17k views

### Why do we need to know both groundspeed and airspeed? [duplicate]

As far as I understood it correctly: airspeed: is obtained by measuring the difference in airpressure (using Pitot tubes I guess?) around the aircraft and the airpressure caused by propulsion. ground ...
• 789
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### Please describe ram pressure in simple terms [duplicate]

Please someone describe the following sentence in simple words: The Airspeed Indicator is calibrated for 'standard' sea level density, so it will only read TAS if the density of the air through which ...
• 27
907 views

### How can ground speed be higher than airspeed? [duplicate]

I've heard that ground speed is higher than air speed when the plane is being pushed by wind wind. But how is this possible? Wouldn't your AirSpeed also increase since you're going faster?
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1 vote
8k views

### What is the difference between TAS and GS? [duplicate]

I'm looking for an explanation of true airspeed and ground speed.
• 11
346 views

### Is the point of “groundspeed” in aircraft just to have a second reference of speed but two totally different measurements of speed? [duplicate]

From not understanding groundspeed will always be significantly higher than airspeed, unless the plane is pitching up and down. Is the ground speed just there for pilots to look at and say “okay we ...
2k views

### How can an aircraft travel faster than speed of sound without breaking the sound barrier? [duplicate]

An excerpt from the BBC article here https://www.bbc.co.uk/news/uk-england-london-51433720 "Despite travelling faster than the speed of sound the plane would not have broken the sonic barrier as it ...
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3k views

### What is the difference between ground speed and airspeed? [duplicate]

What is difference between ground speed and airspeed? Is ground speed used only for takeoff or is it used for flight too?
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1 vote
283 views

### Why can’t aircraft use GPS to generate the IAS, instead of using pitot tubes? [duplicate]

I’m mostly asking after reading about Aeroperu Flight 603, which was caused by a piece of tape blocking the sensor. Is there any other way to gather IAS or is this the best way to do it?
221 views

### Fighter Jets speed [duplicate]

How does an aircraft measures (or calculates) its speed while in air? Which equipment or sensors are used for measurement of speed? Does it takes Earth as a reference frame for its speed measurement ...
• 155
11k views

### What is the commercial passenger aircraft top speed record?

Aircraft manufacturers claim that commercial passenger aircrafts cruise at the speed of 400-500 knots. But, is the top speed of a commercial passenger aircraft recorded (while in air)? If so, what is ...
43k views

### Why are planes slower at higher altitudes?

On many flight simulators, I have noticed that planes tends to get slower with increasing altitude. For example, I can reach 1100 knots just above the sea level in Google Earth flight simulator(F16), ...
• 353
3k views

### What is a jet (unit) shown in Windows 10 calculator? [closed]

From Windows 10's calculator: What is a "jet" (physical unit)? And why does it equal 480 knots or 888,88 km/h, if a jetliner's cruising speed is around 950 km/s? Or why does it equal 0.73 M, if a ...
• 4,162
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### What is the reference used when measuring flight speed?

I'm a physicist who was amused by the argument in the comments of this question about gravity. The correct answer about the affect of the accelerating reference frame of the plane on the apparent ...
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### How do head- and tailwinds affect airspeed?

I'm sure this was asked somewhere, I just can't find it. So if it's a dupe, let me know. Anyway, I'm one of those guys that actually looks at the flight information when I'm flying. I fly ...
• 241
3k views

### Is it right to extend flaps only in the white arc?

If the cruise speed is >80kts on the downwind leg but I can only extend flaps in the white arc, am I right in saying I need to get to the white arc, even if I'm on - for example - 100kts? For ...
57k views

### How to calculate the real Ground Speed from True Air Speed?

In most of the formulas I've found online GS = TAS + Vw, i.e. true air speed plus wind. However, on the simulator, GS changes drastically if I dive or climb which is obvious because I'm covering 0 ...
• 207
13k views

### How to calculate Equivalent Airspeed immediately from Calibrated Airspeed?

I want to calculate each step like IAS -> CAS -> EAS -> TAS as a chain. Each chain step should depend on the previous step. IAS is clear. This is a function of pressures. With the Bernoulli equation, ...
999 views

### Why is it safe flying in a tailwind when taking off is not? [duplicate]

If taking off in q tailwind is unsafe (due to loss of lift from reduced air speed), then why is it safe flying in tailwind, such as in jet stream?
1k views

### What should be the minimum time spent in cruise (for e.g. a B737)?

Having a short sector to fly, it would not be convenient to climb all the way up to the best cruise altitude, since the time in climb would burn more fuel than that necessary for a flight at lower ...
• 2,575
2k views

### Ground Speed vs True Airspeed from Departure Point to Destination - time interval

Looking at navigation theory right now and I'm stuck in the understanding of TAS and GS. How does GS determine the time interval it takes for an aircraft to fly from the DP to the DEST, if TAS ...
• 303
756 views

### Measuring speed and altitude from personal phone midflight [duplicate]

Given that there is no need now for one to swith off their cellphone midflight, inflight wifi is now a norm and common, Is it possible for me to measure the velocity and altitude of an aircraft using ...
• 8,549