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Guest tallpilot

Taking off with the wind, not against

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Hiya.Watching the planes at my local airport yesterday (NZWN), with a brisk northerly and planes landing and departing from the south.Then an ATR-72 taxis to runway 16, and takes-off with the wind behind it!Can anyone tell me why an aircraft would take-off with the wind, when the accepted rule is to go against it?Given how regulated the industry is, I can't imagine for one minute it's at pilot discretion, and if the tower witnessed a pilot taxi-ing in the wrong direction, then surely a forceful reminder would be issued.ThanksAllblack

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Don't have the answer, but here is a little story from a B737/MD80 Captain that gives a pretty good explanation as to why many prefer to takeoff into the wind.(FL and FAL indicates Frontier Airlines, the "Original")."I flew both the MD-80 and the 737 and in myhumble opinion, a grossed out 737 on a hot day at DEN orABQ, using one degree improved takeoff performance,made it the real lead sled. Coming out of ABQ toDEN one hot summer afternoon in a 737, we had a DENtower controller on the jumpseat and a full house inback and below. The controller couldn't seem tounderstand why FAL sometimes insisted on using 17L at DENfor takeoff when everyone else was using 35R evenwith a light tailwind. That day the active at ABQ was08 but with a slight tailwind. I wanted 26 fortakeoff. While we were waiting at the end for 08 traffic Igot out the "whiz wheel" and computed the actualground speed at lift off. It was 206 mph and I soadvised the controller. After using most of the runwayand after we got settled down in the climb, I askedthe still wide-eyed controller if he now understoodwhy we sometimes wanted to take off into even a lightwind. He now had a whole new perspective on pilotrunway requests. He must have passed the word becausethere seemed to be alot less hassle when requestinginto the wind takeoffs at DEN on hot days."Darrell

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Bizzare.I thought taking-off into the wind was virtually mandatory i.e. you go for all the airspeed over the wings that you can get.Maybe I don't know as much about aviation as I thought I did !!!!!Allblack

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Sometimes, you do not have the option to takeoff into the wind. Here in New Mexico there are several airports that you land one direction and depart in the opposite no matter what the winds are doing. Los Alamos has such a runway. I cannot remember the runway numbers but they are basically east/west. When our company would fly in there, they had to land to the west and depart to the east "Unless" they were flying the Twin Otter. Then they were approved to depart to the west due to the STOL capability of the Otter. The reason for the strange airport arrival/departures was to keep the traffic away from the restricted airspace (Los Alamos Labs) and the rocks (mountains) to the west.I never got to fly into LAM but I have heard that you also had to watch out for power lines to the east. Terry

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I provide WAN support for my company, and one of my branches is in Los Alamos. The airport is quite interesting--and on the main drag into town, so you get a good view of it as you drive in. To the west you come on the mountains rather rapidly, and you also fly over the main core of town. To the east, there is a rather sharp drop in elevation, and other than the hazards mentioned, it is safer for those above and below. I've never had to fly into that airport, and pray I never will. But the drive itself is scary enough. During the fire, I was asked to set up a temporary LAN outside of Los Alamos (in Santa Fe), which required me to visit the office there for equipment while the town was under evacuation. The airport there looked like ORD.... As busy as any major airport... Press, fire corps, you name it..... It was like Grand Central Station!I do recall the winds were always brisk there....-JohnKPHX

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"While we were waiting at the end for 08 traffic Igot out the "whiz wheel" and computed the actualground speed at lift off. It was 206 mph and I soadvised the controller. After using most of the runwayand after we got settled down in the climb, I askedthe still wide-eyed controller if he now understoodwhy we sometimes wanted to take off into even a lightwind."Please humor the newbie; I didn't understand that. It looks like the pilot says "we have to go 206 mph so therefore we have to go with the wind" Why not "we have to go 206 mph so we'd better go into the wind"I guess I'm just not following it.

