Possible Wake?

fng Newcomer

If a large AC departs runway 27L and a small AC departs runway 27R, is there any wake turbulence seperation needed to turn the small AC behind the large? or can the small just pass a mile behind the large and just give an advisory? I can't find anything in the 7110.65 talking about this and someone told me that 3 miles was needed.

Thanks

atcbrownie Trusted Member Warrenton Va

it depends on how far the parallel runways are separated.

noid Curtis E. Carr Jawja

The only separation minimum for a small behind a large is on an arrival which is 4 miles or when conducting same runway opposite direction or intersection departures which is 3 minutes (waiverable). It's just good practice to have the smaller aircraft rotate prior to the larger aircraft's rotation point. Everything else has to do with Heavy/747's.


3-9-6.

f. Separate IFR/VFR aircraft taking off behind a
heavy jet/B757 departure by 2 minutes, when
departing:

2. A parallel runway separated by less than
2,500 feet.


i. Separate a small aircraft behind a large aircraft
taking off or making a low/missed approach when
utilizing opposite direction takeoffs on the same
runway by 3 minutes unless a pilot has initiated a
request to deviate from the 3-minute interval. In the
latter case, issue a wake turbulence advisory before
clearing the aircraft for takeoff.
-------------------------------------------------------------------

3-9-8.

b3. Separate IFR/VFR aircraft taking off behind
a heavy jet/B757 departure by 2 minutes when
departing:

(b) A parallel runway separated by 2,500 feet
or more if projected flight paths will cross.
-------------------------------------------------------------

5-5-4

e. Separate aircraft operating directly behind, or
directly behind and less than 1,000 feet below, or
following an aircraft conducting an instrument
approach by:

NOTE-
1. When applying wake turbulence separation criteria,
directly behind means an aircraft is operating within
2500feet of the flight path of the leading aircraft over the
surface of the earth.
2. Consider parallel runways less than 2,500 feet apart as
a single runway because of the possible effects of wake
turbulence.

1. Heavy behind heavy- 4 miles.
2. Large/heavy behind B757- 4 miles.
3. Small behind B757- 5 miles.
4. Small/large behind heavy - 5 miles.

fng Newcomer

The runways are more then 2500 feet apart. It is the small passing a mile behind the large in the air after both have taken off that I am curious about...

Thanks

ATCinWI Senior Member Illinois

If #2 is providing his own visual separation (or is VFR), all you need is an advisory.

fng Newcomer

Thankyou, that is what I thought...

atcguruaf Rico Suave AZ

Technically, you don't even need that. According to the rules, you can just clear the guy for takeoff.

fng Newcomer

The takeoff part isnt the issue, the questions is wether or not there is a wake turbulence requirement for a small to pass behind a large in the air.

fng Newcomer

I dont even think the small has to have the large in sight, but an advisory would be appropriate. Does anyone think otherwise?

Roddy_Piper Resident Knucklehead Vegas baby

no wake turbulence in that situation. u don't even need 6000 feet (obviously).