Why is indicated airspeed rather than ground speed used during the takeoff roll?What is the difference between ground speed and airspeed?Does adding flaps during ground roll perform better in short-field takeoff?What is the reference used when measuring flight speed?What's the difference between Rotation speed vs takeoff speed?What aircraft fly faster than 250 knots indicated airspeed under 10,000 feet for safety reasons?Why does indicated airspeed change with altitude?How to calculate normal takeoff ground roll when the POH only has Short Field Takeoff tables?In light aircraft, non-instrument flight, apply (nearly) full aft elevator before beginning the takeoff roll or at some predetermined speed?Why is the normal operating airspeed so much lower than the cruise speed in this table?Why do pilots normally fly by CAS rather than TAS?

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Why is indicated airspeed rather than ground speed used during the takeoff roll?


What is the difference between ground speed and airspeed?Does adding flaps during ground roll perform better in short-field takeoff?What is the reference used when measuring flight speed?What's the difference between Rotation speed vs takeoff speed?What aircraft fly faster than 250 knots indicated airspeed under 10,000 feet for safety reasons?Why does indicated airspeed change with altitude?How to calculate normal takeoff ground roll when the POH only has Short Field Takeoff tables?In light aircraft, non-instrument flight, apply (nearly) full aft elevator before beginning the takeoff roll or at some predetermined speed?Why is the normal operating airspeed so much lower than the cruise speed in this table?Why do pilots normally fly by CAS rather than TAS?













5












$begingroup$


My instructor asked me this question during my lesson and I couldn't come up with any answers. He asked why do I need to look at the indicated airspeed rather than ground speed when in takeoff roll or as soon as we touchdown? There is this procedure in my airline that we have to call out airspeeds when we are rolling for takeoff (ex: "80 kts" before THR HOLD).



It would be great if you could give me the reference to back it up.










share|improve this question









New contributor




Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$







  • 53




    $begingroup$
    It seems you are a commercial pilot working at an airline and being trained on a new aircraft type. If that is true, I find it hard to believe that you don't understand the difference between indicated airspeed and ground speed.
    $endgroup$
    – Mike Sowsun
    yesterday







  • 5




    $begingroup$
    What airplane are you flying that has a groundspeed indicator?
    $endgroup$
    – Wirewrap
    yesterday






  • 6




    $begingroup$
    @Kittoes0124 The point is valid. I think anyone involved with aircraft would find it unsettling to see someone training at this level of professional aviation who could not answer this extremely basic question. The only logical conclusion is that either OP is the one trolling HNQ with a sensational question OR they represent a serious danger to the flying public and, hopefully, received a clear and unapologetic failing grade from their instructor.
    $endgroup$
    – J...
    6 hours ago






  • 8




    $begingroup$
    As someone who only has a little reading and no practical training on the subject I knew the answer from the title. A novice may not, but then you get to the word "airline" and a description of regular practice. That suggests a few possibilities: Trolling, story-telling in the name of an instructive but basic question (sometimes seen on other sites in the network), mistranslation (but the Q reads like it was written by a native speaker), or a pilot who somehow qualified without knowing much about aerodynamics. The reader can draw their own conclusion as to which one applies (@Kittoes0124)
    $endgroup$
    – Chris H
    6 hours ago







  • 8




    $begingroup$
    @Kittoes0124 Day 1 of somebody's flying training isn't compatible with "the procedure in my airline." There's nothing at all wrong with asking basic questions but asking basic questions while claiming to be a professional in a safety-critical job is something completely different. If the asker is in the position they claim to be in, they should have known the answer to this question long ago. Random member of the public asks why surgeons wash their hands? Fine. Somebody says "I took a shower this morning but, in my hospital, procedure is we should wash our hands before surgery -- why?" Problem
    $endgroup$
    – David Richerby
    5 hours ago















5












$begingroup$


My instructor asked me this question during my lesson and I couldn't come up with any answers. He asked why do I need to look at the indicated airspeed rather than ground speed when in takeoff roll or as soon as we touchdown? There is this procedure in my airline that we have to call out airspeeds when we are rolling for takeoff (ex: "80 kts" before THR HOLD).



