RUNWAY ARRANGEMENT FOR SIMULTANEOUS LANDING AND TAKE OFF

Abstract

An airport runway arrangement for commercial aircraft comprises a first runway section, a second runway section extending substantially in prolongation of the first runway section and an intermediate section between the first and second runway sections.

Claims

1.-4. (canceled)

5. An airport runway arrangement for commercial aircraft, comprising: a first runway section; a second runway section extending substantially in prolongation of the first runway section; a first marked threshold provided on the first runway section, the first marked threshold being for use during a first mode of operation; and a second marked threshold provided on the second runway section, the second marked threshold being spaced from the first marked threshold and being for use during a second mode of operation, wherein the first marked threshold and the second marked threshold have the same direction of operation.

6. The airport runway arrangement according to claim 5 further comprising an intermediate section between the first runway section and the second runway section, the intermediate section being designated as at least one of: not to be used for landing; not to be used for taking-off; and not to be used by aircraft under normal operation.

7. The airport runway arrangement according to claim 5 wherein the first runway section and the second runway section are each suitable for landings and/or take-offs and/or wherein the first runway section and the second runway section are each between 1000 m and 8000 m long.

8. The airport runway arrangement according to claim 5 wherein the second threshold is spaced at least one of: between 1 km and 5 km from the first threshold, between 1.5 km and 3 km from the first threshold, and 2 km from the first threshold.

9. The airport runway arrangement according to claim 5 wherein the first threshold and the second threshold are landing thresholds.

10. The airport runway arrangement according to claim 5 wherein the first threshold and the second threshold are take-off thresholds.

11. The airport runway arrangement according to claim 9, wherein the first threshold designates only the first runway section as being useable for landing in the first mode of operation and the second threshold designates only the second runway section as being useable for landing in the second mode of operation.

12. The airport runway arrangement according to claim 10, wherein the first threshold designates only the first runway section as being useable for taking-off in the first mode of operation and the second threshold designates only the second runway section as being useable for taking-off in the second mode of operation.

13. The airport runway arrangement according to claim 6 wherein the second threshold is at an end of the second runway section proximate the intermediate section such that in the second mode a landing aircraft overflies the first runway section.

14. The airport runway arrangement according to claim 6 wherein the intermediate section is at least one of: at least 200 m in length; and between 240 m-600 m in length; between 175 m and 1500 m in length; between 600 m and 1500 m in length; and approximately 600 m in length.

15. The airport runway arrangement according to claim 6 wherein the designation of said intermediate section comprises at least one of lights, markings and reflectors on said runway arrangement.

16. The airport runway arrangement according to claim 5, further comprising: means for defining the first runway section; means for defining the second runway section; and means for defining the first threshold and the second threshold, wherein the means for defining comprises at least one of: markings; lights; painted markings; reflectors; and means for communicating the definitions of the sections.

17. An airport runway arrangement according to claim 5 further comprising a safety area at an end of each runway section.

18. The airport runway arrangement of claim 5, being for at least one of: commercial passenger carrying aircraft; and aircraft operating under civil regulations.

19. A method of operating an airport runway arrangement for commercial aircraft, the method comprising the steps of: providing a first runway section; providing a second runway section extending substantially in prolongation of the first runway section; providing a first marked threshold provided on the first runway section, the first marked threshold being for use during a first mode of operation; and providing a second marked threshold on the second runway section, the second marked threshold being spaced from the first marked threshold and being for use during a second mode of operation, wherein the first marked threshold and the second marked threshold have the same direction of operation.

20. The method of claim 19 further comprising: in the first mode of operation, directing an aircraft to land using the first threshold; and in the second mode of operation, directing an aircraft to land using the second threshold, wherein the direction of landing is the same in the first mode of operation and the second mode of operation.

21. The method of claim 19 further comprising: in the first mode of operation, directing an aircraft to take-off using the first threshold; and in the second mode of operation, directing an aircraft to take-off using the second threshold, wherein the direction of take-off is the same in the first mode of operation and the second mode of operation.

22. The method of claim 20 wherein directing an aircraft to land comprises a two-stage approach where the angle of descent changes from a steeper angle to a shallower angle.

