Honeywell Aerospace and Boeing last week reported that they have successfully demonstrated GPS-based Category III precision landing on a 787 airliner. Flights were conducted back in December 2014, using Honeywell’s SmartPath ground-based augmentation system (GBAS) and upgraded reference receivers at the airframer’s Moses Lake Airport in Washington state. The tests established that aircraft can safely land in weather conditions that allow for no decision height and a minimum visual range as low as 150 feet.
According to Jared Louwagi, Honeywell’s senior manager for navigation and sensors, GBAS is set to be a key enabling technology for the U.S. NextGen and European Sesar modernization of air traffic management. The digital system is set to replace instrument landing systems and promises to be more flexible and less expensive for airports to maintain. It will increase airport capacity by giving the option for aircraft to land further down the runway and so exit to the taxiway sooner.
Airports need to be equipped with GPS reference receivers (usually four) that receive signals from satellites. These are connected to a central ground station that calculates any necessary correction to ensure the integrity of data that is then relayed to aircraft via VHF. In addition to Moses Lake, seven public airports are GBAS equipped: Houston, Newark, Malaga, Frankfurt, Bremen, Zurich and Sydney.
According to Louwagi, the majority of current Boeing production aircraft, and all Airbus models, already have GBAS capability. Older aircraft can be upgraded by adding multi-mode receivers and making changes to the flight management system and displays.
“Honeywell has the first and, so far, only FAA-certified GBAS and we have broken barriers in terms of advancing the technology,” Louwagi told AIN. “One of the ways we are differentiated is that we provide both ground and air systems, and so we are well placed to understand how everything works.”
During the 787 tests, the Boeing/Honeywell team flew 12 Category III approaches and demonstrated the use of a higher, 3.2-degree glideslopes and displaced thresholds 1,000 feet down the runway. “We also showed how GBAS can result in noise and emission reductions [around airports] and shorter track miles to get on short final approach,” said Louwagi.
The test aircraft was fitted with Honeywell’s Integrated Navigation Receiver, which is its Category III prototype multi-mode receiver. It installed its SmartPath GBAS ground station at the Moses Lake.
Next month, Honeywell expects to complete certification of the Block 2 software for SmartPath. This will bring several benefits, including improved availability and being adaptable to low latitude environments. It also means that operators can exercise optional upgrades such as incorporating a satellite-based augmentation system that covers a wider area rather than just a specific airport so that users don’t have to overcompensate for possible poor weather conditions.