helmet-mounted displays. “We chose monocular because it met our requirements for a lightweight, competitive product that would offer an operational benefit,” Perrot explained.

TopMax will be available for retrofit and as an option installed on the aircraft production line. It remains to be seen how aircraft manufacturers will offer TopMax. Perrot declined to name any OEMs but he did say that while some are considering offering TopMax alone, others see it as complementary to a HUD. In an aircraft with both, the pilot could use the HUD and the copilot would use TopMax. Another option would be for the pilot to use both, for enhanced capability.

Thales claims TopMax will be 30 to 40 percent less expensive than a conventional HUD.