The boss of Heathrow Airport has said that refitting the airport to have seamless "full power" energy resilience to avoid a repeat of last month's emergency shutdown would cost more than £1 billion.
Chief executive Thomas Woldbye was being questioned by MPs about the power cut at the airport, caused by a fire at a nearby substation, that interrupted the travel plans of about 270,000 passengers and shut the west London airport for almost an entire day.
The airport was closed to all flights until about 6pm on Friday, March 21. The Heathrow Airline Operators Committee says it cost airlines £60 million to £100 million.
Mr Woldbye said once it became clear that the power was not going to be restored, the decision had been taken to switch to an alternative supply, but it was “highly complicated” and took 10 hours to power down, rewire, then power up about 1,000 systems.
“If we were to refit a ring round Heathrow that would give you that full resilience, the best estimates of our engineers is that would exceed £1 billion to refit today,” Mr Woldbye said.
"It’s easy to ask for resilience. The cost would be very high and I don’t think it’s something airlines could expect to be there. It’s never been asked for.”
Mr Woldbye said there was “not endless, seamless switch-over for everything in the airport” and that bosses were “still at a stage where we don’t know why it happened”.
When asked if the 10-hour time frame was resilient enough, he said that was “the playbook” because the risk of such an incident was considered to be so rare.
He defended the decision to close the airport, amid claims that some flights could have landed or taken off earlier. He said keeping the airport open would have been “disastrous”.
He told the Transport Select Committee: “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 [of] personal injury, gridlocked roads around the airport, because don’t forget 65,000 houses and other institutions were powered down.
“Traffic lights didn’t work, just to give you an example. Many things didn’t work. Parts of the civil infrastructure didn’t work.
“So the risk of having literally tens of thousands of people stranded at the airport, where we would have nowhere to put them, we could not process them, would have been a disastrous scenario.”
Asked if some of the airport’s terminals could have reopened sooner, he said: “The fact that the lights were on at Terminal 5, which is entirely correct, doesn’t mean the terminal was operational.
“We didn’t have all CCTV, we didn’t have fire surveillance. The fire systems would work … but the fire surveillance systems of the airport were down, so we didn’t know where the systems were up and safe. All that had to be secured before we started operation.”
Mr Woldbye added: “I cannot guarantee you whether T5 could have opened an hour earlier. We did all we could to get it open as soon as we could, because we fully understand the airlines’ concerns around getting repatriated flights, repatriated passengers, and also getting flights in there.”
He said an earlier reopening could have resulted in injuries to passengers.
“If we had got this wrong, we might be sitting here today having a very different discussion about why people got injured, and I think it would have been a much more serious discussion.
“So, there is a margin within which our people have to take very serious safety decisions, and that is what they are trained for, that is what they do, and that requires that every single system is up and running, tested and safe.”
The airport has faced criticism for the length of time it took to get up and running.
Nigel Wicking, chief executive of the Heathrow Airline Operators Committee, said not only was 10 hours too long to switch, but it had taken too long to make the decision. He said airlines did not know the failure of a substation would mean the airport would close.
"I'm not hearing there was a lack of power to come into Heathrow but that it took time to move that power to where it needed to be. Ten hours was too long.”
He said that although the fire was unusual, had airlines known how long it would take to rewire supply they would have challenged it. He also said the resilience of the airport’s power supply “should have been there”.
He said: “We already pay enough for Heathrow. I don’t feel that we should be paying more for further resilience. The resilience should have been there in the first place, frankly.”
