3. Current Airside and Terminal Infrastructure
3. Current Airside and Terminal Infrastructure
Runway
Geometry
3.1. The UK Aeronautical Information Publication (AIP) published by the CAA indicates that in December 2012, Dundee's single runway was:
- orientated at 09-27,
- 30m wide by 1400m long,
- at a height of 5 metres above mean sea level, and
- horizontal with a straight longitudinal profile.
3.2. The AIP for Dundee also reports the following declared distances:
| Runway | TORA | TODA | LDA | ASDA |
|---|---|---|---|---|
| 09 | 1,319m | 1,319m | 1,400m | 1,400m |
| 27 | 1,319m | 1,319m | 1,400m | 1,400m |
3.3. The meaning of the declared distances above is:
TORA - Take-Off Run Available - This is the length of runway available and suitable for the ground run of an aeroplane taking off.
TODA - Take-Off Distance Available - This is the length of the TORA plus the length of any associated clearway.
LDA - Landing Distance Available - This is the length of runway available and suitable for the ground landing of an aeroplane.
ASDA - Accelerate Stop Distance Available - This is the length of TORA plus the length of any associated stop-way.
These distances are illustrated in Appendix A (Drawing NK017413_100).
1.1. 3.4. The Aerodrome Manual indicates that the runway is declared as a Code 2C runway with Runway 09 being a Category 1 Precision Instrument Runway, and Runway 27 being a Visual Runway. A Code 2 runway is defined by a TODA or ASDA distance not greater than 1200m. The declared distances at Dundee exceed those stated in CAP 168 for a runway of this type having been approved by the Civil Aviation Authority in 1995 when the runway was extended to 1400 metres (see Appendix A). The CAA did not at that time allow the full 1400m to be declared for TORA and TODA, and it was understood, at that time, that this restriction was to prevent the employment of aircraft at Dundee which exceeded a size that the CAA felt appropriate for the circumstances of the aerodrome. Concurrently the CAA also decided that it would not allow the runway to be declared within the less demanding criteria for the lower third of Code 3 runway designation, because of obstacles in the side protection surface north of Riverside Drive (i.e. the transitional surface). There are no obstacles along the extended centre line of the runway that would preclude the full 1400m being declared if the other criteria could be met, or a further relaxation obtained, but such an extended TORA and TODA could bring obstacles outwith the aerodrome more strongly into play within the Type A Chart.
3.5. In the present circumstances, the safety strip surrounding the runway varies depends on the runway direction being used, with a 75m wide strip, measured from the runway centreline, being required for Runway 27, and a 40m wide strip being required for runway 09. These strips are illustrated in Appendix A, which demonstrates that they are clear of the taxiways and aprons serving the runway. An assessment of the space available between the runway strip at the end of the runway, and the airport boundary, suggests that the airport can provide the minimum Runway End Safety Areas (RESA) required by CAP 168. For a Code 2 instrument runway, i.e. runway 09, it is recommended that a 120m RESA is provided, whereas for a Code 2 visual runway a RESA is only to be provided if deemed appropriate by the airport. In this instance there is a full RESA for Runway 27. The RESA areas are again shown in Appendix A. In order to achieve the full recommended RESA for Runway 09 it would either be necessary to obtain a small amount of ground from the University and re-site the localiser aerial just east of the present line of the airport east fence, or extend the runway westwards by 15 metres and relocate both thresholds westwards by 15 metres.
Pavement Construction
3.6. The current PCN for the runway at Dundee Airport is 27/F/D/Y/T. The runway was overlaid strengthened and resurfaced between 2000 and 2002 and then again approximately two years ago. From some core information that was made available, the asphalt pavement thickness varies between 305-560mm overlaying 250mm layer of granular material.
Pavement Strength
3.7. The UK AIP for Dundee Airport, dated December 2012, reports a Pavement Classification Number (PCN) of 27/F/D/Y/T for runway 10/28. The meaning of the PCN code is as follows:
The PCN Number of 27 - the permitted ACN of the aircraft at the appropriate sub-grade category.
