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Navaids Impact

Navaids Impact assessments

Why assess Navaids Impact effects?

Building developments can potentially interfere with signals received from aeronautical navigation beacons – also known as Navaids. Beacons such as DVOR and NDB can be affected with bearing errors occurring on aircraft instruments.

Large buildings and structures near Navaids can cause potential interference with the most sensitive beacons being Conventional Omni Range (CVOR).  Developments can also impact air – ground radio systems used for voice and data communications.

What are the benefits of a Pager Power Navaids Assessment?

Navaids are typically operated by civil or military aviation authorities and may be safeguarded to distances of up to 15 kilometres.

A Navaids impact assessment can reassure developers that their project will not have an adverse impact whilst reassuring Navaids operators that their navigation services will not be adversely impacted.

What does a Pager Power Navaids Impact Assessment cover?

There are typically two forms of assessment. The first is a geometric safeguarding assessment where the relative height and distance of the proposed development are evaluated against national or international safeguarding rules for the particular type of Navaid.

The second is an impact assessment which consists of a technical and operational assessment to determine the likely overall impact of the proposed development on a particular Navaid.

When are developments assessed?

Proposed developments are typically assessed at the design, planning and permitting stage so as to ensure that a proposed development will not impact a Navaid when it is built.

In a specific case in Mauritius Pager Power assessed the impact of a wind farm on a DVOR after the wind farm became operational – the purpose of the assessment being to identify the unknown cause of interference.

When should an assessment be considered?

It is unlikely that an assessment is likely to be required for developments more than 15 kilometres from a Navaid (note that this threshold does not apply to radar).

Developments are generally more likely to require assessment when one or more of the following apply:

  • Development is within 1km of a Navaid
  • Development is a wind turbine
  • Top of development is higher than the Navaid
  • Navaid is a CVOR or DVOR
  • Development is close to a runway approach
  • Assessment has been requested by Navaid operator

Where are Navaids typically located?

Many Navaids are located on airports or aerodromes. Some beacons are located on hills or high ground away from airports.

Navaids are typically operated by en-route air navigation service providers, airports or military authorities. The two largest consultees in the UK are NATS and the Ministry of Defence.

What types of Navaid can be assessed?

Typically impacts on the following can be considered:

  • NDB – Non Directional Beacon
  • DME – Distance Measuring Equipment
  • ILS – Instrument Landing System
  • LOC – ILS Localiser
  • GP – ILS Glidepath
  • VOR – VHF Omni Range
  • CVOR – Conventional VOR
  • DVOR – Doppler VOR
  • VDF – VHF Direction Finder
  • AGA – Air Ground Air voice communications

What does an assessment typically include?

A typical assessment will include:

  • Development Details
  • Navaid Details
  • Assessment Methodology
  • Safeguarding Assessment
  • Interference Calculations
  • Operational Impact Assessment
  • Conclusions and Recommendations

What countries require Navaids assessments?

Civil and Military Navaids are operated throughout the world and require assessments for developments proposed nearby. Pager Power has undertaken Navaids assessments in:


Next steps

If you are planning a development that may impact an aeronautical navigation aid please get in touch – we can advise whether a Navaid assessment may be able to help your development progress.

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