# Laboratory Assessment of In-Pavement Airport Lamp's Luminous Intensity Distribution
## 6 Quality Assessment of Used and Refurbished In-Pavement Airport Lamps  
Comprehensive research related to the assessment of the quality of in-pavement airport navigation lamps was carried out in cooperation with Poznaru-Lawica Airport. During tests to verify the operation of the automatic navigation lighting control device, several measurements of the lamps that operated in airport areas and required maintenance during a routine inspection of the system were made. On the basis of statistics, it can be concluded that the touchdown zone lamps were the most degraded, as they are exposed to the greatest damage from planes passing over them. The red centerline lamps were in the best condition, which may be due to the fact that they mark the end of the runway and, therefore, planes do not move on them as often as on other luminaires. The white centerline lamps located on most of the runway have also deteriorated, but not as much as the touchdown zone lamps. These observations prove how necessary it is to control the photometric characteristics of airport lamps to ensure their proper functioning and to select lamps that require replacement. The results of measurements carried out with the use of a device for automatic control of in-pavement navigation lamps are heatmap graphs showing the distribution of luminous intensity at measurement points depending on the position of the sensor moving horizontally and vertically in relation to the light source. They illustrate, similarly to the graphs presented in the standards, the location of the main light beam, which is a key element  
Figure 21: Luminous intensity measurements of TAXI yellow lamp: (**a**) Sonopan L-200P, (**b**) BH1750. Figure 20: Luminous intensity measurements of TAXI green lamp: (**a**) Sonopan L-200P, (**b**) BH1750. when assessing the efficiency of airport lamps. The scale of the graph is selected depending on the type of lamp and the colour of the light emitted by it. Values close to and exceeding the minimum indicated by the standard are yellow, while with a decrease in the value, they turn to a blue shade. Figures 22-24 show exemplary graphs of the luminous intensity characteristics as a function of horizontal and vertical angles for the selected lamps that require repair. The heatmaps presented of the photometric characteristics of the lamps show a significant deterioration in the values of the intensity of the light beam. In the case of the RCL clear lamp (Figure 22), the main light beam is well below normal values, as shown by the dark colour on the scale. In the case of a lamp of the same type but emitting red light (Figure 23), it still meets the EASA requirements, but a significant decrease in the luminous intensity value can be observed. For the touchdown zone lamp (Figure 24), it is impossible to clearly distinguish the area in which the main beam is located on the graph due to the strong degradation of the prism. Figure 23: Luminous intensity measurements of used RCL red lamp: (**a**) heatmap chart; (**b**) lamp view. Figure 22: Luminous intensity measurements of used RCL clear lamp: (**a**) heatmap chart; (**b**) lamp view. After the lamps were refurbished, consisting of the replacement of prisms, cleaning or replacement of the housing, replacement of halogen light sources, and sealing, the photometric characteristics were re-examined. The test results showed that all the in-pavement navigation lighting lamps met the required standards, significantly exceeding the prescribed minima. Figures 25-27 are heat maps of photometric characteristics for luminaires with the same serial numbers as those shown in Figures 22-24. The heatmaps presented with photometric characteristics confirm the efficiency of the luminaires. In any case, the clearly marked main beam of light significantly exceeds the minimum values prescribed by the standards. These lamps can be reused on airport surfaces. The angular pattern shows the exact location of the main beam that runs in an area that corresponds to brand-new lamps.