Type of Pavement, F - the runway is a flexible construction.
Sub-grade Category D - this indicates that the sub-grade is of an "ultra low" category, typically a CBR of 3%.
Tyre Pressure Y - this states the maximum tyre pressure authorised to use the pavement is low, limited to 1.0 MPa (145 psi).
Pavement evaluation method T - the PCN has been determined by technical design or evaluation methods.
3.8. Table 3.2 shows the Aircraft Classification Number (ACN) for a variety of aircraft that operate within the UK and are likely to be reasonably compatible with operations from Dundee. The ACN values depend on the aircraft weight and type of wheel/tyre, but also the pavement type (concrete "Rigid" or bituminous "Flexible") and the ground conditions. The Table provides the ACN for each aircraft based on a flexible pavement and ground conditions of "ultra-low" standard, i.e. a CBR of 3%. It should be noted that this list is not comprehensive, particularly with reference to business jets. There are a large number of potentially compatible types of small business jets that are not listed in the table; those that are included are intended to be illustrative.
3.9. Any decision to accept an aircraft above the PCN of the runway (in Dundee's case a PCN of 27), subject to a safety case, is a commercial decision for an airport to make in terms of the additional runway maintenance costs that it may incur if it regularly accepts aircraft that apply loads in excess of the PCN of the runway. Much will depend on whether the aircraft is operating at maximum weight or at a more limited weight of fuel and passengers, - and the extent to which the PCN will be exceeded. Operations up to 110% of the PCN are acknowledged in CAP 168. With a suitable safety case and low frequency use, higher loads might also be acceptable.
Obstacles
3.10. Runway 09 is classified as a CAT 1 Precision Instrument runway, whereas runway 27 is visual only. As a result each runway has a different profile for obstacle clear zones. These are summarised in Table 3.3.
3.11. The AIP reports a number of obstacles in the approach and take off areas. The majority are trees, plus a pylon, chimney and windsock. Again similar types of obstacles are recorded in the circling area and at the aerodrome.
Taxiways
Geometry
3.12. The taxiways at Dundee are also notified as Code 2 taxiways, in accordance with the requirements of CAP 168. Table 3.4 of CAP 168 states that the separation between the runway centreline and a parallel taxiway centreline should be 87m for this code of runway and taxiway. The current separation is 94 metres, and therefore materially in excess of the minimum.
Pavement construction
3.13. The taxiways are of a flexible construction. The asphalt material for the two main taxiways, Taxiway Alpha and Beta, comprise a thickness between 150mm to 380mm. The two other taxiways have an asphalt thickness between 55mm to 145mm
Pavement strength
3.14. There are five taxiways at Dundee Airport. The UK AIP for Dundee Airport (December 2012) reports a Pavement Classification Number (PCN) for each, as follows:
Taxiway Alpha PCN 26
Taxiway Bravo PCN 26
Taxiway Charlie PCN 8
Taxiway Delta PCN 8
Taxiway Echo PCN N/A
3.15. Based on the data collected from a pavement investigation undertaken by URS (Scott Wilson) in July 2010 slightly different PCN's are suggested:
Taxiway Alpha PCN 27
Taxiway Bravo PCN 6 (lowest PCN advised)
Taxiway Charlie < PCN 5
Taxiway Delta PCN 22
Taxiway Echo PCN N/A
1.1. 3.16. However the URS (Scott Wilson) investigation was carried out using borehole techniques, - necessarily widely spaced, on land that had all been reclaimed from the estuary by inconsistent tipping of hard and soft materials such that the characteristics of the base material vary greatly over small distances. The URS (Scott Wilson) results showed PCN figures that were much higher than anticipated for parts of the runway and much lower than anticipated for some taxiways if viewed against the figures calculated by Dundee City Engineer prior to the takeover of the airport by HIAL.