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He was waiting at the end of 26--holding short, actually, for the traffic departing on 08 to clear the area. The other traffic was using 08 with a slight tailwind, while this Captain wanted to use 26 and take advantage of the slight headwind.Darrell

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Hi Allblack,It is not manditory for an airplane to takeoff or for that matter land into the wind and it is the pilot in commands decision alone as to what direction he will takeoff or land. Most airplanes have as part of their certified limitations a maximum tail wind component that they can takeoff and land with. As a retired airline pilot and still flying my own airplane I have made takeoffs and landings with a tail wind hundreds and hundreds of times when the takeoff weight of the aircraft was light enough that the tail wind did not degrade the performance to a critical point. There are many reasons for taking off with a tail wind. Taking off away from approaching storms for instance. So it's not unsafe and it's not that unusual.Regards,Ed Weber a.k.a tallpilot

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Ahhh, what does Ed know anyway....(chuckle)Actually Ed is correct, and there is some environmental concerns as well, ie, noise abatement procedures that may dictate what the runway selection is limited to.HOWEVER (isn't there always a "However"), 99% of the time the controller, politician or who-ever is not sitting on your plane-remember it's your tail-section and if you don't have the conditions you feel comfortable with ask for a change.I recall flying right seat in a '27 into KDFW the day after the tragic L1011 windshear event. ATIS and tower called the actives in a northerly directions. My Captain just said "ask for 18 (or whatever it was)" We were still out about 40 miles. "You watch, when that cell goes over they'll have a 180 degree windshift" he said. I looked at the scope and it was not perfect weather but the guy knew DFW weather!They vector us around and I started hearing the other traffic being sent in line behind us.Another little tidbit that isn't in FS2k2 is some jets are very touchy about having strong wind up thier tailpipe during the start so most pushes if at all possible keep the wind from the tailpipe.Tim-797 (sitting in Ed's shadow)

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.......but hang on.Thinking about these busier airports, doesn't everyone have to follow the same line so take-offs and landings are all in the same direction?I mean, if you have 10 planes on approach to R36, you don't want some cowboy deciding he knows best, and barreling in to R18.These responses have been interesting, but I'm still not entirely convinced and am surprised at the inferences that the pilots can make the decision. They're not the one's sitting in some ATCC vectoring 24 planes into an approach queue....Allblack

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First of all you don't get to be an Airline Captain by being a " cowboy". The Captain as Tim pointed out has the FINAL authority for operating his flight in a safe manner and they don't take that responsibility lightly. The pilot in command of an airplane (even small private airplanes) knows more about flying his airplane than a controller (although some controllers are private pilots) and that is why the regulations give the pilot in command the emergency authority to deviate from any instruction given by ATC if he deems it unsafe from his stand point.Air traffic controllers and pilots generally have a great working relationship. When a pilot makes a request for a different runway for takeoff it is usually for a very good reason and you can be assured that he has checked the situation out and that it is safe and legal and for that reason controllers will try to clear him as requested.Many small airplanes (and feeder airlines) operate into and out of airports that don't have control towers and the pilots use a common frequency (unicom)to self control traffic. If an inbound flight reports that they want to make a downwind landing (by regulation the landing aircraft has the right of way over takeoff aircraft at non tower airports)an aircraft that is wanting to takeoff into the wind can either advise the inbound pilot that he will wait until he lands or tell him he will takeoff and stay clear of his path to landing. I hope your convinced, if not come fly with me in my Baron and I'll show you how it works. :-)Regards,Ed Weber a.k.a tallpilot

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>The pilot in command>of an airplane (even small private airplanes) knows more about>flying his airplane than a controller (although some>controllers are private pilots) OUCH! .. I'll be kind and not show that comment to the controllers I work with, some of whom have more hours that the guy in the LEFT seat (let alone the nebwie First Officer) in Lears, 737s, heavy military transports and combat helos to name a few. Quite a few controllers are pilots who got tired of the hours away from home, the BS and the lousy food. Quite a few also moonlight (legally) flying charters, instructing or running flying schools. In addition and at least in Canada, part of the basic training for ATC includes knowledge sufficient to pass the PPL written exam. Besides, we get to watch and analyse a lot of pilots demonstrating their skills (or occasional lack of same).>and that is why the regulations give the pilot in command the emergency authority to deviate from any instruction given by ATC if he deems it unsafe from his stand point.Actually the regulations permit it because the controller isn't in the airplane risking his butt or pushing the throttles and only the pilot can "react" to the situation. (Screaming into the mike doesn't count)>>Air traffic controllers and pilots generally have a great>working relationship. When a pilot makes a request for a>different runway for takeoff it is usually for a very good>reason and you can be assured that he has checked the>situation out and that it is safe and legal and for that>reason controllers will try to clear him as requested.It's not just the controller who can initiate variations. In most countries ANY runway may be ASSIGNED by ATC if the wind is less than 5 knots ("CALM") and can otherwise be negotiated to suit traffic or other considerations (such as reduced taxi distance, anticipated traffic flows, direction of intended flight, conflict with overflying or other traffic). The wind must be given and if the pilot accepts (since he knows the operational limitations of his aircraft) then any runway permitted by airport operations can be authorized. THEN, it's a matter of providing separation/traffic. One of the airports I worked had 2 crossing runways in an "X",, but the sked 737's, among others, always wanted to land toward the ramp to save a long taxi in.. and then wanted to depart from the near end to save $$ on fuel taxiing out. Since we had a 737 departure and another sked arrival at aboutthe same time every morning it was COMMON to run opposing traffic: "XXX40 Cleared for takeoff, right turn 30 degrees within 4 miles to avoid company Boeing traffic on a 15 mile final". Another had a lack of taxiways so departing aircraft were often given the opposite end to avoid a 7000 ft backtrack which would require the inbounds to be spaced up to 10 miles apart or send on a scenic tour on downwind. Some days it was their idea, some days it was just easier for us to manage the traffic that way. Also, at non-radar airports IFR seperation may mean that you either use the "wrong end" for arrival or departure or plan to sit until landing/departing traffic is out of the way... up to 10 minutes in some cases. Put that in your fuel budget!-- 30 years of watching the scariest moment in a pilot's life (landing) 500 or more times a day! -- :-zhelp ATC_Rob

