It showed that an increased moisture reading was initially reported in July of 2018 but that something had been done to address that which was not until basic maintenance by National Grid was cancelled.The cause of a power cut led Heathrow to close the next day resulting in thousands of flights being cancelled and others stranded.
In response the report detailing why risks were not dealt with, energy Secretary Ed Miliband said the report was deeply concerning.He noted that Ofgem, the energy watchdog, launched official enforcement investigation "in order to examine any potential licence infringements" concerning development and maintenance of its substation in North Hyde which was constructed in the 60-ies.
National grid stated that it had an "asset Inspection and maintenance programme comprehensive". It added that since the fire it had acted further.This, it said, involved "re-testing the resistance of substations which serve strategic infrastructure".Heathrow Airport identified a combination of poor regulation, lack of appropriate safety mechanisms and failure of the National Grid to maintain its own infrastructure that caused this this disastrous interruption of power.
It added: "We will be expecting that National Grid will be putting serious thoughts on what they can do to ensure that this never happens again."Giving his view, Akshay Kaul, Ofgem director general of Infrastructure, said it was expected of the energy companies to maintain their equipment and networks well, in order to avoid such instances.
In places where we see that they have not we will act and hold companies entirely to account he added.According to Neso, the other electrical supply points of which there are three at Heathrow were not known to the energy firms that the loss of one of the electrical supply points would lead to a power failure to some of the key systems of the airport.It said the review revealed that energy network operators do not necessarily know whether their customers hooked into their systems are Critical National Infrastructure.
Although power was restored Heathrow by 06:25 on 21 March, and using circuits of another nearby substation, the electricity flow to all four of the passenger terminals at Heathrow was restored not until 10:56.It was only after 18:00 on the same day that flights resumed after the safety checks were done. The planes could land and take off in the night so that Heathrow could resume full capacity.Heathrow chief executive Nigel Wicking told the BBC that closure of Heathrow has cost airlines between 80m-100m.