Chances are that your flight this summer will be significantly delayed or you will be waiting a long time for your luggage to arrive at the baggage claim carrousel. Welcome to the complex world of aviation and its sensitivity to convective weather impacts!
Touchdown delay (black triangles) and taxi-in time (red crosses) of arrivals and gate pushback delay (black triangles) and taxi-out time (red crosses) of departures.
Thunderstorm and especially lightning pose a safety risk to airline and airport personnel that work outdoors servicing gate-side parked aircraft and maintaining airport grounds. Thus, airport and airline stakeholders at major airports employ procedures to ensure the safety of their outdoor workers. When lightning is impacting an airport, these safety procedures trigger ramp closures to suspend outdoor work and bring baggage handlers, airplane fuel and food suppliers, mechanics and other logistics and maintenance personnel inside for protection. Ramp closures cause downtimes (and thus delays) that operators would like to minimize, yet the decision-making process for closing and reopening a ramp is burdened with notable uncertainties.
The Federal Aviation Administration (FAA) has been funding a study to elucidate the challenges associated with airport and airline operations under thunderstorm and lightning impacts and identify opportunities for minimizing avoidable impacts through improved guidance. NCAR’s analyses so far determined that lightning-induced ramp closures cause notable air traffic impacts on both departures and arrivals. The inability to ready aircraft for departure during ramp closures will result in a delayed gate pushback time (on average amounting to several tens of minutes per affected fight). Prolonged or multiple successive ramp closures can create a backlog of departing aircraft that will have to queue up for taxiing out after operations resume again, which yields additional delays (on average five to fifteen minutes). Notable delays were also found for arriving flights in form of increased taxi-in times (on average five to twenty minutes), which is a consequence of unavailable gates that remain occupied by aircraft unable to get readied for departure. Compounding this, the delays incurred at one lightning-impacted airport will likely ripple through the US airspace system and grow, as flights might no longer be able to stay on schedule throughout the day. Thus, the patience of travelers during the summer months is often tested, as delayed flights may result in missed connections, cancellations, or late luggage among many other stressors.
NCAR’s research has shown that the ramp closure decision-making process is burdened with a number of significant uncertainties related to the lightning data, the safety procedures and effectiveness of implementing them. Today’s approaches to lightning safety remain reactive (rather than proactive) relying heavily on lightning observations. Yet the lightning data were found to exhibit their own share of marked uncertainty related to the measurement technique, network detection efficiency, and subsequent data processing. In addition, observing operators at work revealed that the implementation of the safety procedures is affected by human cognition and behavior, often producing delayed or inconsistent ramp closures that can yield avoidable safety risks for outdoor personnel and operational inefficiencies.
All these uncertainties have implications on personnel safety and operational efficiency. NCAR is working toward a better characterization of the true lightning hazard that is needed as basis for improving the safety of outdoor personnel and minimizing avoidable operational inefficiencies. Research is underway to combine multiple sources of relevant information (e.g., radar and lightning data from more than one source) for a robust diagnosis of lightning threats (BoltAlert). Moreover, a nowcasting component is developed that enables recognizing lightning threats prior to impact allowing for proactive actions. Such a capability to alert of impending lightning impacts is of particular interest not only to airports, but sites for handling or testing equipment, fuel, ammunition and missiles, outdoor venues (e.g., baseball parks, swimming pools) and special events (e.g., Olympics), construction and open-air mining sites, utilities (e.g., energy, electricity transmission), recreation (e.g., hiking, camping, boating), transportation, and many others more.
In collaboration with AvMet Applications, Inc. analyses are underway to more fully understand the relationship between lightning and other convective weather impacts on airports. Air traffic simulations will help to also show under what circumstances local impacts may propagate throughout an airline’s daily schedule.