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The "What airlines don't want you to know" tone of this post is misplaced and misguided. I also question the suggestions that longer published flight times mean

• deleted 8y ago
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• sjg007 8y ago
  NYC has always been subject to long delays... it’s a major pita.
• netsharc 8y ago
  > As for CO2 [...] 40+ minutes of being in a queue to take off Guess what the engines are doing at this time. Even worse if they tell planes to circle before landing because there are too many landings at this time.
  • jak92 8y ago
    > Guess what the engines are doing at this time. Usually one engine is turned off...
    • dx034 8y ago
      Only with some airlines and at some airports. Not all airports allow it and some airlines don't like it (apparently due to higher stress on the other engine).
  • VBprogrammer 8y ago
    I once wondered why aircraft don't have electric motors (either battery or APU powered) to move them to the holding point at which point the fire up the engines. Turns out Airbus has a patent on it, it's not yet being used due to complexity / weight tradeoffs.
    • zuron7 8y ago
      There was this other start up which planned to use AGV to tow the planes till the take off point. Would be much simpler than trying to modify the plane itself. https://en.m.wikipedia.org/wiki/TaxiBot https://en.m.wikipedia.org/wiki/TaxiBot
• rizwank 8y ago
  Totally agree. No strong reason how CO2 emissions are affected by padding - yes IF there is additional time circling in the air, but then the airline is rarely solely responsible and a clear financial incentive exists. Note that the bottom half of the article is a sales pitch for his business flow product!
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  • dingaling 8y ago
    > No strong reason how CO2 emissions are affected by padding Quite often airliners arriving at my local airport ask ATC for a dogleg course for 'additional track miles' on approach to pad their arrival time or burn-off fuel. It's purely a request by the pilots, not a traffic issue. CO2 being traded directly for convenience.
    • VBprogrammer 8y ago
      Requesting additional track miles could be because the aircraft wasn't yet configured for landing, perhaps because ATC held the aircraft high due to traffic, or because the pilots didn't manage the decent well. There are also maximum landing weights (which are different from max takeoff weights) which could potentially be a factor.
    • dx034 8y ago
      That doesn't seem to be related to padding. Airlines still like to arrive early. If there's no gate available, it's cheaper for the airline to wait on a taxiway than to circle in the air. Fuel costs are a major driver of airline profitability, hence airlines have no incentive to spend time in the air if it's not absolutely necessary.
• frobozz 8y ago
  > As for CO2, the plane flying slower is more fuel-efficient. Isn't this lower CO2 emissions? Possibly lower emissions per minute, but if they are in the air for significantly longer, then that may be cancelled out by the extra time. Often, although fuel efficiency drops off sharply as you go above a certain speed in a vehicle, going slower than that speed is not significantly more efficient per minute, and can therefore be less efficient per distance. Driving a car for 100 miles at 30MPH is typically less efficient than doing so at 60MPH. Driving that distance at 90MPH is even less efficient.
  • cletus 8y ago
    Think of it this way: if you need to drive from Kansas City to Boise the distance is constant (barring route changes). If you drive at 120mph vs 60mph you will get their faster but you will also use a lot more fuel in total even though when you're going slower you're on the road for twice as long. Fuel expenditure falls in to two buckets: 1. Moving the vehicle. Accelerating to cruising speed and fighting the deceleration of friction and air resistance. 2. Keeping the vehicle running. Lights, climate control, that sort of thing. My guess would be that the vast majority of fuel usage for planes is (1) not (2). As evidence of this, airlines care deeply about costs. It's not a high margin business (any more). My argument is that if it wasn't overall more fuel efficient to fly slower airlines just wouldn't do it. More evidence, the latest planes (A350, B787) have a lower cruising speed than, say, the 747. This also wouldn't be the case (IMHO) if it didn't decrease fuel costs.
    • SketchySeaBeast 8y ago
      Isn't there's a 3. for airplanes - the constant force required to keep the plane in the sky? Cars don't have that, and there's going to be a particular speed at which that speed / time ratio changes for a plane compared to a car. Also, is it necessarily fuel costs behind the decision to steer away from 747, or could it be other costs, like plane utility and capacity, parts and service cost, and the requirements of cross training?
      • logfromblammo 8y ago
• paultopia 8y ago
  I would agree with this predictability point, except that they still find ways to undermine predictability down the line. For example, the latest thing American Airlines seems to be doing is changing schedules in radical ways between time of purchase and day of travel. The last three itineraries I've had on American, I've gotten an e-mail weeks after buying the ticket saying that one of my flights now had a schedule several hours after the originally booked and ticketed flight. What then, predictability?
