Heathrow Airport closed all day Friday 21 March 2025

[whole diary]

[Clan Line]

There is either a serious design flaw, lack the right switchgear systems / control system  or lack of competent people

Very profound statement - based on ?

Perhaps the substation control room was pretty close to the fire - or the blast wall (well illustrated by MarkA) was about to collapse - and the night shift decided to leave ..............quickly !
Stuving has summarised what did happen at Heathrow itself............everything essential worked ! The airport was still capable of handling aircraft - even if that was only to tell them to go elsewhere.

Closing the airport entirely was the correct decision............imagine the chaos today if they hadn't.
Just supposing Heathrow had 100% electricity back up (at what enormous cost ?) - the surrounding area had lost all power. No trains, no properly functioning roads (M4 was/is shut), no nothing ! What would be the point of trying to keep the airport open ?

What happened at North Hyde will unfold - making unfounded statements will help no one in the mean time.   
 

[Bob_Blakey]

I am taken back to the late 1980's when I started my employment with a large telecommunications company that had just established a new data centre (DC^▸ (Direct Current)) in Exeter. The DC supported all the company's business application IT for Cornwall (inc. the IoS), Devon and a significant part of Somerset. Staff numbers were around 150 people and it was a 24/7 operation.

Pretty small beer compared to Heathrow Airport.

As part of the new employee 'tour' we discovered that the building had two separate mains power supplies, which could be switched over very rapidly, two fairly hefty UPS (Uninterruptible Power Supply) battery packs which automatically fired up in a matter of seconds in the event of a mains power failure, and a diesel generator which could be brought online in 10 minutes . These units were fully tested on a quarterly basis.

It seems to me that, given the importance of LHR in the national picture, Heathrow Airport management, possibly aided & abetted by the National Grid, have completely failed to render the site as operationally secure as should have been the case (e.g. automatic switching to one of the alternative mains power supplies should have been an absolute requirement).

[Electric train]

There is either a serious design flaw, lack the right switchgear systems / control system  or lack of competent people

Very profound statement - based on ?

Perhaps the substation control room was pretty close to the fire - or the blast wall (well illustrated by MarkA) was about to collapse - and the night shift decided to leave ..............quickly !
Stuving has summarised what did happen at Heathrow itself............everything essential worked ! The airport was still capable of handling aircraft - even if that was only to tell them to go elsewhere.

Closing the airport entirely was the correct decision............imagine the chaos today if they hadn't.
Just supposing Heathrow had 100% electricity back up (at what enormous cost ?) - the surrounding area had lost all power. No trains, no properly functioning roads (M4 was/is shut), no nothing ! What would be the point of trying to keep the airport open ?

What happened at North Hyde will unfold - making unfounded statements will help no one in the mean time.   
 

There is no control room at North Hythe,  NG^▸ (Natural Gas) operations control is in Sindlesham, Wokingham in Berkshire, SSE^‡(resolve) and UKPN have theirs located in a number of places in the UK^▸ (United Kingdom).

I was refereeing to the control of electrical power within Airport

A location of stratigic National importance such as Heathrow should have a robust backup system whilst they 100% may not be warranted they should be able to run core business at a acceptable degraded mode

[TaplowGreen]

Flights resuming later today - pretty impressive recovery all in all............

From the BBC^» (British Broadcasting Corporation - home page)

We've just received a fuller statement from Heathrow Airport, which says it can restart some flights later today and hopes to be fully operational tomorrow:

"Our teams have worked tirelessly since the incident to ensure a speedy recovery. We're pleased to say we're now safely able to begin some flights later today.

"Our first flights will be repatriation flights and relocating aircraft. Please do not travel to the airport unless your airline has advised you to do so.

"We will now work with the airlines on repatriating the passengers who were diverted to other airports in Europe. We hope to run a full operation tomorrow and will provide further information shortly.

"Our priority remains the safety of our passengers and those working at the airport. As the busiest airport in Europe, Heathrow uses as much energy as a small city, therefore getting back to a full and safe operation takes time. We apologise for the inconvenience caused by this incident."

