Well here’s something you don’t see every day. One of the world’s biggest airports will be closed for all of Friday, which will have impacts on aviation globally.
In this post:
Heathrow Airport closed all day Friday, March 21
London Heathrow Airport (LHR) is closed for the entire day on Friday, March 21, 2025, and isn’t accepting any arrivals or departures. This is a result of a huge fire breaking out at a nearby electrical substation, which wiped out power to the airport. The cause of that is still being investigated (one wonders if this was a failure of some sort, or an act of sabotage). If you’re scheduled to fly from or through Heathrow today, of course don’t bother going to the airport.
We’ve seen a huge number of diversions as a result of this closure, including for transatlantic flights. The logistics here are just a total nightmare. In some cases, planes returned to their origin, while in other cases, they’ve had to divert to other airports.
As one example, one of last night’s American flights from Dallas (DFW) to London ended up first diverting to Bangor (BGR). Then when it was clear that Heathrow wouldn’t be reopening anytime soon, the plane continued to Boston (BOS), so that passengers would at least be stranded at a major station, where it’s easier to accommodate passengers and find a new crew, once the flight can depart.
Cirium, the aviation analytics company, estimates that as many as 145,000 passengers could be directly impacted by this disruption. There were 665 flights scheduled to depart from the airport today, and 669 flights scheduled to arrive at the airport. I guess the one silver lining is that this happened during Heathrow’s curfew, so there were limited short haul aircraft enroute to the airport.
British Airways is obviously most impacted by this, as Heathrow’s largest airline. The carrier has released the following statement:
“Due to a power outage in the London Heathrow area, London Heathrow Airport is currently closed. As a result, customers due to travel from Heathrow on Friday are advised not to travel to the airport until further notice. This will clearly have a significant impact on our operation and our customers and we’re working as quickly as possible to update them on their travel options for the next 24 hours and beyond.”
Heathrow Airport hopes to reopen Saturday, March 22
Heathrow hopes to reopen for operations tomorrow, Saturday, March 22, 2025. However, that’s far from a sure bet at this point. Furthermore, even when operations do resume, expect that it won’t immediately be smooth sailing.
After all, there’s a huge domino effect to irregular airline operations, with planes and crews out of place. It’ll likely be several days before operations at Heathrow are fully back to normal.
Even if you have no plans to travel to or from Heathrow, you can expect that your journey may still be impacted by this disruption, given how planes cycle through networks. It could be that you’re scheduled to fly from Dallas to Sao Paulo, but your aircraft was supposed to originate in London, and is stuck there. So be extra vigilant in monitoring your travels over the next day or so.
Bottom line
London Heathrow Airport is closed today, Friday, March 21, 2025. This is due to a fire that broke out at an electrical substation, which is causing a power outage at the airport. This obviously has major implications not just for traffic at Heathrow, but also for airlines globally. So if you’re traveling over the next couple of days, be aware that this could impact your journey.
Any OMAAT readers impacted by this Heathrow outage?
All is well when it ends well.
As there was no reported injuries or deaths as a result of the electrical systems coolant fire, one is extremely thankful to all first responders and others who work so hard to minimise the effects of the fire.
Thank you.
Well, I was supposed to be traveling from Warsaw on Lot. I only got a text from Lot that my flight was cancelled after boarding my flight from RZE to WAW. That was at 5:40 AM on Friday. Heathrow was already closed from around midnight.
I landed at WAW, I went to the airline desc (with no help from any Lot personal on the ground to find it). They told me that I can rebook...
Well, I was supposed to be traveling from Warsaw on Lot. I only got a text from Lot that my flight was cancelled after boarding my flight from RZE to WAW. That was at 5:40 AM on Friday. Heathrow was already closed from around midnight.
I landed at WAW, I went to the airline desc (with no help from any Lot personal on the ground to find it). They told me that I can rebook on 20:40 flight (which was later cancelled). I couldn’t go with that flight because I’m Jewish and I had to be home before Shabbos.
They told me there that they can only rebook me on new flights to the same airport, so they didn’t even try to rebook me on other airlines arriving at other airports. They told me that if I wanted I can pay myself for a new flight and get refunded on the cancelled flight.
I found a Ryanair flight from Lodz to Stansted for quite cheap, It was only around £130 for last minute (and it was a full flight). I took an Uber to Lodz that was around £200 split between 4 people. And I arrived home at around 1PM.