23. The method of claim 22 wherein: the steeper angle is 5 and the shallower angle is 3; the change in angle of descent is a gradual change; and/or the angle of descent changes at a point 3 km from landing.

24. An airport runway arrangement for commercial aircraft, comprising: a first runway section; a second runway section extending substantially in prolongation of the first runway section, the second runway section having the same direction of operation as that of the first runway section; and an intermediate section between the first and second runway sections, wherein the intermediate section is marked as an intermediate safety area, said marking indicating that the intermediate section is not to be used by aircraft under normal operation; thereby simultaneously allowing a landing aircraft to land on one of said first and second runway sections, and a departing aircraft to take off from the other of said first and second runway sections, whilst not using the intermediate section; said landing and departing being independent of one another.

25. The runway arrangement according to claim 24 wherein the intermediate section is one or more of: between 240 m and 600 m in length, or between 600 m and 1500 m in length, or approximately 600 m in length; of variable length; suitable for use in an undershoot or overshoot; marked separately at each end as an intermediate safety area; marked as not to be used for taxiing; marked as to be used only for emergencies; and containing instrument landing systems.

Description

[0087] The invention extends to methods and/or apparatus substantially as herein described with reference to the accompanying drawings in which:

[0088] FIG. 1 is an example of an existing airport arrangement;

[0089] FIGS. 2A and 2B are examples of a runway arrangement according to one embodiment of the invention;

[0090] FIGS. 3A-3D show the operation of a runway arrangement according to another embodiment of the invention;

[0091] FIG. 4A shows the runway arrangement of FIGS. 3A and 3C together;

[0092] FIG. 4B shows the runway arrangement of FIGS. 3B and 3D together;

[0093] FIGS. 5A-5G show steps in an example method of expanding a runway arrangement according to one embodiment of the invention;

[0094] FIGS. 6A-6B show alternative steps of expanding a runway arrangement to that shown in FIG. 5D;

[0095] FIGS. 7A and 7B show an example landing approach according to one embodiment of the invention which can be used with the runway arrangements of FIGS. 2A, 2B, 3A-3D, 4A and 4B;

[0096] FIG. 8A shows another example landing approach which can be used with the runway arrangements of FIGS. 2A, 2B. 3A-3D, 4A and 4B; and

[0097] FIG. 8B shows the landing approaches shown in FIGS. 7A and 7B and 8A combined.

DETAILED DESCRIPTION

[0098] The term runway used in this description preferably refers to an area designated and certified by the regulatory and safety authorities for use by an aircraft for taking-off and/or landing. Typically, this is a suitably hard surfaced area which is demarcated (i.e. distinct to taxiways etc.) as a runway.

[0099] In the description below the term longitudinal length or length preferably refers to the length of the runway along which an aircraft typically moves when landing or taking-off. The term lateral width or width preferably refers to the width of the runway, or group of runways (depending on context), measured perpendicularly to the longitudinal length.

[0100] Existing commercial airports for passenger carrying aircraft often have two or more runways to increase the capacity over a single runway. The configuration of these runways depends on the layout of the airport terminal(s), the space available, the surrounding geography and the prevailing weather conditions (amongst other factors).

[0101] FIG. 1 shows an example of an existing airport arrangement 100 using two runways 102, 104. This arrangement is common where the two runways 102, 104 are sufficiently far apart so as not to interfere with one another's operations during normal use, and each runway is close to the terminal 106, or alternatively an aircraft-parking stand. Each runway is often designated as a landing or take-off runway, or as mixed mode where aircraft use the same runway for both landing and taking off in turn, with the aircraft moving in the same direction. Such designations may not be permanent, and, for example, may be dependent on time of day or wind conditions.

[0102] Adding a third runway (shown by dotted runways 108) to such an existing arrangement would inevitably either interfere with operations, as shown by runway 108-1, or require a long taxi from the terminal 106 or the aircraft-parking stand, as shown by runway 108-2. This arrangement may also require aircraft to cross runway 102 when taxiing between runway 108-2 and the terminal or aircraft-parking stand. Such arrangements of additional runways may also make go-arounds (where an aircraft aborts approach or landing and loops round for another attempt) more dangerous as the aircraft may have to cross the flight path of other aircraft approaching or departing from the other runways.

