But on an airplane they...

[Teysa]

I work on a passenger train. This was related to me by one of the rail guides. On a recent run we experienced major delays because of wildfires near the tracks and sun kinks. Normally the trip from Talkeetna to Whittier is about 5 and a half hours. This time it took over seven.

C said he had a passenger on the southbound leg who would say that when flights are running late airplanes go really fast to make up for it. Later she said that on an airplane they give out free drinks if they're running late so could she have a free drink? He told her no. Later she wanted free snacks or icecream. Again he told her no. He told me this went on until we reached the ship.

I just want to know what airline she's flown with because I don't recall ever getting anything special if my flight was late.

[Jay 2K Winger]

"On a plane they--"
"Look out the window. We're on the ground. We're not in a plane. We're on a train."

[catcul]

I just want to know what airline she's flown with because I don't recall ever getting anything special if my flight was late.

When my flight from Atlanta, GA, to Orlando, FL, was delayed an hour, all I got was an apology.

[wolfie]

C said he had a passenger on the southbound leg who would say that when flights are running late airplanes go really fast to make up for it.

Planes normally fly at their "best fuel economy" speed. Trying to make up time by going faster would use a LOT more fuel, and airlines don't like spending money. Someone get that passenger a laxative - she's full of shit.

Later she said that on an airplane they give out free drinks if they're running late so could she have a free drink? He told her no. Later she wanted free snacks or icecream. Again he told her no. He told me this went on until we reached the ship.

Sounds to me the customer is just looking for an excuse to demand freebies.

[Teysa]

No doubt on the excuse for demanding freebies. My roommate worked in the same car as C that day. She said the lady kept asking her for free stuff too. All I can say is it is probably a good thing that I'm a cook and not a bar tender because I would have had a hard time resisting the temptation to hand the lady a cup of water and tell her it's a free drink.

[smileyeagle1021]

Planes normally fly at their "best fuel economy" speed. Trying to make up time by going faster would use a LOT more fuel, and airlines don't like spending money. Someone get that passenger a laxative - she's full of shit.

The airline might go faster than best fuel economy to make up time in a few situations... namely the cost of having to cancel a flight down the line may cost them more than the fuel now... but that would probably be a rare case and normally don't give a darn about on time arrival.

[wolfie]

Even so, there's a limited amount of time they can make up by going faster. First of all, the economical cruising speed is not that much slower than "balls to the wall". Second, since it burns more fuel, they need to carry more fuel. Depending on the length of the flight, they may not be able to carry enough fuel to go faster, and a refueling stop would kill the time savings.

This is what killed Boeing's SST. It was designed to be faster than the Concorde, but due to the higher speed aerodynamic heating would bring it above the temperature at which aluminum gets annealed, so they had to build it out of titanium. This made it heavier, and the weight budget had to come from somewhere - either passengers and cargo (making it unable to fly at a profit) or fuel (so it wouldn't have the range to fly between NYC and London nonstop).

[Chromatix]

It's actually subtler than that, smiley:

The most economical cruising altitude is "as high as possible", because the air is thinner there and presents less resistance to forward travel.

The higher you go, the faster the *minimum* cruising speed is, because the air is thinner there and provides less support to keep the plane in the air. This minimum speed also depends on the weight of the aircraft, which goes down appreciably during the flight as fuel is burned; often, the highest altitudes are simply unavailable for the first hour or two, because the plane is too heavy to safely reach them.

The *maximum* cruising speed is more-or-less constant with altitude - at least, once you get above 30000 feet where almost all modern airliners prefer to cruise - because it is related to the speed of sound by that point (and this is why jets have swept-back wings). At lower altitudes the maximum speed is also limited by denser air, and I believe there's also a 250-knot regulatory speed limit below 10000 feet (which is where most small aircraft fly).

In general there is actually sufficient engine power to exceed the speed limit at any altitude, but the speed limit exists to prevent damage to the aircraft.

The practical upshot is that there's not only a remarkably small difference between typical and maximum cruising speeds, but a remarkably small difference between the maximum and minimum cruising speeds at the highest altitudes. The flight crew thus has very little control over the actual speed of the journey, as far as "trying to make up time" goes.

There are however several external reasons why journey time might differ. A following wind helps, while a headwind hinders (and the two might be present at different altitudes, so a good flight crew will pay attention to this). There might be more or less queuing at either the origin (on the ground) or destination (in the air) airports for use of the runway. Weather might force diversions around dangerous storms, even if there is no problem at either end.

None of these things make any difference to the flight crew's ability to make up time - except that the possibility of hindrances has to be factored into the schedule, so their absence provides a margin to absorb delays incurred elsewhere. Indeed, it's quite common for a headwind incurred delay on one flight to be cancelled out by the tailwind existing for a flight in the opposite direction on the same day.

And that last factor probably explains the SC's impression of airlines' timekeeping skills. Sigh.

Headwinds and tailwinds are practically irrelevant to railways. Far more important is congestion on a finite collection of infrastructure. Some margin is built into schedules, but if one train gets stuck behind a slower one for whatever reason, there's limited opportunities for overtaking, and the resulting delay can easily overwhelm any reasonable schedule margin.

And, again, there are *maximum* speeds, which cannot legally be exceeded; the best that can be done is to stick as closely as possible to them, and hope that the signalman is sharp enough to clear the way as quickly as possible.

[sstabeler]

In the UK, she might have jad a point about the free drink- I'm not sure if it's the train company I traveled with, but I remember reading on the train company's site that after a certain length of delay ( i think it was an hour) you get a free drink. (not to mention that by the two hour mark, you would get a refund of what you paid for your ticket)

but yeah, he reasoning was off. on airplanes, they generally go as fast as they can anyway. ( not to mention that the only time I am aware of that delays caused a train to speed up, it was achieved by not stopping at certain stations ( so the train didn't have to slow down) not by going faster as such.

[Teysa]

We have certain spots along the route where the train can make up some time but the wildfires delayed us too much. The onboard manager went to each car, explained the situation, and let everyone know the ship would not leave without them. Fortunately, the passengers in my car were pretty laid back about the whole thing.