The verdict has been in for a long time; stabilized approaches are an essential part of a safe landing. Airlines and business aviation operators almost universally require pilots to fly stabilized approaches, but until now there has been no way to monitor approach performance in real time other than an alert fellow pilot to warn flying pilots that they might be venturing outside the boundaries of track, glidepath, proper configuration, airspeed and sink rate. Honeywell aims to change that with its new SmartLanding, a software extension of the company’s enhanced ground proximity warning system (EGPWS).
SmartLanding simply warns pilots via verbal announcements and messages on the EGPWS display when they are flying outside predefined standard operating procedure (SOP) criteria during approach to landing. If there is no deviation outside the SOP tolerances, then SmartLanding is silent.
SmartLanding is Honeywell’s second software-based extension to the EGPWS hardware system. The first was the SmartRunway System, and all of these products take advantage of the EGPWS’s airports and terrain database and other capabilities.
The SmartRunway System is designed to help prevent runway incursions, said Michael Grove, Honeywell marketing director for safety and information management surveillance systems and also a key member of the EGPWS development team. SmartLanding was developed as a runway-excursion-prevention product, something that can help pilots avoid damaging and dangerous runway overruns.
In research for its approach-and-landing accident reduction (ALAR) tool kit, the Flight Safety Foundation (FSF) found that between 1984 and 1997 unstabilized approaches “were a causal factor in 66 percent of 76 approach-and-landing accidents and serious incidents worldwide.”
Both the FSF and National Business Aviation Association recommend that approaches be stabilized at 1,000 feet above airport elevation on IFR approaches or 500 feet VFR. “The stabilized approach requires the aircraft to be established on the desired track, glidepath, in landing configuration and with airspeed and sink rate constant,” according to the NBAA. The FSF ALAR briefing note gets into more detail, but the bottom line is that if the approach isn’t stabilized by the required altitude, pilots should initiate an immediate go-around. The benefits of a stabilized approach, according to the FSF, are that “landing performance [is] consistent with published performance.”
Honeywell research found that runway excursions are far more prevalent than incursions and account for far greater accident- and industry-related costs, by a factor of about 10. “It’s a very significant problem, and it’s one that enhanced ground prox is pretty well-suited to help address,” Grove told AIN.
SmartLanding is not a new idea, but the ability to make it work depended on modern databases and GPS capability. Honeywell is always looking at accident causes and how technology could be applied to help prevent accidents, and the runway excursion problem was a worthwhile target. Honeywell worked with airlines and aircraft operators for two years to find out how SmartLanding might help them, including asking airlines what kind of exceedances they were seeing from flight operational quality assurance (FOQA) or flight data monitoring (FDM) system data and also by running simulator trials.
For an operator, the ideal setup is to have SmartLanding, FOQA and/or FDM all working together. Analysis of the FOQA/FDM data can show where pilots might be exceeding criteria in a specific area, such as approaches. SmartLanding can then help pilots avoid these exceedances because the operator can configure it to address specific criteria.
SmartLanding has dozens of parameters. Some criteria are built-in, like the approach gradient, which is determined based on each airport’s own configuration. The standard gradient is a three-degree glidepath. SmartLanding is typically set up to remain silent as long as pilots remain within one degree on the up side of the glidepath.
Another important parameter is approach speed. SmartLanding normally is set to reference speed plus 25 knots, but this is configurable, too. Airbus, for example, uses a more aggressive V approach plus 15 knots.
When SmartLanding calls out an alert–in a choice of actual male or female voices–the first and second calls (or three in the case of flaps) state the nature of the exceedance. A speed above the Vref+25 standard, for example, would generate a “too fast, too fast” verbal annunciation plus a text annunciation on the EGPWS display (usually the PFD). If the pilot slows down and remains within the required speed, SmartLanding remains silent. But once the aircraft gets below 450 feet and is above the exceedance speed, or too high or in the incorrect flaps configuration, then SmartLanding announces and displays “unstable, unstable.” “At that point,” said Grove, “we expect the pilots to go around.”
SmartLanding can be purchased separately from the SmartRunway System, or operators with the SmartRunway System can add SmartLanding and the two systems work together. For an EGPWS-equipped aircraft, SmartLanding will cost roughly an additional $20,000, but if the SmartRunway System is already installed, SmartLanding will cost less. Fleet pricing will also be available. Certification of SmartLanding as a supplemental type certificate installation is due to be completed this month and the first two approvals were expected for Honeywell’s own Hawker Beechcraft King Air C90 and Convair 580 aircraft, followed by a United Airlines jet.
The SmartRunway System and SmartLanding are the first two software extensions to the EGPWS, and Honeywell engineers are busy developing additional products that live on and take advantage of the EGPWS platform. One is a new altimeter-monitoring system to help pilots avoid missetting the altimeter, when either transitioning into Class-A airspace or setting the altimeter properly before beginning an instrument approach.
“The most prevalent situation is to set [the altimeter] off by one inch, about a 1,000-foot difference,” said Grove. “That digit is significant enough to where it can get you into trouble, and sometimes it results in an altitude bust if you’re lucky. But if you’re not so lucky, it can result in a controlled-flight-into-terrain accident.”
The altitude-monitoring system determines correct altitude based on the geometric altitude for the aircraft’s GPS-derived location as well as radar altimeter data, when available. The system is capable of detecting errors as small as about 150 feet. “This has a lot of uses other than just the safety aspect,” he said. “We feel it’s going to be important for people transitioning to RNP because RNP operations today are still based on barometric altitude for vertical [separation].”