Low visibility procedures: what you need to know

With the great British weather being reliably unreliable, we occasionally need to put additional measures in place to safely manage flights in UK airspace. These measures ensure we can handle as many flights as possible, with minimal disruption and without compromising on safety, which is always our primary objective.

In heavy rain, foggy or snowy weather, you may hear that ‘low visibility procedures’ (LVPs) have been put in place at airports. But what are they and what does that mean?

What are LVPs?

LVPs are a set of procedures implemented by Air Traffic Control when visibility falls below a safe level to operate in the usual way. LVPs help guide both pilots and air traffic controllers to manage aircraft operations effectively and safely during challenging conditions.

When are LVPs activated?

Airports have lots of sensors around them, including around the runways. These sensors can measure visibility and, if visibility is reduced beyond a certain level, this will trigger the implementation of LVPs. In LVPs, extra safety precautions are put in place to ensure that aircraft separation, approach, landing and taxiing are all managed safely.

What are the safety precautions?

When LVPs are activated, the aircraft are usually kept further apart to account for the difficulty in visually tracking them and ensuring safe distance between them. This helps the air traffic controllers to manage the aircraft safely.

When LVPs are activated, any aircraft on the ground are kept further away from the runway.  The Instrument Landing System (ILS) uses radio transmissions to help guide aircraft safely down the approach to the runway at night and during these times of reduced visibility.

By minimising the number of aircraft moving on the airfield and close to the runway, the ILS gives the most accurate signal to the incoming flight as possible, becoming the pilot’s ‘eyes’ when visibility is poor.

Why are LVPs important?

While they may cause some delays, LVPs are essential for ensuring that aircraft can continue to land, take off, and move on the ground, safely, even in poor conditions. They also facilitate smooth and predictable operations in reduced visibility.

NATS air traffic controllers are well-trained to deal with challenging conditions, and our teams work closely with airlines and airports to safely and effectively handle as many flights as possible, whatever the weather.