my flight got delayed but the pilot said they would go faster to make up for lost time and we ended up arriving early. This got me thinking why can’t planes always go at this faster speed?
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I’m not an expert but I believe the main reason is fuel efficiency. Traveling faster means more air resistance which means lower fuel efficiency. The same is true in your car. You will get better mileage at 35 miles an hour then at 75 miles an hour.
Flying faster burns more fuel, and getting there before your landing slot doesn’t work. Air traffic control sends you into a landing pattern where you just hang out until it’s your turn. More fuel to get there faster and more fuel to circle waiting maximizes fuel costs and reduces airline profits, so that’s not going to happen.
This likely has to do with fuel efficiency which has to do with cost. The customer experience is very important so if there’s more cost to make up for lost time because of some delay than that ensures a good customer experience, but if you’re on time and everything is running in sync, then you can fly at a slower speed and save money. It all adds up.
Pilots fly at the fastest economical speed. Flying above that speed will put more strain on the aircraft and the engines. Ultimately, costing more in fuel. Which will cost more for patrons in the long run.
There are lots of possibilities on how, depending on the route, and the airline.
If it’s trans Atlantic for example, a strong tailwind can make a +/- an hour difference.
The pilot may be able to go faster than is optimum, burning more fuel and costing more, but catching up time. This might actually be offset by fees at the re landing at, if they arrive out of sequence it can be costly to the airline.
Or it could just be down to utter fuckery from the likes of Ryan Air advertising longer flight durations than it actually takes so they can claim to always be on time or early, and that 10 minute delay just gets swallowed up in the time buffer.
I’ll take it a step further: aircraft are designed with an optimal speed in mind, which is highly driven by cost – fuel consumption is the most significant of those costs, I believe.
Planes have actually gotten “slower” over time, as we’ve built more efficient turbine engines. Simply put, we’ve found a sweet spot that balances aircraft efficiency of the engines with design characteristics of the aircraft that further reduce the fuel consumption.
There are additional reasons to stick with these speeds. Using the engine at its most efficient output also reduces the wear and tear on components, for example. It’s kind of like running a marathon: if you sprint, you will have to stop and rest many times. The aircraft would need a lot more maintenance, which is costly to complete and means the aircraft isn’t flying – when it’s not flying, it’s not making money.
Airline pilot here. “Flying faster” usually means taking shortcuts on the route if air traffic allows. For shorter flights, making the plane go faster barely makes any difference in the time as the optimum speed is already pretty close to the max speed possible. For super long transalantic flights maybe flying faster will make an appreciable difference.
The power required to overcome air friction increases with the cube of speed, so going 10% faster burns fuel at a 33% higher rate. You get there 10% quicker but that still means the journey required 21% more fuel.
This assumes that the engines have 33% more power available. Even if they do, they could operate less efficiently than at their normal cruising settings, causing even greater fuel costs.
Another factor is that airline pad their arrival time so their On Time average looks better.
People don’t complain when they get there a little earlier, but sure grumble when they are late.
Its funny that this hasn’t been mentioned, yet I’ve experienced this a couple of times. I’ve been in flights where the pilot has requested a change in altitude so they can catch a better tailwind. I was on a corporate Learjet rigged out as an ambulance (I mention this as the option may not be available on commercial airliners) and they requested an increase in altitude. It was a while ago, but we crossed from California to Toronto in a lot less time. He mentioned the relative ground speed and it was insane.
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