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As of 06:24 US Eastern the appears to no longer be true. There is a NOTAM outage but no full ground stop is mentioned, just a few specific due to weather.

Edit: obviously a developing situation, see responses to this comment for current advisories.

I don't know how these things work, but the most recent advisory, 027, seems to imply that United Airlines has a full ground stop until 15:00 UTC / 10:00 Eastern.

Edit: Of course as I was typing that, Advisory 028 pops up with a nationwide ground stop until 9:30 Eastern: "GROUND STOP ALL FLIGHTS / ALL DESTINATIONS EXCLUDES MILITARY AC AND MEDEVAC FLIGHTS"

https://www.fly.faa.gov/adv/adv_otherdis.jsp?advn=28&adv_dat...

- "All US domestic flights have been grounded for several hours because of a glitch with the flight control system."

https://www.bbc.co.uk/news/world-us-canada-64236047

Yep, the situation has changed since the post was made. Parent comment was correct at the time, however.

At 5:40am Eastern, the agent at my departure gate told us that there was a ground stop affecting all flights, which was reflected in my original title. This was not reflected in the NOTAM I posted, as was pointed out by several early commenters, and in fact my flight was able to board and depart around 7:00am Eastern before the ground stop took effect.

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Any source for the claim of a ground stop? I see plenty of flights still taking off.
The most recent one seems to say something like that. ATCSCC ADVZY 023 DCC 01/11/2023 ALL UAL MAIN AND SUBS GROUND STOP

Not that I know how to read it. The event time is three minutes ago.

https://www.fly.faa.gov/adv/adv_otherdis.jsp?advn=23&adv_dat...

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Reads United Airlines apparently.
I can see that East Coast UA flights are currently delayed because of this.
MESSAGE:

EVENT TIME: 11/1126 - 11/1500 UAL GROUND STOP ALL FLIGHTS / ALL DESTINATIONS PER USER REQUEST DESTINATION AIRPORT; ALL FACILITIES INCLUDED: ALL GROUND STOP PERIOD: UNTIL 1500Z REASON: USER REQUEST REMARKS: US NOTAMS SYSTEM DOWN

https://www.fly.faa.gov/adv/adv_otherdis.jsp?advn=23&adv_dat...

https://www.fly.faa.gov/adv/advADB.jsp

UAL = United Airlines, not “all North American flights” as OP claimed
The advisory posted by OP wasn't UA specific. You're looking at a later one.
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This was based on a P.A. announcement from a gate agent, so not authoritative. I've updated the title to reflect what is in the link.
Nothing in the linked page confirms the ground stop mentioned in the title.

Reddit comments say that there is no FAA ground stop, but airlines are making individual decisions about it.

https://old.reddit.com/r/flying/comments/108yjgz/faa_notams_...

There was a brief ground stop (I'm currently flying and it momentarily held us up) but Delta at the least isn't stopping entirely.
I really like the advisory page -- all info, no sugar.
https://lite.cnn.com/en

It's the best way to get the news. No filler, no adds and it works on a 2g mobile.

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Not sure CNN is the "best" way to get the news.

Try this: https://en.wikinews.org/wiki/Main_Page

No ads, no adds, no filler, no filters.

Make the news objective again. Repeal Smith-Mundt.

https://www.congress.gov/bill/112th-congress/house-bill/5736

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Updated title from "FAA Ground Stop for All North America Flights Due to NOTAM Outage" to reflect comments that initial title was not accurate.
Confusing title, as Canadian departures with Canadian destinations do not appear to be affected.
If I'm understanding the situation correctly: the system stopped processing updates yesterday afternoon and it wasn't a big deal, then they tried restarting it this morning to fix it and it didn't come back up, so now older NOTAMs from before the issue started are not available. Is that right?

Do airlines/planes keep a cached copy of these? How large is the NOTAM database?

