Parallel Echo Taxiway Ligth Fittings

The project is to buy a Aeronautical Ground Lighting design. Aeronautical Ground systems are a safety critical asset used as a visual aid by pilots in low visibility conditions. It is very important when selecting and specifying an AGL fitting to consider the existing light types currently in use and maintain commonality between existing and proposed lights.

This is a purchase of supply of Aeronautical Ground Lights for Parallel Echo Taxiway at Keflavik Airport

According to article 32 in paragraph 3. in directive 2014/24/EU The negotiated procedure without prior publication may be used for public supply contracts: (b) for additional deliveries by the original supplier which are intended either as a partial replacement of supplies or installations or as the extension of existing supplies or installations where a change of supplier would oblige the contracting authority to acquire supplies having different technical characteristics which would result in incompatibility or disproportionate technical difficulties in operation and maintenance.

DESIGN STANDARDS ARE CRITICAL

EASA CS-ADR-DSN Certification Specifications and Guidance Material for Aerodrome Design

ICAO Annex 14, Volume I

ICAO Doc 9157 Part 4, “Visual Aids”

ICAO Doc 9157 Part 5, “Electrical Systems”

ICAO Doc 9157 Part 6, “Frangibility”

FAA Advisory Circulars

FAA Engineering Briefs

IEC/TS-61827, Electrical installations for lighting and beaconing of aerodromes - Characteristics of inset and elevated luminaires used on aerodromes and heliports.

IEC-61823, Electrical installations for lighting and beaconing of aerodromes - AGL series transformers.

IEC-61822, Electrical installations for lighting and beaconing of aerodromes – Constant current regulators.

IEC-61821, Electrical installations for lighting and beaconing of aerodromes – Maintenance of aeronautical ground lighting constant current series circuits

ENV 50230, Aeronautical ground lighting electrical installation - Control and monitoring systems: General requirements

RISKS

Adopting an alternative product or light fitting manufacturer increases the risk of :-

a) Potential for variations in photometric performance between new and existing taxiway centreline lights and risk of change in performance characteristics of related equipment such as Constant Current Regulators and AGL Control Systems.

b) Loss of commonality between new and existing light fitting components and requirement to retain multiple differing spare parts inventories for different manufacturers i.

c) Lamp failure response and action time may be hindered as the need to identify an individual component manufacturer is introduced.

d) Torque settings vary between different manufacturers recommendations. Failure to torque in accordance with the manufacturers recommendations can result in failure ii of the inset fitting installation and pose a significant risk and danger to life.

Conclusion

It is therefore in accordance with the article 32 in paragraph 3. in directive 2014/24/EU that the Aeronautical Ground Lighting for Parallel Taxiway Echo is installed as per the design and specification recommendations and a common manufacturer consistent with the existing AGL fittings installed across the airfield is maintained.

Parallel Echo Taxiway Light fittings

DESIGN CRITERIA

Aeronautical Ground Lighting systems are a safety critical asset used as a visual aid by pilots in low visibility conditions.

It is common and best practice in any Aeronautical Ground Lighting design to ensure compatibility and uniformity across an airfield and this encompasses not just the light itself, but also the installation criteria as defined by a light fitting manufacturer (deep or shallow base can installation, seating and adapter ring size, fitting bolt torque settings, horizontal and vertical beam direction etc).

When selecting and specifying an AGL fitting, particularly a centreline fitting, it is also important to consider the existing light types currently in use and strive to maintain commonality between existing and proposed lights. This provides greater assurance of consistent photometric performance between existing and new installations, which is crucial to a pilot during low visibility manoeuvres. Inconsistent photometrics can create confusion and alter a pilot’s perception of depth and speed.

A design that adopts this best practice will also ensure unabated continuity of existing maintenance regimes without introducing additional risk through implementation of supplementary manufacturer specific procedures, such as fitting installation tolerances and torque settings. Furthermore, a common component mitigates inventory errors occurring in respect of spare parts. This is particularly crucial at airports where light fittings are at an increased risk of damage due to snow ploughing.

AGL light fittings in a non-holistic environment may also be susceptible to system performance and control system issues. Maintaining the same light fitting type assists in mitigating these risks. For example, LED light fittings and addressable devices, may create a non-linear or reactive load on the circuit. In such circumstances, having varying types of fixtures and addressable devices makes fault finding and rectification challenging as these devices can include switching power supplies which may impart a capacitive characteristic to the circuit load. In addition, when the circuit is energised, these devices can initially appear to provide a relatively high voltage drop and suddenly change to a lower drop.