[0103] An alternative runway arrangement for commercial, passenger carrying aircraft operating under civil regulations is shown in FIG. 2A where a single runway is split into two sections 202-1, 202-2 separated by an intermediate area 210-3. In the example shown, the first runway section 202-1 is used as a landing runway and the second runway section 202-2 is used as a take-off runway. The total runway length of this arrangement is longer than those shown in FIG. 1 to allow aircraft to simultaneously land and take-off from each section of the runway. Safety areas 210-1 and 210-2 are provided as required by regulatory and safety authorities at each end of the runways (where they may be called Runway End Safety Areas (RESAs)) to reduce the risk of damage to aircraft in the event of an undershoot, overshoot, or excursion from the runway. A similar intermediate safety area 210-3 to fulfil the same purpose (that is, preferably, to reduce the risk of damage to aircraft in the event of an undershoot, overshoot or excursion from the runway, as appropriate, of aircraft) is provided at the boundary between the two sections of runway. As used herein, the term intermediate safety area or intermediate safety section preferably connotes an area or section of runway that is not used during normal operations, but preferably is only used in the event of an undershoot, overshoot or excursion from the runway, and preferably is not used in the case of a manoeuvre across the runway. Preferably, the intermediate safety section is variable or movable. Preferably, the intermediate safety section is removable, for example in the event that the entire runway is used for an aircraft manoeuvre (such as take-off or landing). Each section of runway is suitably marked so that aircraft pilots can see where the section of runway designated respectively for arriving and departing aircraft starts and finishes. A person skilled in the art would realise that a wide variety of runway markings and lighting that are currently known in the art would be suitable.

[0104] A go-around is shown in FIG. 2A indicating how landing aircraft turn away from the runway in the event of an aborted approach or landing. This occurs at the start of the landing section 202-1 and therefore avoids conflict with departing aircraft.

[0105] FIG. 2A shows equal length runway sections each side of the intermediate safety area. However, the position of the intermediate safety area is not fixed, allowing the length of the runway sections each side to be increased or decreased in length according to operating requirements. Preferably, the safety areas 210 are adjustable with respect to their dimensions and/or positions depending on the wind direction and spatial requirements of landing and departing aircraft.

[0106] This runway arrangement can also be used in the opposite direction of operation, i.e. the runway section 202-1 being used as a take-off runway and section 202-2 being used as a landing section. Preferably, in use, the directions of operation of the runway sections 202 are switchable.

[0107] A runway arrangement for commercial, passenger carrying aircraft operating under civil regulations, identified generally by the reference numeral 200, where a pair of runways is provided, is shown in FIG. 2B. In the example shown, the first runway sections 202-1 and 204-1 are used as landing runways and the second runway sections 202-2 and 204-2 are used as take-off runways. The total length of each runway of this arrangement is longer than those shown in FIG. 1 to allow aircraft simultaneously to land and take-off from each section of the runway.

[0108] Safety areas 210-1, 210-2, 210-3 and 210-4 are provided as required by regulatory and safety authorities at the each end of runway (where they may be called Runway End Safety Areas (RESAs)) to reduce the risk of damage to aircraft in the event of an undershoot, overshoot, or excursion from the runway. A similar intermediate safety area 210-5 and 210-6 to fulfil the same purpose is provided at the boundary between the two sections of runway. Each section of runway is suitably marked so that aircraft pilots can see where the section of runway designated respectively for arriving and departing aircraft starts and finishes. A person skilled in the art would realise that a wide variety of runway markings and lighting that are currently known in the art would be suitable. Preferably, the safety areas 210 are movable/variable by adjusting the associated markings (eg lighting) on the runway. Preferably, the safety areas 210 are sterile under normal operation, in that the areas are free from on-ground aircraft, including any aircraft that are taxiing or being manoeuvred. Preferably the safety areas 210 are free from aircraft that are taxiing or being manoeuvred across the runway.

