Aviation suffers many delays due to the lack of timely air traffic flow management. These delays are also caused by the uncertainty weather information; and the lack of efficient dissemination of weather products to pilots. It is clear that better models are needed to quantify air traffic flow in three flight regions - en-route, in the terminal, and on the ground, to determine aviation weather information requirements at each region, and to quantify their bandwidth requirements. Furthermore, the results from those models can be used to select alternative future aviation communication systems. In this research, the 'ITHINK' and 'MATLAB' software packages have been used to develop a lumped Air Traffic Flow Model (ATFM) and an Aviation Weather Information and Bandwidth Requirements Model (AWINBRM). The ATFM model is used to quantify the volume of air traffic in each phase of flight in three flight regions. This model can be used to study navigation, surveillance, and communication requirements. The AWINBRM model is used to study aviation weather information requirements in different flight phases of flight. Existing and potential communication systems used for transmitting aviation weather information are explored in this research. Finally, a usable and practical computer model - Aircraft Impacted and Detour Model (AIDM) around an aviation weather system is developed. This model is used to compare the costs between detoured flights around a weather system and delayed flights at the airports. The purpose of this research is to study air traffic flow and aviation weather information and bandwidth requirements through modeling. The ultimate goal of the models described here is to serve as a living laboratory where policies can be tried before implementing them into the real system. Moreover, these computer models can evolve dynamically through time allowing decision makers to exercise policies at various points in time to quantify results with ease. This research would be a first integrated model for combing air traffic flow and aviation weather requirements and determining the quantity of aviation weather information between pilot and ground service centers. This research would be a guideline for aviation industry to build an efficient and timely aviation weather information transmission system with minimum budget. Consequently, this research will reduce aviation delays and improve aviation safety. / Ph. D.

Approved for public release, distribution is unlimited / 235 Class A Navy and Marine (Naval) aviation mishaps involving aircrew error between FY 90 and FY 98 are analyzed for the possibility of being weather related. In addition to determining the overall role of weather, weather related mishaps are compared to aircraft category, mishap characteristic, the Naval Safety Center human factors (HFACS) taxonomy, and flight phase. In addition, weather related mishap trends have been analyzed. Results show 19% of mishaps involving aircrew error are weather related with helicopter category and controlled flight into terrain (CFIT) mishap characteristic having the largest percent of weather related mishaps for their respective groupings. Visibility related weather elements account for over half of all weather related mishaps, and nearly two-thirds of all weather related mishaps were judged to be preventable with a perfect weather forecast believed by aircrew. These and other findings are presented to develop intervention strategies for reducing the number of weather related flight mishaps (FMs) per year. / Lieutenant Commander, United States Navy

As a complement to existing weather forecast products for aviation, a prototype of a new product is presented and evaluated. It shows the atmosphere in a vertical cross section along the intended route. This Vertical Route Forecast introduces the possibility to examine the vertical distribution of cloud layers, wind, precipitation, turbulence and more along the flight path. Through a market research with 166 participating Swedish pilots it was found that the demand for the product is high and that 90 % of the participants would use it if available. The Vertical Route Forecast is inspired by the existing product GRAMET by Ogimet (Ballester Valor, n.d) but instead of using forecasts from the weather prediction model GFS (Global Forecast System) at 0.5° (56 km) resolution it uses data from the 2.5 km resolution model HARMONIE-AROME. The latter is operational at SMHI (Swedish Meteor-ological and Hydrological Institute) and because of its high resolution it enables more detailed structures of the weather to be presented. The product differs further from GRAMET by showing only the lower parts of the atmosphere so as to be of more use to small aircraft pilots flying at low levels. To assess the accuracy of the forecasts, a model evaluation of HARMONIE-AROME has been conducted through a case study in which the model was verified and compared to GFS over Sweden. The two models were verified against their own analyses at four different atmospheric pressure levels in terms of bias, root mean square error, standard deviation and correlation. HARMONIE-AROME performed best for temperature while GFS had the best forecasts of relative humidity. Wind speed and direction were also evaluated with insignificantly better results for GFS. However, the weather did not vary very much during the study as the two weeks were dominated by high pressure systems. Other evaluations made of HARMONIE-AROME by e.g. the HIRLAM consortium (2016a) have shown good or adequate performance of the model. It was concluded that HARMONIE-AROME would be well suited as the forecast producing model for this Vertical Route Forecast. / För att piloter ska kunna planera en säker flygning behöver de tillgång till bra och användbara väderprognoser. Med de prognosprodukter som finns tillgängliga idag kan det dock vara svårt att få en detaljerad uppfattning om hur vädret kommer vara längs med vägen. Här presenteras och utvärderas därför ett förslag till en ny prognosprodukt som visar atmosfären i en sidovy längs en valfri sträcka. Med den kan piloten granska utbredningen av bland annat molntäcken, vind, nederbörd och turbulens i höjdled längs den planerade färdvägen. Denna vertikala ruttprognos är inspirerad av den redan befintliga produkten GRAMET från Ogimet (Ballester Valor, n.d) men visar mer detaljerade prognoser som är bättre anpassade till flygningar på låga höjder. Vid en marknadsundersökning utförd med 166 medverkande svenska piloter stod det klart att efterfrågan på produkten är hög och 90 % av de medverkande påstod att de skulle använda den om den fanns tillgänglig. För att bedöma prognosernas precision har en utvärdering gjorts av den prognosmodell som använts till produkten. Modellen används annars hos SMHI (Sveriges Meteorologiska och Hydrologiska Institut) och kallas HARMONIE-AROME. I en fallstudie jämfördes den med modellen GFS som skapar prognoserna för GRAMET. Studien täckte Sverige och sträckte sig över 14 dagar i början av februari, 2017. HARMONIE-AROME visade bäst resultat för temperatur medan GFS gjorde de bästa fuktighetsprognoserna. Vindhastighet och vindriktning undersöktes också och för dem var modellerna ungefär lika bra. Vädret varierade dock inte så mycket under tvåveckorsperioden som dominerades av högtryck. Andra utvärderingar som gjorts av HARMONIE-AROME togs också i beaktande och modellen verkar generellt sett göra bra prognoser. Från samtliga resultat drogs slutsatsen att prognos-produkten skulle underlätta för småplanspiloter samt att HARMONIE-AROME är en lämplig modell att använda för att skapa dess prognoser.