3.17. The runway PCN of 27 appears to be consistent with earlier calculations but taxiways Bravo and Charlie have performed very much better in reality than the figures assessed by URS (Scott Wilson), with no evidence of tracking or deformation over many years of fairly unrestricted use. It might be worth considering a PCN re-assessment of the Dundee surfaces based on an alternative technique that would be more appropriate for highly variable base materials. The assumption made by Dundee City Engineer in the creation and upgrading of the runway and taxiway at various dates was that the construction had to be capable of coping with settlement and a weak and variable base material. Among other measures, fabric re-enforcement of the asphalt was widely employed in the initial the runway construction, and during several subsequent upgrading phases.
3.18. Taxiway Alpha is the widest taxiway and is of similar construction to runway 09-27. It is the main route that larger aircraft take between the runway and apron when operating at Dundee Airport, but Taxiway Bravo has also been used extensively for a wide variety of movements over many years, without any apparent adverse consequences. It would nevertheless be prudent, when resources can be found, to reconstruct Taxiway Bravo to improve its horizontal profile, slightly increase its width and ease the tightness of the turn midway along its length as well as upgrading its PCN.
Aprons
Geometry
3.19. The main apron serving the passenger terminal allows aircraft to operate on a self-manoeuvring basis with three aircraft stands. The main apron measures 145m x 31 metres, south of which it is served by a Code C parallel taxiway giving full 28.5m clearance from the stands. North of the apron a 7m wide hatched area gives clearance from apron floodlights and the apron service road.
Apron Construction
3.20. The main apron comprises an asphalt layer of approximately 300mm thick overlaying a 250mm granular layer, but thickening towards its northern edge as a result of overlays constructed to create southwards drainage from the terminal, away from which it slopes downwards at 1:100.
Apron Strength
3.21. Apron reconstruction in 2001, was intended to deliver a PCN of 27. However tests immediately following this work resulted in a flaw in the underlying asphalt layers being identified, reportedly due to the bitumen coating having been applied to inadequately cleaned stone. This caused the pavement structure to have a lower material stiffness than had been planned. A full remedy would have involved digging up the entire apron to considerable depth and was considered to be an excessive response. Compensation was therefore paid and it was expected that, as a result, the apron could show some tendency to incur small wheel indentations after the parking of higher PCN aircraft for long periods, but this was not considered to amount to a serious problem. It was anticipated that minor wheel indentations - often only visible at all after rainfall, would be resolved by a number of different repair techniques every few years, and that a permanent solution could await the life expiry of the surfacing. However, following the URS (Scott Wilson) report giving a PCN of 15 for the apron, it was overlaid by HIAL in 2010. This does not appear to have stopped the wheel indentation issue entirely as the fault lies at a lower level, but there is no evidence of a major problem. Continued overlaying may not now be the best solution, not least because it would not accord at all well with the drainage profile at the terminal wall.
Terminal
3.22. The current passenger terminal was opened in 1997; it is a single storey Yorkon modular building built in 1996, with a forecast life of at least 30 years. It comprises two check-in desks, landside retail, security, airside departures lounge, domestic and international arrivals, customs/immigration and an arrivals area. Baggage handling is a manual system using roller beds and lift conveyors.
Rescue and Fire Fighter Service
3.23. The UK AIP for Dundee Airport states that the level of Rescue and Fire Fighter Service (RFFS) available at the airport varies between RFF Category 3 and RFF Category 6. Categories 3 and 4 are provided at set times, whereas Categories 5 and 6 are provided only by prior arrangement. The range of aircraft with potential to operate from Dundee all appear to fall within a maximum of RFF Category 6, which is within the current capabilities of the Rescue and Fire Fighting service at Dundee Airport, albeit that permanent Category 6 working would involve an increase in staffing, and might require some improvement to RFFS facilities.
Fuel Facilities
3.24. Avgas and Jet A-1 aviation fuel are available. Jet A1 is provided directly by the airport from an underground store immediately north west of the main apron. A recent decision transferred Avgas provision to Tayside Aviation, which has built a bunded facility east of the main apron. The removal of Avgas from the airport fuel store has released underground tank capacity that could double Jet A1 storage capacity to circa 100,000 litres.