[0109] In one example, one and the same intermediate safety area is used for landing and take-off. If, in an emergency, such as an overshoot, a longer portion of runway is needed, then the intermediate safety area (typically in the form of a set of runway markings, for example lights) is varied so as to designate a longer portion of runway. In one example (with the figures given being approximate to the nearest 5 or 10%), a runway that is 6400 m long in total has a 2800 m long first runway portion, an intermediate safety area 400 m in length and a second runway portion that is 3200 m in length. Alternatively, there is a 2600 m long first runway portion, an intermediate safety area 600 m in length and a second runway portion that is 3200 m in length. In a further alternative example, there is a 2800 m long first runway portion, an intermediate safety area 600 m in length and a second runway portion that is 3000 m in length. In each of the above examples, at least two sets of markings are used in order to accommodate adjustments to the length of the runway and/or the direction of operation of the runway arrangement. The take-off runway length is available to be made longer by the length of the intermediate safety area (e.g. an additional length of 600 m or 400 m as per the above examples) or a portion of the length of the intermediate safety area, since the intermediate safety area is preferably redundant for take-off, but is preferably required for landing. The designation of the intermediate safety area is varied for different directions of operation of the runway arrangement. Preferably, there are at least two intermediate safety areas or four intermediate safety areas in two, preferably contiguous, pairs (for example, one pair for Westward operations and another pair for Eastward operations). Preferably, the intermediate safety area is available to be partitioned into a plurality of component portions so as to allow greater granularity in the adjustment of the intermediate safety area and the length and/or position of runway sections.

[0110] FIG. 2B shows equal length runway sections each side of the intermediate safety area 210-5 and 210-6. However, the position of the intermediate safety area is not fixed, allowing the length of the runway sections each side to be increased or decreased in length according to operating requirements.

[0111] A go-around is shown for both landing runways in FIG. 2B indicating how landing aircraft turn away from the runway in the event of an aborted approach or landing. This occurs at the start of the landing sections 202-1 and 204-1 and therefore avoids conflict with departing aircraft.

[0112] This runway arrangement can also be used in the opposite direction of operation, i.e. the runway sections 202-1 and 204-1 being used as take-off runways and sections 202-2 and 204-2 being used as landing runways. Reversing the direction of operation of the runways in this way would be particularly advantageous where the wind direction changes or different directions of approach are preferred at different times of day, for example to limit aircraft noise on areas around the airport. Flexibility in the adjustment of the position and/or size of the safety areas 210 helps facilitate dual-direction operation.

[0113] Dashed lines show typical aircraft movements on the ground to and from the taxiways 212. A person skilled in the art will appreciate that aircraft ground movements are in reality more complicated than shown but ground movement of arriving and departing aircraft is possible without conflict.

[0114] Table 1 below shows dimensions of an example runway arrangement in FIGS. 2A and 2B:

TABLE-US-00001 TABLE 1 Example dimensions of elements of a runway arrangement Reference numeral Description Length 202-1, 202-2, 204-1, 204-2 Runway sections 2200-3200 m 210-1, 210-2, 210-3, 210-4 Runway end safety areas 300 m 210-5, 210,6 Intermediate safety areas 300-600 m d Runway separation 1035 m

[0115] The lengths provided in Table 1 are purely by way of example and depend on various factors such as the type of aircraft that use the runway and the space available. For example, the runway sections may be between 1000 m and 8000 m long, preferably between 2000 m and 4000 m in length. Similarly, the dimensions of the RESAs and the intermediate safety areas may be longer or shorter as defined by local regulatory requirements; in one preferred example they are between 240 m and 600 m in length, but preferably up to 1500 m in length. The intermediate safety area is preferably at least 175 m, 180 m, 200 m, 240 m, 250 m or 300 m in length. Furthermore, the runway separation (d) is often defined by local regulations and may be longer or shorter.

[0116] By extending the length of existing runways and taxiways at an airport, the arrangements shown in FIGS. 2A and 2B can substantially increase capacity without the need to construct entirely new runways which might expose more areas around the airport to aircraft noise. Improving the efficiency of an airport by increasing capacity reduces the need for arriving aircraft to be held in stacks circling whilst waiting for a landing slot, and thus reduces overall CO.sub.2 emissions per flight. Furthermore, the runway arrangement shown increases efficiency and capacity, reduces taxiing distances compared to multiple runway layouts, and reduces hold times for aircraft awaiting a take-off slot, which also reduces the CO.sub.2 emissions per flight.

[0117] The arrangement shown in FIGS. 2A and 2B may be somewhat limiting in certain examples if regulatory and safety authorities require departing aircraft to wait for a landing aircraft to slow to a safe speed before the departing aircraft is allowed to enter the take-off section of the runway.

