Navigational hazard


A navigational hazard or hazard to navigation has been defined in various, slightly different, ways:
  • An obstruction, usually sunken, that presents sufficient danger to navigation so as to require expeditious, affirmative action such as marking, removal, or redefinition of a designated waterway to provide for navigational safety.
  • Any obstacle encountered by a vessel in route posing risk or danger to the vessel, its contents or the environment.
  • An obstruction determined to have a substantial adverse effect on the safety and efficient utilization of the navigable airspace.

    Types

s to navigation and airspace hazards to navigation.

Hazards to marine navigation

Hazards may be permanent, or temporary, including seasonal, and fixed or mobile,
  • Fog is temporary, but may occur frequently in some areas and seasons
  • Icebergs are mobile and temporary, and also seasonal in some areas
  • Some river channels are variable
  • Some underwater obstructions are unidentified, others may be known.
  • Both shipwrecks with a fixed position and floating derelicts and other flotsamcan be hazards
  • Seabed obstructions
  • Mined international waterways
The risk associated with a hazard is aggravated when the position is uncertain, or the hazard is unmarked or obscured by poor visibility.

Consequences

  • Marine accidents can occur, which can cause loss of life and vessels, or delays of shipping, unreliable transport of people and goods, and environmental damage.

    Hazards to airspace navigation

  • Weather conditions such as high winds, icing, thunderstorms, wind shear and clear air turbulence, low visibility.
  • Physical obstructions such as tall buildings, radio masts, cranes, wires, mountains, cliffs, power lines.
  • Volcanic ash.
  • Smoke and convection from wildfires.
  • Human factors, such as fatigue, poor navigation, inattention, bad communication and aircrew error.
  • Entering restricted airspace without proper authorisationand warning.
  • Wildlife such as birds can be a hazard, particularly during takeoff and landing.
  • Dysfunctional navigation systems such as radio and radar beacons, lights, etc.

    Conditions determining a hazard

When deciding whether a static hazard will be marked,the following factors may be considered:
  • Location of the obstruction relative to the navigable channel and relative to other hazards
  • Difficulty of navigation near the obstruction
  • Depth of water over the hazard, and how much it is likely to vary
  • Type of vessel traffic in the vicinity of the hazard, particularly draft, but also amount of traffic
  • Physical characteristics of the hazard
  • Probability that the hazard may move
  • Weather conditions that are likely in the vicinity
  • How long the hazard has existed in that location, and any history of accidents involving the hazard, and
  • Whether the object is considered a hazard in terms of alternative legislation

    Marking of navigational hazards

An aid to navigation is any device external to a vessel or aircraft specifically intended to assist navigators in determining their position or safe course, or to warn them of dangers or obstructions to navigation.
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    Navigational warnings

A navigational warning is information published or broadcast providing information on the status of one or more navigational hazards.