Not really. And for most commercial pilots this may come down to whether or not ForeFlight caches theirs or not. I'd actually be really curious to see unofficial commentary from ForeFlight developers about this because it's a pretty unique scenario in the age of electronic flight bags.
The problem isn't keeping a copy, it's sending updates that are very time critical (for example restricted areas around POTUS, any impactful event, etc.)
Are 2020s the years where the cold war is back as a lukewarm war, and also all of NA aviation needs to reconvene with its decrepit software? Next plot-twist, it was all ready to blow, but ultimately triggered by Russian/Chinese/North Korean hackers.

Ok, taking off my tinfoil hat. Still, maybe I'm suffering of nostalgia bias but the last few years really make for a lot of prime source material for docudramas.

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No need for a tinfoil hat. Such systems are prime targets for states hostile to the U.S. If this one wasn't before, it will be now.
Forensic analysis will reveal that there were multiple hidden failures over the past years that were covered up by foreign hackers to ensure their backdoors were not revealed in an in-depth investigation.
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ATC can tell pilots what they need to know, right?
The question is, how will ATC know? I'm not that familiar with their systems, but maybe they rely on them to get critical information?
ATC will be fine to get everyone on the ground safely. There are procedures for everything including ATC itself being down.
I never doubted that. The question is if they could've worked without a ground stop by having ATC give them all info.
No. ATC gets busy enough as is, each plane needs NOTAMs covering their entire route, and if the system is down ATC isn’t getting them either anyways.
If I print the NOTAMs for a 600nm flight, they're going to typically go 4+ pages of NOTAMs that are fairly specific to my flight (just for departure, along route, and destination airports) and 15+ pages if I print all available NOTAMs in a fairly small font.
ATC can get them back down, but no new flights should start.
NOTAM notices are not only for planes but for other people and equipment using airspace, like drones, skydivers, ... Those are not always connected with ATC, but need the information from NOTAM to plan their activities
The NOTAMs for a commercial flight from JFK to LAX, for example, would be several pages long. Warnings about construction work at either airport, closed taxiways, cranes in the vicinity of the airport, enroute navigational aids which are unusable, etc. ATC can't relay that for every departing flight. Additionally, the NOTAM system is where they'd retrieve these from, so if that's down they have nothing to relay.
Its a flight planning mystery.

Lets say you are not flying to, but flying by, my hometown airport. You decide arbitrarily to use it as a divert in case of awful weather or engine trouble enroute or you just want a bathroom break (this is more of a Cessna 172 airport than a 747 airport)

I found a cached list of nine current NOTAMs for my home airport. Because its always better to overinform than to underinform, until the system overloads and crashes:

A long ramble that boils down to you can't use one of the IFR plates for a helicopter approach because of (its a very long story but relates to the crane mentioned below)

The modulation level on the closest VOR for identification/verification is low, although in legal tolerance, so you can use it but please stop trying to open the equivalent of a trouble ticket. We know the volume is both technically legal although low and not "turned up all the way". The techs say its safe until new parts arrive.

There's three failed tower lights in the area (three? Supply chain problems? Labor problems? WTF?) and one temporary crane obstruction. The crane is flagged and lit, and could theoretically be 60 ft AGL which is normally below the legal limit but its on airport grounds 0.13 miles away from one runway off to the side, so please try not to hit it. Also please don't bother reporting a crane off to the side of the approach; we know all about it...

Clearance delivery for the "big city" airport nearby has a remote trans/rec site nearby that's broken. Legal coverage is adequate (kind of a RAID array of retrans sites) so please stop reporting the reduced signal strength, we already know.

There's some kind of flood on runway 10 when it very heavily rains; the groundskeepers will fix the drainage problem; the NWS reports 0% chance of rain today so it probably won't be an issue, but don't act all surprised. This is not a NOTAM for groundskeeper work, that would be a separate new NOTAM.

Nailed it exactly. Also be advised that birds are in the vicinity of the airport.
One of our local muni airports adjacent woods always has a NOTAM advising of potential for deer on the runway.
Be advised somebody is mowing the grass near the baggage terminal.
Is someone who is planning multiple divert airports seriously expected to retain all of that information and recall it in the case of an emergency?