[0118] FIGS. 3A-3D show an alternative embodiment identified generally by the reference numeral 300, where the landing sections 302-1, 304-1 are offset laterally from the respective take off sections 302-2, 304-2. This reduces the risk of any perceived potential conflict between arriving and departing aircraft. The total width of each runway 302, 304 is greater than that of FIGS. 2A and 2B (say 70 m to 170 m preferably 85 m to 95 m, as opposed to 40 m to 50 m, but in any event as required by the regulatory and safety authorities), whilst runways and taxiway lengths are extended in the same way as those shown in FIGS. 2A and 2B.

[0119] This arrangement would be particularly advantageous where an existing runway is wider than is required by the regulatory and safety authorities and can be divided longitudinally to provide two contiguous, parallel runways. Alternatively, the existing runway can be widened, to one or both sides, to provide the required width.

[0120] FIGS. 3A-3D illustrate the ways in which this runway arrangement can be used. FIGS. 3A and 3B illustrate two arrangements when Southerly operations are used and FIGS. 3C and 3D show the corresponding runway arrangements when Northerly operations are used. In one example, a switch in runway operation modality from that shown in FIGS. 3A to 3C would represent a change from Southerly to Northerly operations; the designation of the safety areas is adjusted accordingly.

[0121] The positions and/or preferably the length of the intermediate safety areas vary as shown by the different arrangements, allowing the length of the runway sections each side to be increased or decreased in length as shown and according to operating requirements. Preferably, the length of the intermediate safety area is dynamically varied in dependence of various factors, including aircraft propulsion blast effects, aircraft performance effects and/or obstacle limitation surfaces (for example, so as to allow a departing aircraft adequate clearance past potential obstacles, such as the tail fin of a ground aircraft). Examples of where different length runways and/or preferably intermediate safety areas would be advantageous is where light/medium aircraft land and take off from shorter sections and large/heavy aircraft land and take off from the longer sections. This arrangement also avoids the problem of smaller aircraft being affected by the vortices produced by large aircraft which have landed/taken off immediately beforehand. The lengths of these sections could be tailored to the exact type of aircraft using the runway arrangement and would not necessarily be permanent. Table 2 shows example dimensions for such a scenario:

TABLE-US-00002 TABLE 2 Example dimensions of elements of a runway arrangement Reference numeral Runway type Length 302-1 Landing - large/heavy 2500-4000 m 302-2 Take-off - light/medium 1000-2500 m 304-1 Landing - light/medium 1000-2500 m 304-2 Take-off - large/heavy 2500-4000 m

[0122] The lengths provided in Table 2 are purely by way of example and depend on various factors such as the type of aircraft that use the runway and the space available. For example, the overall length of each runway 302, 304 may be between 3000 m and 8000 m, preferably between 4000 m and 6000 m, more preferably approximately 5400 m (excluding intermediate safety areas). In a preferred example the longer runways 302-1, 304-2 are substantially 3200 m long and the shorter runways 302-2, 304-1 are approximately 2200 m long. Preferably, the total length of the runway arrangement is at least 5000 m, 6000 m, 6400 m, 6600 m, 6800 m or 7000 m in length. This may extend the runway arrangement beyond the existing bounds of the airport, possibly into a less densely populated area, which might bring noise advantages as described later in relation to FIGS. 7A and 7B.

[0123] Safety areas 310-1, 310-2, 310-3 and 310-4 are provided as required by regulatory and safety authorities at each end of the runway (where they may be called Runway End Safety Areas (RESAs)) to reduce the risk of damage to aircraft in the event of an undershoot, overshoot, or excursion from the runway. A similar intermediate safety area 310-5 and 310-6 to fulfil the same purpose is provided at the boundary between the two sections of each runway. Each section of runway is suitably marked so that aircraft pilots can see where the section of runway designated respectively for arriving and departing aircraft starts and finishes. A person skilled in the art would realise that a wide variety of runway markings and lighting that are currently known in the art would be suitable. Preferably, the safety areas 310 are movable by adjusting the associated markings on the runway.

