Shakespeare could have written those famous lines to reflect the issue raised by many associated within the tourist and other aviation related industries in Grand Cayman, “To build or not to build a runway extension, that is the question…”
In order to be able to handle the long-haul direct traffic be it from South America, Middle East, Europe, Owen Roberts International Airport would be required to handle aircraft such as:
Boeing B767 / 777 / 787 / 747 (particularly the B747 freighter)
Airbus A330 / 340
Of those listed only the British Airways B767 operates four times a week into ORIA. Due to the existing runway length, BA cannot fly direct to London and has to make an intermediate stop in Nassau, resulting in an additional journey time of approximately two hours over similar flight distances such as London to Montego Bay or Kingston.
Based on the standards and recommended practices of the International Civil Aviation Organisation, the areodrome code for ORIA is 4D. The areodrome code is determined using the following parametrs: the runway length, the wing span of the largest aircraft operating into an airport and the distance between the outer edges of the main wheels.
The aerodrome reference code permits planners to establsh the critria for distances between the runway and associated taxiway centreline and back of aircraft parking stand as shown in Table 2. For a non precision instrument approach runway as is at ORIA and a refernce code of 4D, it can be see that the distances between the runway centreline and taxiway centreline is 577.4 feet and a subsequent distance from the taxiway centreline to the back of the aircraft parking position of 132.9 feet. The current ORIA runway and taxiway plan as shown in Figure 1 (Owen Roberts International Airport Master Plan Version 1.0 dated May 2007), does comply to the standards as set by ICAO.
Before determining what runway extension, if any is required, the question that needs to be addressed is what is the future role of the airport? In order to maximize airport revenues through increased aircraft operations, the airport will have to change from its current origin / destination role to that of both a cargo and passenger hub. As a hub, passengers and cargo may not be destined for the Cayman Islands but are on route or transferred to another airline or aircraft in Grand Cayman to their final destination. Hubs normally attract the larger aircraft such as those indicated above. In particular, for freight operations this will require the ability for the airport to handle the B747F freighter.
The Boeing B 777 / 787 / 747F and Airbus A330 / 340, commonly used for long haul operations will require ORIA’s reference code to change from a 4D to a 4E, as the wingspans of all these aircraft fall between 137.8 feet and 213.3 feet ref Table 1. The subsequent taxiway centreline to runway centreline would have to be extended by 21.4 feet over the planned location and 23 feet from the taxiway centreline to the back of the aircraft parking position. In addition, the existing aircraft stand capable of parking a B767 whose overall length is 159.2 feet will have to be extended to accommodate aircraft such as the B777 which has an overall length of 209.1 feet. As a result of this, the front of the existing aircraft parking position would have to be moved northwards by as much as 94.3 feet, which may in turn, require the footprint of the terminal to be moved northwards also to accommodate the larger aircraft.
British Airways will at some point replace the aging fleet of B767 on their route to Grand Cayman with either the new B787 or B777, both of which will require ORIA to be a recoded as a 4E aerodrome. What runway length would then be required to permit non-stop operations to London? Whilst the full details of the B787 are not available at this time, it is indicated that a runway length of 9,000 feet would be required. For all the other aircraft, i.e. B777 / B747F / A330 / A340, a runway length of 10,000 feet or approximately 3,000 foot extension. In order to maximise the potential use of the airport, the 10,000 foot runway length is recommended. This distance permits those aircraft to operate out of ORIA at their maximum load capability, i.e. Maximum Take-Off Weight and maximum range.
Any runway extension will require the runway to extend into the North Sound, but by how much? The existing runway length is approximately 7,000 feet in length. There are two options available; the first is to extend the runway westward i.e. towards Georgetown by 1,000 feet and the remaining 2,000 feet into the North Sound. The second option is for all 3,000 foot extension is located in the North Sound.
The first option is considered as not the most optimal option as larger aircraft will be required to land further down the runway in order to mitigate against noise and “down-wash” from the landing aircraft. Landing 2,000 feet further down from the existing landing position will result in aircraft being 105 feet higher above the ground in Georgetown than they are currently. In addition maintaining the end of the runway (08 – westerly approach) in its existing position, there is no need for closing off the road adjacent to the runway or possibly moving CAL maintenance facility. With a landing distance required of 8,000 feet for the larger aircraft, the available existing runway with the displaced landing position would be 5,000 feet therefore the additional 3,000 foot extension to provide the 8,000 feet of runway distance would have to be constructed in the North Sound.
With an existing runway length of 7,000 feet and an extension of 3,000 feet, this then provides the overall length for departing aircraft whether a westerly or easterly departure of 10,000 feet.
There are a number of methods for constructing runways over water. The traditional method is to use fill, compact and construct the runway and associated taxiway over the fill. An alternative is to use piles and in essence build a bridge. The following images show such a method used for the runway extension at Tokyo’s Haneda International Airport. Such a construction methodology could minimise any environmental concerns with respect to the currents and sand shift within the North Sound.
A full cost analysis needs to be undertaken.
“To build or not to build, that is the question?”
Edward A. Jerrard,
Lecturer in Air Transport Studies – UCCI