The two intersecting runways at Malta International Airport will no longer be known as Runways 32/14 and Runways 24/06 but, rather, 31/13 23/05.

Of course, nothing in the infrastructure will change. It is only the runways' designation that will change, necessitated by magnetic variations.

The direction that the needle of a magnetic compass points towards is not the geographic north pole. Magnetic compass needles point towards the earth's magnetic north pole. In simple terms, the earth has two north poles and two south poles. Malta being within the earth's northern hemisphere, we refer to the magnetic north being located south of the geographic north.

The geographic north and south poles are the points on the northern and southern hemispheres respectively, where the earth's axis of rotation meets the earth's surface. They are the meeting point of all meridians of longitude. The term True North represents the direction from one's position of the geographic north pole. This direction lies along a meridian of longitude.

In contrast, the earth's two magnetic poles are the focus of the planet's magnetic field and these are the points where a magnetic compass needle would point directly into the earth's surface if allowed to float freely. The positions of the magnetic poles wander continuously and the opposite magnetic poles are not located on a straight line passing through the centre of the earth.

Since the geographic and magnetic poles do not coincide, there will almost always be an angular difference between True North and the north direction on a compass. This angular difference is called Magnetic Declination or Magnetic Variation. In a twist of added complexity, the earth's magnetic field is not uniformly aligned between the magnetic poles. This is due to complex factors including the composition of the earth's crust, particularly the presence of iron ore deposits or magnetite. Magnetic declination thus varies from place to place and with the passage of time.

The extent of Magnetic Variation has a direct impact on aircraft navigational charts and the aerodrome infrastructure. This information is therefore very significant to Malta International Airport plc, in the case of Malta. Obligations derived from the International Civil Aviation Organisation (ICAO) standards and recommended practices require MIA to monitor and declare the value of Magnetic Variation on the aerodrome site. In particular, since runways are named according to their magnetic heading, the extent of magnetic variation determines the formal designation of runways.

The present designations for the longer runways at MIA are 32 (from Kalafrana) and 14 (from Luqa). Being one asphalt strip, the latter is in the complementary direction to the former, that is, they are 180 degrees apart. Runway designations are declared as two digit numbers. They represent the whole number which is nearest to one-tenth of the magnetic heading of the centreline of the runway. For example, the last declared magnetic heading for Runway 32 was 315 degrees (magnetic), which divided by 10 and rounded up, becomes 32.

In the early half of 2007, MIA commissioned the Istituto Nazionale di Geofisica e Vulcanologia in Italy to conduct site measurements to determine the prevailing magnetic headings of the runways. INGV determined that the magnetic headings of the azimuth of the main runway now read 312°42' for Runway 32 and 132°40' for Runway 14. These values are decreasing at the rate of 0.08 degrees a year. The value for the magnetic variation is 2° 06' 34" (positive, to east). The results imply that the runway designations must change with Runways 32/14 becoming Runways 31/13 and Runways 24/06 becoming Runways 23/05.

This change will require all documented references to the runway designations to be amended, aerodrome signage to be changed, runway markings to be replaced, radar and control system maps to be updated and, not least, to encourage a rapid transition by pilots, MIA and Air Traffic Control staff to using the new designations. Considering that accurate and efficient communication has a significant bearing on aerodrome safety, this is seen as a major challenge. Considering that each digit is pronounced separately for clarity in radio communications (say, Runway three one), the recurrence of number "three" within the new designations is expected to make differentiation between the new headings somewhat difficult during the transition phase.

To meet the objectives, a task force comprising representatives from the Department of Civil Aviation, MIA and Malta Air Traffic Services Ltd has been set up to plan the transition.

A spokesman for MIA said it is intended that stakeholders from the aviation community will also be invited to participate in planning for the transition process in due course.

The implementation date for the new runway headings has been set by the Department of Civil Aviation for this month.

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