All those people who screen transit passengers who have already been screened for their originating flights got the day off...
This exact sort of thing happened at Atlanta in 2017.
Why don't they have generator backup on-site. The cost would surely be less than a day's disruption ?
Because Heathrow is larger than many small cities. Even hospitals don't have that kind of backup.
Well, yes and no. The power outage affected mainly what is called "Heathrow Central", that is T2, T3, the control tower and runway lighting. T4 was partly affected and T5 had power throughout - but with ATC and runways offline, they could still not operate.
In that sense I agree with henare that a full back up with generators is not realistic. But I also agree with Henry Young that at least some back up...
Well, yes and no. The power outage affected mainly what is called "Heathrow Central", that is T2, T3, the control tower and runway lighting. T4 was partly affected and T5 had power throughout - but with ATC and runways offline, they could still not operate.
In that sense I agree with henare that a full back up with generators is not realistic. But I also agree with Henry Young that at least some back up for ATC and perhaps one runway would be possible, indeed expected, and could have reduced the chaos to some degree.
What a cataclysmic failure caused by a lack of infrastructure investment.
Countries like the US and the UK are decking precipitously and this is another example of this.
Maybe stop sending money to Israel to commit genocide, and invest in infrastructure at home instead
I get that Gatwick was full, but couldn't they have diverted some more flights to other parts of the UK, such as Stansted, Luton, Birmingham, Manchester, or Edinburgh?
Things are getting better and the Government has lifted the overnight noise curfew so aircraft can run 24/7 until Monday to help operators.
This has been crazy for me. I am serious of the fire that happened at london heathrow airport (LHR).
Putin the undersea-cable cutter offered to stop attacking Ukraine for a month. He didn't say anything about British (home of Storm Shadow missiles) infrastructure.
I assume you're referring to Zelenskyj. ;)
Zelensky cut a pipeline. The Russians are cutting cables.
See, now that Trump and Musk are in charge, these incidences no longer even touch the US. The external threats now have to resort to targetting weaker countries to make a noise because they don't dare to attack us.
I'll say this now, but there will never be any more flight incidences in the US for as long as Trump or Musk are in charge.
I hope this is sarcasm
Trump was president when the 2017 power outage at ATL happened.
I once experienced something like this at HAM airport a few years back. Also there the airport was closed for the day.
Someone told us: Yes, we do have a back up power supply. However, we are only allowed to operate the airport with full redundancy - which one doesn't have when you're already operating on the back up system.
In essence that means you need to have two back up systems for maintaining operations. A bit weird in my view.
Haha, that’s Germany for you.
Major mess exacerbated by the fact that BA wouldn't allow calls into queue or to connect to a live chat agent. Beyond frustrating. I got remarkably lucky by rebooking to a non-UK end destination without LHR, but the seats to anywhere in Europe are very few and far between. BA's tech sh*t show from a customer care and reservations perspective makes a terrible situation untenable.
BC- do you expect all their staff to be able to handle potentially over 100,000 calls within a few minutes , with many of them taking time as customers wont hang up, and dotards blaming the airline ?
The airport is closed ! Well why can't you put me on another airline's flight? There are no seats available for the next few days . Why ? Say BA is forced to disrupt 80,000 customers do they expect to find the same number of seats on other airlines ?
No, but I would expect that their app/website allows for rebookings. This would greatly reduce pressure on customer service agents.
I am currently leading a spring break study abroad trip for 16 college students. We are scheduled to fly back to America on Saturday. We've been informed by our travel agent that, if we can't actually get out on Saturday, our next best opportunity will be Tuesday. Huge mess!
16 college students stuck for a long-weekend where the legal age for drinking is 18. Good luck this weekend, Ben.
Sky News reporting that the National Grid have restored power on an ‘interim basis” so fingers crossed for you.
Good grief. This is an expensive mess. LHR should have had its own secured and back up fueled substation. And the cost of that would be minimal compared to the final bill from this event.
Good article about redundancy in the power connection to LHR...or lack thereof.
https://www.bloomberg.com/opinion/articles/2025-03-21/heathrow-shutdown-highlights-dangers-of-a-single-point-of-failure
I wonder why Bournemouth is not used for diversions like this? In the 1970s fog would close Heathrow and Bournemouth would quickly be crowded with airliners. It is only 1hr 30mins to LHR or maybe a bit more by coach, so why fly across the Chanel?
