QantasA332 From Australia, joined Dec 2003, 1500 posts, RR: 50 Reply 3, posted (5 years 8 months 2 weeks 5 days 4 hours ago) and read 7033 times:
Wake turbulence is, as Ua935 stated, a disruption of air behind any (not just "heavy") aircraft. It comprises wingtip vortices primarily, and various other disturbances and eddies. The recent AA A300 crash was due in part by the wake of the previously departing aircraft, and I'm sure there have been many other instances of crashes caused by wake turbulence.
Cheers,
QantasA332
EDIT: your last reply got in just after I posted mine... "Air pockets" are unrelated to wake turbulence -- they are simply strong vertical updrafts/wind gusts.
EK413 From Maldives, joined Nov 2003, 1536 posts, RR: 1 Reply 4, posted (5 years 8 months 2 weeks 5 days 4 hours ago) and read 7001 times:
Just curious if Wake Turbulance when at cruising altitude is due to a aircraft traveling along the same channel OR is it due to cross wind?(I love the feeling of Turbulance)
WhiteEaglePL From Poland, joined Mar 2004, 44 posts, RR: 0 Reply 5, posted (5 years 8 months 2 weeks 5 days 4 hours ago) and read 6967 times:
Yeah I wondered about the same thing. By the way what can happen if a plane will cross the smoke of another airplane which traveled the same route ? Sorry for the simple way of saying it but I'm not a professional in this kind on stuff.
Starlionblue From Greenland, joined Feb 2004, 13598 posts, RR: 68 Reply 6, posted (5 years 8 months 2 weeks 5 days 3 hours ago) and read 6916 times:
Experiencing wake turbulence at cruise altitude is becoming more commmon due to GPS making aircraft follow each other so precicely. However, due to the large distances between aircraft, it's no big deal. Wake vortices tend to slowly sink towards the ground.
As for smoke, I'm assuming you mean contrails (the white condensation trail). This tends to indicate the wake, so you might get a little wake turbulence if you crossed the contrail of another aircraft. But it will be much less intense than wind gusts/clear air turbulence.
[Edited 2004-03-27 11:50:16]
Tact Is For People Who Aren't Witty Enough To Be Sarcastic
EK413 From Maldives, joined Nov 2003, 1536 posts, RR: 1 Reply 8, posted (5 years 8 months 2 weeks 5 days 3 hours ago) and read 6876 times:
Starlionblue
Experiencing wake turbulence at cruise altitude is becoming more common due to GPS making aircraft follow each other so precisely. However, due to the large distances between aircraft, it's no big deal. Wake vortices tend to slowly sink towards the ground.
As for smoke, I'm assuming you mean contrails (the white condensation trail). This tends to indicate the wake, so you might get a little wake turbulence if you crossed the contrail of another aircraft. But it will be much less intense than wind gusts/clear air turbulence.
That would explain why they usually climb OR descend during turbulence....Very interesting.
Vikkyvik From United States, joined Jul 2003, 3813 posts, RR: 26 Reply 11, posted (5 years 8 months 2 weeks 5 days 3 hours ago) and read 6831 times:
I am curious....the few times I've been waterskiing/tubing, the calmest part of the water surface has been directly aft of the boat (in the wake), whereas the roughest part has been outside of that area, where the waves caused by the boat are spreading. I was curious to know if the wake of an airplane is at all related to this phenomenon, as it seems the wake directly aft of an airplane is not where you want to be.
Responses appreciated.
~Vik
The spirit of Massachusetts is the spirit of America!
Mconway From , joined Dec 1969, posts, RR: Reply 13, posted (5 years 8 months 2 weeks 5 days 2 hours ago) and read 6817 times:
In Atlantic oceanic airspace, aircraft are permitted a deviation of 2 NM either side of track to avoid wake turbulence. Such deviations do not require ATC clearance, and it is enough for an airliner to tell you he is deviating 2 NM for wake turbulence and that is all that is required. This "policy" has been in effect for two or three years now and aircraft do it all the time. I guess it's not a big deal when the lateral separation between tracks is 60 NM.
Regards.
On a side note if memory serves me correctly, a B757 which is classified as a medium aircraft due to weight, is classified as a heavy for wake turbulence advisories. Normally ATC/FSS would not give a "possible wake turbulence" advisory for one medium aircraft departing or arriving after another medium aircraft but I believe a few years back a medium bizjet was flipped upside down and crashed while arriving after a 757 departure. Hence the reason B757's are classified as heavies for such advisories.
