Ulic Posted April 26, 2014 Share Posted April 26, 2014 Jetstream headwinds. Link to comment Share on other sites More sharing options...
lumply Posted April 26, 2014 Share Posted April 26, 2014 The answer are high level winds in the atmosphere that move faster at altitude because of fewer air molecules and therefore resistance. These jetstreams are largely predictable depending on the seasons and if the aircraft is flying in the N/S hemispheres. They will always exist at varying altitudes/Flight levels and invariably the headwind and tailwind components are known to the Pilot who will be checking the Met. Info at the forecasting station before the flight in order to choose the quickest and most economical (to the airline) flight level at which to fly. Delays near to the terminal area due to traffic can also be largely predicted and a flight may have to 'lose time' by going into a holding pattern or 'racetrack' hold, or indeed requested to slow down to allow approaching aircraft ahead of it to approach the airfield in turn. Going on from this the ATC Approach Controller or 'Radar' would need to ensure adequate separation between aircraft, normally 6 nm, before handing over to 'Approach'. This requires a lot of skill by the handling officer not least because aircraft speeds vary. There may also be wake turbulence to take into consideration. The whole scenario can be upset if a pilot declare an emergency due to a low fuel state in which case that flight will be given priority to land.....that's for another time perhaps! 1 Link to comment Share on other sites More sharing options...
nonthaburial Posted April 26, 2014 Share Posted April 26, 2014 Can I add my two sating hopefully more intelligent than Samrans. Yes jet stream is a huge factor, but also take Into account both outbound and inbound legs cannot be flown in the same jet lane, therefore one of the routes, and I would suggest east to west have to take a longer route, adding extra flying time, also airlines do not like to appear to be constantly late, so their flight times are always advertised as being longer that they really are. Example a very recent flight from Xian to Shenzhen was advertised as a 2.40 hour flight, we pushed back on time, had not holds on taxi way and actually took off smack on time, to arrive in Shenzhen after 2 hours. Now that is on a short leg, can you imagine what the airlines add on for a flight six times that long. Link to comment Share on other sites More sharing options...
lucifer666 Posted April 26, 2014 Share Posted April 26, 2014 Seeing as were 7 hours in front of the UK ( time zone wise). Why can't a plane just hover for 7 hours and wait for the world to spin round ?? Link to comment Share on other sites More sharing options...
nopmypomplem Posted April 26, 2014 Share Posted April 26, 2014 Headwind also possible holding pattern trying to get clearance to land. Link to comment Share on other sites More sharing options...
Andre0720 Posted April 26, 2014 Share Posted April 26, 2014 Tell her she is right... Will lead to a good night's sleep... Link to comment Share on other sites More sharing options...
khunPer Posted April 26, 2014 Share Posted April 26, 2014 Both headwind (or tailwind on the way out) and Earth spin. You will be flying some part en route in the so-called Western Wind corridor (a Jet stream), which may give you tail wind outbound (to BKK) and head wind homebound (to LON). Earth spin counts for some 30 minutes, most airlines calculate that into their timetables. Link to comment Share on other sites More sharing options...
KonKorat Posted April 26, 2014 Share Posted April 26, 2014 Maybe the plane was flying up hill,or caught a few red lights along the way,maybe was stuck in peak hour traffic , Link to comment Share on other sites More sharing options...
KonKorat Posted April 26, 2014 Share Posted April 26, 2014 Maybe the pilot was having a bit of a bludge and was pushing for overtime Link to comment Share on other sites More sharing options...
larsjohnsson Posted April 26, 2014 Share Posted April 26, 2014 When I fly from Denmark or Sweden it's about 50 minutes longer to go back home. And it's the wind. I would guess it's normally 1 hours difference to UK Link to comment Share on other sites More sharing options...
kovaltech Posted April 26, 2014 Share Posted April 26, 2014 Actually both, wind and indirectly rotation. Can you please tell me what factors cause airplane times to differ between travels to east and to west. It's interesting that you ask this - I am directly experiencing it right now as I sit on an airplane from the UK. It took 5 hours to go West-East on this journey, but is taking about 7 East-West. The reason for the difference is a atmospheric phenomena known as the jet stream. The jet stream is a very high altitude wind which always blows from the West to the East across the Atlantic. The planes moving at a constant air speed thus go faster in the West-East direction when they are moving with the wind than in the opposite direction. Every planet has global wind which are mostly determined by the way the planet rotates and how evenly the Sun illuminates it. On the Earth the equator gets much more Sun than the poles. resulting in warmer air at the equator than the poles and creating circulation cells (or "Hadley Cells") which consist of warm air rising over the equator and then moving North and South from it and back round. The Earth is also rotating. When any solid body rotates, bits of it that are nearer its axis move slower than those which are further away. As you move north (or south) from the equator, you are moving closer to the axis of the Earth and so the air which started at the equator and moved north (or south) will be moving faster than the ground it is over (it has the rotation speed of the ground at the equator, not the ground which is is now over). This results in winds which always move from the west to the east in the mid latitudes. One source here - Cornell university "Every planet has global wind which are mostly determined by the way the planet rotates and how evenly the Sun illuminates it. " i love this... People have been on other planets .... and there was wind..... 1 Link to comment Share on other sites More sharing options...