It would be great if you could give me the reference to back it up.










share|improve this question









New contributor




Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$







  • 53




    $begingroup$
    It seems you are a commercial pilot working at an airline and being trained on a new aircraft type. If that is true, I find it hard to believe that you don't understand the difference between indicated airspeed and ground speed.
    $endgroup$
    – Mike Sowsun
    yesterday







  • 5




    $begingroup$
    What airplane are you flying that has a groundspeed indicator?
    $endgroup$
    – Wirewrap
    yesterday






  • 6




    $begingroup$
    @Kittoes0124 The point is valid. I think anyone involved with aircraft would find it unsettling to see someone training at this level of professional aviation who could not answer this extremely basic question. The only logical conclusion is that either OP is the one trolling HNQ with a sensational question OR they represent a serious danger to the flying public and, hopefully, received a clear and unapologetic failing grade from their instructor.
    $endgroup$
    – J...
    6 hours ago






  • 8




    $begingroup$
    As someone who only has a little reading and no practical training on the subject I knew the answer from the title. A novice may not, but then you get to the word "airline" and a description of regular practice. That suggests a few possibilities: Trolling, story-telling in the name of an instructive but basic question (sometimes seen on other sites in the network), mistranslation (but the Q reads like it was written by a native speaker), or a pilot who somehow qualified without knowing much about aerodynamics. The reader can draw their own conclusion as to which one applies (@Kittoes0124)
    $endgroup$
    – Chris H
    6 hours ago







  • 8




    $begingroup$
    @Kittoes0124 Day 1 of somebody's flying training isn't compatible with "the procedure in my airline." There's nothing at all wrong with asking basic questions but asking basic questions while claiming to be a professional in a safety-critical job is something completely different. If the asker is in the position they claim to be in, they should have known the answer to this question long ago. Random member of the public asks why surgeons wash their hands? Fine. Somebody says "I took a shower this morning but, in my hospital, procedure is we should wash our hands before surgery -- why?" Problem
    $endgroup$
    – David Richerby
    5 hours ago













5












5








5





$begingroup$


My instructor asked me this question during my lesson and I couldn't come up with any answers. He asked why do I need to look at the indicated airspeed rather than ground speed when in takeoff roll or as soon as we touchdown? There is this procedure in my airline that we have to call out airspeeds when we are rolling for takeoff (ex: "80 kts" before THR HOLD).



It would be great if you could give me the reference to back it up.










share|improve this question









New contributor




Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$




My instructor asked me this question during my lesson and I couldn't come up with any answers. He asked why do I need to look at the indicated airspeed rather than ground speed when in takeoff roll or as soon as we touchdown? There is this procedure in my airline that we have to call out airspeeds when we are rolling for takeoff (ex: "80 kts" before THR HOLD).



It would be great if you could give me the reference to back it up.







takeoff airspeed






share|improve this question









New contributor




Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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share|improve this question









New contributor




Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|improve this question




share|improve this question








edited yesterday









ymb1

67.4k7213357




67.4k7213357






New contributor




Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









asked yesterday









SteveSteve

3812




3812




New contributor




Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





New contributor





Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






Steve is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







  • 53




    $begingroup$
    It seems you are a commercial pilot working at an airline and being trained on a new aircraft type. If that is true, I find it hard to believe that you don't understand the difference between indicated airspeed and ground speed.
    $endgroup$
    – Mike Sowsun
    yesterday







  • 5




    $begingroup$
    What airplane are you flying that has a groundspeed indicator?
    $endgroup$
    – Wirewrap
    yesterday






  • 6




    $begingroup$
    @Kittoes0124 The point is valid. I think anyone involved with aircraft would find it unsettling to see someone training at this level of professional aviation who could not answer this extremely basic question. The only logical conclusion is that either OP is the one trolling HNQ with a sensational question OR they represent a serious danger to the flying public and, hopefully, received a clear and unapologetic failing grade from their instructor.
    $endgroup$
    – J...
    6 hours ago






  • 8




    $begingroup$
    As someone who only has a little reading and no practical training on the subject I knew the answer from the title. A novice may not, but then you get to the word "airline" and a description of regular practice. That suggests a few possibilities: Trolling, story-telling in the name of an instructive but basic question (sometimes seen on other sites in the network), mistranslation (but the Q reads like it was written by a native speaker), or a pilot who somehow qualified without knowing much about aerodynamics. The reader can draw their own conclusion as to which one applies (@Kittoes0124)
    $endgroup$
    – Chris H
    6 hours ago







  • 8




    $begingroup$
    @Kittoes0124 Day 1 of somebody's flying training isn't compatible with "the procedure in my airline." There's nothing at all wrong with asking basic questions but asking basic questions while claiming to be a professional in a safety-critical job is something completely different. If the asker is in the position they claim to be in, they should have known the answer to this question long ago. Random member of the public asks why surgeons wash their hands? Fine. Somebody says "I took a shower this morning but, in my hospital, procedure is we should wash our hands before surgery -- why?" Problem
    $endgroup$
    – David Richerby
    5 hours ago