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nothing to do with wind, everything to do with time lost sitting on the ground waiting for enough room in the pattern to fly against it.Time == money, lots of it.

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>Thinking about these busier airports, doesn't everyone have to>follow the same line so take-offs and landings are all in the>same direction?>ideally, yes.>I mean, if you have 10 planes on approach to R36, you don't>want some cowboy deciding he knows best, and barreling in to>R18.>he can ask for it, and if there's room in the pattern he may get it.If there's no room, he can choose to either wait until there's room at the discretion of ATC or go elsewhere.Most pilots will take what ATC offers in such situations...>These responses have been interesting, but I'm still not>entirely convinced and am surprised at the inferences that the>pilots can make the decision. They're not the one's sitting in>some ATCC vectoring 24 planes into an approach queue....>The pilot can request what he wants, if ATC can't honour the request he has to live with what he can get or divert.That's his decision, just as it's ATC's decision to honour the request or not (which they may by law not be allowed to do, noise abatement comes to mind).

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at ORD it is what the controllers want (and what their magical computers state) rather than winds which dictate the flow of traffic.going into a smaller airport like KXNA it is usually time. do i really want to taxi to 16 and then turn crosswind and downwing heading back northbound or simply take a 5 kt tailwind and takeoff on 34 heading where i want to go?of course, if it is the last leg of a 4 day trip, then by all means its time (as in i want to get home as fast as possible).each airline will have performance data dictating whether or not an aircraft can takeoff with the tailwind. most airplanes are certified up to 10kts of tailwind. ATC knows this and "messages" winds sometime just like they do with visibility when approaches are being conducted.

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I was nearby Burbank airport a few weeks ago and saw this happen. A Fedex A300 taxied to 15 when the winds were coming from the north and everyone else was using 33. Even the UPS A300 took off from 33, but that fedex waited about 25 minutes, and finally was given clearance to takeoff on 15 with a tailwind. Very cool to watch, looking at all the traffic in the pattern coming into the usual 33 approach while the fedex guy hung out on the other side just waiting

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At Heathrow (EGLL) the procedures state:Preferential Runway Systema in weather conditions where the tail wind is no greater than 5 knots on the main Runway 27R and 27L, these runways will normally be used in preference to Runways 09R and 09L, provided the runway surface is dry.b when the associated crosswind component on these main runways exceeds 25 knots, Runway 23 will normally be made available if there is a lesser crosswind component affecting it.c Pilots who ask permission to use the runway into wind when in accordance with these procedures, Runway 27R and 27L are in use should understand that their arrival or departure may be delayed.Note item c.

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It would also depend on the airport and numerous other restrictions, which is why some airports cannot be certified for certain aircraft, although the runway technically might be long enough. At Heathrow there is no way on this Earth any controller will let you takeoff or land in the opposite direction to everybody else. On top of that sometimes at LCY or LHR they are using runways with the wind for noise abatement reasons. a plane landing is by nature much quieter than one taking off, and if you look at I believe it to be Heathrow's website it shows the times of change for active runways, where by in the morning for example they will takeoff and land in one direction, while in the afternoon the opposite. That happened in '04 when I went to Fairford with BA on a 747, we took off facing London and landed facing away.

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