Since there's a lot of confusion in the comments below I'm going to hijack one of the top comments to make a couple points clear from the article and FlightRadar24 data: [1]

They did reroute earlier. It was 2 failed attempts on Prestwick (Glasgow), 45 minutes in the landing pattern, then they diverted to Edinburgh (15 minute flight), a failed attempt at Edinburgh (~5-10 minutes), and then they diverted to Manchester (45 minute flight) and landed successfully there. Likely they hit their reserve just as the Edinburgh landing failed and decided to fly to Manchester, with clearer skies, rather than risk another failure in their reserve.

IMHO the only questionable pilot decision here is to divert to Edinburgh rather than Manchester immediately. But this is somewhat understandable: first of all, dropping the passengers off at Edinburgh (an hour drive from Glasgow) is significantly less costly and less inconvenient than dropping them at Manchester (an overnight bus ride). Second, if the Edinburgh landing had been successful they would not have eaten into their reserve and no investigation would've been needed. Third, the Monday-morning quarterbacking could've easily gone the other direction if they had diverted to Manchester ("Why did you choose an airport 178 miles away and risk eating into your fuel reserve when Edinburgh was right there?")

[1] https://www.flightradar24.com/data/flights/fr3418#3c7f91f4

> IMHO the only questionable pilot decision here is to divert to Edinburgh rather than Manchester immediately. But this is somewhat understandable: first of all, dropping the passengers off at Edinburgh (an hour drive from Glasgow) is significantly less costly and less inconvenient than dropping them at Manchester (an overnight bus ride).

Yeah, as someone who knows next to nothing about airlines, but has seen these type of decisions in businesses, this was the thing that stood out to me. This is all pure speculation of course, but I'd be curious how clear it was that Edinburgh would also have a high risk of being unsuccessful and whether the pilots felt any pressure to try that anyway. E.g. are there consequences for pilots who cause delays for passengers?

> E.g. are there consequences for pilots who cause delays for passengers?

I'd imagine heavily depends on how often that happens vs other pilots on same route. Tho I'd imagine consequences are "here is more training".

To me the 45 minutes in the landing pattern also seems questionable.

At the point they left it, they still had about an hour and 20 minutes of fuel remaining, with an alternate airport 20 minutes away. They had not declared an emergency, so they were in with any other traffic waiting for takeoff and landing. (Which does make me wonder, did any other planes try to land at Prestwick at the time and how did they fair?)

Quick note that Preswick is not really Glasgow (35 miles away) and Glasgow has its own airport which presumably was also affected by the same weather so they couldn't divert to that. Between the Scottish lowlands (where they had already tried all the commercial airports) and anywhere else, Manchester is about the closest option.

As someone totally ignorant of British airports, a Google maps search for "airports northern england" shows Teesside, Carlisle, and Newcastle all significantly closer to Edinburgh than Manchester. Are these not places where a 737 under emergency could land? Or was the weather also bad there?

Carlisle is small (and not currently licensed for public use) - not an ideal place to drop a 737 if there's a choice. It's also not that far from Prestwick so may have had similar weather. Newcastle and Teesside are both on the East coast and likely to be affected by similar weather to Edinburgh given the storm coming in from the North East. The next closest will be Manchester or Leeds/Bradford, with Manchester being larger, closer to where passengers want to go (Glasgow) and further away from the storm.

There's precedent for this kind of situation to generate quite extensive investigations. An incident in 2017 where a flight from the Isle of Man to Belfast was unable to land in a storm, diverted back to the IOM, then landed in unsafe weather conditions because of insufficient fuel to divert again got a 48 page report[0], safety recommendations, and the airline being banned from the UK.

[0]: https://assets.publishing.service.gov.uk/media/5a82ede440f0b...

Leeds/Bradford is on a plateau and can get affected by wind.

Carlisle is a small domestic airport. The other two might have been affected by the storm as well. The weather was bad enough to down trees in London.

> Or was the weather also bad there?

That's likely, these places are not very far apart, and weather systems that cause 100mph winds don't tend to be small. And presumably if you have at most one landing attempt remaining you don't want to be taking any more chances.

so the pilot fucked up either way right????

when you piece it together like that its a close call and maybe a hindsight but its understandable if pilot do this

> IMHO the only questionable pilot decision here is to divert to Edinburgh rather than Manchester immediately.