  • 53




    $begingroup$
    It seems you are a commercial pilot working at an airline and being trained on a new aircraft type. If that is true, I find it hard to believe that you don't understand the difference between indicated airspeed and ground speed.
    $endgroup$
    – Mike Sowsun
    yesterday







  • 5




    $begingroup$
    What airplane are you flying that has a groundspeed indicator?
    $endgroup$
    – Wirewrap
    yesterday






  • 6




    $begingroup$
    @Kittoes0124 The point is valid. I think anyone involved with aircraft would find it unsettling to see someone training at this level of professional aviation who could not answer this extremely basic question. The only logical conclusion is that either OP is the one trolling HNQ with a sensational question OR they represent a serious danger to the flying public and, hopefully, received a clear and unapologetic failing grade from their instructor.
    $endgroup$
    – J...
    6 hours ago






  • 8




    $begingroup$
    As someone who only has a little reading and no practical training on the subject I knew the answer from the title. A novice may not, but then you get to the word "airline" and a description of regular practice. That suggests a few possibilities: Trolling, story-telling in the name of an instructive but basic question (sometimes seen on other sites in the network), mistranslation (but the Q reads like it was written by a native speaker), or a pilot who somehow qualified without knowing much about aerodynamics. The reader can draw their own conclusion as to which one applies (@Kittoes0124)
    $endgroup$
    – Chris H
    6 hours ago







  • 8




    $begingroup$
    @Kittoes0124 Day 1 of somebody's flying training isn't compatible with "the procedure in my airline." There's nothing at all wrong with asking basic questions but asking basic questions while claiming to be a professional in a safety-critical job is something completely different. If the asker is in the position they claim to be in, they should have known the answer to this question long ago. Random member of the public asks why surgeons wash their hands? Fine. Somebody says "I took a shower this morning but, in my hospital, procedure is we should wash our hands before surgery -- why?" Problem
    $endgroup$
    – David Richerby
    5 hours ago







53




53




$begingroup$
It seems you are a commercial pilot working at an airline and being trained on a new aircraft type. If that is true, I find it hard to believe that you don't understand the difference between indicated airspeed and ground speed.
$endgroup$
– Mike Sowsun
yesterday





$begingroup$
It seems you are a commercial pilot working at an airline and being trained on a new aircraft type. If that is true, I find it hard to believe that you don't understand the difference between indicated airspeed and ground speed.
$endgroup$
– Mike Sowsun
yesterday





5




5




$begingroup$
What airplane are you flying that has a groundspeed indicator?
$endgroup$
– Wirewrap
yesterday




$begingroup$
What airplane are you flying that has a groundspeed indicator?
$endgroup$
– Wirewrap
yesterday




6




6




$begingroup$
@Kittoes0124 The point is valid. I think anyone involved with aircraft would find it unsettling to see someone training at this level of professional aviation who could not answer this extremely basic question. The only logical conclusion is that either OP is the one trolling HNQ with a sensational question OR they represent a serious danger to the flying public and, hopefully, received a clear and unapologetic failing grade from their instructor.
$endgroup$
– J...
6 hours ago




$begingroup$
@Kittoes0124 The point is valid. I think anyone involved with aircraft would find it unsettling to see someone training at this level of professional aviation who could not answer this extremely basic question. The only logical conclusion is that either OP is the one trolling HNQ with a sensational question OR they represent a serious danger to the flying public and, hopefully, received a clear and unapologetic failing grade from their instructor.
$endgroup$
– J...
6 hours ago




8




8




$begingroup$
As someone who only has a little reading and no practical training on the subject I knew the answer from the title. A novice may not, but then you get to the word "airline" and a description of regular practice. That suggests a few possibilities: Trolling, story-telling in the name of an instructive but basic question (sometimes seen on other sites in the network), mistranslation (but the Q reads like it was written by a native speaker), or a pilot who somehow qualified without knowing much about aerodynamics. The reader can draw their own conclusion as to which one applies (@Kittoes0124)
$endgroup$
– Chris H
6 hours ago





$begingroup$
As someone who only has a little reading and no practical training on the subject I knew the answer from the title. A novice may not, but then you get to the word "airline" and a description of regular practice. That suggests a few possibilities: Trolling, story-telling in the name of an instructive but basic question (sometimes seen on other sites in the network), mistranslation (but the Q reads like it was written by a native speaker), or a pilot who somehow qualified without knowing much about aerodynamics. The reader can draw their own conclusion as to which one applies (@Kittoes0124)
$endgroup$
– Chris H
6 hours ago





