Basic Aeronautical Knowledge questions
Join Date: Nov 1999
Location: UK
Posts: 1,990
Originally Posted by mickjoebill
Escape velocity. I don't get it.............If there was a ladder that extended 100 miles...........
Isn't it just the distance from Earth that matters, Earth's gravity fades, why do we need to cover the distance at speed?
Mjb
Isn't it just the distance from Earth that matters, Earth's gravity fades, why do we need to cover the distance at speed?
Mjb
A rocket could fly straight up at a constant 1 mph and eventually get away from the Earth's gravity, but it would need so much fuel to do so, and more engines to lift the fuel etc., that it would not be physically possible.
Escape velocity is where the vehicle's kinetic energy equals (well, exceeds) the gravitational pull of the planet.
Join Date: Jan 2020
Location: Melbourne
Posts: 50
>The VNO was 167 Kts IAS. I never flew her
>above that IAS, because I never knew, for sure,
>when I might encounter unexpected turbulence
if the turbulence hits you at Vno, it can be too late. Have a look at Vb and Va speeds..
>Why didn’t my wings or ruddervators break off?
because all V speeds are IAS/CAS, not GS
>above that IAS, because I never knew, for sure,
>when I might encounter unexpected turbulence
if the turbulence hits you at Vno, it can be too late. Have a look at Vb and Va speeds..
>Why didn’t my wings or ruddervators break off?
because all V speeds are IAS/CAS, not GS
Last edited by Bosi72; 18th Apr 2022 at 19:16.
Thread Starter
Join Date: Mar 2000
Location: Canberra ACT Australia
Posts: 309
Only if someone decides to prosecute you on the basis that 733 minus the forecast wind equals a number greater than the VNE for the aircraft you were flying. But I reckon you'd have to be at best incompetent and at worst malicious to prosecute on that basis.
Join Date: May 2010
Location: australia
Posts: 312
Originally Posted by Clinton McKenzie
Only if someone decides to prosecute you on the basis that 733 minus the forecast wind equals a number greater than the VNE for the aircraft you were flying. But I reckon you'd have to be at best incompetent and at worst malicious to prosecute on that basis.
In that case there is no need to apply the forecast wind as the actual IAS will be known...
Thread Starter
Join Date: Mar 2000
Location: Canberra ACT Australia
Posts: 309
Originally Posted by mikewil
Didn't you just say above that ADSB transmits IAS?
In that case there is no need to apply the forecast wind as the actual IAS will be known...
In that case there is no need to apply the forecast wind as the actual IAS will be known...
The reason should be obvious: IAS is a perfectly useless piece of information to ATC and other aircraft.
Moderator
Join Date: Apr 2001
Location: various places .....
Posts: 6,848
IAS is a perfectly useless piece of information to ATC and other aircraft.
I would have thought that IAS (IMN in the FLs) was a rather useful measure for traffic separation as it is what the typical pilot has available for speed reference on the panel ?
I would have thought that IAS (IMN in the FLs) was a rather useful measure for traffic separation as it is what the typical pilot has available for speed reference on the panel ?
Thread Starter
Join Date: Mar 2000
Location: Canberra ACT Australia
Posts: 309
Separation is about predicting where aircraft will be at points in time. That's about groundspeed (and track).
I'm sure a bunch of qualified ATCers will pile on to me if I'm mistaken.
(On the weekend I watched a very graceful bird flying 'backwards'. Heading west into a stiff breeze but tracking east along a waterfront, looking for juicy morsels. Airspeed 25 kms per hour, heading 270. Groundspeed 5 kms per hour, track 090. How does knowing the bird's IAS is 25 kms per hour help avoid a collision with it?)
(PS: The bird was neither an African nor European swallow.)
I'm sure a bunch of qualified ATCers will pile on to me if I'm mistaken.
(On the weekend I watched a very graceful bird flying 'backwards'. Heading west into a stiff breeze but tracking east along a waterfront, looking for juicy morsels. Airspeed 25 kms per hour, heading 270. Groundspeed 5 kms per hour, track 090. How does knowing the bird's IAS is 25 kms per hour help avoid a collision with it?)
(PS: The bird was neither an African nor European swallow.)
Last edited by Clinton McKenzie; 20th Apr 2022 at 03:52. Reason: To add the PS.
Thread Starter
Join Date: Mar 2000
Location: Canberra ACT Australia
Posts: 309
Originally Posted by Gne
Clinton,
Get ready for the pile on. IAS based standards used to be all the rage when I was a boy controller.
Gne
Get ready for the pile on. IAS based standards used to be all the rage when I was a boy controller.
Gne
I'll don my helmet and brace!
Join Date: Oct 2002
Location: The Coal Face
Posts: 957
Originally Posted by Clinton McKenzie
(On the weekend I watched a very graceful bird flying 'backwards'. Heading west into a stiff breeze but tracking east along a waterfront, looking for juicy morsels. Airspeed 25 kms per hour, heading 270. Groundspeed 5 kms per hour, track 090. How does knowing the bird's IAS is 25 kms per hour help avoid a collision with it?)
Last edited by Chronic Snoozer; 20th Apr 2022 at 11:45.
Thread Starter
Join Date: Mar 2000
Location: Canberra ACT Australia
Posts: 309
Good point (assuming the tracks are identical). The IASs of the same aircraft on the same track at the same altitude will show that they are e.g. converging and, if so, when they will collide (if you know the distance between). So will ground speed. And ground speed will also show where they will collide.