The decision will have been made based on the forecast weather at Edinburgh prior to the flight (that is used to select a suitable alternate), and the actual reported weather at the time. Both the forecast and actual weather are precisely reported in an aviation weather language ("TAF" and "METAR") and assessed objectively. The investigation will certainly consider if the pilots erred there. Mostly likely the outcome will be that the decision was the correct one given the weather information they had available to them - this is what has been found in similar previous incidents.

Claiming you're low when you are not is going to cause a major headache for the PIC, they're going to have to write that up and they may well be investigated. If it turns out they were lying they would likely find out that that is a career limiting move and if it happens too often then that too should result in consequences. The main reason is that your fake emergency may cause someone else to have a real one.

What’s the mechanism for them to get caught?

When you declare a fuel emergency or even urgency, there's often follow up to figure out why (mechanical issue? problem with dispatch? problem with flying technique? exceptional weather condition that could be forecast better? etc). And there is plenty of data in aviation to know what happened.

Dispatch knows how much fuel they say they put in.

Your flight time, speeds, and profile are known.

ACARS may be reporting fuel use throughout the flight.

etc, etc, etc.

Random spot checks. Every day at every airport some of these will get verified. Also, the next pilot would have to be willing to cover for you because they are going to have to falsify their records to make your trick invisible. You record the amount of fuel in the tank when you take command of the aircraft, the amount of fuel that was loaded and from that it is trivial to compute how much was left the last time it landed.

Lets say a plane crew claims low fuel.

The pilot in charge has to file a writeup.

When someone accepts the writeup, there's a random chance it's selected for followup. If/when they discover there was enough fuel, it will affect the career(s) of person(s) involved.

First, generally, people don't like having to do paperwork, and especially don't like doing paperwork to help you land a little quicker.

While one time may not be a fireable offense, you will find you career affected in the number of ways people can find to be uncooperative with you, or not support you when you attempt to advance your career within the company.

Developing a habit would lead your interlocutors to escalate the situation, which would lead to discipline up to and including the company firing person(s) involved.

Which airlines? I feel like if this is an issue we should be naming names.

RyanAir is famously one of them.

Edit: I was recalling articles claiming the company purposely fueling less than other airlines in order to increase their rate of claims for priority landing to have a better "on time" statistics.

This forum post disputes that: https://aviation.stackexchange.com/questions/38501/is-it-tru...

also carrying less fuel does save on fuel usage

No way.

Having attended meetings at ICAO I can also tell you many details of various aviation incidents, including their existence, are covered by some secret classification. This fact being disclosed caused most of the attendees to lose all hope in the rest of the proceedings. To their credit the FAA reps on that occasion were by far the most reasonable gov representatives in the room, and the FAA are one of the major voices pushing for greater transparency on it.

Which specific civil aviation incidents are covered by some secret classification?

> Which specific civil aviation incidents are covered by some secret classification?

You would have to have secret clearance to know which ones

It's cool, I have Top Secret Level 3 (Omega Sector) clearance so you can go ahead and tell me.

It’s generous of the classifying authority to send to the ICAO meeting somebody both appropriately credentialed to know about the information in question, and willing to talk coyly about it. Did these additional incidents inform the policy discussions at the meetings you attended?

It's funny you say that, because the way it happened was it was blurted out by a diplomat from a certain country, at which point most of the regulators facepalmed and all of those of us from outside were having the same reaction as many here.

The whole subject of discussion prior to this was efforts to improve data sharing wrt incidents.

Kinda surprised there's no data link for that sort of telemetry so that you don't necessarily have to take the pilot's word for it.

Second guessing a pilot saying they have a problem is a really bad idea. ATC second guessing an emergency is a really bad idea. Making a pilot explain why they're actually low on fuel, despite whatever some computer is saying, instead of focusing on flying the plane is a really, really bad idea.

Also, that sort of telemetry does exist for most major airlines, however it goes via satellite to the airline not the ATC.

I am not saying you are wrong, but both Type I and Type II errors are problematic. What if the pilot is wrong?

Korean Air Flight 801 could have used someone 2nd guessing a pilot. They didn't until they were almost dead and then it was too late. Not 2nd guessing the pilot was a really really bad idea.

If the pilot is wrong you hope the copilot or someone else on the crew picks up on the error and corrects it. If they’re both wrong, or if they don’t feel empowered to challenge the pilot like in Korean Air 801, everyone is usually fucked.

