Could having less weather data make the cockpit safer?

 - September 18, 2006, 5:47 AM

“How much weather information does a pilot really need?” This was a question posed by meteorologist James Tauss at a recent NASA conference on integrated communications, navigation and surveillance in Baltimore. Tauss, an aviation weather specialist at Aviation Management Associates, Alexandria, Va., who has worked with the FAA, NASA and private industry for close to 30 years, has developed a different way of looking at this question.

In his view, pilots are increasingly provided with masses of information, before departure and–with today’s uplinked weather broadcasts–in flight, but much of it is extraneous to the planned mission. The pilot must determine its relevance, assess its potential impact and make the correct decisions before departure and as the flight proceeds.

In many ways, Tauss observed, “Weather [technology] disrupts the system,” when it provides an “incorrect mix of information of decision-making value in the cockpit,” potentially leading to flight diversions, compromises in safety and even fatalities.

One problem, he noted, was that weather information from the many different providers of uplinked data comes in a variety of styles, colors, symbology and emphasis. In other words, there are no standards in presentation, creating pilot uncertainty and possible misunderstanding of the real situation.

Tauss pointed out that in most cases, and particularly in general aviation, the true weather needs of the flight deck remain largely unknown. Studies of the use of current weather products in the cockpit leave unclear the question of how pilots use integrated weather displays under deteriorating conditions, yet this is of vital importance, since general aviation VFR flight into IMC leads to a disproportionate percentage of fatalities. One study suggested that cockpit pictorial Nexrad weather depictions led to “tunneling,” pilots focusing their attention on the weather information, to the detriment of keeping an external lookout. But when Nexrad picture resolution was improved, it merely increased tunneling and decreased lookout.

Pilots Need Only the Right Information
What was first required, Tauss said, was an accurate determination of what weather information pilots need to safely complete the flight and how best to present just this on the flight deck.

With that established, he proposed a new approach to weather data use, where uplinked weather information would be filtered automatically through an onboard system and its output presented only when the pilot is required to make an operational decision based on changes in the weather. In other words, weather information would be presented as an intelligent, automated, decision- aiding tool, rather than today’s generalized information that pilots often feel obligated to monitor and interpret constantly.

Tauss sees the concept as based on an imaginary 4-D decision zone projected ahead of the aircraft out to between five and 15 minutes at the current groundspeed. The onboard system would continuously monitor uplinked weather data within that zone, and also at the destination airport, to detect any changes that would adversely affect the current flight plan. These changes would be presented to the pilot as decision point alerts and would include such things as increased turbulence and convection, the onset of icing, as well as wind shear and lowered ceilings and visibility at destination.

Importantly, the alerting levels could be set to match the capabilities of the aircraft and its pilot. For example, icing alerts would have much higher thresholds in ice-capable aircraft than in aircraft that are not so equipped.

Similarly, ceiling and visibility alerts for qualified instrument pilots could be keyed to, say, Category I limits but would sound at much higher values for less experienced, non-instrument-rated pilots. Put another way, the onboard system could be pre-
programmed to automatically provide a decision point alert when the weather conditions ahead or at the destination exceeded the abilities of the aircraft or its crew. On the other hand, if the conditions remained essentially as forecast, the system would display no weather data other than the pilot’s selection.

Tauss sees the need for another mode between the decision point alerts and the otherwise “all clear” modes. He envisions a trend weather awareness mode that would advise the pilot of weather conditions within the decision zone ahead, or at the destination, which, while not reaching decision point alert limits, would indicate trends in that direction that require closer pilot monitoring. For a VMC general aviation pilot, for example, an unforecast lowering of the cloud base ahead, even though the conditions were still better than IMC, could call for increased situational awareness as the flight continued.

Tauss’ ideas exist merely as a concept, and no systems of this type are on the market. Nevertheless, the rapid advances in computing power and artificial intelligence suggest that such an approach could be reasonably achievable in the future. And unquestionably, in weighing critical weather conditions and relieving the pilot of constant–and, too often, inaccurate–interpretation of uplinked weather information, such decision aids could clearly play an important role in enhanced situational awareness and, consequently, flight safety.