Talk:True airspeed

Electronic Flight Information System changed to Electronic Flight Instrument System for reason shown in discussion of EFIS page. Paul Lockheed 07:58, 29 August 2006 (UTC)

Air Data Computers are installed a large number of aircraft incuding aircraft that are not EFIS equipped. An ADC is not part of the actual EFIS system. EFIS is an electronic method if displaying flight information. The same or almost the same information is displayed on analog instrument aircraft including information from an ADC. The ADC is just one of the inputs used by either an EFIS, or analog instrumentation. —Preceding unsigned comment added by 69.168.165.131 (talk) 19:28, 6 February 2010 (UTC)

misses examples of how the instrument calculates the true airspeed Frizstyler (talk) 23:20, 17 January 2012 (UTC)

TAS indicator

Atleast on many older jet airliners, a TAS indicator existed. It was typically "hidden" below 200 knots, in order to not confuse the pilots during take-offs and landings. Most of them were electro-mechanical with digits (as oppose to a needle at an analogue indicator). The indicated airspeed, IAS (at older aircragt, atleast) didn't function at cruise altitude (it showed too low). At the article of airspeed indicator, there is a picture of a subsonic jet IAS indicator with a hidden TAS indicater hidden due to the low speed. Boeing720 (talk) 15:17, 4 June 2013 (UTC)

airspeed of objekts not aircraft

the airspeed is the speed of an object relative to the air

this might be diffrent on other planets or objects that have air

ok, im not very good at making articles so please improve — Preceding unsigned comment added by 78.54.165.11 (talk) 18:39, 18 November 2013 (UTC)

How about using English as well as SI units in technical articles. Half of your audience doesn't use SI units. Including the entire US aeronautical community. English units: atmospheric pressure 14.7 psi, SI 101325 pascals. Which would you rather work with? Sbxstr (talk) 22:57, 23 April 2018 (UTC)

In your case, the most common English unit would be inches of mercury, while the most common SI unit would be hectopascals. 14.7 psi would thus rather be reported properly as either 29.93 inHg or 1013 hPa. You obviously would want to work with hPa, since that is what most of the world uses, not only in aviation, but for everything that has to do with weather. Sauer202 (talk) 23:00, 26 October 2019 (UTC)

Questions about the accuracy of this article

In the first few sentences of this article I read that TAS is important for navigation, and analogue TAS sensors/meters may be superseded by GPS.

I cannot see how TAS would be at all important for navigation. Navigation is concerned with knowing the position of the aircraft relative to geographical markers - ground speed is the important metric here.

Also, why would GPS make a TAS indicator redundant. since GPS cannot give any insight at all into airspeed! GPS provides ground speed information. Only aerodynamic sensors can give airspeed information. A TAS indicator would never be excluded from any cockpit - airspped is the thing that keeps the plane airborne, and essential information. — Preceding unsigned comment added by 195.147.82.34 (talk) 15:09, 4 August 2019 (UTC)

You are right - ground speed and its associated direction are vital for aerial navigation. How do the pilots of light aircraft with basic instruments determine their ground speed? Answer: they use the triangle of velocities, making use of their true airspeed and their knowledge of the wind speed and direction. If the pilot of such an aircraft is unaware of his or her true airspeed the triangle of velocities cannot be used to determine ground speed and direction.

These days, many pilots have a GPS they can use in the cockpit. GPS shows ground speed and direction so the triangle of velocities and true airspeed are not essential. However, if pilots with GPS want to determine wind speed and direction they need to use the triangle of velocities, and that will require knowledge of both ground speed and true airspeed.

You have written "airspeed is the thing that keeps the plane airborne …" Yes, but it is indicated airspeed (IAS), not TAS, that determines whether the aircraft will stall or continue flying; and it is IAS, not TAS, that determines control feel and flying qualities of a low-speed aircraft. That is why the big gauge directly in front of each pilot displays indicated airspeed, not true airspeed. Dolphin (t) 12:07, 5 August 2019 (UTC)

--- Your comments in reply do not address the concerns I raised and tell me nothing I do not already know. The article on TAS seems to have errors as I pointed out. TAS is not useful to navigation and GPS does not give any insight into TAS (and therefore does not replace a TAS instrument). I wasn't looking for a conversation: I was looking at someone who maintains this article to correct it.comment added by 195.147.82.34 (talk)

The universal principle at Wikipedia Talk pages is that if someone argues persuasively that there is an error, and equally persuasively that a correction is available, the error will be erased and the correction inserted. The key word here is persuasively. It isn’t sufficient to merely assert that there is an error, or to assert that an alternative is the correct one.

Firstly you wrote “I cannot see how TAS is at all important for navigation.” Secondly you asserted that “TAS is not useful to navigation ...” You haven’t yet made much of an effort to persuade on that point, have you?

We agree that, as you correctly stated, “Ground speed is the important metric here.” Please explain how you imagine pilots of aircraft in flight determine their ground speed (in the absence of GPS or flight management computer.) Hint: See my previous reply. Dolphin (t) 22:24, 8 August 2019 (UTC)

You're such a dork. You're saying you know the article is nonsense but you want a persuasive argument before you amend it. I'm afraid it's difficult for people like me to deal with people like you, so gfy. comment added by 195.147.82.34 (talk) —Preceding undated comment added 11:27, 9 August 2019 (UTC)

I’m not saying the article is nonsense, but I am agreeing with your statement “Ground speed is the important metric here.” Dolphin (t) 11:31, 9 August 2019 (UTC)

I just came across this article and there are many inaccuracies, I'll look up some references and update it. TAS is not used for Navigation. There should be some reference to IAS (indicated air speed), this is the speed needed to keep the airplane safe and airborne regardless of altitude and depends on both static pressure on the side of the fuselage and pitot pressure from the forward motion of the aircraft registered on a pitot tube. It decreases with altitude. Landing and takeoff use IAS regardless of the airport altitude. The TAS increases with altitude with a constant IAS and is computed manually or by a computer using altitude, temperature and indicated airspeed. Pilots in the early days before computers had a circular slide rule to compute the True Airspeed. Avi8tor (talk) 07:58, 12 February 2024 (UTC)

Thanks for offering to update our article. You have written TAS is not used for Navigation. If you have a look at Triangle of velocities you will see the following comment about the air vector: “It is described by true airspeed and true heading.” Dolphin (t) 09:45, 12 February 2024 (UTC)

I should have read my post better, IAS is what I meant. I did plotting for my commercial license, but after NASA made Inertial Navigation Systems for the moon landing they were in most large aircraft by 1975. Avi8tor (talk) 12:46, 12 February 2024 (UTC)

Understood. You also wrote “[IAS] decreases with altitude.” Really? Dolphin (t) 13:15, 12 February 2024 (UTC)