HerbalEd Posted April 26, 2014 Share Posted April 26, 2014 Assuming the same plane speed in both directions, it's the headwinds. However, the earth's rotation is a factor also, albeit a slight one. The earth's counterclockwise (west-to-east) rotation will actually get you to London faster ... but again, only slightly so. Link to comment Share on other sites More sharing options...
Sheryl Posted April 26, 2014 Share Posted April 26, 2014 Ever seen the Xfiles? Link to comment Share on other sites More sharing options...
blazes Posted April 26, 2014 Share Posted April 26, 2014 Nothing to do with jetstream. He was on Air Asia on the longer flight. Simple. Link to comment Share on other sites More sharing options...
dutchman Posted April 26, 2014 Share Posted April 26, 2014 when i fly to the netherlands it take also more time They fly now with 777 instead 747 Also they fly lower speed to save kerosin that is what i thin k Link to comment Share on other sites More sharing options...
Thongkorn Posted April 26, 2014 Share Posted April 26, 2014 (edited) Was it the day the UK put there clocks back, and your actual journey only took one hour longer. Edited April 26, 2014 by Thongkorn Link to comment Share on other sites More sharing options...
wandasloan Posted April 26, 2014 Share Posted April 26, 2014 You are flying uphill on the way back, on the way here its downhill. Common error. In fact, it's because Thailand sucks. . Link to comment Share on other sites More sharing options...
smokie36 Posted April 26, 2014 Share Posted April 26, 2014 After all the Dom Perignon I can't remember where I am.... Link to comment Share on other sites More sharing options...
Oxpilot Posted April 26, 2014 Share Posted April 26, 2014 <script type='text/javascript'>window.mod_pagespeed_start = Number(new Date());</script> Pilots are always in a hurry to get to Soi Cowboy. Not so much of a hurry to get anywhere in London- especially back to the wife.... There is truth in what you say. Mach .85 going to BKK and .78 going home was my norm. But, it is primarily the prevailing southwest to northeast winds. A second consideration is altitude, since winds vary with altitude as well as geo position. The route will usually be different, longer or shorter in terms of route miles and finally the type of aircraft used and the airline flown can influence time flown. Some aircraft perform better at higher mach speeds and some at lower. For the airlines, in most cases a lower mach speed around .75 may save fuel while other airlines are worried about curfews at the arrival airport and will adjust the speed to make it in before the curfew. And then there are ATC delays you may not have been made aware. But you got there so all went well. Link to comment Share on other sites More sharing options...
Tywais Posted April 26, 2014 Share Posted April 26, 2014 Actually both, wind and indirectly rotation. Can you please tell me what factors cause airplane times to differ between travels to east and to west. It's interesting that you ask this - I am directly experiencing it right now as I sit on an airplane from the UK. It took 5 hours to go West-East on this journey, but is taking about 7 East-West. The reason for the difference is a atmospheric phenomena known as the jet stream. The jet stream is a very high altitude wind which always blows from the West to the East across the Atlantic. The planes moving at a constant air speed thus go faster in the West-East direction when they are moving with the wind than in the opposite direction. Every planet has global wind which are mostly determined by the way the planet rotates and how evenly the Sun illuminates it. On the Earth the equator gets much more Sun than the poles. resulting in warmer air at the equator than the poles and creating circulation cells (or "Hadley Cells") which consist of warm air rising over the equator and then moving North and South from it and back round. The Earth is also rotating. When any solid body rotates, bits of it that are nearer its axis move slower than those which are further away. As you move north (or south) from the equator, you are moving closer to the axis of the Earth and so the air which started at the equator and moved north (or south) will be moving faster than the ground it is over (it has the rotation speed of the ground at the equator, not the ground which is is now over). This results in winds which always move from the west to the east in the mid latitudes. One source here - Cornell university "Every planet has global wind which are mostly determined by the way the planet rotates and how evenly the Sun illuminates it. " i love this... People have been on other planets .... and there was wind..... Hmm, it's called physics and remote observation - look up Mars for example Link to comment Share on other sites More sharing options...
mdmayes Posted April 26, 2014 Share Posted April 26, 2014 Headwinds Link to comment Share on other sites More sharing options...
