Why don't airplanes fly quicker?

Factual Questions
21

Yep. The airlines are all about money, and carefully managing it, since they’re in a commodity industry. Fuel is fully a third of an airline’s entire cost structure, so it pays to operate at the most economical speed, all else equal. Going much faster would only help if they could squeeze in more flights per day (which would need a whole lot more speed), or if it created a marketing advantage (which it mostly doesn’t, not over other airlines). Plus, only on the longest routes is the time enroute, as opposed to on the ground or climbing or descending, would a faster cruise speed make much difference in total trip time.

Having different aircraft types going different speeds is an issue already, which air traffic control handles by sending different types along different routes or in different traffic patterns, to oversummarize. Jet airliners mostly go at similar cruise airspeeds, typically Mach 0.86 or so, because they’re all following the same laws of physics and economics.

22

Faster speeds mean less time for the pilot to react when something goes wrong. Which has been known to happen.

23

It should be noted that an airspeed indicator is profoundly influenced by the density of the air. So at any significant altitude it reads less than your true speed through the air (the rule of thumb is 2% per thousand feet of altitude).

24

It has indeed. But a pilot who could not react both promptly and correctly when flying at the full rated speed of his aircraft would certainly be deemed incompetent.

25

By far the majority of accidents in which a pilot’s reaction time counts occur close to the ground as in landing and taking off where speeds are relatively low and not at high altitude cruise.

26

Scheduling. Arrival time is very important. If a flight arrives 15 minutes too soon, the pilot may need to circle the airport for that 15 minutes wasting more valuable fuel.

27

I’m surprised not much mention has been given to Air Traffic Control particularly the Center controllers that control in route traffic for virtually all of the U.S. and beyond. Commercial airliners can’t just fly how they want too. They have to file a flight plan and ATC works with them to determine the heading, altitude, and speed although pilots can try and negotiate with them if there is a good reason. I’m a perpetual flight student and an aviation buff. I have a aviation band scanner and I listen to the full flight conversations when I take United who offers that on their headphones. ATC dictates speed on planes although they may give just a maximum, minim or range to the pilots. They are trying to strategize the whole picture of airplanes moving smoothly in their area and planes trying to go too fast would likely cause a problem with traffic like someone barreling down a busy interstate highway and slowed down for at least part of the trip by ATC.

Here is a list of the ATC Centers in the U.S. and they overlap one into another:

* Albuquerque Air Route Traffic Control Center, Albuquerque, New Mexico (KZAB)
* Atlanta Air Route Traffic Control Center, Hampton, Georgia (KZTL)
* Boston Air Route Traffic Control Center, Nashua, New Hampshire (KZBW)
* Chicago Air Route Traffic Control Center, Aurora, Illinois (KZAU)
* Cleveland Air Route Traffic Control Center, Oberlin, Ohio (KZOB)
* Denver Air Route Traffic Control Center, Longmont, Colorado (KZDV)
* Fort Worth Air Route Traffic Control Center, Euless, Texas (KZFW)
* Houston Air Route Traffic Control Center, Houston, Texas (KZHU)
* Indianapolis Air Route Traffic Control Center, Indianapolis, Indiana (KZID)
* Jacksonville Air Route Traffic Control Center, Hilliard, Florida (KZJX)
* Kansas City Air Route Traffic Control Center, Olathe, Kansas (KZKC)
* Los Angeles Air Route Traffic Control Center, Palmdale, California (KZLA)
* Memphis Air Route Traffic Control Center, Memphis, Tennessee (KZME)
* Miami Air Route Traffic Control Center, Miami, Florida (KZMA)
* Minneapolis Air Route Traffic Control Center, Farmington, Minnesota (KZMP)
* New York Air Route Traffic Control Center, Ronkonkoma, New York (KZNY)
* Oakland Air Route Traffic Control Center, Fremont, California (KZOA)
* Salt Lake City Air Route Traffic Control Center, Salt Lake City, Utah (KZLC)
* Seattle Air Route Traffic Control Center, Auburn, Washington (KZSE)
* Washington Air Route Traffic Control Center, Leesburg, Virginia (KZDC)
28

How fast can you afford to go?
Since the airlines are almost broke all the time, this is very important.

29

Former Airline pilot …

You guys have pertty well covered it.

  1. We normally cruise at a speed that is close to best gas mileage. From that we can speed up maybe 10% to max cruise at about a 20% increment in fuel burn.
  2. The skies in the US, especially eastern US are quite full these days. Unlike car traffic, this doesn’t lead to a slowdown, but it does mean we’re all running at more or less the same speed, a lowest common denominator amongst the various jet types, and just follow the guy ahead until we get there. Out West, or late at night when traffic is light, you could go faster for quite awile before you catch up to the guy ahead on the same route & altitude. But you will eventually catch up & be stuck following. That was one of the large reasons the Boeing Sonic Cruiser never went anywhere; as a practical matter it would not have been able to use its superior speed almost anywhere on Earth.
  3. The airlines are trying to optimize two competing factors, schedule / on-time reliablity and least cost. Leaving a little slop in the schedule improves relaibility, but costs money. Flying fast to make up time also costs money. Over the years I’ve seen the pendulum of management attention swing from “never fly fast”, to “always fly fast”, to “fly fast only if the difference saved will keep us under the 15-minutes late = reportably late to DOT window.”
  4. Traffic permitting, on a shortish (<3 hours) flight one can make more gain in climb & descent through superior routing and tactics than you can by simply stompin’ on the gas in cruise.
  5. For airlines that use hub & spoke (which really includes SW with their several almost-hubs with transient concentrations of jets) you get an additional factor: ground congestion.

I used to fly a flight that left the major hub at 5pm & flew ~400 miles. The plan called for 45 minutes from push-back to takeoff, ~43 minutes in the air, and 7 minutes from landing to parking for a total of 1:35 gate-to-gate. In other words, it took longer to get from the departure gate to the departure runway than it took to fly to the destination! That same route had another flight that left at ~9:30 pm & planned 10 minutes of departure taxi for 1:00 total gate-to-gate time!

Consider we’re working the 5pm flight, but we’re late pushing back. So we push back at 5:20 instead. So instead of joining the middle of the herd going to the runway, we’re at the back of the rapidly dwindling pack. Bottom line: we get airborne at 5:45, back on schedule & never need to fly fast at all.

In my experience, barring bad weather at arrival time, almost all the variability in airline on-time results comes from inability to get off the gate & off the ground. Once airborne, I can predict our gate arrival time to within a couple minutes over 95% of the time.