Redtailmsp From United States, joined Feb 2004, 204 posts, RR: 6 Reply 16, posted (5 years 8 months 2 weeks 5 days ago) and read 6714 times:
Flying across the Atlantic, now that it is RVSM airspace, there is now only 1000ft separation between aircraft on the NAT tracks - which means that aircraft flying in one direction can fly 1000ft below another aircraft and can theoretically fly all the way across right beneath another aircraft. If you are 1000ft beneath and behind another aircraft, your aircraft is very susceptible to wake turbulence - which can be very uncomfortable. So typically, crews of the lower aircraft will fly offset a little upwind of the aircraft ahead. As MConway states, given the allowed deviation of 2nm and the 60nm lateral separation of the parallel tracks, this is usually not a safety issue at all. Incidentally, there have been times when there has been considerable turbulence across the Atlantic resulting in RVSM being cancelled and reverting back to the previous 2000ft separation (for example, FL330/350/370 versus FL320/330/340/350/360/370/380) . Doesn't happen very often thankfully.
WhiteEaglePL From Poland, joined Mar 2004, 44 posts, RR: 0 Reply 18, posted (5 years 8 months 2 weeks 4 days 20 hours ago) and read 6572 times:
Can you guys tell me what's the possibility that we will follow another airplane on the way to MUC from LAX ? Perhaps you have a tracking route or something to get a clue because I know there's lots of flights overseas every day.
HAJ_OW From Germany, joined Nov 2001, 113 posts, RR: 0 Reply 19, posted (5 years 8 months 2 weeks 4 days 18 hours ago) and read 6526 times:
Hello all,
it seems to me that some things got mixed up. You are talking about some comlete differend issues.
If the rockies are the most turbuilent area that has nothing to do with wake tubulence. That's simply a matter of winds flowing over the mountain ranges causing turbulence sometimes up to 40000 ft. This phenomen could be experienced above all riidges which run parallel to each other. This is called mountain waves.
Wake tubulence is an issue mostly during take offs and landings. This turbulence is caused by the differend pressures under and over the wing (these differedn pressures make the planes fly). During cruise flight planes also cause wake turbulence but that's no risk.
During take off and landing the planes fly at a high angle off attac which causes the haviest turbuleces. And they only fly with little ditances behind each other. Therefore they pose a risk. Usually the havier a plane is the stronger the turbulence will be. Under certain metrological situations you even can hear this turbulence in the air about 15 - 30 seconds after an aproaching plane flew by.
And this turbulence had caused many serious accidents. It might happen that planes loose control if they experience the wakes of the preceeding plane. As far as I remember there were at least 2 crashes of this kind. One DC9 crashed in the wake of a preceeding DC10 in the 1970s (See the book Airdesaster Part 1) and a Learjet crashed in the wake of a 757 (thereafter the 757 was put into the heavy categorie).
Starlionblue From Greenland, joined Feb 2004, 13598 posts, RR: 68 Reply 20, posted (5 years 8 months 2 weeks 4 days 18 hours ago) and read 6488 times:
HAJ_OW, thanks for that. Yes I did not bother to really clarify that there is a big difference between weather related turbulence and wake turbulence.
As for crashes due to wake turbulence, the AA A300 crash near JFK a few years ago was at least partly due to it.
WhiteEaglePL: with LAX-MUC you will almost certainly have some other plane (most likely several) using the same track. I can't remember the exact number of transatlantic crossings per day but we're talking several hundred.
Tact Is For People Who Aren't Witty Enough To Be Sarcastic
Mconway From , joined Dec 1969, posts, RR: Reply 21, posted (5 years 8 months 2 weeks 4 days 17 hours ago) and read 6444 times:
"I can't remember the exact number of transatlantic crossings per day but we're talking several hundred."
Starlionblue, I wish there were only several hundred a day - that would make my job much easier On very busy days, we will have over 1000 aircraft cross 50W in a 24 hour period.
Coa764 From United States, joined Feb 2004, 328 posts, RR: 5 Reply 22, posted (5 years 8 months 2 weeks 4 days 17 hours ago) and read 6414 times:
You are probably experiencing Clear Air Turbulence (CAT) associated with the jet streams. The jet stream or streams (there is usually more than one) can cause both vertical and horizontal shear that will effect your flight as it passes through. Depending on conditions a flight can experience anywhere from light to severe while flying outside of mountains terrain, with no weather on clear days. While not as common over the ocean regions it is quite common over land and you will usually find it at FL300 and above.
Mountain Wave Turbulence can also get quite bumpy. As the the wind flows over the mountains it is disturbed creating eddy currents as it flows over the leeward side. Actually when the rotor clouds start to appear over the rockies they can sometimes be very defied if your looking at a visible satellite depiction. Your flight can start picking up bumps as far as 300 miles down range above FL400.
