The 757 and wing tip vortices

[Will]

I remember when the world was getting used to the 757, and it was discovered to generate stronger wingtip vortices than comparable aircraft. (There were two aircraft accidents attributed to wake turbulence behind 757s, and even one occasion when a 757 passed over a sailboat on final at KSFO, and wake turbulence destroyed the boat!) So the FAA amended the separation rules such that the 757 was treated as a heavy aircraft by ATC.

Question: do those rules still apply to 757s that have been retrofitted with winglets? Theoretically, winglets would reduce wake turbulence, but I don't know if winglet manufacturers are interested (obligated?) to study the implications of winglets on ATC separation. Theoretically the industry would benefit if winglets were shown to allow a 757 to be safely treated as a "large" aircraft instead of a "heavy" aircraft, since capacity would increase.

Any ideas about this?

[localiser]

Hi Will,

As far as I'm aware there is no distinction made for aircraft (retro-)fitted with winglets.

The wake categories in our Ops Manual are based on maximum take off weight, so any aircraft >136,000 kgs (ICAO) would be considered a heavy, and 7,000-136,000kgs would be medium. In the UK a medium is 40,000-136,000. The An225 and A380 are still "heavy", but call "Super" on rt.

In UK 757 is classified as Upper medium. Other medium aircraft types are classified as lower medium.

Upper/lower medium is considered for arrivals, and doesn't exist for departing aircraft and the threshold is 104,000kgs

In the US there are some airfields recategorising the wake categories based on weight, wingspan and approach speed but I don't know which ones they are.

[emerydc8]

I remember the accident that caused them to re-classify the 757 as a heavy for separation purposes. It was a corporate jet that rolled upside down and crashed after it hit the vortex of a 757 going into Orange County, California. The passenger was the founder of the famous In-And-Out Burger. It's been so long, but I think it was back in the '90's. I'd have to check. I hope someone comes up with information on this because that question came up a few months ago in the cockpit. Maybe it's been changed back.
Jon

[DougSnow]

Per the FAA 7110 (ATC Handbook)

"Issue wake turbulence advisories, and the position, altitude if known, and the direction of flight of:

The super or heavy to aircraft landing behind a departing/arriving super or heavy on the same or parallel runways separated by less than 2,500 feet.

The B757/large aircraft to a small aircraft landing behind a departing/arriving B757/large aircraft on the same or parallel runways separated by less than 2,500 feet."