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16 votes

Why did my transatlantic flight meander off the great circle?

Most flights across the Atlantic don't fly direct great circle routes; they use the North Atlantic Track system, which is an array of "lanes" you might say, usually 60Nm apart, like one of ...
John K's user avatar
  • 132k
15 votes

Why do flight times differ between traveling East versus traveling West?

Seven years late!) but all the answers that say "wind" attribute speed difference to the "trade winds" which are the wrong prevailing winds to name as they act in opposition to OP'...
Pilothead's user avatar
  • 20.2k
12 votes

Why did my transatlantic flight meander off the great circle?

can an autopilot be programmed to follow a route dictated by a winds aloft forecast? Yes, but the question is how it is done, and these days it's better to think of it as not just the autopilot, but ...
Terry's user avatar
  • 39.2k
10 votes

What is the best option when the headwind exceeds the maximum airspeed?

Before even taking off, a pilot is required to get a weather briefing, including winds. Wind speeds are usually predictable and well known. If a pilot was flying against strong headwinds, with no ...
abelenky's user avatar
  • 30.7k
8 votes
Accepted

How can the wind speed and direction be calculated from on-board measurements?

With the set of parameters available to you, you cannot do this. If you have the actual track instead of the desired track, you will be able to calculate the wind. The simplest way to do this is ...
DeltaLima's user avatar
  • 83.5k
7 votes
Accepted

Did the jet stream really stop the B-29, or was it just bad luck?

Jets form along warm/cold airmass boundaries, such as the mid latitude Polar and Tropical air mass borders, where the warm side tapers off into a wedge shape at the top of the airmass at the ...
John K's user avatar
  • 132k
6 votes

How do jet streams affect the fuel consumption?

Best way to conceptualize it is to just analogize it to a ship navigating ocean currents. If a ship going 15 knots through the water is riding with a current going 3 knots, it's speed over the ocean ...
John K's user avatar
  • 132k
6 votes

How do jet streams affect the fuel consumption?

As far as aerodynamics is concerned, there is no jet stream1. The aircraft flies at a fixed airspeed with respect to the surrounding air2. How much thrust it needs, how much lift it experiences and so ...
Bianfable's user avatar
  • 55.9k
5 votes

Why did my transatlantic flight meander off the great circle?

The North Atlantic (NAT-HLA) High Level Airspace is special use airspace where a series of optimized routes called the OTS, Organized Track System, are published every day, twice a day. This airspace ...
skipper44's user avatar
  • 1,615
5 votes

Could winds of up to 150 km/h impact the structural loads on a Boeing 777?

No, there's no considerations on structural load because the airplane is moving in relation to the air mass. Think of the jet stream as a river, as air is just another fluid. A boat heading downstream ...
GdD's user avatar
  • 54k
4 votes
Accepted

Are weather balloon launches NOTAM'ed?

Yes, they are NOTAM'ed. In the FAA case, the FAA wants to know first when you intend to launch, where from (distance and direction from a town on a map), how high you expect to go and what direction ...
Hugo Woesthuis's user avatar
4 votes

Could winds of up to 150 km/h impact the structural loads on a Boeing 777?

ymb1's and GdD's answers are very good, I'd like to expand them a bit further. The loads on the airplane structure are caused by forces between air and the plane. If the stream can be described as ...
Crowley's user avatar
  • 271
3 votes

How are extreme winds aloft handled and how do they affect flight?

Is there a maximum or safe winds aloft value / crosswind for say, a 737 to fly? Crosswind limits are in place for landing not flying. Cross wind limits have to do with how effective the control ...
Dave's user avatar
  • 101k
2 votes

What is the best option when the headwind exceeds the maximum airspeed?

This question is actually applicable to a power off emergency gliding situation, where your best option may be behind you. The way the question is worded (and one of the reasons light GA air craft ...
Robert DiGiovanni's user avatar
2 votes
Accepted

What is the best way to determine Run-in direction for parachute activity?

I used to skydive and was going to fly the jump plane but didn't have a commercial license at the time (required in Canada). I was jumping at the dawn of the ram-air era in the late 70s. I had a ...
John K's user avatar
  • 132k
2 votes

Why does the Winds Aloft ‘For Use Time’ start before the ‘Valid Time’?

Wind and temperature aloft forecasts (FB) are computer-prepared and issued by the National Centers for Environmental Prediction (NCEP) at Suitland, Maryland. The forecasts are valid 6, 12, and 24 ...
Juan Jimenez's user avatar
2 votes

Did the jet stream really stop the B-29, or was it just bad luck?

The B-29 could carry high explosive or incendiary bombs, or a mixture of both. High explosive bombs have a much higher terminal velocity, there for in the presence of appreciable cross winds, high ...
Robert DiGiovanni's user avatar
2 votes

Did the jet stream really stop the B-29, or was it just bad luck?

The above picture has been described as an illustration of the effect of the jet stream on bombing accuracy. If the suggestion is that the physical effect of the wind shear around the jet stream ...
quiet flyer's user avatar
  • 22.7k
2 votes
Accepted

How are extreme winds aloft handled and how do they affect flight?

I like to show people videos of planes flying backwards. These videos show that wind does not have an effect on how well the aircraft stays in the air - no matter how strong it is, it only effects ...
Ben's user avatar
  • 14.5k
2 votes

How do jet streams affect the fuel consumption?

There are some excellent answers here already, and I won’t try to compete directly with their explanations. However, your comment about “free lift” from a headwind was an important clue about your ...
Michael Hall's user avatar
  • 26.4k
1 vote

How do jet streams affect the fuel consumption?

You are correct that airspeed is key to aerodynamics and flight performance. Whereas groundspeed is key to navigation. Neither really affects fuel consumption rate as far as endurance. Fuel endurance ...
Dean F.'s user avatar
  • 16.5k
1 vote

What is the best option when the headwind exceeds the maximum airspeed?

If you are flying into a headwind, that means that there is an area of High pressure to your right. Frequently, as you leave move further away from the low pressure area, the winds will diminish. This ...
George Fendler's user avatar
1 vote

Why do flight times differ between traveling East versus traveling West?

Short answer: As you have indicated in the question description, the answer is winds. Better known as Jet Streams. Long answer: https://alliknowaviation.home.blog/2019/03/29/why-do-planes-travel-...
Saurabh Kala's user avatar

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