Aircraft Types Compatible with Dundee Airport
3.25. The question as to which aircraft types can use any airport is highly complex and involves a large number of variables. In the end, the final answer on a particular day and time will only emerge from the calculations conducted by a pilot immediately prior to take off. One approach to this issue is to size a runway for worst case scenarios related to the most demanding aircraft type and climatic conditions that can be anticipated. However this is anything but a cheap solution in terms of capital and operating costs and is not an option for Dundee Airport due to the restrictions of the site.
3.26. To give the non-technical reader a brief indication of the factors determining which aircraft can take off and land at Dundee Airport, with a full, or almost full, passenger load (which should be regarded as a fundamental yardstick as these considerations will be key to attracting scheduled services), they include the following:
- The basic runway performance of the aircraft at Maximum Structural Take Off Weight (MTOW).
- Whether the aircraft is configured for maximum density seating or not.
- The distance to destination - affecting to the weight of the fuel load.
- The baggage load (e.g. business schedules have much less baggage than holiday charters).The height of the runway above sea level.
- Whether the runway is flat and entirely horizontal.
- Whether the runway is wet and what are its measured braking characteristics.
- The temperature, barometric pressure and headwind-over-the-runway on the day.
- Upstanding obstacles along the extended centre-line of the runway for some distance outside the airport.
- Whether the aircraft is operating under Public Transport or Private Flight regulations.
- Whether the ACN of the aircraft is reasonably compatible with the PCN's of the airport surfaces.
- Whether the airport can provide the required category of Rescue and Fire Fighting Service.
Commercial Aircraft Types
3.27. Therefore, to provide a comprehensive list of aircraft and associated runway length requirements could provide a misleading picture of what is operationally and commercially realistic at Dundee, since the validity of any such numbers would be hugely modified by the application of some or all of the factors listed above. For the purpose of this review, the key requirement is to develop an understanding of those aircraft which can reasonably be expected to be able to use it reliably and consistently at more-or-less full passenger loads - and with the fuel loads needed to take them to useful destinations that are significant for the Dundee market. Almost all of the mainstream potential destinations that Dundee could expect to try to serve, with the exception of holiday charters, are less than 450 nautical miles from Dundee; that distance includes anywhere in the UK or Ireland plus Brussels, Amsterdam, Dusseldorf, Bergen and Stavangar.
3.28. A reasonable question might then be: What is the list of commercial aircraft types that could be expected to carry a full - or almost full passenger load from Dundee, to a destination 4-500 nautical miles away, with normal safety fuel reserves?
3.29. This is what is attempted in Table 3.4, but even this list requires some qualification because it wouldn't be appropriate or sensible to try to go that distance in some of the smaller or slower types listed, and notes to that affect have been attached.
| Aircraft Type | Propulsion | Seats | UK or Irish Operators? | Comments |
|---|---|---|---|---|
| BAe Jetstream 41 | Turbo Prop | 29 | Yes | High costs per seat and speed, means that it is only likely to be suitable for shorter distance, high value business routes. |
| Dornier 328 | Turbo Prop | 31 | Yes | Current London service aircraft. Fast, quiet capable of near continent destinations, but can only provide high fare services. |
| Saab 340b | Turbo Prop | 34 | Yes | Birmingham service aircraft until recently. Not suitable for long range destinations due and speed issues. Suit thin premium routes. |
| Embraer 135 | Jet | 37 | Yes | Able to operate from London City, but would only achieve 400nm at full pax load with limited baggage. High costs per seat. |
| ATR 42 | Turbo Prop | 48-50 | Yes | Current Dundee-Jersey service aircraft. Previously on the Birmingham route. Limited speed constrains it to UK routes, but is economical and only Cat 4 RFFS. Later 500 series is faster; new 600 series more fuel-efficient with more range. |
