why do airliners take a strange route when taking off instead of just going in a straigt line ?

Question

On the Hong Kong approach take off chart, I read once the aircraft takes off, it flies round in a rectangle whilst ascending then to its assigned altitude and direction and this is for all aircrafts. Any suggestions ?

Answer 1

Airliners fly Instrument Flight rules and often file for a specific Departure Procedure to get them to the route they want to fly to the destination. Looking at KATL (Atlanta, Ga) BRAVS THREE (RNAV)
Departure, the track actually looks like a heart!

To see the graphic depiction see:http://www.airnav.com/depart?http://204.108.4.16/d-tpp/0610/00026BRAVS.PDF

Here is the written description of the proceedures:
(BRAVS3.BRAVS)
(RNAV)
(BRAVS3.BRAVS)
(RNAV)
WALET TRANSITION (BRAVS3.WALET)
DEPARTURE ROUTE DESCRIPTION
06103
06103
T
ATLANTA/ HARTSFIELD - JACKSON ATLANTA INTL (ATL)
ATLANTA, GEORGIA
HARTSFIELD - JACKSON ATLANTA INTL
SL-26 (FAA)
ATLANTA/ (ATL)
ATLANTA, GEORGIA BRAVS THREE DEPARTURE
BRAVS THREE DEPARTURE
NOTE: Rwy 8L: Multiple trees beginning 996’ from DER, 533’ left of centerline, up to 58’
AGL/1048’ MSL. Bldg 2762’ from DER, 1062’ left of centerline, 72’ AGL/1068’ MSL.
NOTE: Rwy 8R: Antenna on tower 4816’ from DER, 1637’ right of centerline, 153’ AGL/1148’
MSL. Tower 4804’ from DER, 1666’ right of centerline, 148’ AGL/1145’ MSL. Stack on
Bldg 1734’ from DER, 945’ left of centerline, 47’ AGL/1043’ MSL. Tree 1028’ from DER,
419’ left of centerline, 25’ AGL/1021’ MSL.
NOTE: Rwy 9L: Rod on pole 5306’ from DER, 1731’ left of centerline, 187’ AGL/1137’ MSL.
Bush 101’ from DER, 453’ left of centerline, 3’ AGL/981’ MSL.
NOTE: Rwy 26L: Tree 1370’ from DER, 186’ left of centerline, 53’ AGL/1060’ MSL. Tree 2832’
from DER, 564’ left of centerline, 50’ AGL/1097’ MSL. Rod on Bldg 1249’ from DER,
752’ left of centerline, 52’ AGL/1059’ MSL. Bldg 1138’ from DER, 636’ left of
centerline, 43’ AGL/1057’ MSL.
NOTE: Rwy 26R: Multiple trees beginning 1786’ from DER, 110’ right of centerline, up to 83’
AGL 1135’ MSL. Multiple trees beginning 1988’ from DER, 143’ left of centerline, up
to 100’ AGL 1112’ MSL. Pole 3196’ from DER, 997’ right of centerline, 49’ AGL/1101’
MSL. Antenna on tower 3382’ from DER, 1024’ right of centerline, 76’ AGL/1128’ MSL.
Antenna 3857’ from DER 1069’ right of centerline, 69’ AGL/1121’MSL.
NOTE: Rwy 27L: Hopper 3936’ from DER, 1255’ right of centerline, 96’ AGL/1131’ MSL.
NOTE: Rwy 27R: Tree 4396’ from DER, 1005’ right of centerline, 92’ AGL/1137’ MSL. Antenna
on hopper 3568’ from DER, 862’ right of centerline, 68’ AGL/1113’ MSL. Light pole
1012’ from DER, 729’ right of centerline, 28’ AGL/1046’ MSL. Multiple hoppers
beginning 3680’ from DER, 201’ right of centerline up to 96’ AGL/1131’ MSL.
NOTE: Rwy 10: Tower 4223’ from DER, 400’ left of centerline, 216’ AGL/1135’ MSL. Antenna
on tower 4240’ from DER, 407’ left of centerline, 217’ AGL/1134’ MSL. Pole 59’ from
DER, 467’ right of centerline, 51’ AGL/1016’ MSL. Pole 198’ from DER, 520’ right of
centerline, 43’ AGL/1011’ MSL.
NOTE: Rwy 28: Catenary 2001’ from DER, 771’ left of centerline, 60’ AGL/1051’ MSL.
TAKE-OFF RWY 8L: Climb heading 092^ heading to at or above 1500, then on 072^
course to HRSHL, then via depicted route to BRAVS, thence....
TAKE-OFF RWY 8R: Climb heading 092^ to at or above 1500, then on 070^ course
to HRSHL, then via depicted route to BRAVS, thence....
TAKE-OFF RWY 9L: Climb heading 092^ to 1480 then on 111^ course to CUBAL, then
via depicted route to BRAVS, maintain 250 KIAS until NOFOR, thence....
TAKE-OFF RWY 9R: Climb heading 092^ to 1500, then on 108^ course to CUBAL, then
via depicted route to BRAVS, maintain 250 KIAS until NOFOR thence....
TAKE-OFF RWY 26L: Climb heading 272^ to at or above 1540, then on 279^ course
to SNUFY, then via depicted route to BRAVS, thence....
TAKE-OFF RWY 26R: Climb heading 272^ to at or above 1520, then on 278^ course
to SNUFY, then via depicted route to BRAVS, thence....
TAKE-OFF RWY 27L: Climb heading 272^ to at or above 1540, then on 248^ course
to FUTBL, then via depicted route to BRAVS, maintain 250 KIAS until ZALLE, thence....
TAKE-OFF RWY 27R: Climb heading 272^ to at or above 1520, then on 247^ course
to FUTBL, then via depicted route to BRAVS, maintain 250 KIAS until ZALLE, thence....
TAKE-OFF RWY 10: Climb on assigned heading for radar vectors to BRAVS, thence....
TAKE-OFF RWY 28: Climb on assigned heading for radar vectors to BRAVS, thence....
....Maintain 10,000 (or requested altitude, if lower), expect clearance to filed altitude
ten minutes after departure.
SE-4, 28 SEP 2006 to 26 OCT 2006
SE-4, 28 SEP 2006 to 26 OCT 2006