[0124] Preferably, the safety areas 210 are sterile under normal operation, in that the areas are free from on-ground aircraft, including any aircraft that are taxiing or manoeuvring, preferably the safety areas 210 being free from aircraft that are taxiing or manoeuvring across the runway.

[0125] A go-around is shown for both landing runways in FIGS. 3A-3D indicating how landing aircraft turn away from the runway in the event of an aborted approach or landing. This occurs at the start of the landing sections 302-1 and 304-1 (FIGS. 3A and 3B) and landing sections 302-4 and 304-4 (FIGS. 3C and 3D) and therefore avoids conflict with departing aircraft. The outer pair of runways (302-1 and 304-1 in FIGS. 3A and 3B and 302-4 and 304-4 in FIGS. 3C and 3D) are designated as landing runways to allow aircraft to turn away from the runway without conflicting with departing aircraft on the inner pair of runways.

[0126] In FIGS. 2A-2B and 3A-3D designating areas as safety areas 210 and 310 may comprise physical changes such adding lighting, runway markings and/or software-implemented changes such as alerting pilots and air-traffic controllers to the runway length available via a user interface. These designations may be altered by a user and/or computer system altering the active lighting and/or markings on the runway and making corresponding changes to the user interface display for the pilots and air traffic controllers. Such a system would allow flexibility in the location of intermediate safety areas. Also, in the event of an aircraft needing a much longer runway than usually required, the full length of each runway could be used since the intermediate safety areas, as well as being flexible in location, can also be used as part of the runway if required.

[0127] Instrument Landing Systems (ILS), used to aid landing, are typically arranged such that the aerials of the ILS are placed at the distal end of a runway. With reference to FIGS. 2A and 2B, ILS signal degradation is expected due to the distance between a landing aircraft and the ILS aerial, in addition to potential obstruction from departing aircraft. The offset of runway sections 302-1 and 304-1 (or 302-3 and 304-3) from runway sections 302-2 and 304-2 (or 302-4 and 304-4) respectively, as shown in FIGS. 3A-3D, allows the ILS aerials to be preferably placed nearer to landing aircraft, immediately beyond the landing runway section (e.g. runway sections 302-1 and 304-1 in FIG. 3A). In this manner, the ILS aerial has free line-of-sight to landing aircraft, is more proximate to landing aircraft and is safely offset from departing aircraft. To improve safety, preferably fixed, but frangible ILS aerial structures are used so as to prevent damage to aircraft, for example in an aircraft landing incident. Additionally, the ILS aerial is low-lying so as to avoid contact with aircraft wings.

[0128] FIG. 4A shows a runway arrangement as shown in FIGS. 3A and 3C showing both directions of operation. Similar reference numerals refer to similar elements; thus FIG. 4A is essentially the two directions of operation shown in FIGS. 3A and 3C superimposed on one-another. Areas 400 are shown on the take-off runways which are aligned with the intermediate safety areas 310-5, 6. In one example, these areas 400 are not used; aircraft that are taking off to the North start their take-off from the Northern end of the area 400. Similarly, aircraft taking off to the South start their take-off from the Southern end of the area 400. In another example, this section can be used in either direction; i.e. aircraft taking off to the North start their take-off from the Southern end of the area 400 and vice versa. This alternative use would lengthen the effective take-off runway length but may require coordination between aircraft taking off with landing aircraft in certain circumstances.

[0129] FIG. 4B shows a similar figure to FIG. 4A, corresponding to the runway arrangement shown in FIGS. 3B and 3D.

[0130] FIGS. 5A-5G show various stages of an example method of (preferably phased) expanding an airport to provide the additional capacity afforded by the arrangements shown in FIGS. 2A, 2B, 3A-3D, 4A and 4B and described above. Taxiways 212, aircraft movement and other features shown in previous figures are omitted from FIGS. 5A-5G for clarity.

