Re: comments upthread about wake turbulence.
Why is the 757 so more "wake inducing" than other aircraft (or similar / larger size)?
Is it left the pilots to assess nearby traffic and adjust or are there systems to predict / adjust?
It's not particularly pleasant from a pax seat - two notable instances IME were on a BA A320 AMS-LHR we hit a solid big pocket (captain reassuring on intercom about 5 seconds after, and crew were excellent doing lap of cabin checking on all pax and reassuring!) and another on takeoff with EK (A380) ex-DXB (screens suggested we were at a few thousand feet) - felt like about a 1-2 second (?relative) loss of lift - somewhat disconcerting on both occasions!
ATC apply Wake Turbulence Separation, lose the separation and you are stood down pending investigation, it is reported as a Breakdown of Separation i.e. a serious offence.
The 757 is an interesting one. The FAA has been investigating wake as a result of several incidents and accidents, some with the 757 as the lead aircraft, this was upon NTSB recommendations after investigations. They installed some Lidar radars at some airports (San Francisco, JFK were two I remember). They got a bunch of data from different distances from touchdown. Their findings were that the 757 was not to blame and there must have been other factors at play. They also determined it was the Wing rather than the Maximum Take Off Weight (MTOW) that determined the Wake (along with speed).
The upshot was that the FAA introduced what they call a 'Recat of wake turbulence' (recat being recategorization). It moved away from Heavy, Medium and Light and moved to a 7 category system, labelled from A (being the biggest wing i.e. A380) through to G, being the smaller wing. Most of what operates in Australian fell into the same Wake Turbulence separation standards as what is currently applied The big change was that the 757 went back to the equivalent of a current Medium. Currently in Australia we class a 757 as a Medium if following, but a Heavy if leading ( a 737 is a Medium for comparison). They introduced at airports they thought it would make an improvement in movement rates, and are selling the data collection to other agencies (I went to a presentation here, what I wrote above is based upon their presentation as I remember).
The other noteable piece was that they found the 737-800/900 wing had some 'interesting' Wake characteristics. I have had 3 Wake reports, all on left circuit ILS Runway 19 at BNE, all over water, all Mediums following 738's, all about 8-9 mn behind (there is no Wake Turbulence Separation for a Medium following a Medium, just the radar Separation of 3 nm is required), all several months apart. They all offset themselves (after seeking approval).
There was some talk of Australia introducing the Recat of Wake, we'll wait for the new ATC system to display the A-G instead of the H, M, L.