Seems like 10% of that info might be kinda useful to know and 90% of it is “BY FLYING IN OUR DIRECTION YOU AGREED TO ACCEPT …”

Not retain it, you probably have a copy with you which you would read if you did end up diverting somewhere. NOTAMs also affect which airports go in your "would divert to" list when you're planning the flight. E.g. if the NOTAMs say AirportA's lights are unserviceable, you wouldn't plan it as a diversion airport for your night flight.
Seems to me like “I am in a sudden aircraft emergency” is not the best time for a pilot to begin reading dry material.
There are many reasons to divert, not all of them big emergencies. Weather at your destination is worse than forecast, for example.
You're expected to have the information with you. Having read it before flight also increase the chance that it jogs your memory; "closest airport is CVG, didn't I see something... ah, yes, nuked last week, let's go to Columbus".
If I were a helicopter in IFR conditions and I just need a gas stop, I've never landed here, I'd forget about it, there's five heliports within 20 miles that have absolute zero drama. Legally technically the heliport is open but why risk it?

If I were shooting an IFR approach for currency in perfectly clear air, or with an instructor and its midday and cloudless right now, sure, have some good training.

If the engine's on fire, well, your odds are vastly better trying to land than trying to fly 20 miles away. If you're 600 feet off course and below 60 feet AGL you're probably going to crash anyway so don't worry about a crane.

They just have a crane onsite fixing some things, its not like the airport is closed just don't be surprised seeing some extra flashing lights and flags.

> Is someone who is planning multiple divert airports seriously expected to retain all of that information and recall it in the case of an emergency?

I am a pilot and yes, you are absolutely expected to be aware of all NOTAMS relevant to your flight.

FAA examiners will make you do it on checkrides, and depending on how cute they are feeling that day, they may very well quiz you, and will gleefully fail you because you weren't aware that, say, one particular runway was out of service, or there was a runway light out somewhere.

The implication is that someone planning a long cross country trip may have dozens of NOTAMS at many diversion airports to review. At some point all the NOTAM lawyering seems a bit much.
There's a ground stop for all flights now.

GROUND STOP ALL FLIGHTS / ALL DESTINATIONS EXCLUDES MILITARY AC AND MEDEVAC FLIGHTS DESTINATION AIRPORT; ALL FACILITIES INCLUDED: ALL GROUND STOP PERIOD: UNTIL 1430Z REASON: EQUIPMENT OUTAGE REMARKS: US NOTAMS SYSTEM DOWN

This might be a silly question, but is that a NOTAM saying that NOTAM system is down? How does it get out?
As I understand it there's a hotline and periodic teleconferences and webinars today that for sure everyone at the airlines is participating it.
The website and the system that gets it out to all the planes are related but not the same.
With all the hate in HN regarding SOA, here’s a great example of adding resilience by separating concerns at a systems level.
NOTAM is a notice to alert aircraft pilots of potential hazards along a flight route...

Command control can see that NOTAM system is out and publish advisory. (Not via NOTAM system)

Reminds me of that screenshot of a windows popup unable to display an error.
I will never forget trying to set up a printer on a linux desktop 20+ years ago: tried to print a diagnostic/test page. All that printed was a single line of text: "Unable to connect to printer."
Gonna be a bad day for those sys admins
May none of our fuckups be bad enough to get an article written about them. Amen.
heh, my boss was on a public sector project that went so far south she was stalked by news crews leaving the office. The experience left a pretty deep scar on her. This was before my time thank babyjeebus.
Kinda wondering the odds of there being one crying into their coffee over a stack of memos saying they should do something before it fails, or some greybeard angrily pointing to their quality control concerns on a new system. Both are pretty common with federal IT.
Why do all aviation IT systems feel like they are so fragile?

It feels like not a single month can pass these days without some "Airline X has major outage and ruins tons of people's days!" story on the news.

What is the tech behind these frail systems?

More modern systems are also down once in a while. With aviation it's just more visible because one system can affect a lot of people.

I'm not sure when ATC systems (which I would count NOTAM to be one of) have last failed, I always had the feeling they're very stable. It's usually airlines that struggle with their applications.

I think it's just a question of media visibility. Aviation outage = queues in airports = easy article to write
All hyper optimized systems become fragile until they collapse.