  • cletus 8y ago
    So I fly AA a lot because of Oneworld basically so I'm familiar with their faults. If this is recent however it's not entirely their fault. AA is a big customer for the 737 MAX. That plane's grounding has hit their schedule pretty hard. Most of those flights involved Miami for some reason but to backfill those routes they've taken planes off existing routes that weren't fully utilized. Like I'm fairly sure some weekend JFK-SEA flights were canceled and my guess was to free up an old 737 for some other route. They're also the largest airline in the world I believe so i can't even begin to imagine the complexity of the logistics of this like making sure you have a flight crew in the right place as well as all the other changes to services like maintaining the plane, cleaning it after a flight, baggage handling, stocking the plane with food and drinks and so on. If your changes in itinerary were less recent than that then my next question is does this involve regional flights? I fly between hubs mostly so I haven't had that experience.
    • paultopia 8y ago
      Huh, ok, that seems fair. I was wondering if the 737 max was involved, but didn't realize the ripple effects were that big. I've had schedule changes from them in the last month or so all up and down the NE corridor mostly.
    • rootusrootus 8y ago
      American has 24 Boeing 737-MAX8 planes out of a fleet of 963. For comparison, Southwest, who also has a large fleet of planes, has 34 out of 754. Effectively they are operating a fleet that is 2.5% smaller than normal. I expect some impact to their schedule, but it shouldn't hit it that hard.
• jetrink 8y ago
  > As for CO2, the plane flying slower is more fuel-efficient. It's counter-intuitive, but an aircraft can be more efficient at higher airspeeds. The reason for this is that, unlike a ground vehicle, an aircraft in level flight must expend energy generating lift to balance its weight. This loss of energy shows up as lift-induced drag [1]. As airspeed increases, the losses to lift-induced drag decrease, while the losses to aerodynamic drag increase. Where the point of minimum total drag lies depends on several factors including weight and altitude. See [2], which contains a chart for a generic aircraft which is 5% less efficient at Mach 0.72 than it is at Mach 0.80. 1. https://en.wikipedia.org/wiki/Lift-induced_drag https://en.wikipedia.org/wiki/Lift-induced_drag 2. http://atmseminar.org/seminarContent/seminar11/papers/481-Jensen_0126150437-Final-Paper-5-7-15.pdf http://atmseminar.org/seminarContent/seminar11/papers/481-Je...
  • ses1984 8y ago
    Sure, aircraft can be more efficient at higher speeds, but then when speeds pass a certain threshold, drag starts to dominate and efficiency drops like a rock. There's a sweet spot, and it's certainly less than the plane's top speed.
    • FiddlyPack 8y ago
      ...this is exactly what the commenter you’re replying to said, except also with nice charts/graphs showing the sweet-spot for various aircraft...
      • SilasX 8y ago
        Except the comment was making a point that was irrelevant for the domain in consideration (typical aircraft speeds for commercial flight). It's like if someone said, "going a little slower on the highway [typically ~60 mph+] saves on fuel" and someone pedantically ButAkshully'd that cars are more efficient at 40 mph than 30 mph because of engine performance. Edit: Ironically, I'm the one normally promoting my "Scylla-Charybdis heuristic", that you should be able to identify when tweaking a parameter goes too far. But here I think the context of the tweak was clear enough that this caveat was a distraction from the core point.
• duxup 8y ago
  While flying sucks. In recent years I felt like I've been able to make connections way easier than in the past. It used to be any two flights even remotely close to landing and departing time and I was really hesitant to book them .... less so now.
• mikeash 8y ago
  The idea that padded schedules leave airlines with no reason to be efficient is idiotic. It’s a heavily capital-intensive industry with razor-thin margins that has historically been a bad place to make money. There’s even a classic joke about it: “How do you make a small fortune in the airlines? Start with a large fortune.” This is the industry that generated the famous story where American saved $40,000/year by going from two olives to one in their in-flight salad. United saved $300,000/year by printing their magazine on lighter paper. If you work at an airline and find a way to shave off a dime in fuel costs per flight, you’ll get articles written about you. And we’re supposed to believe that these companies don’t care about wasting fuel now that their schedules are padded out a bit?
  • ChicagoBoy11 8y ago
    The iead that airlines have no reason to be efficient in it of itself is idiotic. It is an incredibly competitive industry, and the lengths to which airlines go to explore every possible margin is enough testament of that. To add to your list of examples. KLM, for instance, was one of the first to introduce a system that would allow certain flight data to be uploaded into the flight computer as opposed to be requiring the pilots to enter it by hand. Other than fewer errors, they touted potentially saving pilots a couple minutes of data entry as one of the chief gains of the system.