8




8




$begingroup$
@Kittoes0124 Day 1 of somebody's flying training isn't compatible with "the procedure in my airline." There's nothing at all wrong with asking basic questions but asking basic questions while claiming to be a professional in a safety-critical job is something completely different. If the asker is in the position they claim to be in, they should have known the answer to this question long ago. Random member of the public asks why surgeons wash their hands? Fine. Somebody says "I took a shower this morning but, in my hospital, procedure is we should wash our hands before surgery -- why?" Problem
$endgroup$
– David Richerby
5 hours ago




$begingroup$
@Kittoes0124 Day 1 of somebody's flying training isn't compatible with "the procedure in my airline." There's nothing at all wrong with asking basic questions but asking basic questions while claiming to be a professional in a safety-critical job is something completely different. If the asker is in the position they claim to be in, they should have known the answer to this question long ago. Random member of the public asks why surgeons wash their hands? Fine. Somebody says "I took a shower this morning but, in my hospital, procedure is we should wash our hands before surgery -- why?" Problem
$endgroup$
– David Richerby
5 hours ago










4 Answers
4






active

oldest

votes


















39












$begingroup$

Because wings work on air moving past them, not ground moving below them.



Heck, in a 35 knot headwind, the Antonov-2 could be rolling backwards at 2 knots and still take off!






share|improve this answer











$endgroup$








  • 1




    $begingroup$
    This is already explained in the existing answers. Why add one more?
    $endgroup$
    – Mast
    yesterday






  • 17




    $begingroup$
    @mast My explanation is far simpler. Which seems to be warranted here.
    $endgroup$
    – Harper
    yesterday










  • $begingroup$
    Agreed, this is why carriers head into the wind. More than one aircraft landed with negative ground speed during WW1.
    $endgroup$
    – mckenzm
    21 hours ago







  • 2




    $begingroup$
    Other answers are based on the same ideas, but this one puts it most directly.
    $endgroup$
    – David K
    17 hours ago


















33












$begingroup$

Because what determines the amount of lift generated is the indicated airspeed, not the ground speed. As usual, it is always easier to think about an extreme case. If you have an aircraft with VR (speed at rotation for takeoff) of 90 knots, and there is an 80 knots head wind, in theory it will rotate with ground speed of 10 knots even though the indicated airspeed will be 90 knots.






share|improve this answer











$endgroup$








  • 9




    $begingroup$
    @Notts90 True, but it seems like OP is a pilot or studying to become one. Let's hope they know what Vr is
    $endgroup$
    – DeepSpace
    yesterday







  • 2




    $begingroup$
    My guess is airline-sponsored primary training. I'd hope he knows what Vr is by now, but I'm not sure we can assume it was explained correctly if he's asking this question.
    $endgroup$
    – StephenS
    yesterday






  • 10




    $begingroup$
    I don't remember offhand what every V speed means, and this site isn't exclusively for pilots anyway, so why not tell everyone what Vr is? Save some google searches.
    $endgroup$
    – Xen2050
    yesterday






  • 5




    $begingroup$
    For those interested: Vr is defined as the speed at which the rotation of the aircraft should be initiated to takeoff attitude.
    $endgroup$
    – Mast
    yesterday






  • 5




    $begingroup$
    @DeepSpace While OP may be training to be a pilot, let's try to remember that SE is for everyone, and is likely to involve others viewing this question later who may not be training as a pilot. For that reason it's usually worth avoiding jargon or adding a quick explanation
    $endgroup$
    – Jon Story
    20 hours ago


















5












$begingroup$

Airspeed is always important as it determines lift which keeps you in the air. At the moment of takeoff or landing, airspeed is critical because it is the point at which you transition to or from flight; you need to be going fast enough but not too fast so that the transition is positive without being abrupt or overly stressful on aircraft components.



Ground speed matters in navigation because it determines flight time which affects fuel required to get from A to B.






share|improve this answer









$endgroup$












  • $begingroup$
    +1 for mentioning why both are important
    $endgroup$
    – MPW
    8 hours ago


















1












$begingroup$

The IAS includes factors such as Wind Component (Tail, Head or Cross), Pressure and Temperature. All these have an influence on your takeoff. The takeoff Speed Vr is calculated as Indicated Airspeed. Imagine you have a Headwind Component of +50. You Groundspeed would be way lower than your Airspeed. What counts is the amount of air that flows over the wing in order to takeoff, not the speed relative to the ground.






share|improve this answer








New contributor




Windshear is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






$endgroup$











    protected by Federico 4 hours ago



    Thank you for your interest in this question.
    Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).



    Would you like to answer one of these unanswered questions instead?