| Saab 2000 | Turbo Prop | 48-50 | Yes | Has flown into Dundee on quite a number of occasions. Fast turbo prop, but availability is limited and cost per seat is relatively high. |
| Embraer 145 | Jet | 50 | Yes | Could not carry a full passenger load to 450nm, and would be marginal on landing distance at Dundee. Relatively high cost per seat and RFFS Cat 6 due to aircraft length. |
| Bombardier Dash 8-300 | Turbo-Prop | 48 | Yes | Operated Dundee-Jersey at full load for a number of seasons. A sound prospect for domestic services, but not fast enough for other than short continental destinations. |
| ATR 72 | Turbo Prop | 66 - 78 | Yes | Has used Dundee on one occasion. Very economical and has the ability to allow lower fares, but limited speed would keep it to UK routes and short continental routes only. |
| Bombardier Dash 8 Q400 | Turbo Prop | 78 | Yes | Very fast turbo prop. Reported to have the lowest operating cost per seat of any regional aircraft. Range of +600nm. |
| BAe 146-100/ Avro RJ 70 | Jet | 70+ | No | Not likely to be available for service. Not considered economical. |
| BAe 146-200/ Avro RJ85 | Jet | 85-100 | Yes | Extensively used at London City. Not now favoured elsewhere because of its high operating costs. Has been used to fly a Dundee-Toulouse charter with a full passenger load |
| BAe 146-300/ Avro RJ100 | Jet | 100-116 | No | Still widely employed in Europe but being replaced more economical aircraft. |
| Embraer 170 | Jet | 70-78 | Yes | Limited availability at the moment. A new design capable of long-range operations from Dundee at full payload. |
| Embraer 175 | Jet | 78-88 | Yes | Greater availability. A stretched EMB 170, capable of carrying a full payload from Dundee for more than 500nm. Maximum payload range from Dundee shown in Appendix B. |
| Embraer 190 | Jet | 98-114 | Yes | Limited availability in the UK at the moment. A new design capable of carrying a full payload from Dundee for more than 500nm. Maximum payload range from Dundee is suitable for domestic routes. |
| Embraer 195 | Jet | 108-124 | Yes | Greater availability. A stretched EMB 190. Limited range from Dundee. Might manage London with a full passenger load - or with small restrictions. Has a high ACN at MTOW, but would be well below that from Dundee. |
| Airbus 318 | Jet | 107-132 | Yes | Limited availability. Known to operate from London City at restricted passenger load. Might well be able to operate domestic sectors from Dundee but has a high ACN. |
3.30. What this shows is that Dundee Airport is suitable for a range of aircraft (jet and turbo-prop) used by regional carriers. However, it is not suitable for narrow-bodied jets used by Low Cost Carriers (e.g. Airbus 319 and 320 and Boeing 737 variants) because of its runway length, load bearing and classification. There is little scope for changing this position without increasing the runway to Code 3, which requires wider aircraft and safety surface clearances than can be accommodated within the curtilage of the airport, implying extensive land reclamation from the adjacent River Tay at a cost of £40-50m according to work previously undertaken by the City Council. The passenger numbers required to justify such an expansion go well beyond the scope of this report, and consequently, as agreed with Transport Scotland, such an option is therefore not considered further in this document,
Private and Chartered Business Aircraft Types
3.31. Attempting to list the range of business jets, turboprops - and indeed piston-engine aircraft that can use Dundee Airport, is unnecessary because of the large number of aircraft types involved and the varied regulations under which they operate. Essentially, Dundee can handle the full range of small private and business aircraft including more or less all of the Learjets, Citations, and Falcons. It currently accepts Gulfstream 4's and 5's and Bombardier Global Expresses.
3.32. The largest visitors in business/private configuration have included the Embraer 190 Exec, and Queen's Flight BAe 146's. Gulfstream V's routinely go transatlantic from Dundee and a Global Express has come directly from Tokyo across the Pole. A Falcon 900 went one-stop to Tokyo, refuelling at Novosibirsk. Business aviation can therefore function fairly freely at Dundee with the exception of very large private aircraft. The main charter and fractional ownership operators are regular users of Dundee at the present time. The main restriction on its future development will be a shortage of enough apron space to permit long stopovers by business aircraft, but that can be remedied by investment.