    • brlewis 8y ago
      I generally avoid the word "idiotic", but it fits here. Can we flag articles for stupidity? Article tl;dr -- Airlines used to get from airport to airport faster. Airlines used to be late a lot of the time. Airlines increased their estimated flight times in order to achieve higher on-time percentage. The reason they did this instead of just being faster is that they love using more fuel. I'm not anywhere near the airline industry myself. The next time I see misreporting on my own company or industry I'll look back at this and remind myself it could be worse.
      • sjg007 8y ago
        The increased the time so that they won’t be fined for not being on time.
• matwood 8y ago
  > If a plane takes less time to fly somewhere some of the time because of weather, timely takeoff from departure airport, landing slot availability at the arrival airport or whatever, I don't really care. If they arrive late however, that can be a huge problem, particularly for making connections. This is exactly how developers need to think about how they communicate schedules to management. Missing an agreed upon date is usually a much bigger deal than pushing the agreed upon date out from the get go.
• jermaustin1 8y ago
  > Here the airlines are doing pretty much exactly what I, as a passenger, want, which is to predictably arrive at an airport by a certain time more often. I was flying to Edinburgh for Christmas a couple of years ago, we were slated to leave at 9pm and arrive at 9am (7 hour flight + 5 hour time difference, made sense). Then the plane was late getting to us, and they didn't arrive until 9:30, they quickly kicked out the passengers, then the new crew climbed aboard to start cleaning. By 10pm, we were still waiting in the terminal. at 10:45, we were finally allowed to board the plane, and after a couple of minutes it backed away from the gate and taxied to the runway, where we sat for over an hour. We were the last scheduled departure, and when the plane arrived late, the de-icing crew had gone home. We didn't leave until after midnight. And we arrived... at 8:45 am, 15 minutes earlier than scheduled. I slept, so I'm not sure if we hit some massive jet stream, or a black hole, or what, but that was the day that I stopped believing flight times. Edit: Took this photo[1] waiting outside the hotel for an early check-in. 1: https://megapickles.photo/2017/12/25/reflections-of-edinburgh/ https://megapickles.photo/2017/12/25/reflections-of-edinburg...
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  • Wowfunhappy 8y ago
    If you arrived within 15 minutes of the scheduled time, that sounds like a success? One way or another, the airline gave your flight almost exactly the right amount of padding.
    • jermaustin1 8y ago
      Without a doubt, but it makes me incredibly sceptical of flight times now.
      • Wowfunhappy 8y ago
        That's what I'm not understanding, what are you skeptical about? At least from this data point, they got the time right! I suppose "flight time" should technically be defined as "time in the air", but realistically, "time it will take you to get from airport A to airport B" is a much more useful metric to passengers.
• simonebrunozzi 8y ago
  Except that in certain areas (e.g. US domestic flights) most/all airlines reduce average flight speed on purpose to save fuel, knowing that no other airline will compete with them. This is precisely what a functioning Antitrust should fight.
  • gojomo 8y ago
    I think other public-interest agencies, besides antitrust-enforcement, might not want airline competition to be based on "who's willing to burn the most jet fuel to shave a few minutes off business travel".
• thorwasdfasdf 8y ago
  i agree. with fuel prices so high and airlines being so conscious of them, i would imagine they're making every last bit of effort to conserve fuel. The incentives all seem to be correct. The leading "What airlines don't want you to know" tone of this post is probably to manipulate the reader into reading the whole article, so you can find out what "they don't want you to know", which never really comes.
• cc439 8y ago
  >I also question the suggestions that longer published flight times mean more CO2 and there's no incentive for airlines to become more efficient. >Just the other day I flew out of NYC and it took us 40+ minutes of being in a queue to take off behind 15-20 other planes because reasons. That anecdote is exactly why the claim that there is no incentive for airlines to increase efficiency is so bogus. The vast majority of scheduling delays occur because of on-the-ground and ATC issues that are the sole responsibility of the airports involved. An airline can't do much to combat the inefficiencies that result from a notoriously incompetent airport and their inability to properly manage traffic so gates clear on time.
• stunt 8y ago
  > As for CO2, the plane flying slower is more fuel-efficient. Isn't this lower CO2 emissions? It is not only about fuel. Right? Article is talking about punctuality. People will use competitors if an airline is not on-time. So with padding they create a safety gap to make sure they arrive on-time. I believe 15mins safety gap is fair as it is extremely difficult and expensive to always operate on-time without a major airport redesign and technological advancement in how the system works. It gives passengers a reliable arrival time to plan whatever they have next.