Airlines warned Heathrow about risks to its power supply days before the airport was shut down by a substation fire, a Commons committee has been told.
Heathrow’s chief executive, Thomas Woldbye, apologised for the disruption, which affected more than 200,000 passengers on Friday 21 March, but defended the decision to close as he said staying open was potentially “disastrous”.
Speaking to MPs on the Commons transport select committee, Woldbye said that such a power outage had been seen as a “very low probability event” and the airport had paid for a “supposedly resilient” supply.
However, Nigel Wicking, the chief executive of Heathrow Airline Operators’ Committee, representing airlines, said that incidents including cable theft had made him concerned and he had spoken to senior airport officials.
He told MPs he had spoken to the Team Heathrow director a week before, and Heathrow’s chief operating officer and chief customer officer on 19 March, only two days before the fire at the North Hyde substation closed the airport. He said the conversations took place after “a couple of incidents of, unfortunately, theft of wire and cable around some of the power supply” – which had on one occasion affected the lines on a runway.
Wicking criticised Heathrow for the speed of making a decision to turn to its alternative power supplies and the length of time the process took – claiming that Terminal 5 could have been partly operating much earlier.
Woldbye said: “It became quite clear we could not operate the airport safely quite early in this process, and that is why we closed the airport.
“If we had not done that, we would have had thousands of passengers stranded at the airport at high risk to personal injury … The risk of having literally tens of thousands of people stranded at the airport, where we have would have nowhere to put them, we could not process them, would have been a disastrous scenario.
“Just because the lights were on doesn’t mean all the systems were working … We didn’t have CCTV or fire surveillance.”
Asked if more flights could have entered Heathrow without full power at the airport, he replied: “We would be able to land aircraft … But we would then be leaving passengers on the runway, which would not be acceptable.”
Wicking said, however, that the decision to close the airport for 24 hours “should have been constantly under review”, and that more inbound flights could have been processed with manual systems, including immigration controls. “We had checks in with Border Force during the day and they had resource and capability,” he said.
He told the committee the cost of the closure to airlines was difficult to quantify but estimated it was in the range of £60m to £100m.
Woldbye, however, said the cost of ensuring more resilient power backup than the current process would be far higher than airlines would accept. “If we were to refit, the best estimates of my engineers is that it would cost a billion pounds,” he said.
He said the airport paid £135m for its power supply. “We rely – for resilience – on our suppliers,” he said. “We have contracted specifically a resilient setup which includes backup transformers and three different power lines … All of that is supposed to be resilient.”
He later said he had been well aware of the copper theft incident Wicking referred to in his conversations with airport directors, but that it was “a much smaller substation than the one that went on fire … we did a full security scan with the relevant police authorities”.
Representatives from the electricity transmission and distribution network said Heathrow’s internal configuration was a matter for the airport’s private network but that it had continued to receive power from two other substations.
National Grid’s president for UK electricity transmission, Alice Delahunty, told MPs it was a “very rare and serious event”, with the extreme heat from the blaze at the substation knocking out the two other backup transformers. “This is the first time a fire on a transformer has had knock-on consequences on the entire substation,” she said.
The operations director for Scottish and Southern Electricity Networks, Eliane Algaard, said there were “two additional intakes available throughout”, which Heathrow had been using ever since. She said SSEN “did not have visibility” of the airport’s internal setup, but added: “What I do know is that Network Rail was able to transfer automatically.”
Woldbye told MPs he believed the process that was followed ensured safety and was correct for “an event as unlikely as this one. We are still at a stage when we don’t know why it happened.”
Heathrow has commissioned a full review of the incident and its response, to be carried out by the independent director and former transport secretary Ruth Kelly.
A Heathrow spokesperson said that the power supply issue Wicking referred to had “no relation to the North Hyde substation … We were well aware of that incident before Mr Wicking raised it. Our contingencies were stood up and the incident was resolved quickly.”
