• Low Visibility Procedures - LVP

    How does an aeroplane land when you cannot see at all?

Have you ever wondered how to land a plane when it’s foggy? What do pilots do to touch down successfully when there’s zero visibility?

As you can imagine, flight operations can be severely affected on foggy days. That’s where Low visibility procedures or LVP come into play. Nothing is left to improvisation in aviation. Everything is organised and planned out according to the highest safety requirements.

Although aeroplanes spend most of their time above clouds, there are moments, such as when taking off, approach and landing where this is not the case.

We explain below everything about procedures and instruments available to pilots to fly with zero visibility. But before we do so, you just have to watch this incredible video where a Boeing 777 carries out a spectacular landing under LVP procedures. Don’t miss it as the view from the cabin will take your breath away!

How do pilots instantly know what level of visibility there is?

At airports, a METAR or meteorological report is emitted every 30 minutes. These reports explain, in a technical manner, the meteorology at the airport at the time it is measured. It’s the pilot in command’s responsibility to check the last meteorological report before the flight.

In bigger airports, such as in the case of the airport of Malaga, there’s an ATIS or Automatic Terminal Information Service. This system is continually issuing the last METAR as well as other information of interest to pilots.

The base of clouds

Pilots have to know the height at which the base of clouds is located in order to decide what type of approach or take off they are carrying out. Also, the value of visibility will allow them to estimate when they’ll be able to see the runway.

To obtain this data, airports have meteorological departments who are in charge of doing the required measuring and forecasts. In Spain, we also have the AEMET, short for Agencia Estatal de Meteorología.

Nephobasimeter:

A nephobasimeter is used for measuring the base of the clouds. The way it functions is by emitting a vertical ray of light and measuring how long the beam takes to return to the instrument; thus, being able to obtain the height of the clouds’ base. It is also known as a ceilometer.

Transmissometer:

A transmissometer is an instrument used for horizontal visibility and, as in the case of the previous one, by means of a light beam, it estimates horizontal visibility or runway visibility range: RVR.

RVR is usually measured in three different positions: runway header, half and end.

Other low visibility procedures

Within low visibility procedures, there are endless practices activated to ensure aeroplanes´ manoeuvres when there´s zero visibility outdoors.

In these cases, coordination among various airport departments activates certain functions, such as the following:

  • Changing taxi holding positions to create more distance from the runway.
  • Increasing the intensity of taxi lights (for further info on this, please take a look at our post on visual night flights).
  • Aircraft led by a marshaller to the parking area or main taxiway.
  • Additional actions.

Air controllers also have to know the minimum heights of approach in low visibility procedures.

What are minimum heights?

Although it may seem strange, commercial aeroplane pilots can spend most of their flying time without taking a look outside as aircraft have the required systems and instruments available so that pilots know where they are at all times.

Still, ‘minimums’, as they are termed in aeronautical jargon, is the lowest altitude from which a pilot can visualise ground sufficiently in order to begin the approach. If the runway is visible, the manoeuvre can be carried out normally but if there isn’t, landing must be aborted.

Some airports have a system permitting particular aircraft to land automatically when in zero visibility, however, for this to happen, airports and aeroplanes have to be certified with the highest safety levels.

This type of flight is what is known as IFR or instrumental flight rules. Certified for this type of instrumental operations, we have Cirrus SR20, Diamond DA40 and Diamond DA42 NG at One Air. We also fly IFR from Malaga International Airport, which operates 24hrs.