## 3 Results and Discussion  
### Emission Results  
Results of the single aerodrome circuit for one piston engine aircraft and results for 1 h of cruise phase are presented in Table 6. As pilot training also includes aerodrome circuits without a taxi phase, the sum of the emissions for a single aerodrome circuit without taxi have also been presented. As can be seen, the greatest NO\({}_{\text{x}}\) emissions are generated during the climb out phase, when the engine operates at 85% of maximum engine power. For CO, HC, and CO\({}_{2}\), the greatest emissions are generated during the taxi phase, but for CO the values are similar with climb out and landing. Emission of HC during the taxi phase is 3.5 times higher than for climb out and almost 6 times higher than for the landing phase. Emission of CO\({}_{2}\) for taxi and climb out is similar and only 3 kg higher than for landing phase. The lowest emission values were seen during take-off, where the power settings are maximum. For 1 h of cruise phase on lean mixture, the highest emission value is CO\({}_{2}\), which reaches almost 160 kg of CO\({}_{2}\) during 1 h of flight. From toxic exhaust gas compounds, the highest emission is for CO and is equal to 23.5 kg per 1 h of flight. Emission of NOx is about 1 kg per 1 h of flight. Emission of HC is the lowest and is equal to approximately 279 g per 1 h of flight. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Flight Phase** &
\begin{tabular}{c} **Engine** \\ **Settings \%F** \\ \end{tabular} & **NOx [g/kg]** & **CO [g/kg]** & **HC [g/kg]** & **CO\({}_{2}\) [kg/kg]** \\ \hline Cruise & 65 & 23 & 473 & 5.4 & 3.17 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Emission indexes for cruise phase for piston engine aircraft [23]. \begin{table}
\begin{tabular}{c c} \hline \hline
**Compound** & **Emission Factor for PL [g/kWh]** \\ \hline CO\({}_{2}\) & 685 \\ \hline CO & 0.261 \\ \hline NO\({}_{\text{x}}\) & 0.456 \\ \hline SO\({}_{\text{x}}\) & 0.436 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Electricity emission factors for different compounds in Poland. Figure 3 presents the results of the NOx and HC emission assessment generated during complete pilot training on a one piston engine aircraft. The highest emission is seen during the climb out phase, which is approximately 3.5 kg from training on one engine aircraft and about 1.5 from the training on two engines aircraft. The lowest NOx emission is during the taxi phase and take-off phase. This is due to the short duration of the take-off phase and not every aerodrome circuit including the taxi phase, meaning that the taxi phase is much lower than other phases. HC emission is much higher than NOx emission due to emission indexes and the way it is formed in the engine during combustion. Minimal NOx emissions are a result of the low combustion temperature in the chamber. The increase in emissions of other compounds is caused by the continuation of processes started upon landing--a reduction in pressure at the inlet to the combustion chamber and depletion of the combustible mixture [26]. The highest HC emission is also from the climb out phase during the training on one engine aircraft and is approximately equal to 7.3 kg; for the same phase, the emission is about 3.2 kg from two engine aircraft. HC emission from training on two engines aircraft is the highest in the taxi phase, but it is almost at the same level from training on one piston engine aircraft (about 6.5 kg). Figure 4 presents the results of the CO2 and CO emission assessment generated during complete pilot training. The highest CO and CO2 emissions are for the climb-out phase for both types of aircrafts, with the highest value of CO2 equal to about 1900 kg for one piston engine aircraft and about 800 kg for two piston engine aircraft, and CO equal to about 400 kg for one engine and 200 kg for two engine aircraft. CO emission for two engine aircraft is very similar for climb-out, approach, and taxi.