Air speed

Why does’nt an airliner go the air speed that’s posted on flightaware.
Most of the time on SW they go faster, but on occassions they will go slower.

It is generally just an estimate. You can only file for one airspeed (the initial expected airspeed) and generally over the course of a flight, the winds aloft change as well as the aircraft weight because of fuel being burned off. Lesser weight, faster airspeeds.

I’m not crazy about flying, and have this thought that the flight I go on something will go wrong and it will be domesday. I was given medication to help calm me, but I want to get there at the faster speed than a slower one. Can I request the pilot to go faster?

The filed speed is the true airspeed while the one you see while the airplane is flying is ground speed.

They’re unlikely to do it; they’ve had an optimized airspeed planned for them by dispatch and going faster generally requires a tremendous amount of fuel.

Is it normal for one to feel that by getting on a flight that their sub-concious tells them no?

Sounds like a great episode for Dr. Phil…

Sure you can. Just knock on the door and ask.

knocking on the door these days might get you knocked out. wouldnt it. :stuck_out_tongue: :smiley:



you can request anything you like, personally i would request a stronger sedative from my doctor…

Why couldn’t that be indicated with a KIAS after the Scheduled speed called out and a GS after the Actual/Estimated speed?

Wait, that’s still confusing. because GS is rougly 1.15077945 times the KIAS. Knowing that calculation, can’t the website be defined and converted so that both speeds are in KIAS or in Ground Speed (with a disclamer that Ground Speeds are approximate to allow for wind and fuel)?

Seems to me that would make it easier for those not familiar with the differences could see the difference without having to calculate on their own…making it more user friendly. :slight_smile:


Roughly 1.15077945???

What use is KIAS to you other than simple curiosity? If you’re tracking an aircraft the only thing that should matter to you is GS, that’s what is going to tell you when the aircraft will arrive, not KIAS.

1.15??? That’s the conversion of statute miles to nautical miles! It has nothing to do with ground speed. Groundspeed (GS) is the true airspeed +/- a wind component affecting that aircraft. ie. An aircraft flying 400 kts with a 100 kt tailwind component would have a groundspeed of 500 kts. The FAA and Flightaware have no idea of what the exact IAS of any given aircraft is. The only available speed information is the ground speed that is calculated from radar returns. :unamused:

Forget it Fly. Most people will never understand the diff between a nautical or statute mile, or the concepts of GS, IAS, TAS (and filed TAS), MN, QNH, QFE, MSL, AGL, bla bla bla… Even though much of it has been thoroughly explained here many times before.

Good point! But still, wouldn’t it make sense to indicate “KIAS” under the Scheduled speed then an “MPH Groun Speed” under the Actual? Just something to make it more easily understood.


But the values for actual/ground speed are in knots.

And it’s not IAS it’s TAS.