Navigational hazard

• 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

Hazards to marine navigation

• 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

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

• 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

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Navigational warnings