Answer 2

Aircraft have arrival and departure procedures they must follow.
They fly on "invisible highways".
These routes are predetermined so that incoming and exiting aircraft do not cross paths.
As an example, they will fly a rectangular climbing pattern, and when they reach a predetermined altitude will head out on the vector that has been chosen by air traffic control.
The routes take a lot of care for the aircraft separation in flight.
If they did not plan ahead there would be a lot of kaos in and around the airport.
It is a very complex and strictly adhered to rules of Instrument Flight Rules. IFR for short.

Answer 3

Let me put it this way. If you were driving across town you can’t just drive straight across, you would need to take different roads. Well pilots have a system of “roads” they take as well.
The main “roads” they take are called low altitude airways and high altitude airways, which are highways of the sky. There are also several navigation aids pilots use, the most common is VOR or very high frequency ominidirectioal radio range. In a nutshell it helps pilots navigate. So here is a situation. A pilot will take off and fly to a VOR, once it gets there he will turn to a airway or “highway” Depending on the route there may be several different highways the pilot will take. If pilot was flying from Chicago to Omaha and he can’t just head towards Omaha, if all planes did that it would be too confusing. So air traffic control can use these airways to control all the planes and know where they are. It keeps it flowing and reduces collisions. Air traffic control also uses systems like SIDS and STARS, standard departure and standard arrival route respectively. So on takeoff and landing planes can follow these routes to either land or to airways and it keeps it organized and reduces traffic. So just think of it like driving.

Answer 4

Airliners Take off direction is dependant on the wind direction. For the cheapest and quickest take off an aircraft must fly in to wind.

Once airbourne they are directed by air traffic control. What may seem a strange route will be intentional to ensure the sircraft has the safest route to its main flight path

Answer 5

don't know about HKG but it's usually connected with which way the wind's blowing, planes take off into the wind for a lower ground speed for take-off, the tower control will instruct pilot as to which runway to use and the route will have been entered into the plane's on-board computer already. some manoeuvers are pre-programmed to avoid built-up areas and obstacles or just other aircraft on approach. That good enough?

Answer 6

Guess 7862 isn't John Pugh by any chance? Famed Rugby Player for Chinnor RFC and Virgin Atlantic Senior Pilot for the South East Asian Routes. Kaitak eat your heart out, it's to easy now to land at the new Hong Kong Airport. Any way, everything he said is right.

Answer 7

well the answer is simple it is like why do we have a certain side of the road to drive on because of on coming traffic each aircraft has a designated flightpath to keep from crowding aerospace at any one time as the busier the sky gets it becomes more important for these flight paths to be layed , and as aeroplanes travel much faster than cars it dont take long for one plane to get close to another so each journey has to be planned specifically .. tried lamens terms but oops sorry

Answer 8

This is done for a number of reasons. Among them is noise "abatement", - keeping the noise away from"sensitive areas", traffic control, - to keep airplanes from all flying within the same area, -- or crossing through the same area all at one time,-
(so they don't collide), and also to allow the aircraft to get to a reasonable "cruising altitude" before it crosses over highly populated areas! Obviously you don't want one to "fall down" within the congested area of big cities, - should something catastrophic happen,- and the plane can't stay in the air to reach safety! And within your specified area it may also be to keep military aircraft and civilian aircraft from coming together, -( and then of course you want to make sure China doesn't think they are being invaded, and get a "rocket" through your wing!)

Answer 9

i think it has a lot to do wih SID ( standard instrument deopartures) and STARS standard arrival routes, basically aircraft have to join airways at certain heights and headings and this may require aircraft to make turns soon after takeoff or before landing. Noise abatement regulations also play a hand in routing

Answer 10

Many of these SIDs (Standard Intrument Departures) are designed to coordinate traffic out of busy airports. Special procedures are used for different reasons which could be to avoid conflict with inbound approaches, for noise abatement over residential areas, and to ensure obstacle clearance from radio towers or terrain such as mountains.

Answer 11

It's due local departure procedures.

The pilot - if cleared for 'standard departure' will follow a prescribed pattern in the air.

This ensures that everbody knows who is going where.

Same for approach - they refer to what are known as 'approach plates' - diagrams and routing information -which gives all the info for a safe approach and landing.