    4 Answers
    4






    active

    oldest

    votes








    4 Answers
    4






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    39












    $begingroup$

    Because wings work on air moving past them, not ground moving below them.



    Heck, in a 35 knot headwind, the Antonov-2 could be rolling backwards at 2 knots and still take off!






    share|improve this answer











    $endgroup$








    • 1




      $begingroup$
      This is already explained in the existing answers. Why add one more?
      $endgroup$
      – Mast
      yesterday






    • 17




      $begingroup$
      @mast My explanation is far simpler. Which seems to be warranted here.
      $endgroup$
      – Harper
      yesterday










    • $begingroup$
      Agreed, this is why carriers head into the wind. More than one aircraft landed with negative ground speed during WW1.
      $endgroup$
      – mckenzm
      21 hours ago







    • 2




      $begingroup$
      Other answers are based on the same ideas, but this one puts it most directly.
      $endgroup$
      – David K
      17 hours ago















    39












    $begingroup$

    Because wings work on air moving past them, not ground moving below them.



    Heck, in a 35 knot headwind, the Antonov-2 could be rolling backwards at 2 knots and still take off!






    share|improve this answer











    $endgroup$








    • 1




      $begingroup$
      This is already explained in the existing answers. Why add one more?
      $endgroup$
      – Mast
      yesterday






    • 17




      $begingroup$
      @mast My explanation is far simpler. Which seems to be warranted here.
      $endgroup$
      – Harper
      yesterday










    • $begingroup$
      Agreed, this is why carriers head into the wind. More than one aircraft landed with negative ground speed during WW1.
      $endgroup$
      – mckenzm
      21 hours ago







    • 2




      $begingroup$
      Other answers are based on the same ideas, but this one puts it most directly.
      $endgroup$
      – David K
      17 hours ago













    39












    39








    39





    $begingroup$

    Because wings work on air moving past them, not ground moving below them.



    Heck, in a 35 knot headwind, the Antonov-2 could be rolling backwards at 2 knots and still take off!






    share|improve this answer











    $endgroup$



    Because wings work on air moving past them, not ground moving below them.



    Heck, in a 35 knot headwind, the Antonov-2 could be rolling backwards at 2 knots and still take off!







    share|improve this answer














    share|improve this answer



    share|improve this answer








    edited yesterday

























    answered yesterday









    HarperHarper

    3,591721




    3,591721







    • 1




      $begingroup$
      This is already explained in the existing answers. Why add one more?
      $endgroup$
      – Mast
      yesterday






    • 17




      $begingroup$
      @mast My explanation is far simpler. Which seems to be warranted here.
      $endgroup$
      – Harper
      yesterday










    • $begingroup$
      Agreed, this is why carriers head into the wind. More than one aircraft landed with negative ground speed during WW1.
      $endgroup$
      – mckenzm
      21 hours ago







    • 2




      $begingroup$
      Other answers are based on the same ideas, but this one puts it most directly.
      $endgroup$
      – David K
      17 hours ago












    • 1




      $begingroup$
      This is already explained in the existing answers. Why add one more?
      $endgroup$
      – Mast
      yesterday






    • 17




      $begingroup$
      @mast My explanation is far simpler. Which seems to be warranted here.
      $endgroup$
      – Harper
      yesterday










    • $begingroup$
      Agreed, this is why carriers head into the wind. More than one aircraft landed with negative ground speed during WW1.
      $endgroup$
      – mckenzm
      21 hours ago







    • 2




      $begingroup$
      Other answers are based on the same ideas, but this one puts it most directly.
      $endgroup$
      – David K
      17 hours ago







    1




    1




    $begingroup$
    This is already explained in the existing answers. Why add one more?
    $endgroup$
    – Mast
    yesterday




    $begingroup$
    This is already explained in the existing answers. Why add one more?
    $endgroup$
    – Mast
    yesterday




    17




    17




    $begingroup$
    @mast My explanation is far simpler. Which seems to be warranted here.
    $endgroup$
    – Harper
    yesterday




    $begingroup$
    @mast My explanation is far simpler. Which seems to be warranted here.
    $endgroup$
    – Harper
    yesterday












    $begingroup$
    Agreed, this is why carriers head into the wind. More than one aircraft landed with negative ground speed during WW1.
    $endgroup$
    – mckenzm
    21 hours ago





    $begingroup$
    Agreed, this is why carriers head into the wind. More than one aircraft landed with negative ground speed during WW1.
    $endgroup$
    – mckenzm
    21 hours ago





