Graham Warwick/Atlanta

NASA is working to interest airlines in technology which could allow full-tempo airport operations to continue in low visibility.

Airport capacity often decreases as weather worsens, because of the increased risk of ground collisions. NASA's Low Visibility Landing And Surface Operations (LVLASO) programme aims to sustain safe and efficient airport operations in Category IIIb conditions.

A demonstration was conducted at Atlanta's Hartsfield Airport in late August, using NASA's Boeing 757. Pilots from four US airlines participated in the trials, which were witnessed by airline, airport and regulatory officials. NASA plans a more-comprehensive demonstration in 2000 and has scheduled a meeting for early 1998, to seek operator and manufacturer input on what should be demonstrated, says LVLASO programme manager Wayne Bryant.

The demonstration involved two LVLASO elements. The roll-out and turn-off (ROTO) system provides braking and steering cues to help the pilot sustain runway-occupancy times as visibility deteriorates. The taxiway-navigation and situational-awareness (T-NASA) system displays taxi guidance and traffic information.

NASA's 757 was equipped with a Flight Dynamics head-up display (HUD) and a Rockwell-Collins liquid-crystal display (LCD) for the trial. ROTO and T-NASA symbology, including a virtual runway, was displayed on the HUD. An airport moving-map, showing the taxi route and surface traffic, was displayed on the LCD.

ROTO symbology includes virtual cones delineating the runway edges and selected edges. On touchdown, the system displays the distance to the exit, the exit speed required, and a speed-error cue, assisting the pilot with braking and steering in low visibility.

T-NASA HUD symbology uses the same virtual-runway cues to guide the pilot along the cleared taxi route, which is also displayed on the head-down moving map. Information from the airport's surface-movement radar and traffic-identification system, including hold bars triggered by the conflict-alert software, is datalinked to the aircraft for display on the map.

Atlanta was chosen for the trial because Hartsfield is equipped with a Cardion proof-of-concept airport surface-traffic identification system (ATIDS). This was also used to track the aircraft, using automatic dependent-surveillance - broadcast and for controller-pilot datalink communications, using Mode S. The US Federal Aviation Administration plans to install a prototype ATIDS at Dallas/Fort Worth in 1998.

Source: Flight International