Even fighter jets have more fuel reserves when they land. This is insane.
Ryanair flight landed at Manchester airport with six minutes of fuel left
401–410 of 586 posts
Re: Ryanair flight landed at Manchester airport with six minutes of fuel left
#402Earlier quoted context omitted.
That is perplexing. Of course you get the potential energy back. It turns into kinetic energy as you descend. That is why you need not pedal downhill, and often even need to brake to prevent the bike from speeding up too dangerously.
> often even need to brake to prevent the bike from speeding up too dangerously. Indeed, which is what the airplane would have done on its way down to land. So it's more like riding the brakes on your way down the hill, and now at the bottom when you realize you need to abort the landing, you are at low speed and it's quite an exercise to get back uphill to try again
100%. You are correct on that. You can’t use your kinetic energy to go around after a landing attempt.
But not because “you don’t get the energy back”. (As recursive suggested about a downhill bike ride which is the part i am disagreeing with.) You do get it back, but because you want to land you bleed it away to drag. And once it is bled away you don’t have it anymore.
So we don’t disagree about the practical implications for flying. I’m disagreeing with recursive’s particular statement about downhill cycling and what it implies about the physics of the problem.
Re: Ryanair flight landed at Manchester airport with six minutes of fuel left
#403Earlier quoted context omitted.
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?
As others have said, final fuel reserves are typically at least half an hour, and you shouldn't really be cutting into them. What if their first approach into MAN had led to another go around? With a major storm heading north-easterly across the UK, the planning should have reasonably foreseen that an airport 56 miles east may also be unavailable, and should've further diverted prior to that point. They likely used t…
Suspect they were IFR. All your points stand. First time flying things with a jet engine, I was shocked how much more fuel gets burned at low altitude. It almost always works out better to max climb to altitude and descend than to fly low and level. On a small jet, things can get spicy fast when ATC route you around at 5000' for 15 minutes or so. Three aborted landings would gobble gas like crazy.
§ 91.167 Fuel requirements for flight in IFR conditions.
(a) No person may operate a civil aircraft in IFR conditions unless it carries enough fuel (considering weather reports and forecasts and weather conditions) to—
(1) Complete the flight to the first airport of intended landing;
(2) Except as provided in paragraph (b) of this section, fly from that airport to the alternate airport; and
(3) Fly after that for 45 minutes at normal cruising speed
Re: Ryanair flight landed at Manchester airport with six minutes of fuel left
#404Earlier quoted context omitted.
Imagine a hill with 500 feet of elevation descent, followed immediately by 500 feet of ascent. No curves. If you coast all the way down the first part, you'll get about 20 feet up the other hill before you need to start pedaling. This is a direct analogy to "getting your energy back" by losing elevation.
That is exactly what a rollercoaster does and it doesn’t start “pedaling” after 20 feet. Of course real systems have losses and you can’t practically use all the energy. But you don’t have to believe me. Look at the video of this glider doing an unlicensed airshow: https://youtu.be/QwK9wu8Cxeo?si=L-0Mfmu8wk1ZlQU7 It is a glider so it can’t “pedal”. You can see it steeply descending from 5:13 to 5:30 while it is speed…
The more water you put in your system the leakier your buckets get. Drag is not linear with speed. That was my point.
Re: Ryanair flight landed at Manchester airport with six minutes of fuel left
#405Between overworked, understaffed ATC and undertrained pilots, I'm expecting some major disasters in the coming years.
> Between overworked, understaffed ATC and undertrained pilots, I'm expecting some major disasters in the coming years. Maybe in the US, but this story is based in Europe, each country maintains a regulated standard and there are no EU wide disruptions that have ever happened to the best of my knowledge. Also Ryanair don't travel transatlantic flights.
I mean, the US also hasn't had any widespread waves of disruptions that led to incidents or flight problems. Same as the EU. American flights and airspace are usually safer too, statistically speaking.
Re: Ryanair flight landed at Manchester airport with six minutes of fuel left
#406Earlier quoted context omitted.
I have known former air traffic controllers that won't fly certain airlines because of a notorious habit some have for queue jumping by claiming they're low on fuel. If they are low on fuel is something else, but in any case when the ATCs have noticed a pattern then something is up. This situation sounds a lot less nefarious, but it does also sound like they should have rerouted earlier.
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…
> 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.
Re: Ryanair flight landed at Manchester airport with six minutes of fuel left
#407> 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.
Each of the four F1 engines on the Saturn V burned 1.8 metric tonnes of liquid oxygen and 0.8 tonnes of rocket fuel every second .
And each engine's propellant pumps required 55,000 HP to deliver that propellant.
Re: Ryanair flight landed at Manchester airport with six minutes of fuel left
#408Earlier quoted context omitted.
Yes and no. I had this happen recently and looked into it. My wife has been using my car, which is a Diesel Golf with a fuel capacity of 14.5 gallons. We set off driving one Saturday to visit my parents, and I noticed the fuel gauge was below empty already. By the time I got to the gas station, I put 14.3 gallons of fuel into it. I calculated that that works out to be about a cup and a half of fuel. So once you hit e…
You shouldn't tempt fate with a diesel, or any direction injection car for that matter. The high pressure pump will shred itself very quickly as the diesel is used for lubrication.
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Re: Ryanair flight landed at Manchester airport with six minutes of fuel left
#409Earlier quoted context omitted.
As others have said, final fuel reserves are typically at least half an hour, and you shouldn't really be cutting into them. What if their first approach into MAN had led to another go around? With a major storm heading north-easterly across the UK, the planning should have reasonably foreseen that an airport 56 miles east may also be unavailable, and should've further diverted prior to that point. They likely used t…
Suspect they were IFR. All your points stand. First time flying things with a jet engine, I was shocked how much more fuel gets burned at low altitude. It almost always works out better to max climb to altitude and descend than to fly low and level. On a small jet, things can get spicy fast when ATC route you around at 5000' for 15 minutes or so. Three aborted landings would gobble gas like crazy. § 91.167 Fuel requi…
Why does it burn fuel so fast?
Re: Ryanair flight landed at Manchester airport with six minutes of fuel left
#410That 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…
> I'd be very wary to get ahead of the investigation and make speculative statements on how this could have happened, the one thing that I know for sure is that it shouldn't have happened, no matter what. Just watch Juan Browne, he usually turns out pretty good in analyzing the mishaps. He didn’t upload anything for Manchester yet but will probably soon: https://youtube.com/@blancolirio
I'm also a Blancolirio subscriber. Juan also doesn't try to get ahead of the investigation, really. It's part of what makes him a valuable voice in the space.