Keywords

1 Introduction

With the development of China from a big civil aviation country to a powerful civil aviation country, people pay more attention to flight safety. The premise for airlines to pursue economic benefits is to ensure the safety of aircraft at all stages and meet the requirements of operation regulations. However, the take-off stage is a key stage of aircraft flight mission, and it is also the stage of frequent aviation safety accidents, so the take-off performance has become one of the main contents of flight performance research. It is very important to study the take-off performance of the aircraft in the take-off stage for ensuring the safety of the aircraft, optimizing the take-off performance of the aircraft and improving the economy of the aircraft operation. This paper aims to explore the law of the influence of different interval temperature on the aircraft take-off obstacle surmounting, and put forward corresponding suggestions for the take-off analysis of aviation companies according to the law.

2 The Influence of Temperature on Aircraft Take off Obstacle Surmounting

There are many limiting factors in the process of flight take-off, such as the limitation of aircraft performance and the limitation of meteorology. The atmospheric temperature in meteorology is a typical influencing factor, which has a direct impact on the obstacle surmounting of aircraft after take-off. Air temperature is the air temperature at the height specified by surface meteorological observation (i.e. 1.25–2.00 m, 1.5 m in the distribution map of temperature forecast in China). Air temperature records can characterize the thermal condition of a place. Air temperature is one of the conventional elements to be measured in surface meteorological observation. Air temperature is expressed in centigrade (℃), some in Fahrenheit (f), all to one decimal place, and negative values below zero. With the change of air temperature, the output thrust of the engine also changes. For example: analysis of the impact of temperature on aircraft take-off obstacle surmounting when the temperature rises, the air density will decrease. On the one hand, the engine thrust will decrease, the aircraft will accelerate slowly, and it will not reach the take-off speed quickly, so that the take-off distance and take-off distance will increase.

3 Impact Analysis

In this paper, B737-700/7b24 is used in Jiuzhai Huanglong Airport and B737-800/7b26 is used in Chongqing Jiangbei Airport for performance calculation. BPS carries the data obtained from various variable calculation into BCOP for obstacle surmounting judgment. The operation interface is shown in the Fig. 1.

Fig. 1.
figure 1

BPS calculation interface

Full size image
Fig. 2.
figure 2

BCOP calculation interface

Full size image

Different data are applied to different temperature conditions to study the existing factors that affect the take-off obstacle surmounting, and the influence of different temperatures on the aircraft take-off obstacle surmounting is obtained, so as to improve the economy of aircraft operation and provide guidance for operators.

4 Example Analysis

Airport is the place for aircraft to take off and land. Its various “states” naturally have a considerable impact on the take-off distance of aircraft. Here we mainly choose two typical airports to analyze.

Taking the data of Chongqing Jiangbei Airport (ordinary Airport) and Jiuzhai Huanglong Airport (High Plateau Airport) as examples, Jiuzhai Huanglong Airport uses B737-700/7b24 aircraft, Chongqing Jiangbei Airport uses B737-800/7b26 aircraft for performance calculation, and the take-off flight path results of BPS software under the same condition are compared.

Jiangbei Airport and meteorological data: the runway elevation is 411 m, the external atmospheric temperature is the monthly average maximum temperature of 32 °C, static wind, standard sea pressure. The available distance of take-off taxiing, take-off and acceleration stop are 3200 m. The main road surface and runway slope are 0%, and there are no obstacles.

Jiuhuang airport and meteorological data: the runway elevation is 3447.7m, the external atmospheric temperature is the monthly average maximum temperature of 26 ℃, the static wind, and the standard sea pressure. The available distance of take-off taxiing, take-off and acceleration stop are all 3370 m. On the main road, the gradient of runway is 0%. The selection of obstacles is shown in Table 1.

Table 1. Obstacles in Jiuhuang airport
Full size table

Model data: (1) 737-700/cfm56-7b24, structure weight limit 69399 kg, optimal configuration flap 1, air conditioning automatic, anti icing off. Standard two-stage mode, balanced V1 strategy (2) 737-800/cfm56-7b26, the weight limit of structure is 79010 kg, the optimal configuration is flap 1, and the air conditioner is automatic and anti icing. Standard two-stage mode, balanced V1 strategy.

4.1 Jiangbei Airport, 737-800/CFM56-7B26 Model

The total track height range of BPS is 122 m to 292 m. The following calculation uses 122 m Leveling Height for leveling; The takeoff weight within the maximum takeoff weight range is used to simulate the takeoff of the aircraft. Different temperatures are used to simulate the aircraft take-off, only changing the air temperature of the airport, calculating the altitude of the aircraft when it reaches the designated point, quantitatively analyzing the influence of temperature on the aircraft take-off performance, and exploring its law.

As shown in Fig. 2, the vertical and horizontal tracks of the aircraft take-off simulation are as follows.

Fig. 3.
figure 3

BCOP horizontal interface

Full size image
Fig. 4.
figure 4

BCOP vertical interface

Full size image

The KML file, which is the abbreviation of keyhole markup language, was originally developed by keyhole company. It is a coding specification based on XML syntax and format and used to describe and save geographic information (such as points, lines, images, polygons and models), It can be recognized and displayed by Google Earth and Google maps. As shown in Fig. 3, the track is displayed in Google Earth.

