Varför vände planen? (Wy did the trafficplanes turn 180 degrees?)

[Nicke Nyfiken]

Excuse my use of the Swedish language, but I´m no good in English (maibye someone can help with translation, so there will be a broader select of answers....)


Strax före 11.00 i dag (04-20) såg jag ett trafikplan som kom från väster (över nordvästra Sörmland, Sverige), vilket gick in i en ganska tvär högersväng, som slutade då planet svängt 180 grader, varefter det fortsatte (på kontrakurs). Inom ~10 minuter upprepades samma manöver (ett med vänstersväng) av minst ytterligare två plan. Samtliga vände åter västerut!?

Vart var de på väg? Vilken info fick dem att vända? Vart gick de istället för tänkt mål?

- Blev ganska ovanliga kondensstrimmor....

[Nicke Nyfiken]

Tack för hjälpen, utmärkt svenska! Tanks for help with translation! Now we are two waiting for answers.

[Albin]

It would have been easier for us to help if you maybe remember the callsign of the flights or something. It's hard to say from that information I'd say.

//

Enklare för oss att hjälpa om du kommer ihåg callsign eller dylikt, ganska svårt att säga nu.

[venger81]

hello,

there are a lot of reason for a plane to make an 180 deg. turn, the most frequent causes are :
approaching / deparing procedures.

-during approach procedure the plane may fly low and parallel to the runway and then make a sharp 180 turn and land.

-after a take-off the plan may take an 180 turn and continue climbing parallel with the runway

Some times planes make 180deg. turns or multiple "s" turns in order to lose speed or altitude in an short distance. for example if a plane wants to land but the plane is very close to the airport and it is flying too high or/and too fast, it may go past the airport and then make an 180 turn in order to have enough time to lose speed/altitude.

Some times it depends by the weather, usually the landings are made with the wind coming from the front, so if are coming from the same direction with the wind and want to land you will go past the airport an then make the 180deg turn and land.
Here is a an example of approach at the Stockholm-Arlanda Airport..

i hope my answer helps you.

[Nicke Nyfiken]

Sorry, but I wasn´t by the computer ang I just saw them visually in the sky - the reason to my questions (found this site later).

[Nicke Nyfiken]

I have during a long time (years) seen commercial airliner passing this place, but never manouvres like today. The place is far away from any airport, so it can not be any procedurs linked vith start/landing.
I think that it has connektion with the problem from vulkaic asch (?). At the time Stockholm-Arlanda Airport (~150 - 200 km VSV from the observation) was open, and I heard that Stockholm-Skavsta opened att 11.00.

[venger81]

how high was the plane? maybe they tried to avoid the ash cloud, or they were on hold procedure, because the airport wasn't open yet, or because of traffic..
http://en.wikipedia.org/wiki/Holding_(aviation)
cant tell for sure..

[Nicke Nyfiken]

Normal flight high, as I could see with my eyes (absolute not lower than normal when passing this area)

[Parvelito]

There have been some strange manovers today since airplans passing southern Sweden only was allowed to do it 11.000 meters up in the sky, or higher. The line was first going in Skavsta, later on Norrköping. If the destination is Arlanda, you must do this turns to came down before you land. Usually the airplanes are sinking from 11.000 meters to 0m in a distance of 250-300km. With this ash they only have 100-125km to came down if they don´t try to do some circles. It is possible to sink very fast, but the passengers will feel very ill.