MercoPress. South Atlantic News Agency

St Helena airport on track: runway 70% completed; grooving and sealing begins

Aerial view over the Dry Gut fill, Taxiway and Apron that are also almost completed ( Pic Deon De Jager)

The government of the British Overseas Territory St Helena has given an update on the construction of the airport which is expected to become operational sometime in 2016, and which continues according to original plans.

 The South African company responsible for the works, Basil Read said it was also satisfied with the progress made.

“I am pleased with the progress made and how far the project has come since my last visit”, said BR Airport Project Director, Jimmy Johnston, and DFID Airport Project Manager, Nigel Kirby, who visited the Island at the end of last month, and together with the local team assessed progress to date and engaged in planning works over the coming months.

According to the latest report at the end of April, the main focus of current works at the Airport site is on the Runway, Taxiway and Apron areas. Progress continues with runway nearly 70% complete with a total of 17,492m3 of concrete already paved and 8,413m3 still to be cast. The Taxiway is almost complete with the exception of joint cutting and sealing and the Apron is 91% complete with 370m3 of concrete still to be cast.

Kevin Pickard Projects has been sub-contracted by Basil Read to perform grooving and joint sealing of the concrete pavement works at St Helena Airport.

Grooving of the runway (excluding the two outer lanes, turning pads, Apron and Taxiway) is carried out using a GT1250 Grooving machine with 43 4mm Arix diamond blades. The purpose of the grooving is to prevent aqua planning which can be caused by water accumulation on the runway. The grooves enable the water to evenly drain off the runway. The grooves are in a pattern of 23mm and 28mm and are cut to a depth of 4mm.

This grooving pattern prevents resonance when the aircraft lands on the runway. Joint sealing is done on all concrete longitudinal and transverse joints which are cut to a width of 6mm. The joints are then cleaned using high pressure water jetting and grit. Backing Core is installed at a depth of 17mm and then joint sealant (Silicone 890 Dow Corning self-levelling scalant) is gunned into the joint. The purpose is to prevent water penetrating the sub-structure.

The total length of grooving on the Airport runway will be approximately 3,018 km (over 3 million meters) and the joint cutting/sealing on the Runway, Apron and Taxiway will be 77km.

Various lighting is required on the Runway, Taxiway and Apron which include Approach, End, Threshold, Edge, Flasher and Parking lights. The majority of cabling has been installed for the various lights and for the navigational equipment. Installation of the actual lights will commence shortly.

However Basil Read is rescheduling the date of the Calibration Flights for navigational aids, which will now occur in or around September 2015. The revised date will comfortably meet the schedules of all involved organizations and has no effect on the Certification process in November 2015, nor on the Contract Completion date of February 2016.

This was one of the decisions taken during the recent visit by Jimmy Johnston where he worked with the team on-Island to assess progress and to plan upcoming works.

SHG Airport Project Director, Janet Lawrence, said all parties in the Airport Project fully support the decision taken. ”Moving the Calibration Flights further back in the program gives us greater flexibility in planning the visits of all the stakeholders needed on-Island at this time, not least ASSI, (Air Safety Support International - the regulator) and gives us a greater margin in timing so that we reduce the risk of weather delays.

By the same token, whilst this has moved back in the program, other activities, particularly planning for the ASSI Certification audits in November, have been brought forward. As noted by Basil Read, the rescheduling therefore has no impact on the overall contract completion date in February 2016.”