Fig. 5.
figure 5

Google Earth track view

Full size image

Different temperatures are used to simulate the take-off of the aircraft, and only the air temperature of the airport is changed to calculate the altitude of the aircraft when it reaches the designated point, as shown in Table 2.

Table 2. The relationship between the temperature of Chongqing Jiangbei airport and the height of reaching the designated point
Full size table

According to the change rule of temperature and air pressure height at the designated point in Table 2, draw a line chart, and visually analyze the change rule, as shown in Fig. 4

Fig. 6.
figure 6

Broken line chart of the relationship between temperature and the height at the designated point in Chongqing Jiangbei airport

Full size image

It can be seen from Fig. 4 that the relationship between the airport temperature and the height at the designated point is basically linear in the range of—20 ℃ to 20 ℃ (the slope is about—9.8), and it is also basically linear when it is higher than 20 ℃ (the slope is about—45.6), but the slopes of the two stages are different and very different, with the slope nearly four times. It can be seen that when the temperature is high, the influence of temperature on the obstacle surmounting ability of the aircraft is far greater than that of the relatively low temperature operating environment.

4.2 Jiuhuang Airport, 737-700/CFM56-7B24 Model

The total track height range of BPS is 192 m–464 m; The following calculation uses 192 m Leveling Height leveling; The takeoff weight within the maximum takeoff weight range is used to simulate the takeoff of the aircraft. Different temperatures are used to simulate the aircraft take-off, only changing the air temperature of the airport, calculating the altitude of the aircraft when it reaches the designated point, quantitatively analyzing the influence of temperature on the aircraft take-off performance, and exploring its law. As shown in Fig. 5, the vertical and horizontal tracks of the aircraft take-off simulation are as follows.

Fig. 7.
figure 7

BCOP horizontal interface

Full size image
Fig. 8.
figure 8

BCOP vertical interface

Full size image

The vertical and horizontal tracks of the aircraft are simulated by BCOP tracks, as shown in Fig. 6.

Fig. 9.
figure 9

Google Earth track view

Full size image

Different temperatures are used to simulate the take-off of the aircraft, and only the air temperature of the airport is changed to calculate the altitude of the aircraft when it reaches the designated point, as shown in Table 3.

Table 3. The relationship between the temperature of Jiuzhai Huanglong Airport and the altitude at the designated point
Full size table

According to the variation law of temperature and air pressure height at the designated point in Table 3, draw a broken line chart and visually analyze its variation law, as shown in Fig. 7

Fig. 10.
figure 10

A line chart of the relationship between the temperature of Jiuzhai Huanglong airport and the height at the designated point

Full size image

It can be seen from Fig. 7 that within the range of—20 ℃ to 20 ℃, the relationship between the airport temperature and the height reaching the designated point is basically linear (the slope is about—27.8), and it is also basically linear when it is higher than 20 ℃ (the slope is about—68), but the slopes of the two stages are different and very different, and the slope is nearly three times. It can be seen that when the temperature is high, the influence of temperature on the obstacle surmounting ability of the aircraft is far greater than that of the relatively low temperature operating environment (Figs. 8, 9 and 10).

5 Conclusion

Through the data analysis of the two selected airports, combined with the above data curve, the following conclusion is drawn: with the increase of temperature, the obstacle surmounting ability of the aircraft after take-off is also declining. Moreover, it can be seen from the curve in the table that with the increase of air temperature, the takeoff obstacle crossing height basically increases linearly. Within the range of—20 ℃ to 20 ℃, the relationship between the airport temperature and the height at the designated point is basically linear, and it is also basically linear when it is greater than 20 ℃. However, the slopes of the two stages are different and have great differences. That is to say, the temperature change of ordinary airport and High Plateau Airport is more sensitive to the impact of taking off obstacle surmounting, and the higher the temperature is, the greater the impact on the obstacle surmounting ability after taking off. It can be considered that the temperature is a more sensitive factor for taking off obstacle surmounting, which is consistent with the theoretical analysis.

Analysis reason: the temperature has a great influence on the aircraft take-off obstacle. With the increase of air temperature, the air density becomes smaller, the lift is smaller, the aircraft load is smaller, and the ability to take off obstacle is weaker.

In this paper, the influence of temperature on obstacle surmounting is discussed in detail under two different conditions of ordinary airport and High Plateau Airport, and the corresponding specific values are given through the calculation of performance software. On the premise of ensuring flight safety, different temperatures are selected according to the meteorological conditions of the airport at that time to optimize the take-off performance of the aircraft and obtain better economic benefits. In this paper, the research on aircraft take-off obstacle surmounting is only a preliminary theoretical study. The above data are calculated by using the performance software, and there is a certain error with the actual situation in the practical application. However, the software is released by the original aircraft manufacturer, and the research goal is qualitative analysis, so the analysis conclusion obtained by using the software is still of guiding significance.