[Clan Line]

A location of stratigic National importance such as Heathrow should have a robust backup system whilst they 100% may not be warranted they should be able to run core business at a acceptable degraded mode

As I said, the "robust back up system" did work, if an aircraft HAD to land at Heathrow last night it could have done so safely. Trying to keep an airport running when everything around it has failed is just asking for even more trouble. "Degraded mode" = what ?  Burger King open but not McDonalds ?

Strangely enough, before I retired, I actually worked at an airport setting to work a "robust back up system" such as is probably installed at Heathrow - albeit on a much larger scale at Heathrow. This was not designed to keep the airport restaurants running at that airport either.

[Electric train]

A location of stratigic National importance such as Heathrow should have a robust backup system whilst they 100% may not be warranted they should be able to run core business at a acceptable degraded mode

As I said, the "robust back up system" did work, if an aircraft HAD to land at Heathrow last night it could have done so safely. Trying to keep an airport running when everything around it has failed is just asking for even more trouble. "Degraded mode" = what ?  Burger King open but not McDonalds ?

Strangely enough, before I retired, I actually worked at an airport setting to work a "robust back up system" such as is probably installed at Heathrow - albeit on a much larger scale at Heathrow. This was not designed to keep the airport restaurants running at that airport either.

My current job is looking after the traction power system for a large chunk of South London along with a number of major London stations.  There are always weak spots in a system especially older systems, the modern systems can operate a N-1 including a total loss of a National Grid connection in SE London, a reduced service would have to be implemented but it would not be a total shut down

[Clan Line]

............ hefty UPS (Uninterruptible Power Supply) battery packs which automatically fired up in a matter of seconds in the event of a mains power failure .............

Sorry Bob - but you are making unsubstantiated statements about Heathrow and the National Grid. To provide full backup power for Heathrow ("as much energy as a small city") is economically impossible to contemplate.
I regret to say that your statement regarding UPS is also a little wide of the mark. A UPS does not "fire up in a matter of seconds" when power is lost (in today's digital age this this could be equally catastrophic) - it is on line all the time. A "proper" (not £9.99 from Amazon) UPS is usually fed from a battery, this battery is kept fully charged by the mains supply - if the mains supply fails the UPS continues to supply the load, now depending solely on the battery. There is NO break in the UPS output. This continues for the time specified by the customer. This normally gives the time required to get the diesel up and running - or for non-critical equipment, to carry out a controlled shut down.

[broadgage]

Agree that a UPS provides "no break power" rather than "firing up in seconds"
My relatively cheap UPS provides power without any detectable break, to loads that I consider important (fridge freezer, some lighting, internet router, cordless phone base unit, cellphone charger. It runs indefinitely on mains power and for about 24 hours on battery.
It cost about £50 for the UPS and about £200 for the long run time batteries.

Much larger units are available, up to MEGAWATTS.

[Clan Line]

I note, this morning, that the cause of the Heathrow shutdown was................ready for this ?.............because
 Terminal 2 was burning wood chips to provide power......................................I didn't read any further 

[broadgage]

I note, this morning, that the cause of the Heathrow shutdown was................ready for this ?.............because
 Terminal 2 was burning wood chips to provide power......................................I didn't read any further 

I am opposed to the burning of wood chips for electricity production due to this fuel being almost always imported and of very doubtful greenness.

I fail to see though how it would cause or contribute to the power failure, as distinct from the burning of natural gas or oil.

[Clan Line]

I fail to see though how it would cause or contribute to the power failure, as distinct from the burning of natural gas or oil.

Exactly, just another inane, stupid comment from an "expert" ....................which brings to mind Ed Millibland (sic)

[TonyK]

I would not surprised if international standards require critical systems for air operations - navigation aids, and everything that allows an aircraft to land and clear the runway at least - to be backed up independently of outside supply, and perhaps with backups for those backups. That much they are saying did work as intended.

