Jason McDowell From , joined Dec 1969, posts, RR: Posted (7 years 4 months 1 week 2 days 21 hours ago) and read 2673 times:
I'm posting this question here in an attempt to avoid the 19-year-old armchair CEOs over in the Civil Aviation forum.
One of the major selling points of the A380 is reduced airport congestion. Airbus claims that fewer flights will be required due to the airplane's increased capacity.
As we all know, as an aircraft becomes heavier, it produces stronger wake vorticies. Currently, aircraft are grouped by weight (except for the 757) with different ATC seperation minimums for each category. The heavier the aircraft, the larger the in-trail seperation minimums become.
According to specs here on the A/C Stats page, the 747-400 has an empty weight of 400,000 lbs and a takeoff weight of about 800,000 lbs. The A380 will have an empty weight of 600,000 lbs and a takeoff weight of 1,200,000. Basically, the A380 weighs about 50% more than the 747-400.
Soooooo........
I'm wondering whether the potential increase in wake turbulence would increase the in-trail separation minimums for the A380, and whether this could negate the claimed advantage in airport congestion.
Ikarus From United Kingdom, joined Jan 2001, 3524 posts, RR: 3 Reply 1, posted (7 years 4 months 1 week 2 days 3 hours ago) and read 2174 times:
It is my understanding that the separations are not in fact linearly adjusted by weight, but in steps, by type. So I suspect very strongly that the A380 and 747 will simply be lumped in the same separation category together.
Does anyone know how they treat Antonov 124s and 225s? I would think the A380 would be not much of a difference to either of them
Klaus From Germany, joined Jul 2001, 19933 posts, RR: 57 Reply 2, posted (7 years 4 months 1 week 1 day 20 hours ago) and read 2118 times:
Wake impact is not only determined by weight but also by other factors such as wing/flap design and wing loading (which for the A380-800 is relatively low).
As far as I know, one of the A380 design parameters was to have comparable wake turbulence to a 747. And I guess with circa thirty years of aerodynamic research in between, they could well have succeeded.
Starlionblue From Greenland, joined Feb 2004, 14992 posts, RR: 69 Reply 3, posted (7 years 4 months 1 week 1 day 1 hour ago) and read 2025 times:
As far as I know, one of the A380 design parameters was to have comparable wake turbulence to a 747.
Indeed, and it doesn't stop there. Airbus (in response to operators and airports) wanted the A380 to have as little additional impact as possible. Thus:
- Same or shorter runways as 744.
- Less pavement loading than 773.
- Shorter exhaust plume than 773.
- Comparable wake turbulence to 744.
The only real impacts are:
- Filleting on the inside of tight taxiway turns.
- Extra clearance on sides of taxiways and runways.
- Strengthening of bridges and culverts. It may have lower pavement loading, but the weight is still greater.
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