Did you sleep in this morning Ben haha
I was wondering the same, though his stuff doesn't show up anymore on BoardingArea, which is a whole other question as to why.
@ RetiredATLATC -- Not sure why that is, but looking into it now.
@ chris w -- You're too observant, hah, I actually did. I typically get up at 4:30AM without an alarm. This morning I woke up at 6:45AM. OMG, I don't remember the last time I've slept in that long. Our son gets up at 7AM, so it was a chaotic morning, but now things are back to normal, but I'm a bit behind...
Maybe this happened because you slept in.
I might be looking for Russian cigarette butts on the ground…
first, the chances are that it was just equipment failure, not sabotage.
Why there were not redundancies that could provide backup power or an alternate route for electricity will be a question that should be asked but there is a whole lot more of this stuff in the western world than we care to admit.
second, let's see a list by flights where flights that were too close to Europe to return to their...
first, the chances are that it was just equipment failure, not sabotage.
Why there were not redundancies that could provide backup power or an alternate route for electricity will be a question that should be asked but there is a whole lot more of this stuff in the western world than we care to admit.
second, let's see a list by flights where flights that were too close to Europe to return to their origins diverted but it speaks volumes that the most diversion points for these flights was in continental Europe. not LGW, not STN but CDG and AMS and BRU.
third, for non-LHR carriers, removing a day from the schedule is a lot easier than it is for BA. A flight to/from LHR cancelled. It is far harder if flights were on the ground at LHR when that happened but that was largely not the case.
"second, let's see a list by flights where flights that were too close to Europe to return to their origins diverted but it speaks volumes that the most diversion points for these flights was in continental Europe. not LGW, not STN but CDG and AMS and BRU"
@Tim: Gatwick and Stanstead are busy airports that don't have gates or slots free for a raft of diversions arriving in one morning. Gatwick is already screaming for...
"second, let's see a list by flights where flights that were too close to Europe to return to their origins diverted but it speaks volumes that the most diversion points for these flights was in continental Europe. not LGW, not STN but CDG and AMS and BRU"
@Tim: Gatwick and Stanstead are busy airports that don't have gates or slots free for a raft of diversions arriving in one morning. Gatwick is already screaming for a 2nd runway! It seems in the passenger's best interest to allow all the transatlantic morning flights to divert to "other London airports", but practically it's not possible.
I'm not sure which source is best to trust from but i've seen LGW and Shannon both getting a lot of traffic.
LGW can't take too much though as it's already a congested airport without enough runways. CGD, BRU and AMS all make some sense though as they have Eurostar services into London.
The more surprising ommissions for me are BHX and MAN
@Rain - rather turn around and fly back all the way back to the West Coast than get diverted to MAN. Absolute horror of an airport.
No major global hub currently operates w/ an excess of capacity so it would be fully expected that a shutdown of an airport as large as LHR would require that diversions go to many airports
yes, I know there were multiple diversion points as would be expected. DUB is a big IAG station so could be useful for BA and AA but I still am guessing w/ what I have read that the continental Europe...
No major global hub currently operates w/ an excess of capacity so it would be fully expected that a shutdown of an airport as large as LHR would require that diversions go to many airports
yes, I know there were multiple diversion points as would be expected. DUB is a big IAG station so could be useful for BA and AA but I still am guessing w/ what I have read that the continental Europe hubs got as much or more traffic.
and it could be as much about geography... alot of flights from the US and Canada returned to their origins while flights from Africa and Asia headed for LHR were already too close and continental Europe was the best choice.
There's even more extreme diversion examples than the AA DFW-LHR flight you mentioned. For example, another one of AA's flights on the same route diverted to Goose Bay, and then after some time on the ground, the 77W flew to JFK, landing a little after 7am this morning.
It was quite interesting looking at where flights ended up diverting. A number of flights diverted to Goose Bay. 2 friends on different VS flights ended up...
There's even more extreme diversion examples than the AA DFW-LHR flight you mentioned. For example, another one of AA's flights on the same route diverted to Goose Bay, and then after some time on the ground, the 77W flew to JFK, landing a little after 7am this morning.