    2




    2




    $begingroup$
    Other answers are based on the same ideas, but this one puts it most directly.
    $endgroup$
    – David K
    17 hours ago




    $begingroup$
    Other answers are based on the same ideas, but this one puts it most directly.
    $endgroup$
    – David K
    17 hours ago











    33












    $begingroup$

    Because what determines the amount of lift generated is the indicated airspeed, not the ground speed. As usual, it is always easier to think about an extreme case. If you have an aircraft with VR (speed at rotation for takeoff) of 90 knots, and there is an 80 knots head wind, in theory it will rotate with ground speed of 10 knots even though the indicated airspeed will be 90 knots.






    share|improve this answer











    $endgroup$








    • 9




      $begingroup$
      @Notts90 True, but it seems like OP is a pilot or studying to become one. Let's hope they know what Vr is
      $endgroup$
      – DeepSpace
      yesterday







    • 2




      $begingroup$
      My guess is airline-sponsored primary training. I'd hope he knows what Vr is by now, but I'm not sure we can assume it was explained correctly if he's asking this question.
      $endgroup$
      – StephenS
      yesterday






    • 10




      $begingroup$
      I don't remember offhand what every V speed means, and this site isn't exclusively for pilots anyway, so why not tell everyone what Vr is? Save some google searches.
      $endgroup$
      – Xen2050
      yesterday






    • 5




      $begingroup$
      For those interested: Vr is defined as the speed at which the rotation of the aircraft should be initiated to takeoff attitude.
      $endgroup$
      – Mast
      yesterday






    • 5




      $begingroup$
      @DeepSpace While OP may be training to be a pilot, let's try to remember that SE is for everyone, and is likely to involve others viewing this question later who may not be training as a pilot. For that reason it's usually worth avoiding jargon or adding a quick explanation
      $endgroup$
      – Jon Story
      20 hours ago















    33












    $begingroup$

    Because what determines the amount of lift generated is the indicated airspeed, not the ground speed. As usual, it is always easier to think about an extreme case. If you have an aircraft with VR (speed at rotation for takeoff) of 90 knots, and there is an 80 knots head wind, in theory it will rotate with ground speed of 10 knots even though the indicated airspeed will be 90 knots.






    share|improve this answer











    $endgroup$








    • 9




      $begingroup$
      @Notts90 True, but it seems like OP is a pilot or studying to become one. Let's hope they know what Vr is
      $endgroup$
      – DeepSpace
      yesterday







    • 2




      $begingroup$
      My guess is airline-sponsored primary training. I'd hope he knows what Vr is by now, but I'm not sure we can assume it was explained correctly if he's asking this question.
      $endgroup$
      – StephenS
      yesterday






    • 10




      $begingroup$
      I don't remember offhand what every V speed means, and this site isn't exclusively for pilots anyway, so why not tell everyone what Vr is? Save some google searches.
      $endgroup$
      – Xen2050
      yesterday






    • 5




      $begingroup$
      For those interested: Vr is defined as the speed at which the rotation of the aircraft should be initiated to takeoff attitude.
      $endgroup$
      – Mast
      yesterday






    • 5




      $begingroup$
      @DeepSpace While OP may be training to be a pilot, let's try to remember that SE is for everyone, and is likely to involve others viewing this question later who may not be training as a pilot. For that reason it's usually worth avoiding jargon or adding a quick explanation
      $endgroup$
      – Jon Story
      20 hours ago













    33












    33








    33





    $begingroup$

    Because what determines the amount of lift generated is the indicated airspeed, not the ground speed. As usual, it is always easier to think about an extreme case. If you have an aircraft with VR (speed at rotation for takeoff) of 90 knots, and there is an 80 knots head wind, in theory it will rotate with ground speed of 10 knots even though the indicated airspeed will be 90 knots.






    share|improve this answer











    $endgroup$



    Because what determines the amount of lift generated is the indicated airspeed, not the ground speed. As usual, it is always easier to think about an extreme case. If you have an aircraft with VR (speed at rotation for takeoff) of 90 knots, and there is an 80 knots head wind, in theory it will rotate with ground speed of 10 knots even though the indicated airspeed will be 90 knots.







    share|improve this answer














    share|improve this answer



    share|improve this answer








    edited yesterday









    StephenS

    4,1711725




    4,1711725










    answered yesterday









    DeepSpaceDeepSpace

    1,585713




    1,585713







    • 9




      $begingroup$
      @Notts90 True, but it seems like OP is a pilot or studying to become one. Let's hope they know what Vr is
      $endgroup$
      – DeepSpace
      yesterday