The NOTAM system is ridiculous, no surprise it collapsed ... you can lose your ticket for flying thru a MOA that went active AFTER you took off.

What could possibly go wrong with a "push" notification system for every tiny little detail of aerospace scheduling? No force is as destructive as the good idea fairy.

I'm not sure your specific example is a particularly good one. I can legally fly through an MOA that's active, without needing ATC or military authorization.
That's the curse of niche software. Especially one made to fit, it's easy for penny pincher to decide "it works fine now, it doesn't need ongoing improvements" and you end up with some ancient shit needing java 1.7 (or worse) to run with no plan to upgrade.
Airlines view technology as a cost center.
This is the FAA's system, not the airlines'.
GP asked about both systems. It's worth noting that the FAA's systems are brittle for an entirely different reason than, say, Southwest Airlines'.
The software is tied to a dependency chain of real people (passengers, crew, etc), real equipment, and lots of constraints. So problems have a downstream effect that's more pronounced and visible than many other spaces.
When was the last time NOTAMs went down? It seems remarkably resilient actually.
Edit 2 - * Ground stop Lifted * Update from FAA:

>Update 5: Normal air traffic operations are resuming gradually across the U.S. following an overnight outage to the Notice to Air Missions system that provides safety info to flight crews. The ground stop has been lifted.

>We continue to look into the cause of the initial problem

https://mobile.twitter.com/FAANews/status/161317140080139468...

---

Edit - Update from FAA:

> Update 4: The FAA is making progress in restoring its Notice to Air Missions system following an overnight outage. Departures are resuming at @EWRairport and @ATLairport due to air traffic congestion in those areas. We expect departures to resume at other airports at 9 a.m. ET.

https://mobile.twitter.com/FAANews/status/161316273572174643...

---

Flightradar24 are reporting:

> Flights to US airports have been groundstopped by the FAA until at least 09:30 ET (1430 UTC). This means any flight not in the air already will not be allowed to depart. Image: flights over US now compared to same time last week. About 700 fewer flights airborne now.

> Flights are being held as the FAA works to bring the NOTAM (NOtice To Air Missions) system back online.

https://mobile.twitter.com/flightradar24/status/161315347921...

Latest FAA update:

> Update 3: The FAA is still working to fully restore the Notice to Air Missions system following an outage.

> The FAA has ordered airlines to pause all domestic departures until 9 a.m. Eastern Time to allow the agency to validate the integrity of flight and safety information.

https://mobile.twitter.com/FAANews/status/161314857927045939...

Statement from the white house:

> The President has been briefed by the Secretary of Transportation this morning on the FAA system outage. There is no evidence of a cyberattack at this point, but the President directed DOT to conduct a full investigation into the causes. The FAA will provide regular updates.

https://mobile.twitter.com/PressSec/status/16131535612899328...

I believe this means that nothing can take off, but aircraft already in the air can continue to their planned destinations.

Fun but deadly. They’re not wrong about the absolute avalanche of irrelevant data that will be used to show you “you should have known” - hence the proliferation of “interpretation” services.
But it’s up to airline how they present NOTAMS to the pilot in the briefing package. They can (and do) use geolocation present in some (many) NOTAMs to filter them out. For example do not show the NOTAM just because the flight path intersects with the airspace. They can do even better - consider not only location but also altitude range, the best flight planning systems can consider also estimated time of arrival of the plane near the location of the NOTAM and filter out those which are not yet valid or those which are expired (the validity range usually present in each message). This makes the problem of including the NOTAM a 4-dimensional - geographical location 2 dimensions, altitude 1 dimension and a time. Not the easiest to solve, but solvable. Of course for every dimension margins can be applied to accommodate re-routes or departure delays, or ATC commands. There is no written in stone standard of how to present NOTAMS. Newer may be displayed at the beginning, etc Not to say that they can (and do) separate airfield and airspace messages to segment the large set onto meaningful subsets. I mean there ways to make sure important information is not lost and less important available if needed.
Airlines aren't the only things doing "air missions" - there is software that filters out much of it, but it IS quite archaic (similar to how the "official weather" notifications are set out).

