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Ryanair flight landed at Manchester airport with six minutes of fuel left

theguardian.com

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Re: Ryanair flight landed at Manchester airport with six minutes of fuel left

#271

Post by adastra22 »

abtinf wrote: post #265
kube-system wrote: post #100

Earlier quoted context omitted.

I'm not an aviation expert, but generally in safety engineering, safety buffers are not simply calculated as [normal situation] * [safety factor], but [worst case scenario] * [safety factor] If you ever cut into your safety allowance, you've already fucked up. Your expected design criteria should account for all use cases, nominal or worst-case. The safety factor is there for safety, it is never intended to be used.

This is really helpful and I think I understand now. The approach is basically “accounting for everything that might go wrong to the best of our experience, including problems arising from the complex interactions between the airplane and supporting ground systems and processes, this is how much fuel you need in the worst case scenario. And now lets add more to give us a cushion, and we will treat consumption of this…

Precisely.

Re: Ryanair flight landed at Manchester airport with six minutes of fuel left

#273

Post by davesque »

jacquesm wrote: post #23

That is very exceptional. I've written fuel estimation software for airliners (cargo, fortunately), and the number of rules regarding go-arounds, alternates and holding time resulted in there usually being quite a bit of fuel in the tanks on landing, by design. I've never heard of '6 minutes left' in practice where it wasn't a massive issue and the investigation into how this could have happened will make for interes…

Yeah, to give some idea, I believe the technical term that would have been radioed from the pilot in this situation would have been "mayday fuel."

Re: Ryanair flight landed at Manchester airport with six minutes of fuel left

#274

Post by lazide »

abtinf wrote: post #40
jacquesm wrote: post #23

That is very exceptional. I've written fuel estimation software for airliners (cargo, fortunately), and the number of rules regarding go-arounds, alternates and holding time resulted in there usually being quite a bit of fuel in the tanks on landing, by design. I've never heard of '6 minutes left' in practice where it wasn't a massive issue and the investigation into how this could have happened will make for interes…

Naively as an outsider, this situation seems like everything worked as intended? On a nominally 2h45m flight, they spent an extra 2 hours in the air, presumably doing doing fuel intensive altitude changing maneuvers, and were eventually able to land safely with their reserves almost exhausted. I’m a little confused by what there is to investigate at all. How much fuel should they have landed with?

If you get shot, but had a bullet proof vest on, and hence didn’t die, technically everything worked as intended.

Personally, I’d still want to figure out why I got shot and work on making sure that didn’t happen again.

Especially if you basically got shot multiple times (for an analogy in this case).

Re: Ryanair flight landed at Manchester airport with six minutes of fuel left

#276

Post by bluGill »

jacquesm wrote: post #167
bluGill wrote: post #164

Earlier quoted context omitted.

I agree, well out of comfort zones. However to my reading multiple different things went wrong to get to this point.

That could be. We just don't know right now, but your intuition may well be correct, even if there is a single root cause there could very well be multiple contributory causes.

They failed to land at two airports before the third. I can't say if they made the right decisions but that already is two failures.

Re: Ryanair flight landed at Manchester airport with six minutes of fuel left

#277

Post by prism56 »

dlcarrier wrote: post #149

The latest Captains Speaking podcast has an discussion about one of the hosts being in a similar situation: https://youtu.be/5ovlZ221tDQ Fortunately, the flight left with extra fuel, because it was cheaper to carry excess from the origin airport than to buy it at the destination airport, so reserve fuel wasn't needed, but it was close. Also, there was lots of lightning.

I absolutely love insights like this into areas of the world I have no knowledge. Makes absolute sense in the modern world but also something I'd not think about

Re: Ryanair flight landed at Manchester airport with six minutes of fuel left

#278

Post by pmyteh »

allturtles wrote: post #190
dboreham wrote: post #184

Earlier quoted context omitted.

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...

Re: Ryanair flight landed at Manchester airport with six minutes of fuel left

#279

Post by mulmen »

rappatic wrote: post #136

> the Boeing 737-800 had just 220kg of fuel left in its tanks... enough for just five or six minutes of flying Maybe I'm just unaware, but it's crazy to me that these planes burn 40 kilograms of jet fuel per minute.

40kg of fuel per minute is a lot but airplanes carry a lot of people.

Web searches suggest a 737-800 gets about 0.5mpg at cruise. With 189 passengers in a one-class layout that’s 95mpg per passenger. With 162 in a two-class layout that’s 81mpg per passenger.

This is better than a single person in a car but four people in a Prius gets 50mpg * 4 = 200 mpg.

Re: Ryanair flight landed at Manchester airport with six minutes of fuel left

#280

Post by bluGill »

isaacdl wrote: post #248
bluGill wrote: post #169

Earlier quoted context omitted.

Could have, but pilots practice no fuel landings all the time (in simulators). If they can get to ground that is "level enough" nobody dies. It is not something you ever want to see in the real world (and in the real world people often do die when it happens), but it isn't automating people die.

I don't think that's all that true for airliners. Pilots definitely practice for engine-out scenarios during all levels of training up to the airlines, but the ability of a plane the size of a 737 to safely land on anything but a runway is...limited. And if you're low, slow, and trying to go around, that's not a lot of time to glide to ground that is "level enough".

i didn't mean to imply no runway landings. Landing on grass is questionable. They would practice water landings though
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