The photograph shows the extent to which the infil has been sucked out by heavy seas.
Shetland Islands Council faces a possible £2.5 million bill to rebuild a runway extension at Sumburgh Airport after being sued by its owners, Highlands and Islands Airport Limited.
It has emerged that the east end of the east-west runway is so prone to damage and erosion in south-easterly gales that gaps several feet deep have been discovered beneath the tarmac. On several occasions during the more extreme gales large areas around the end of the runway have been smashed up, requiring urgent repairs.
Since the extension was built into the sea in 2006 HIAL has spent around £400,000 keeping the runway intact but it said the council – which designed it and managed the construction by Balfour Beattie – refused to contribute.
The structural problems are deemed so serious that HIAL says it has no option but to rip up and rebuild the extension during spring and summer at a cost of around £2.5 million. The design contract was due to go out to tender this week.
The remedial work will involve digging out the small stone infill which was packed inside the massive outer rock armouring shipped over from Norway. It will be replaced with larger-gauge rock which will not be prone to being sucked and washed out by the notoriously wild seas that surge into the voe.
According to HIAL managing director Inglis Lyon the local authority has refused to even engage in talks about repair costs over the course of several years, pitching the two former partners in Sumburgh Airport’s future into conflict.
“Thus far SIC have blanked us,” Mr Lyon told The Shetland Times. “We’ve worked very hard over the last few years to engage with SIC who have just not engaged at all.”
Over the course of five years he said HIAL had built up a file on the dispute “as thick as your arm”.
HIAL got the two sides before an independent adjudicator last year – a service intended to resolve disputes and avoid expensive and tedious court action. According to Mr Lyon after technical evidence was presented by both sides the ruling was that the SIC was wholly contractually liable for the defects and the costs. The council disputed aspects of the finding and it went to the Court of Session in Edinburgh.
A two-day hearing was held the week before Christmas into what Mr Lyon said was “a technicality”. He expects a ruling in six-to-eight weeks which will determine how much the council has to pay.
The council declined to comment due to the legal proceedings not yet having concluded.
The gravity of the subsidence problems with the runway and the long-running wrangle over liability has been kept well out of the public arena until now despite the SIC and HIAL being publicly accountable bodies. However, HIAL’s early attempts to extract cash from the council were reported on in 2008 when about £250,000 had been spent on running repairs.
The problems with the flawed runway extension go back to February 2007, just five months after it was completed, jutting out into the sea beyond the Ness Boating Club and marina.
Mr Lyon said: “Some of the repairs have been quite dramatic and some of the situations we have found ourselves in have been quite challenging where we’ve come in after heavy swell and heavy seas to find large parts of the tarmac and the subsequent infill missing – washed out to sea.
“When the excavations were done they did find voids underneath the tarmac which clearly shows that what was put down is no longer there.”
He likened the action of the sea to a piston effect, or a bicycle pump, pushing air through then sucking the infill out. It meant he had to act to end the cycle. “I can’t allow the situation to continue. I have to get something done.”
He moved to quell any fears about aircraft safety in the meantime, saying the extension is the “runway end safety area”, not part of the actual landing and take-off area for flights. He also said that the major repairs would be done without having to close the runway to planes.
An extension was also built into the sea at the west end of the same runway. Together the two extensions cost over £10 million and were intended to allow planes to increase their payload, including allowing the Saab 340 to carry a full load of passengers and luggage.
The west end extension has not suffered to the same extent. Pipes were laid within its structure with holes up to the surface, which appear to prevent the build up of pressure from incoming waves.