Please oh please Mr Moderator Nazi, dont delete my thread.
WhiteEaglePL From Poland, joined Mar 2004, 44 posts, RR: 0 Reply 23, posted (5 years 8 months 2 weeks 4 days 14 hours ago) and read 6294 times:
Do you encounter turbulence above oceans like above mountains ? Or if you fly over seas then then the clouds and air is diffrent and the flight is smoother ?
HaveBlue From United States, joined Jan 2004, 1450 posts, RR: 1 Reply 24, posted (5 years 8 months 2 weeks 4 days 14 hours ago) and read 6263 times:
Wake turbulence is worse when a large, heavy aircraft is slow and at a high angle of attack. So, take off and landing is a much more hazardous area to encounter them than at altitude at cruise speed. Think of that 800,000 lb 747 'mushing' thru the air slow and nose up.
When I was a kid we were on an Easter DC-9 from MCO to ATL. On approach to ATL we did a very quick and abrupt snap roll to the right (seemed like 90 degrees but probably much less) and than back to the left again. My father, being a pilot as well, told me it was probably wake turbulence which snapped us to the right, and the pilots quickly correcting to the left. Upon deboarding the plane, we stopped and talked with the pilots. They said we did indeed hit wake turbulence from a larger plane in front of us.
Not fun stuff.
As was pointed out, the A300 crash shortly after 9-11 was at least in part due to wake turbulence.
A 737 crash in PA in the early 90's was probably due to the weather phenominon known as a 'rotor'. It was clear air turbulence caused by the mountain.
Coa764 From United States, joined Feb 2004, 328 posts, RR: 5 Reply 25, posted (5 years 8 months 2 weeks 4 days 12 hours ago) and read 6229 times:
Yes you can pick up turbulence over the ocean usually frontal driven it can also be caused by the jet stream. Northwest has a good turbulence program and linked is an example of an US Upper Air Depiction off of their web site: http://www.nwa.com/weather/domdep.gif
You can see how they have outlined the areas of forcasted turbulence (note the mountain wave areas over the rockies).
Low Level Windshear (LLWS) could have been another reason for that roll into ATL. Basically it is defined as a sudden change in wind direction and speed vertically and/or horizontally below 2000 feet.
The 737 crash in PA was US Air 427 and it wasn't due to Mountain Waves...
The National Transportation Safety Board determines the probable cause(s) of this accident as follows:
A loss of control of the airplane resulting from the movement of the rudder surface to its blowdown limit. The rudder surface most likely deflected in a direction opposite to that commanded by the pilots as a result of a jam of the main rudder power control unit servo valve secondary slide to the servo valve housing offset from its neutral position and overtravel of the primary slide. http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001206X02233&key=1
Please oh please Mr Moderator Nazi, dont delete my thread.
26 Sr71: There was a movie in a training class I was in back in the early 70's, that outlined wake turbulence with large aircraft outfitted with smoke canister
27 RareBear: The link to the site on Wake Turbulence provided by Coa764 above provides an excellent explanation of what wake turbulence is, how it forms, and how i
28 BR715-A1-30: I've been through wake turbulence before, and I will tell you, it isn't fun. If you aren't buckled in, you WILL be injured.
29 Type-rated: Thank you again HAJ_OW for clearly detailing the differences between the different turbulent conditions out there. Additionally, Wake turbulence is m
30 Phollingsworth: Quick rule of thumb: If it produces lift, it produces down wash; therefore it produces wake turbulence. If you are ever in a plane, in the air, and it
31 Hirisk: there also was a DL DC-9 that was lost in at DFW(?) during a training excercise due to wake turbulance.that one was cause by a DC-10 that was doing to
32 Coa764: Actually wasn't my opinion but just a quote form the official NTSB report. Wx might have been a contributing factor in both the USAir and UAL (over CO
33 Bragi: I was once flying in the wake of a Piper Arrow in a similar sized aircraft, and the turbulence was surprisingly strong, my aircraft banked instantly m
34 Copter808: Here's a good way to demonstrate wake turbulence... Create a source of smoke--incense or a cigarette works well. Next, hold a sheet of paper so that i
35 747srule: This is a very real thing. It happened at SNA afew years back. A 757s wake turbulence caused a smaller jet behind iy to crash.
36 B2707SST: This is wake turbulence: Now imagine a 757 weighing 100 times more going three times faster. Some other great photos, just for fun: The last photo sho
37 QantasA332: Very amazing photos, B2707SST! Wingtip vortices in action! Cheers, QantasA332
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