Why is it so?

[scarps]

Thought it might be interesting to have a thread about the weird and wacky or just a conundrum and see what answers come back.

Like occasionally I have to fly from Brisbane to Perth, and the flight path goes over Adelaide. WT?
Flight path isn't straight, more like a boomerang (and no I'm not Him. I live in Melbourne)
Last week with the storm cells moving across, the flight took 6 hours (or 3 movies for any regular flyers)

I googled this question and the answer came back that it has to do with Jet Streams. Well this makes sense on the flight west to east, but not the other way.

I'm also aware that there is a flight that goes Perth to Ayres Rock to Cairns.

Anyone shed any light on this?

[briann532]

Yes I can...............

Ask any pilot and they will tell you. Its because the earth is round.

Don't believe me???
Grab a globe - most kids have should have one.
Use a piece of string to go from point to point.
You will find that the straight line formed with the string is not parallel with the "grid" lines on your map.

This is because the earth is round so when viewed in 2D it doesn't look right.
In aviation terms it does also depend on wind direction, and allowable flight paths.

Not quite as simple as A to B.

Any pilots to confirm???

Cheers
Brian

[baldheadedgit]

Yes I can...............

Ask any pilot and they will tell you. Its because the earth is round.

Don't believe me???
Grab a globe - most kids have should have one.
Use a piece of string to go from point to point.
You will find that the straight line formed with the string is not parallel with the "grid" lines on your map.

This is because the earth is round so when viewed in 2D it doesn't look right.
In aviation terms it does also depend on wind direction, and allowable flight paths.

Not quite as simple as A to B.

Any pilots to confirm???

Cheers
Brian

Don't think I quiet got that Brian,,,, can you repeat it for me...?

[dungee]

The earth is flat, well it is on my computer screen!

[markg66]

I used to fly Brisbane to Perth quite often (and back obviously) as well and asked the same question, as has been mentioned it's to do with the jet streams (or the wind speed and direction) so head wind or tail wind at certain times of the year.

I was told there is wind blowing directly from Perth to Brisbane at 250 knots and if the plane does 500 knots you are only traveling at 250 knot land speed, so fly down a bit and get out of the 250 knot headwind and while you waste a bit of time going down you pick up double the land speed when you do turn to your destination.

Made sense to me..........

Cheers
Mark

[KieranR]

I have no idea, but I fly from Brisbane to Perth all the time and this year the flights seem to be taking longer, the last two have taken 5.36 & 5.44 hrs.  Even after a couple of beers, a sleep, a movie & 4 toilet trips & we're still not there...

[scarps]

I used to fly Brisbane to Perth quite often (and back obviously) as well and asked the same question, as has been mentioned it's to do with the jet streams (or the wind speed and direction) so head wind or tail wind at certain times of the year.

I was told there is wind blowing directly from Perth to Brisbane at 250 knots and if the plane does 500 knots you are only traveling at 250 knot land speed, so fly down a bit and get out of the 250 knot headwind and while you waste a bit of time going down you pick up double the land speed when you do turn to your destination.

Made sense to me..........

Cheers
Mark

so you get 500km per hour Bris to Adl with a cross wind, then 250km per hour Adl to Perth, shorter distance with a headwind?
Kinda makes sense. But then why not fly direct Perth to Bris with a 250km tail wind? It's a conundrum.

[Garfish]

I have no idea, but I fly from Brisbane to Perth all the time and this year the flights seem to be taking longer, the last two have taken 5.36 & 5.44 hrs.  Even after a couple of beers, a sleep, a movie & 4 toilet trips & we're still not there...

I heard that some of the airlines are flying slow to save fuel

[scarps]

I have no idea, but I fly from Brisbane to Perth all the time and this year the flights seem to be taking longer, the last two have taken 5.36 & 5.44 hrs.  Even after a couple of beers, a sleep, a movie & 4 toilet trips & we're still not there...

feeling your pain. I fly Melb to Syd to Bris every week and become pretty much comatose to that. Only have to do the Perth trip 4, maybe 5 times per year and that's enough for me.

[KieranR]

Comatose.........I'm like that on the way home, I have four hours from when I land in Perth from work before I get the red eye back to Qld, Qantas club gets me right royally sloshed in that time, get my arse on the plane and pass out until I land in Brisbane!   

[TOPNDR]

The most direct airway/s between Brisbane & Perth route via Brisbane, Amberley, Leigh Creek, Kalgoorlie, Perth; some 1986 nm (3678 km).

To track via Adelaide the distance changes to approximately 2027 nm (3754 km) a difference of only 76 km, or just on 2%.

The prevailing upper level winds in Australia flow from west to east, at varying strengths (speed) and direction, depending on the seasons and weather systems.  In nil wind the 76 km difference would take the average jet 6 minutes.  But depending upon where the jetstreams are, moving north or south of the most direct track can reduce the adverse affect of the usual headwind when west bound.  One would obviously sit in the jetstream when eastbound, turbulence permitting.

There is no longer a service Perth - Ayers Rock - Cairns or vice versa, it ceased almost two years ago.  Though Jet* operate a direct Cairns - Perth return nightly, though there are rumours that this might not be for much longer.

[scarps]

The most direct airway/s between Brisbane & Perth route via Brisbane, Amberley, Leigh Creek, Kalgoorlie, Perth; some 1986 nm (3678 km).

To track via Adelaide the distance changes to approximately 2027 nm (3754 km) a difference of only 76 km, or just on 2%.

The prevailing upper level winds in Australia flow from west to east, at varying strengths (speed) and direction, depending on the seasons and weather systems.  In nil wind the 76 km difference would take the average jet 6 minutes.  But depending upon where the jetstreams are, moving north or south of the most direct track can reduce the adverse affect of the usual headwind when west bound.  One would obviously sit in the jetstream when eastbound, turbulence permitting.

There is no longer a service Perth - Ayers Rock - Cairns or vice versa, it ceased almost two years ago.  Though Jet* operate a direct Cairns - Perth return nightly, though there are rumours that this might not be for much longer.

well there you go.  Makes sense, thx.

Next conundrum?

[chester ver2.0]

I heard that some of the airlines are flying slow to save fuel

They are slowing down becuae of congestion at Perth Airport, as about 2/3rs of the fuel is burnt during take off and initial climb to altitude slowing down in flight would only make a marginal difference

Perth is now the busiest commercial airport in Australia when measured of number of landings per runway per hour