    • 2




      $begingroup$
      My guess is airline-sponsored primary training. I'd hope he knows what Vr is by now, but I'm not sure we can assume it was explained correctly if he's asking this question.
      $endgroup$
      – StephenS
      yesterday






    • 10




      $begingroup$
      I don't remember offhand what every V speed means, and this site isn't exclusively for pilots anyway, so why not tell everyone what Vr is? Save some google searches.
      $endgroup$
      – Xen2050
      yesterday






    • 5




      $begingroup$
      For those interested: Vr is defined as the speed at which the rotation of the aircraft should be initiated to takeoff attitude.
      $endgroup$
      – Mast
      yesterday






    • 5




      $begingroup$
      @DeepSpace While OP may be training to be a pilot, let's try to remember that SE is for everyone, and is likely to involve others viewing this question later who may not be training as a pilot. For that reason it's usually worth avoiding jargon or adding a quick explanation
      $endgroup$
      – Jon Story
      20 hours ago












    • 9




      $begingroup$
      @Notts90 True, but it seems like OP is a pilot or studying to become one. Let's hope they know what Vr is
      $endgroup$
      – DeepSpace
      yesterday







    • 2




      $begingroup$
      My guess is airline-sponsored primary training. I'd hope he knows what Vr is by now, but I'm not sure we can assume it was explained correctly if he's asking this question.
      $endgroup$
      – StephenS
      yesterday






    • 10




      $begingroup$
      I don't remember offhand what every V speed means, and this site isn't exclusively for pilots anyway, so why not tell everyone what Vr is? Save some google searches.
      $endgroup$
      – Xen2050
      yesterday






    • 5




      $begingroup$
      For those interested: Vr is defined as the speed at which the rotation of the aircraft should be initiated to takeoff attitude.
      $endgroup$
      – Mast
      yesterday






    • 5




      $begingroup$
      @DeepSpace While OP may be training to be a pilot, let's try to remember that SE is for everyone, and is likely to involve others viewing this question later who may not be training as a pilot. For that reason it's usually worth avoiding jargon or adding a quick explanation
      $endgroup$
      – Jon Story
      20 hours ago







    9




    9




    $begingroup$
    @Notts90 True, but it seems like OP is a pilot or studying to become one. Let's hope they know what Vr is
    $endgroup$
    – DeepSpace
    yesterday





    $begingroup$
    @Notts90 True, but it seems like OP is a pilot or studying to become one. Let's hope they know what Vr is
    $endgroup$
    – DeepSpace
    yesterday





    2




    2




    $begingroup$
    My guess is airline-sponsored primary training. I'd hope he knows what Vr is by now, but I'm not sure we can assume it was explained correctly if he's asking this question.
    $endgroup$
    – StephenS
    yesterday




    $begingroup$
    My guess is airline-sponsored primary training. I'd hope he knows what Vr is by now, but I'm not sure we can assume it was explained correctly if he's asking this question.
    $endgroup$
    – StephenS
    yesterday




    10




    10




    $begingroup$
    I don't remember offhand what every V speed means, and this site isn't exclusively for pilots anyway, so why not tell everyone what Vr is? Save some google searches.
    $endgroup$
    – Xen2050
    yesterday




    $begingroup$
    I don't remember offhand what every V speed means, and this site isn't exclusively for pilots anyway, so why not tell everyone what Vr is? Save some google searches.
    $endgroup$
    – Xen2050
    yesterday




    5




    5




    $begingroup$
    For those interested: Vr is defined as the speed at which the rotation of the aircraft should be initiated to takeoff attitude.
    $endgroup$
    – Mast
    yesterday




    $begingroup$
    For those interested: Vr is defined as the speed at which the rotation of the aircraft should be initiated to takeoff attitude.
    $endgroup$
    – Mast
    yesterday




    5




    5




    $begingroup$
    @DeepSpace While OP may be training to be a pilot, let's try to remember that SE is for everyone, and is likely to involve others viewing this question later who may not be training as a pilot. For that reason it's usually worth avoiding jargon or adding a quick explanation
    $endgroup$
    – Jon Story
    20 hours ago




    $begingroup$
    @DeepSpace While OP may be training to be a pilot, let's try to remember that SE is for everyone, and is likely to involve others viewing this question later who may not be training as a pilot. For that reason it's usually worth avoiding jargon or adding a quick explanation
    $endgroup$
    – Jon Story
    20 hours ago











    5












    $begingroup$

    Airspeed is always important as it determines lift which keeps you in the air. At the moment of takeoff or landing, airspeed is critical because it is the point at which you transition to or from flight; you need to be going fast enough but not too fast so that the transition is positive without being abrupt or overly stressful on aircraft components.