NevNic Posted April 26, 2014 Share Posted April 26, 2014 I just flew back to UK last week via BA10. Flight was one and a half hours over schedule. Reasons given by pilot: - headwinds - more northerly route than normal so as not to overfly Ukraine. Link to comment Share on other sites More sharing options...
rakman Posted April 26, 2014 Share Posted April 26, 2014 wow been a long time since i ever sat on such a long flight. My flight to the US took like 23 hours with a stop over in europe, denmark i think. If going to the US east coast from bkk via europe, you took the long way. Link to comment Share on other sites More sharing options...
kovaltech Posted April 26, 2014 Share Posted April 26, 2014 Actually both, wind and indirectly rotation. Can you please tell me what factors cause airplane times to differ between travels to east and to west. It's interesting that you ask this - I am directly experiencing it right now as I sit on an airplane from the UK. It took 5 hours to go West-East on this journey, but is taking about 7 East-West. The reason for the difference is a atmospheric phenomena known as the jet stream. The jet stream is a very high altitude wind which always blows from the West to the East across the Atlantic. The planes moving at a constant air speed thus go faster in the West-East direction when they are moving with the wind than in the opposite direction. Every planet has global wind which are mostly determined by the way the planet rotates and how evenly the Sun illuminates it. On the Earth the equator gets much more Sun than the poles. resulting in warmer air at the equator than the poles and creating circulation cells (or "Hadley Cells") which consist of warm air rising over the equator and then moving North and South from it and back round. The Earth is also rotating. When any solid body rotates, bits of it that are nearer its axis move slower than those which are further away. As you move north (or south) from the equator, you are moving closer to the axis of the Earth and so the air which started at the equator and moved north (or south) will be moving faster than the ground it is over (it has the rotation speed of the ground at the equator, not the ground which is is now over). This results in winds which always move from the west to the east in the mid latitudes. One source here - Cornell university "Every planet has global wind which are mostly determined by the way the planet rotates and how evenly the Sun illuminates it. " i love this... People have been on other planets .... and there was wind..... Hmm, it's called physics and remote observation - look up Mars for example Mars is mars, not "every planet" if there is no athmosphere, then what ? To topic, pilots follow the jetstream if possible, they avoid it if it goes in the opposite direction Time difference also with winter and summer time if applicable... even sometimes they are not allowed to fly faster then the local authority's are allowing them. ( air traffic control ) Link to comment Share on other sites More sharing options...
Maroon Watcher Posted April 26, 2014 Share Posted April 26, 2014 ... from memory. It's 10 hours from UK to Miami. I once made it back in 7.5 The Captain said it was "Positive Gulf stream winds" Head winds and tail winds can have an effect Link to comment Share on other sites More sharing options...
masuk Posted April 26, 2014 Share Posted April 26, 2014 The earth is spinning You're getting close! The spinning causes strong winds in one direction. The flight from Eastern Australia to Perth in the west can vary by an hour, depending on the head winds and the route the pilot has to take. I once travelled with a strong tail wind and the ground speed was over 1100km per hour. Arrived 45 minutes early and the connecting flight was still a couple of hours away. Link to comment Share on other sites More sharing options...
Sandman77 Posted April 26, 2014 Share Posted April 26, 2014 My last flight from eu to here was one our shorter so it's called jet stream Link to comment Share on other sites More sharing options...
F4UCorsair Posted April 26, 2014 Share Posted April 26, 2014 Upper level winds tend westerly. Say the wind out was 50 knots westerly increasing ground speed, it's 50 knots on the nose going back, so that's 100 knots different. 100 knots for 10 hours = 1000 miles, about 2 hours flying. Link to comment Share on other sites More sharing options...
pigeonjake Posted April 26, 2014 Share Posted April 26, 2014 as long as its still quicker coming home im not botherd, i fly at 2,45pm yehhhhhhhhhh,, Link to comment Share on other sites More sharing options...
simon43 Posted April 27, 2014 Share Posted April 27, 2014 If it was the BA/Qantas flight that flies direct from BKK to Heathrow, and leaves BKK around 11pm, the simple answer for the delay is that Heathrow is not open 24/7 (noise resrictions), and so that overnight flight flies more slowly so as to avoid arriving at Heathrow before the restriction is lifted early morning time. Link to comment Share on other sites More sharing options...
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