Why do airlines have a minimum fuel on landing requirements?


This may not apply to all airlines, or apply to today’s world, but I was watching a video on Britannia 226A crash from 1999. In the video, they mentioned that the pilots were under pressure to land, so they wouldn’t have to explain to their bosses why they landed with less than the minimum amount of fuel required.

If a plane takes off, has to abandon a landing attempt, or complete an extra go around, or has to stay in a holding pattern, or has to divert… but they land safely without incident nor issue, why would that be an issue? What else could the pilots do?

Edit to add the answer (thank you for all of the replies, everyone! I misunderstood entirely what the video was attempting to convey): There are aviation safety boards with strict rules and landing with low fuel is grounds for a report and an investigation into the flight, so the safety boards can find the root cause for why the flight did not have an adequate amount of fuel on landing. The pilots may get into trouble if the investigation finds they were at fault, but it is more geared towards safety and attributing a root cause for the issue to make a low fuel event less likely in the future.

In: 707

it costs fuel to carry fuel, so if they were allowed to airlines would send a plane off with exactly enough fuel to get to its primary and its alternate with nothing more

EASA (idk about the USA) have minimum fuel requirements that make it a legal requirement to carry enough fuel to fly for 30 minutes at 1500 feet above the destination or alternate airport

this is kinda like how a car will have a Reserve Fuel Tank, this means that even when your car says ‘i’m empty’ it has enough to get to the nearest petrol station.

you must report any dip below minimum fuel to ATC when in flight by calling ‘Mayday Fuel’ this allows the ATC to put you to the front of the queue and get you on the ground

EASA enforce this because it’s better to have a pilot get in trouble for not having enough fuel left, than it is for the plane to run out of fuel mid air

ETA. [this video](https://youtu.be/aaxzZvkQtx0) from Mentour Pilot explains it very well. if you’re interested in aviation he is a great jumping off point

I think it’s a common misconception or misinterpretation of the rules that say you must take off with enough fuel to reach your destination, then depending on whether they filed IFR or VFR, land with 45 minutes or 30 minutes of fuel remaining.

It’s not a violation to land with less than the minimum required fuel, as long as you took off with the appropriate amount. Obviously, pilots are hesitant to land with less, because you don’t want to run out.

I’m not familiar with the case you’re talking about, but if the pilots were worried about getting into trouble for landing with less than the required minimums for reasons beyond their control, they didn’t understand the rule, or they had unnecessary pressure being placed on them by their management.

Edit: as pointed out, I clearly applied US rules to what sounds like a British airline. YMMV.

That fuel is for absolute emergencies. It’s not that that fuel can’t be touched, but it is a last resort and for airline operations could require a declaration of an official emergency, and priority handling by air traffic control. Huge pain in the ass if you’re somewhere busy like NY or Chicago. And then paperwork, and yes if the pilots didn’t have a good reason for why it was unavoidable to touch that reserve fuel, they could get in trouble. Crazy unexpected things happen and that fuel sometimes does need to be touched, but you better hope things go smooth from that point forward. If the norm was to always land with close to zero lbs of fuel at your destination or even alternate for that matter, any thing like you mentioned (go around, holding, diversions) could result in engines flaming out. Those minimum fuel requirements over time have become law to protect the public.

Unexpected delays and go arounds happen significantly more frequently than people think. As does higher than normal fuel consumption enroute due to altitude changes, air traffic control slowing planes down, go arounds while coming in for landing, or deviations around storms for example. A place like Chicago O’Hare could see multiple go-arounds on a good weather day due to traffic spacing issues or pilots not complying properly with taxiing instructions. So there definitely should be some line drawn as to how much extra fuel is needed when you touch down at “plan A” airport and that line became law. That minimum number changes based on which type of operation you’re flying (private/commercial/domestic/international), but generally includes a go around at the destination, some amount of time flying enroute to a new planned alternate airport, and landing there. For some International flights it might include some brief holding fuel at this alternate or even an enroute buffer additive to the alternate airport. So the legal minimum offers these protections for what is somewhat of a normal plan B if I can’t get to plan A.

If you plan to land with this legal minimum amount, and then can’t all of a sudden and need to divert, you need to follow this plan B exactly. It is not nearly as much fuel to play with as you think. If something then happened at the alternate airport and you couldn’t get in, now you’re really in trouble. I’ll give you an example. You’re flying Madrid Spain to NY JFK. Your dispatcher starts planning your flight over 2 hrs before you’re even supposed to show up to the airport. The predicted weather in JFK (like 10-12 hrs in the future) shows a strong cold front coming in with rain and visibility is supposed to be good enough to get in but you’re given an alternate of Boston just in case. As you’re over the Atlantic you have to descend to a lower altitude for an hour because of unforecasted turbulence, and now you’re planning on landing right at your minimum fuel number. The cold front brought much stronger storms in NY and some to Boston as well. Turns out you can’t get to JFK due to the storms so you go towards your planned alternate of Boston. Boston right at your time of landing is really busy with numerous other diverting aircraft and makes you hold for an extra 10 min before clearing you in. You’re watching that fuel closely now. The weather is getting worse in Boston now, you think you’ll have the visibility to land, but now if you don’t…what now? After another go around you might only have, what, 45 min of fuel left? This is a widespread weather system, the whole Northeast coast sucks, where do you go? Just painting a scenario here. Realistically dispatch would probably be tracking that NY weather and if things looked hairy, might have you divert elsewhere besides Boston and commit to it earlier.

In commercial aviation if you run out of fuel in an airliner your options are extremely limited. You cannot just glide it to the nearest cornfield and expect to make somewhat of a “bumpy grass strip landing” as if you’re in a cessna. You can’t land a Boeing 767 on the nearest highway without some kind of catastrophe. It is very likely a dual engine flameout is talking loss of life. There have been cases of dual engine flameouts that did not result in lost life – these are miracles and are called such for a reason.

Hope this helps!

It’s for safety. They have to ensure they have enough fuel to keep the plane in the air when unexpected things happen, like having to divert to another airport due to weather , or a crowded pattern.

Profit and safety are usually mutually exclusive, so unless companies are forced to do things, they’ll sacrifice safety for profit. Since fuel costs money, and carrying fuel costs money, regulations are needed to force them to carry more fuel than they otherwise might. That’s not to say they wouldn’t choose to do so on their own necessarily, but it would only be because crashing and killing passengers hurts business more than carrying extra fuel.

Going into the final reserve means a lot of paperwork and explaining, avoiding that is preferable. It would probably would go into an investigation on the decision making of the pilot leading upto the event as the 30min is not supposed to be touched, and associated stress and headache of an official investigation. And nowadays aircraft upload all flight data via phone connection automatically right after landing. So HQ probably know already before you arrive at the gate. The data is analyzed automatically and for certain events (landing below reserve fuel is one of them) key management automatically get a text/email.