    Ground speed matters in navigation because it determines flight time which affects fuel required to get from A to B.






    share|improve this answer









    $endgroup$












    • $begingroup$
      +1 for mentioning why both are important
      $endgroup$
      – MPW
      8 hours ago















    5












    $begingroup$

    Airspeed is always important as it determines lift which keeps you in the air. At the moment of takeoff or landing, airspeed is critical because it is the point at which you transition to or from flight; you need to be going fast enough but not too fast so that the transition is positive without being abrupt or overly stressful on aircraft components.



    Ground speed matters in navigation because it determines flight time which affects fuel required to get from A to B.






    share|improve this answer









    $endgroup$












    • $begingroup$
      +1 for mentioning why both are important
      $endgroup$
      – MPW
      8 hours ago













    5












    5








    5





    $begingroup$

    Airspeed is always important as it determines lift which keeps you in the air. At the moment of takeoff or landing, airspeed is critical because it is the point at which you transition to or from flight; you need to be going fast enough but not too fast so that the transition is positive without being abrupt or overly stressful on aircraft components.



    Ground speed matters in navigation because it determines flight time which affects fuel required to get from A to B.






    share|improve this answer









    $endgroup$



    Airspeed is always important as it determines lift which keeps you in the air. At the moment of takeoff or landing, airspeed is critical because it is the point at which you transition to or from flight; you need to be going fast enough but not too fast so that the transition is positive without being abrupt or overly stressful on aircraft components.



    Ground speed matters in navigation because it determines flight time which affects fuel required to get from A to B.







    share|improve this answer












    share|improve this answer



    share|improve this answer










    answered yesterday









    Anthony XAnthony X

    1,8491116




    1,8491116











    • $begingroup$
      +1 for mentioning why both are important
      $endgroup$
      – MPW
      8 hours ago
















    • $begingroup$
      +1 for mentioning why both are important
      $endgroup$
      – MPW
      8 hours ago















    $begingroup$
    +1 for mentioning why both are important
    $endgroup$
    – MPW
    8 hours ago




    $begingroup$
    +1 for mentioning why both are important
    $endgroup$
    – MPW
    8 hours ago











    1












    $begingroup$

    The IAS includes factors such as Wind Component (Tail, Head or Cross), Pressure and Temperature. All these have an influence on your takeoff. The takeoff Speed Vr is calculated as Indicated Airspeed. Imagine you have a Headwind Component of +50. You Groundspeed would be way lower than your Airspeed. What counts is the amount of air that flows over the wing in order to takeoff, not the speed relative to the ground.






    share|improve this answer








    New contributor




    Windshear is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.






    $endgroup$

















      1












      $begingroup$

      The IAS includes factors such as Wind Component (Tail, Head or Cross), Pressure and Temperature. All these have an influence on your takeoff. The takeoff Speed Vr is calculated as Indicated Airspeed. Imagine you have a Headwind Component of +50. You Groundspeed would be way lower than your Airspeed. What counts is the amount of air that flows over the wing in order to takeoff, not the speed relative to the ground.






      share|improve this answer








      New contributor




      Windshear is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.






      $endgroup$















        1












        1








        1





        $begingroup$

        The IAS includes factors such as Wind Component (Tail, Head or Cross), Pressure and Temperature. All these have an influence on your takeoff. The takeoff Speed Vr is calculated as Indicated Airspeed. Imagine you have a Headwind Component of +50. You Groundspeed would be way lower than your Airspeed. What counts is the amount of air that flows over the wing in order to takeoff, not the speed relative to the ground.






        share|improve this answer








        New contributor




        Windshear is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
        Check out our Code of Conduct.






        $endgroup$



        The IAS includes factors such as Wind Component (Tail, Head or Cross), Pressure and Temperature. All these have an influence on your takeoff. The takeoff Speed Vr is calculated as Indicated Airspeed. Imagine you have a Headwind Component of +50. You Groundspeed would be way lower than your Airspeed. What counts is the amount of air that flows over the wing in order to takeoff, not the speed relative to the ground.







        share|improve this answer








        New contributor




        Windshear is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
        Check out our Code of Conduct.









        share|improve this answer



        share|improve this answer






        New contributor




        Windshear is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
        Check out our Code of Conduct.









        answered yesterday









        WindshearWindshear

        1313




        1313




        New contributor




        Windshear is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
        Check out our Code of Conduct.





        New contributor





        Windshear is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
        Check out our Code of Conduct.






        Windshear is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
        Check out our Code of Conduct.















            protected by Federico 4 hours ago



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