[0131] FIG. 5A shows an existing runway arrangement of two parallel runways 502, 504. These are both extended in length as shown in FIG. 5B. This provides the additional length needed for separate landing and take-off sections on the same runway. Notional intermediate areas 510-5, 510-6 and RESAs 510-1, 2, 3, 4 are marked on the runway in a step shown in FIG. 5C to separate the different sections 502-1, 502-2 and 504-1, 504-2, thus producing a runway arrangement as shown in FIG. 2B. The extension of each runway shown in a FIG. 5B in one example would take place one at a time to reduce interference with normal airport operations. The next step shown in FIG. 5D is to widen the runways. This step may not be necessary on some runways which have enough width already. Again, the widening of each runway may occur one at a time to reduce interference with airport operation. The widened runways are then split into two in a step shown in FIG. 5E. Notional RESAs 310-5, 6 are designated on the runways in a step shown in FIG. 5F to produce the runway arrangement shown by FIGS. 4A-4B which has four sections (502/504-1, 2, 3, 4) on each runway 502, 504.

[0132] An optional final stage of expansion is shown in FIG. 5G where the pairs of runways are separated to provide an appropriate distance between each pair. This step may involve further widening the runway as shown in FIG. 5D and re-marking the runway arrangement so as to provide two pairs of separated runways. In one example each pair of runways is separated between runway centrelines by a distance of between 70 m-400 m, preferably between 100 m-250 m, more preferably by approximately 190 m. Importantly this separation can be the same as or similar to that required by regulatory or safety authorities between a parallel runway and adjacent taxiway since parallel inline sections of runway are not both in use at the same time. Thus the same regulatory requirements governing taxiways neighbouring runways are likely to apply to these pairs of runways.

[0133] FIG. 6A shows an alternative means of widening an existing runway to that suggested in FIG. 5D, by widening the runway more at one end than the other (adding fillets to either side of each runway), thereby changing the angle of the runways 602 and 604. This option may be preferable where space constraints such as buildings and taxiways mean that purely lateral extension would be onerous. A person skilled in the art would realise that a number of different runway widening or lengthening methods could be used to provide a final arrangement resembling those described above.

[0134] FIG. 6B shows another means of widening an existing runway. Two fillets 410 are added to an existing runway 600. Two new runway sections 602, 604 are then provided at an angle to the existing runway 600. This arrangement provides two runways 602, 604 with minimal extra runway needed to be constructed. The overall length of the original runway is not extended but to provide yet more runway space further extension at the ends of each runway section 602, 604 can be provided. This arrangement shows the two runway sections 602, 604 separated but depending on the size and position of fillets 610 they may be contiguous.

[0135] ILS aerials arranged at the distal ends of the angled runway sections 602, 604 are preferably available to be installed; such placement allows the aerials to be placed sufficiently close to landing aircraft, have free line-of-sight to landing aircraft and be a safe distance from departing aircraft. To improve safety, preferably fixed, but frangible ILS aerial structures are used so as to prevent damage to aircraft, for example in an aircraft landing incident. Additionally, the ILS aerial is low-lying, so as to avoid contact with aircraft wings.

[0136] Landing guidance systems, such as Ground-Based Augmentation Systems (GBAS) and Microwave Landing Systems (MLS) are preferably available to be installed alongside the aforementioned runway arrangements (in addition to or instead of ILS) in order to aid landing. Advantageously, signal interference and restrictions on placement of components of GBAS and MLS instrumentation, as observed in ILS, are overcome.

[0137] FIG. 7A shows an alternative method of using the runway arrangements described above. There are often restrictions on airport operations early in the morning or late at night due to the noise involved and the consequent disturbance to the surrounding population.

[0138] During times where aircraft are only landing, for example, early mornings, the whole length of one or both runways is available for incoming aircraft. Thus, aircraft can land at the distal end of any runway, thus effectively moving the noise further down the runway. This could be by several thousand metres for a long runway. Thus, the runway is effectively this extra distance further away from the local population, reducing the intensity of the noise for people along the flight path. FIG. 7A shows points 700-1 and 700-2 where aircraft would usually land (see FIGS. 2A, 2B. 3A-3D, 4A and 4B and above) relative to points 702-1 and 702-2 where aircraft can land if there are no aircraft taking off.

[0139] During times when aircraft are only taking off, for example, late evenings, the whole length of one or both runways is available for departing aircraft. Thus, aircraft can similarly start their take off from further down the runway.