Look at the Ukraine one for a pretty scary example.

Nit: it's just "Ukraine" not "the Ukraine." See https://en.wikipedia.org/wiki/Name_of_Ukraine
Try replacing it in the sentence - it doesn't work, "the" is modifying "one" not Ukraine.

I suppose it could have been written "the Ukrainian one" but the the would still be there.

Whoops - yup, I jumped the gun there.
Double nit: this was not a misuse the deprecated term "The Ukraine" but the correct use of 'the' attaching to "Ukrainian one" referring to the NOTAM basically telling everyone to remain clear of Ukrainian airspace.
nit RFI: What is it about "Ukraine" (phonetically maybe?) that makes me, a westerner in the US, want to put a "the" before it every time I reference it as a country instead of just, you know, using the name of the country?

I don't go around calling other proper nouns "the" (mostly). I don't call my son "Hey there, the Bob, how was school today?" (his name is not bob). But if I had named my son Ukraine then I feel like I'd change that sentence to: "Hey! The Ukraine, how was school today?"

Why is this a thing? I have a formal background in applied/computational linguistics and a bit of trivial searching doesn't really reveal why this is a general tendency. Hurt's my brain meat.

Here's some that you want to "the": Alps, Matterhorn, US Navy, Rock.
Depending on your age and general personal history, in the past it was very common to see references and use of "the Ukraine" to talk about the region/area as well as the country (that mostly covers that geographical area). It could be remnants of your recollections popping up subconsciously.

In this case it really was meant to be projected as similar to "Have you seen the Bob document yet?"

Maybe because it's similar to "the UK" (United Kingdom).
In German (maybe some other languages too?) it's common to use "the" to refer to a 3rd person, so if Bob's sister Charlotte came home from school but not Bob, she could say "The Bob went to the mall".

Seems like it's the same way in Finnish, Finnish F1 driver Mika Häkkinen referred to Michael Schumacher as "The Michael".

Whoops - yup, I jumped the gun there.
The official weather notifications (METARs/TAFs) can be displayed in more modern ways, but many pilots like the brief coded weather messages because they can be easily skimmed for an entire route of flight.

In my mind, AIRMETs were a bigger problem - they had limitations in terms of how they were geographically defined, time range, and lack of flexibility (e.g. differentiating turbulence vs LLWS vs strong surface winds for AIRMET Tango) - but that's been fixed with the newer G-AIRMET feed[1], which is based around BUFR[2] instead of plain text.

The catch being you can't easily convey G-AIRMETs via voice or in an non-interactive environment, so we still keep the legacy text-based AIRMET feed around in parallel.

[1]: https://www.aviationweather.gov/gairmet/help

[2]: https://en.wikipedia.org/wiki/BUFR

100%. As a GA pilot who mostly flies under IFR, the NOTAM system is borderline useless to me.

For every warning about an approach being altered or a runway closed, there are 100s of "birds invof airport" or "unlit crane 50' AGL 5 miles from the field" NOTAMs. And even for the relevant NOTAMs, Foreflight will highlight them for approaches etc and ATC won't send you to a closed runway or taxiway.

Yeah, NOTAMs come into play when the shit hits the fan; radios are dead and you can't reach the tower kinda thing, but in that case just be sure you declared emergency, then they (probably) won't get you much for landing on a closed runway or a taxiway.
It works in both directions. If someone hits a crane in the fog they will present a NOTAM and you cannot argue that you have not been warned.
What if the tower’s radio goes down?
They have backup transmitters and if everything fails (tower evacuation has happened) you talk to the overlying approach / tracon / center frequencies to check. And then after that, land anyway and self announce positions for other traffic.

It's basically the same as landing at an airport that doesn't have a tower. Happens every day at hundreds of airports.

Seems like it's the sort of thing that's borderline useless right up until the moment it's absolutely essential.

Like the smoke alarms in my house, which are actually wired up to mains so don't technically need a battery, but they still have to have a battery in them and will give high pitched chirps ever few minutes when the battery is dead. And since there's so many in the house, and the chirp only comes every few minutes, it's a PITA to find the exact one that needs replacing.

