Wake turbulence help

NUWATC Rookie

Picture this senario, an aircraft requesting to depart runway 14, a heavy jet has just landed rwy 14. It makes sense that wake turbulence should apply, but the .65 doesnt say anything about an ac departing after an arriving heavy on same runway.

some might say that it depends where the heavy lands and where the departure lifts should come into play. but that isnt said in the book either. so from what i gather even though to me it doesnt make any sense, i dont think there is wake turbulence criteria for a situation like that one.

GLF5 Senior Member

No criteria, you are correct. Maybe a cautionary advisory, but that's in your opinion.

Roddy_Piper Resident Knucklehead Vegas baby

no wake turbulence separation.

in theory...if the heavy touches down at the numbers the wake turbulence ends there at the approach end. the departure will not rotate until well after the approach end, maybe midfield depending on type and runway length. so the departure in theory will never go through the heavy arrivals wake turbulence.

hope this helps. oh yeah, u can't go wrong by issuing a wake turbulence advisory if in your opinion it's deemed necessary.

polo708 Epic Member tower

^^ x2

No wake turbulence required... U can give a cautionary if you really deem it necessary.

bigrex81 Rookie Oak Harbor, WA

I work at the same facility as the original poster in this forum. We work at a Naval facility that has raised arresting cables. Commonly when a heavy arrives, they land past our cables (about 2,000 ft from the approach end). If we launch an F-18 after this heavy, the F-18 is airborne in about 1,500 ft. Even though the .65 doesnt cover it, is this still a cautionary or should we apply the 2 min rule?

Roddy_Piper Resident Knucklehead Vegas baby

if the threshold is NOT displaced then it's not up to the controller to figure out where the aircraft is going to touchdown on the runway. common practice would make it obvious that the heavy would land pass the cable/barrier. even if the aircraft was airborne in 1 feet (harrier style) then there isn't a rule for that. departure behind a full-stop arrival on the same runway has no wake turbulence. even though it's very possible (and probably more realistic) that the departure could rotate prior to the spot that the heavy touched down.

you won't find in the .65 where it says "apply 2 minutes for a fighter jet that could get airborne prior to the point where a heavy arrival touches down". it just doesn't exist.

it does however say this:
no wake turbulence separation. just need the heavy arrival to exit the runway

again, if the thresholds were displaced then you would need to apply the 2 minutes because the flight paths will (or could) cross. no displaced threshold means no 2 minutes.

polo708 Epic Member tower

Well put Roddy... Its on the pilot, we have no WT requirements in those situations.

Also, your fighters depart over cables too? You have no departure end configuration?

atcguruaf Rico Suave AZ

Not only that, but if a pilot cannot see where a heavy touches down and wants to depart through his wake, that's his bad.

Something else to consider:

You can full stop a small aircraft behind a heavy (departure or arrival, doesn't matter). Yes, I know you need the miles, but in a VFR tower world you don't, you just need a cautionary. By giving this cautionary, it gives the pilot of the small aircraft a heads up. Nevertheless, he's still "cleared to land" and can touch down whenever he feels.

I don't think (as I'm sure you've seen) there is an issue with fighters departing after a heavy lands, especially if a small aircraft can land behind a heavy. If there was an issue with the fighters departing through the wake(military pilots being the whiners that they are), I'm sure something would have been said and a new local procedure would have come out because of it.

bigrex81 Rookie Oak Harbor, WA

Almost all Navy aircraft are capable of departing over the cable. What do you mean about "departure end configuration?

polo708 Epic Member tower

I know they can do it but its odd that that is the daily operations where you are at. I've always seen and run a departure end configuration where the cable is up on the departure end and down on the approach end. Most aircraft would rather not land on a cable if they dont have to.