[0140] FIG. 7B shows the effect of this different landing method on a nearby population 704 a distance x away. The normal flight path 706 passes over a point directly above the population 704 at a distance d. When using the long landing, where the landing point is offset by a distance x, the new flight path 708 is at a distance d+d above this same point. This distance is given by the following relationship:

d=x.Math.tan

[0141] Extending the landing point by say 2 km with a descent gradient of 3 therefore means a higher flight path by around 105 m. This has a significant impact on the noise levels at the ground. The further the landing point is extended, the higher the aircraft will be at a given point away from the start of the runway. This distance is limited however by the available runway length; 2 km is merely an example and the distance may be greater or smaller than this depending on the runway being used.

[0142] A similar method can be used when taking off so that aircraft have climbed to a greater distance when they pass over a nearby population. In such operation, aircraft begin the take-off at an end of a runway, as opposed to nearer the middle as shown in FIGS. 2A, 2B, 3A-3D, 4A and 4B. Such operation would occur independently to aircraft landing.

[0143] Designation of landing thresholds and/or safety areas may comprise physical changes such as adding or removing lighting, additional runway markings (such as threshold markings) and/or alerting pilots and air-traffic controllers to the position of the safety areas, runway length and/or position, possibly using software-implemented changes such as alerting pilots and air-traffic controllers to the runway length available via a user interface. These designations may be altered by a user and/or computer system altering the active lighting and/or markings on the runway and making corresponding changes to the user interface display for the pilots and air-traffic controllers. Such a system allows flexibility in the length and/or position of the runway, direction of operation and permits long landing to be facilitated. The full length of each runway could be used since the intermediate safety areas, as well as being flexible in location, can also be used as part of the runway if required.

[0144] FIGS. 8A and 8B show a further development of the landing approach method described above. To further reduce the effect of aircraft noise on areas near the airport, a two stage approach can be used. Rather than approaching the landing at a constant angle as shown above, the aircraft initially approaches at a steeper angle, which is changed to a shallower angle prior to landing. The use of automated procedures such as auto-pilot and microwave landing systems can be used to make such a staged landing compared to if the aircraft were to be landed manually. FIG. 8A shows an example staged approach 850 as compared to a conventional approach 852. The approach angle is in this example changed from 5 to 3 at a distance a from the landing point. The extra height an aircraft is at, at a distance x from the landing point is given by:

d=(xa).Math.(tan 5tan 3)0.035.Math.(xa)

where (xa) is the distance the point of measurement (i.e. the population) is from the point the angle of approach changes (in km).

[0145] The combination of the long landing described above and a staged descent means that the noise over a nearby population is significantly reduced; however, each of these could be provided independently depending on the situation. FIG. 8B shows an example landing utilising both the staged approach and the long landing described above. The extra height an aircraft is at, at a distance x from the landing point, is given by:

d=(xa).Math.(tan 5tan 3)+x.Math.tan 30.035.Math.(xa)+0.052.Math.x

[0146] For a population 10 km away from the usual landing point, and where the angle of approach changes 3 km from landing; moving the landing point 2 km further means the aircraft are around 350 m higher up over the population. This extra height corresponds to a significant reduction in aircraft noise at ground level.

[0147] The angle of approach may change closer or further away than the 3 km example given above. This may depend on factors such as local regulations and the precise location of the population.

[0148] The angles of approach changing from 5 to 3 is an example step change. A person skilled in the art would realise that a range of differing approach angles could be used depending on the type of aircraft, the airport, the nature of the flight etc. Furthermore, the change may not be a step change; it may be a gradual change from one approach angle to another over a significant distance.

ALTERNATIVES AND MODIFICATIONS

[0149] Although the above description refers to many examples where an airport runway arrangement has two parallel runways, the invention extends to situations where there is a single runway. This would be particularly advantageous in an urban environment where there is only space for a single runway. Furthermore, the invention can also be applied to airports with more than one non-parallel runway. This would be particularly advantageous in order to increase passenger capacity in situations where non-parallel runways are independently used depending on wind conditions or where space constraints require runways to be non-parallel.

[0150] The above description includes numerous references to runway and airport configuration dimensions. These dimensions are merely examples and a person skilled in the art would appreciate that these are dependent on factors such as type of aircraft and the regulations covering the airport. Such modifications could be made by a person skilled in the art and therefore are within the scope of the invention.

[0151] Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

[0152] It will be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.

[0153] Reference numerals appearing in the claims are by way of illustration only and shall have no limiting effect on the scope of the claims.