So annoying, and again it's wired to mains so it worked without batteries! Except in a fire the fire might fry the house's magic box of energy delivery leaving only the batteries as the power source and then I really really really want them to work.

I wish those mains-powered ones would just shriek continually if the battery was low AND mains power failed; then you could kill the breaker and find it easily.
I wish they just had a steady LED from the mains power on them when the battery was dead. Seems much easier to me.
Yeah, I bet one somewhere has it, but most just flash-when-chirp which is kinda annoying:

This alarm has a low/missing battery monitor circuit which will cause the alarm to “chirp’” approximately every 30 - 40 seconds for a minimum of seven (7) days when the battery gets low. The chirp will be accompanied by a flash of the Safety Light. Replace both bat- teries when this condition occurs.

Some of the newer ones come with a built-in Lithium battery that supposedly is good for 10 years.

We recently had a house burn in our neighborhood during a power outage that was running on a generator. Generator itself caught fire, so pretty much would cover that exact situation.
Yes, it wasn't like this in my house until some years ago when we had a small expansion constructed and the contractor installed these in the new portions just as a standard thing he does, and said he was retro fitting the rest of the house that way too. ( We know him, friends, so we know he wasn't just trying to get extra $ out of us)

For a few minutes I thought it seemed a needless detail, until I realized that often enough people forget to change their stand-alone unit batteries and maybe deal with the the occasional chirp in an "I'll get to it" mindset until it runs down completely. Having it tied to the mains solves that because it's relentlessly annoying to hear that chirp at random intervals, and the battery is a nice backstop failover from the mains going unexpectedly molten.

I mean, it is code now to have them hardwired up. Actually, I think the requirement might be for interconnectivity rather than mains power. It's probably both in some areas. It's quite possible, depending on the extent of your expansion, that he was required to retrofit all of the smoke detectors in the home.
I've had way, way, way, too many 'chirp' at 4am situations in my life. The alarms have _literally_ trained me like Pavlov's dogs that it is _always_ a false alarm, to the point where my sleep deprived brain stumbles through the door blindly into the hallway without even checking if there's heat or smoke.

Some of the other solutions here like cry wolf only if battery low _and_ power's out, or a dedicated LED to indicate a problem, or the one I keep thinking of; gently _saying_ there's a problem with a small sound clip of "bat" instead of an angry Chirp that must wake someone up would really help. The alternative that I've heard many others take is to just disable them entirely if you're in a rental. I'll admit that I've been very tempted to do just that for individual alarms which are overly sensitive to bathroom steam.

> gently _saying_ there's a problem with a small sound clip of "bat" instead of an angry Chirp

Those do exist! At least one smoke detector in my house has voice (primarily to differentiate between smoke and CO alarms)

I started replacing the batteries in all of them as soon as the first one starts beeping.

I figure the batteries won't last much longer in the others and I don't need to go hunting.

Your analogy is way off. If smoke alarms worked like NOTAMs, they’d go off every time someone strikes a match, lights the fireplace, turns on the gas cooktop, uses a hair dryer, or plugs in any appliance. Oh yes, when the house is on fire too. All have non-zero risk of inferno.

NOTAMs are full of pages and pages of goop — inconsistent, impossible to accurately filter, hard to read, at times unclear, and mostly noise.

I think you’d not argue that if you flight to the airport without ATC (there are plenty of those), reading NOTAMS about that airfield is kind of essential exercise before flight.
It's all fun and games until you have an F-16 head butting you because you didn't pay attention to NOTAMs and the Vice President happens to be visiting your town.
Interestingly, that seems to be a US-only problem.
The linked booklet specifically refutes that idea, calling out Australia and Greece in particular but implying the problem is much broader.
This is my favorite quote: "In an unintended twist of irony, the agencies seeking to cover their legal ass are party to creating the most criminal of systems – an unending flow of aeronautical sewage rendering the critical few pieces of information unfindable."
"There are three parts to the problem: the system, the format, and the content. The system is actually quite amazing. The AFTN network connects every country in the world, and Notam information, once added, is immediately available to every user. Coupled with the internet, delivery is immediate.

