LED Light Sources in the Approach Slope Indicators and Their Visibility in Inhomogeneous Atmosphere

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60162694%3AG43__%2F15%3A00531577" target="_blank" >RIV/60162694:G43__/15:00531577 - isvavai.cz</a>

Result on the web

<a href="http://vavtest.unob.cz/registr" target="_blank" >http://vavtest.unob.cz/registr</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1109/DASC.2015.7311394" target="_blank" >10.1109/DASC.2015.7311394</a>

Result language

angličtina

Original language name

LED Light Sources in the Approach Slope Indicators and Their Visibility in Inhomogeneous Atmosphere

Original language description

The PAPI (Precision Approach Path Indicator)optical system with incandescent light sources (halogen airport lamps) is already an integral part of the airport lighting system (ALS), both stationary and mobile airfields of The Czech Air Force. The development unambiguously directs to the replacement of the incandescent light sources in the APAPI (Abbreviated PAPI) an optical unit with LED (Light-Emitting Diodes) light source with the high luminous efficacy. Considerable technological and light differences among the LED light sources and the halogen airport lamps lead to high difficulties of the theoretical design, development and construction of the new LED APAPI optical system assembly. This article illustrates the shape, light efficiency and spectral characteristics, differences among the LED light sources and the halogen airport lamps and a possible way of APAPI optical system design with LED light sources. Every element of the approach slope indicator system must be watched for the minimum specific time to provide information. This time is defined at least 2 or 3 seconds and most importantly depends on the pilot and his abilities. The visibility of the APAPI light is caused by its light on the retina surface in the eye. The basic requirement is the fact that the intensity of the light must be on a higher level than the contrast threshold. The contrast threshold depends on lots of conditions - basically on the color of the light or on the bandwidth of the light spectrum, brightness of the background, a current state of the pilot, etc. If the light source dimension is small enough - ten centimeters watched from hundreds meters – it is considered as a spot light. Anyway, Allard’s law is used for the range determination of the simple APAPI light. The results of these eflections are described and defined in the aerodrome standards and documents, especially in ICAO Annex 14 for a long time. However, these kinds of standards are built only for classical light sources.

Czech name

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Czech description

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Type

D - Article in proceedings

CEP classification

KA - Militarism

OECD FORD branch

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Project

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Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2015

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Article name in the collection

34th DASC Proceedings

ISBN

978-1-4799-8939-3

ISSN

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e-ISSN

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Number of pages

9

Pages from-to

1-9

Publisher name

ALR International

Place of publication

Orlando, USA

Event location

Praha

Event date

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Type of event by nationality

WRD - Celosvětová akce

UT code for WoS article

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