ATC doesn’t have the kind of situational awareness or manpower to fix these kinds of problems the vast majority of the time. It only seems like they could have done something after the fact when the disaster has already happened and hindsight activates.

Like the GP said, ATC second guessing pilots is a really, really bad idea. A few incidents doesn’t change that.

That specific incident resulted in a lot of changes to the rulebook and some very specific notes about training in terms of cultural differences.

> Korean Air Flight 801 could have used someone 2nd guessing a pilot.

...yeah, the second pilot. And in this case, also flight engineer.

IIRC The problem was pretty much aside from errors the cultural issues with pilots, the "lower ranks" wouldn't dare to be assertive to seniority and just voiced the issues they saw without doing anything.

I expect that they take the pilot's word in case of a rare situation [1] and then make the fill a ton of paparwork to try to solve the main cause and also discourage lies.

[1] In one case someone mixed imperial and metric unix, and instead of $something-kilograms, they put only $something-pounds of fuel.

This incident is known as the Gimli Glider and was actually due to multiple failures before the pound-kilogram issue (and the backdrop of Canada's then-recent metrication) even became relevant: https://en.wikipedia.org/wiki/Gimli_Glider

Would that be more reliable than just ensuring there are consequences for lying?

Perhaps. If the pilot knows that the ATC can see he's full of it, he might be less likely to lie.

Those who still do can be grounded and be moved into management or take up a career in politics.

I’m surprised the “fuel on board” isn’t something communicated via transponder considering previous low fuel emergencies/crashes.

It wouldn’t change anything. The line between a “mayday - fuel emergency” and any other flight waiting for a landing slot is crystal clear. Of course, in low-but-not-emergency fuel scenarios the pilots can request priority, but the ATC don’t have to oblige them.

As a rule airline pilots don't lie about this stuff. They take safety pretty seriously.

Putting a theory of "you shouldn't trust pilots" into ATC breaks the entire system.

It is a system built out of very regulated parts, very professional people, and tight controls.

Pilots are encouraged to be very forward and proactive about fuel situations because of https://en.wikipedia.org/wiki/Avianca_Flight_052

Minimum fuel requirements are calculated as "Time of fuel for cruise to certain points", which is usually good enough, but if an Airport is stupid busy, or has bad wind patterns, just a couple go-arounds will chew through your fuel way faster than the regulation expects.

Turbofan engines are also dramatically less efficient at low altitude than high altitude cruise. So holding at low altitudes because a congested airport is dealing with traffic will chew through your reserves much faster than you expect.

Ryanair flies short hops to congested airports. They will have relatively low reserves, and you should expect them to run into "Hey we are low on fuel" more often than international flights for example.

"It is a system built out of very regulated parts, very professional people, and tight controls."

Locally, this is true. Globally, not so much. I remember my friend's vivid description of a flight taken in Nepal. It was absolutely wild.

> It is a system built out of very regulated parts, very professional people, and tight controls.

also worth mentioning that most of the civil aviation regulations and SOPs regarding commercial flights are written in blood.

I mean, obviously, it's better to trust the pilots, but if they are jumping the line because "fuel low" when it's not low, well, they're not being very professional, are they?

Might be useful for fire crews in an emergency. Maybe have data for souls on board also.

"claiming they're low on fuel"

It is almost fascinating how humans will stoop to dishonesty even in banal situations - and not just any humans, but pilots, who should be subject to at least some vetting.

Maybe planes should be retrofitted as to transmit their actual fuel state including a qualified assessment in minutes to the ATC. Not just because of the cheaters, but also to warn the ATC in the rare case that some plane crew isn't very assertive about their dwindling fuel, or hasn't noticed the problem.

It would make prioritizing the queue a bit more neutral.

If I designed such a system from scratch, "remaining fuel" would be part of my telemetry.

>If I designed such a system from scratch, "remaining fuel" would be part of my telemetry.

Careful what you wish for. I'd rather people skip the queue by pretending to be low on fuel than people skip the queue by actually being low on fuel.

You mean that ATC would abuse their position by making planes circle as long as they have some fuel left?

No I mean people would take off with less fuel so that by the time they reach their destination they could skip the queue

This is provable, though (there are regulations that say how much fuel you must have at takeoff - enough to divert comfortably to a suitable airport + some reserve for circling), and could be heavily punished. Up to the withdrawal of necessary licences.