The format is, at best, forgivable. It’s pretty awful. It’s a trip back in time to when Notams were introduced. You might think that was the 1960’s, or the 50’s. In fact, it’s 1924, when 5-bit ITA2 was introduced. The world shifted to ASCII in 1963, bring ing the Upper and Lower case format that every QWERTY key board uses today, but we didn’t follow – nope, we’ll stick with our 1924 format, thank you."

https://web.archive.org/web/20230104130153/https://www.faa.g...

"The FAA is changing the format for Notice to Air Missions (NOTAM) to align with international standards. The transition to the new format will ensure U.S. NOTAMs are compliant with standards set by the International Civil Aviation Organization (ICAO) and promote further global harmonization among neighboring Air Navigation Service Providers (ANSPs)."

ICAO NOTAM format

https://vat-air.dk/files/ICAO%20NOTAM%20format.pdf

Example! (decoder ring not included)

"Q) EGTT/QMRXX/IV/NBO/A/000/999/5129N00028W005"

I want to point out that lower-case is possible with ITA2. Start at 4.6 of ITU-T Recommendation S.2 / 11/1988 in the Blue Book, basically 11111 & 11011 11111 switch case in locking/unlocking mode.
Its even more amazing when you really sit down and think about all of the systems (many highly resistant to change like aircraft navigation systems) that all connect and utilize this service.

What appear like simple changes and proposals in the aerospace realm are extremely hard to execute and many times take decades (multiple) to come into play. Global services/systems are even harder.

OpsGroup, the organisation behind that guide is also worth mentioning. It's a self-organised advocacy organization for flight operations personnel. Apparently they have a longstanding campaign to reform the NOTAM system (as explained in the guide).

They also have a summary of today's incident: https://ops.group/blog/us-flights-delayed-after-notam-system...

This is hilarious. Really appreciate the examples of irrelevant clutter obscuring important information. Any UX designer can learn from this as an example of what not to do.
Very entertaining to watch the local TV news this morning.

The reporter keeps pulling people aside as they arrive at the airport and asking them what they're going to do with all the planes grounded.

None of them know it's happening.

So far, they have all admitted that they either don't look at the news, or don't look at the local news, except for one woman who defiantly said, "It wasn't on Facebook," as if that meant that since the grounded flights weren't in her social media feed that it wasn't real.

The NOTAM system is embarrassing. This just tops it off. Actually, our whole ATC system and the way the FAA operates is embarrassing. It all works kind of like waste management in NYC. If they were to add new tech and efficiency, fewer people would have jobs, so we keep doing it the old way to the detriment of everyone else.
It’s easy to say things are about jobs but do we have any evidence of that? There’s a modernization project underway at the FAA so I’d bet that if you looked there’s someone who’s been trying for years to get attention on it before something like this happened.
Shirley you must be joking.
Rumack : I won't deceive you, Mr. Striker. We're running out of time.

Ted Striker : Surely there must be something you can do.

Rumack : I'm doing everything I can... and stop calling me Shirley!

> There’s a problem with the NOTAMs…

>> The NOTAMs? What is it?

> It’s a system for alerting pilots to hazards.

>> I see, thank you

(ETA: haha aw, well I thought it was funny)

What embarrasses you about it, esp compared with more modern systems?

This seems like the kind of critical infrastructure whose uptime requirements can make upgrading challenging once in place.

Others have said it better. If you google 'notams are broken', numerous results will show up explaining various problems with the NOTAM system.

Edit: Here's a good one - https://fixingnotams.org/ending-notam-nonsense-in-the-digita...

A general inefficiency example using two airpots I often have in mind: IAH and JFK. In IAH, traffic is spaced out in cruise well before the arrival begins, where they're burning much less fuel at high altitude. They're then instructed to descend via the full STAR (standard terminal arrival), including the transition to the approach for the runway in use. This looks like a hundreds mile long line of planes all following the same path to the same runway. The only further instruction necessary from ATC is speed adjustment, and allows for an almost continuous descent to the runway provided there's no weather in the way.