It was quite interesting looking at where flights ended up diverting. A number of flights diverted to Goose Bay. 2 friends on different VS flights ended up in Shannon. LGW took only a few long-haul flights (they seemed to all be the first scheduled ones to land at LHR in the morning). DL seemed to fly most of their flights already en-route to AMS. Most US carriers diverted in North America, while most BA flights flew to Europe and diverted to another airport nearby. I would love to be a planespotter at CDG or MAD right now, and see all the widebodies originally destined for LHR.
I was watching the diversions on FR24 last night. One of BA’s JFK flights diverted to Iceland, not sure why it didn’t press on to the UK or Ireland.
Saudia was near Croatia when they turned and headed for Cairo. I’m sure Ben is happy to not been on that flight!
Lucky - Bangor is in the United States
It's also in Wales and Bangladesh. I suspect the American settlers took the one from the British Isles with them.... :)
@ ErikOJ -- Sorry, my mistake, fixed. At first I had a Goose Bay example in there, then I changed it, but I forgot to remove the international part.
Bangor in Gwynedd, North Wales and is is the oldest city in Wales. However it is not known for having an airport:)
The first airport I ever arrived at in the USA was Bangor, Maine from the UK for CBP clearance.
Fortunately this happened during Heathrow's curfew, when there are far less planes on the ground at the airport than usual (except from BA and VS obviously). I think the only foreign airlines widebodies overnight at Heathrow are the United 763 and the Cathay 350/777.
If it happened during daytime it could have stranded 50 widebodies.
Flying too IAD on Sunday, not had any notifications yet but imagine lots of pings tomorrow afternoon :-(
The obvious question: How can a single point of failure in the power grid completely shut Heathrow down? Why isn't there a fallback connection to the electrical grid in case the primary connection fails? This isn't rocket science but basic systems engineering.
The report I just read says there is a back up but it was also impacted by this fire. Britain's Energy Secretary said "it's too soon to say if th incident showed anything about the safety if critical infrastructure in Britain" - well if one fire can knock out both main and backup power, I think that's a pretty glaring soft spot.
The "backup" was insufficient because they made a conscious decision not to use a full diesel solution.
So it was actually a feature of the system, and not a bug.
The foolishness of Netzero.
There weren't sufficient backup diesel generators because they are using "biomass" generators instead.
Does no one remember when this happened at ATL just a few years ago?
https://www.usatoday.com/story/news/2017/12/18/atlanta-airports-main-and-backup-power-lines-flow-through-same-tunnel-damaged-fire/961529001/
Brits don’t do infrastructure. Just finance hocus pocus.
Jack …. False News Report, sounding like gross ignorance on steroids!
Poor darlink, hope you get better soon.
Riiiiiight. Just look at southern England’s bankrupt and falling apart and health-hazardous water system. Or its disgraceful trains (though German trains are competing on the race to the bottom) and HS2 fiasco. Britain still lags its peers significantly in electrification of its train lines. And then there’s the 40 year fight about a third runway at Heathrow.
Because the "first world" is woefully behind on infrastructure. Just compare Europe and Asia. Where do trains run on time and where are they always cancelled and delayed?
It is times like this which make me wonder about all the people whose heads are in the sand ... who think the West is better (more developed, advanced, whatever words you want to use.)
I wonder if this was an act of sabotage like the protestors glueing themselves to runways etc, or purely an accident.
BBC says it's not sabotage.
"It could be that you’re scheduled to fly from Dallas to Sao Paulo, but your aircraft was supposed to originate in London, and is stuck there."
One doesn't usually fly from Dallas to London to Sao Paulo, so this situation is very remote for most people bar some #Avgeeks. ;)
But it might be that the plane (not person) that was planned to operate Dallas to Sao Pulo flight was previous scheduled to fly from London to Dallas. And now is stuck in London. So airline has to find new plane for that flight....
He's saying that for people flying nonstop from Dallas to Sao Paulo, their plane could be stuck in London because it was supposed to operate a previous flight from London to Dallas. So the point is that even if you aren't flying through London at all, you could be affected if your plane was supposed to pass through London today on a previous flight.
Flying Monday back from LHR. UA issued a travel waiver. Tried to change to a Tuesday flight as an additional night in London would be OK with me. But app is handling as a regular change...and very expensive. Don't have time to sort it now...I'll have a think about it and try again later.
Deo, snark is only effective when you know the context of what you’re talking about.
Nice fail.