In a dire emergency, an aircraft can be landed on a runway without any of the electrical systems working, so long as the pilot can see it from a few miles away. Instrument landing systems and PAPI lights are always welcome, but even the most modern aircraft can be landed using the Mark 1 human eyeball. I had a lot of fun landing an A330 at Heathrow last week (in a pilot training simulator, not Flight Sim or a real aircraft) and it isn't hugely different in principle to a Piper Cherokee apart from height and speeds - which surprised me. It would be a problem if nobody knew you were coming though - the runway maintenance crews took immediate advantage of unexpected available time to go and sort a few things out.

Airport closures happen all the time, but seldom on this scale. The normal practice is to divert, either to another airport in the same country, or somewhere en route, and wait for a resumption. That poses its own problems, with crew hours, refuelling, possibly deplaning passengers and accommodating them, and in the case of A380s, limited airports with the right kit.

The fire seems to have started accidentally, with the 25,000 litres of cooling oil (I read cooking oil first time) being the fuel. A mistake by an engineer has been suggested ("Whoops! Mu bad...") but I think that is conjecture. The resilience aspect is certainly going to be the topic of a few urgent conversations, for sure. The BBC^» (British Broadcasting Corporation - home page) report mentions back-ups, UPS, all that. I don't think Heathrow will want any chance of this happening again.

[ellendune]

The BBC^» (British Broadcasting Corporation - home page) is reporting

There are also backup diesel generators, and uninterruptible battery-powered supplies which provide enough power to keep safety critical systems such as aircraft landing systems running.

However, when the fire broke out the substation, it was out of action, along with its backup.

[stuving]

The BBC^» (British Broadcasting Corporation - home page) is reporting

There are also backup diesel generators, and uninterruptible battery-powered supplies which provide enough power to keep safety critical systems such as aircraft landing systems running.

However, when the fire broke out the substation, it was out of action, along with its backup.

That's very badly worded. What it's trying to say is that the fire destroyed one transformer and damaged the surrounding equipment so that both circuits were put out of action.

The North Hyde grid supply point is fed by two underground cable circuits from Iver grid switching substation (and GSP). Each is rated at about 400 MW, but the grid operates on the principle that any circuit (or anything else) can be taken out of service without any user losing supply, so the GSP as a whole is rated at 400 MW. So it's not strictly a backup, but the effect is the same. There is a plan to put in a third link, I think at the same rating, which would raise the GSP's capacity to 800 MW.

PS: In fact, this is the plan -
There is planned 275kV circuit reinforcement on NGET’s network between Iver and North Hyde with an estimated completion date in the early 2030s. The existing Iver – North Hyde 1 and 2 circuits need to be replaced and uprated to a larger capacity. Build of a third circuit between the two sites is also planned. Alongside this, NGET are also undertaking a wider, strategic review of the 275kV cable circuits in West London and future network requirements.

However, ETYS24 - last year's ten-year statement from NESO (was NGESO) - does not mention that. Note that the GSP is not overloaded now, but the demand is forecast to rise very steeply. In what's called the Future Energy Scenarios that are used for planning, total grid demand rises from 48 GW^» (Great Western - used as an abbreviation for the area / lines under the Great Western franchise, as opposed to FGW which includes "First", the company operating them too. For tickets - about) this winter to 73 GW in 2031/32. For the North Hyde GSP it rises from 173 MW to 431 MW!

[ChrisB]

Heathrow got back up & working without the substation that was damaged being repaired - so power must have been fed from the the other two substations that feed Heathrow. Apart from maybe a a bit of switching circuits, I reckon Heathrow had power from likely before lunchtime, but having said that the airport was staying shut until midnight, decided that it was prudent to stay with that, rather than open immediately.

The CEO^▸ (Chief Executive Officer) was interviewed and said that all systems worked as they were designed to.

so why did the coolant oil catch fire & how? The flash point for that oil is 140 degrees C. So what heated to that point?