At JFK, the spacing occurs much later and, even though the airport has some similar arrivals (though none quite as thorough), they instruct every altitude change and speed adjustment for every aircraft individually, along with vectoring them to the approach for the runway in use. It results in an incredibly busy radio environment and numerous inputs from pilots flying planes capable of simply following a STAR and transition, like in IAH (or ORD, SFO, LAX, etc). There's also much more time spent at low altitude burning more fuel. It reminds me of everything else in NYC, which seems to be inefficient on purpose (NYPD, MTA, DSNY, etc.).

JFK and IAH have a similar number of aircraft movements. Yes, NYC has busier airspace with numerous airports, however, I don't see how this prevents the design and implementation of more modern procedures. Flying around at 4000 feet in an airliner getting numerous vectors just seems ridiculous compared to what I experience elsewhere.

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Based on this and the other great PDF someone posted, it sounds like the system itself is fine, but the content is the core problem.
This whole comment seems like a charming case of advanced Dunning-Kruger. You sound very confident in your assessment, but then it seems you are honestly suggesting that NYC TRACON controllers are being inefficient on purpose… for what? Fun times? You said it yourself— it is a busier airspace. The approach and departure spacing of EWR, JFK, LGA and TEB— not to mention the changeable airspace restrictions over parts of NYC itself and managing GA traffic into and out of the Hudson River Corridor— makes a simple single hundred mile long elephant walk to your preferred runway at JFK logistically untenable. Not to mention potential conflicting traffic from smaller airports in Connecticut and Long Island… And just a gentle reminder that as pilot in that airspace you have precisely one small piece of the big picture when it comes to being aware of exactly how complicated that can be for the ATC personal.
So basically it's the same as every other government entity?
REALLY IMPORTANT NOTAMS tend to alert pilots to RESTRICTED AIRSPACE or AREAS OF UNUSUAL AIR OPERATIONS. You can't fly anywhere near the President of the United States, the movements of which can change from day to day.

We get NOTAMS about military aircraft operations; often military airspace which is usually permitted may be shut down for a week or so.

Wildfire tanker operations or other natural emergencies can close an airspace.

It's quite dynamic, all on top of the scheduled flight plans and routes.

They are also for notifying pilots of potential caution areas.

I used to operate a 550+ meter tower and when I had a tower light out, I had to file a NOTAM.

Cool, you filed NOTAMs; I just read them.

If you like lots of daily mail, become responsible for the operation of a Cessna 172 (Skyhawk), the type of aircraft with the most units built of any, ever. Endless variations.

Unending stream of paper NOTAMS via US first class post office... at least, when I had a 172, 20 years ago.

These notices are exactly like a recall notice on an automobile: get someone to validate the steering wheel etc. I would suppose that many HN readers have gone through the car hardware remediation process.

I would suppose that this class of NOTAM, although in my particular case the most common, are not immediately relevant to a total Ground Stop Order for the USA. But -- consider that airline and other commercial operators may have their own internal requirements that could ground a fleet in the absence of an ability to state that they have complied with all relevant FAA NOTAMS. Oh, the liability!!

(Holy cow, just did remedial maths: 550m is a Large Number! Would like to know more details.)
The tower was used by a TV station to broadcast their channels. You can see the curvature of the earth at the top when it's a clear day.
Was it database failure or did they get hacked?
For anyone looking for previous FAA outages: In 2014, an U-2 plane’s flight plan crashed LAX’s ERAM system because the system ran out of memory.

https://www.oig.dot.gov/sites/default/files/FAA%20Actions%20...

Why do secretive spy planes need to file flight plans?
That was a training flight, it's in the PDF.
I imagine operational flights might "officially" start and end as routine training flights, at least on paper.
LAX, an air traffic control tower, does not employ ERAM. Los Angeles Center (ZLA), the overlying air route traffic control center, does.
They're resuming operations despite "still searching for a cause." Comforting.
You've never rebooted a computer to get it working again, without immediately knowing why it crashed?
Not since I stopped using Microsoft Windows.