wake turbulence separation for touch-n-go

rogervisual · #21 (**permalink**) 08-16-2008, 04:08 PM

Just to compare our rules/regulations - within the UK we would have to apply
2 minutes vortex from the preceeding departure and 3 if from a intermediate
position. The issue of being visual with the aircraft ahead does not alter it here in the UK. If the c172 was in the circuit and following the higher vortex weight a/c on final approach we have to use the following " report final number two to the C130 , caution vortex wake , recommended spacing 4 miles" (6 miles after a B737 , 8 miles after a B747)

**Towerboss** · #22 (**permalink**) 08-16-2008, 05:08 PM

Wow you have to say all that?? Don't tell the FAA they'll start having us do that too. I believe we'll be starting the "line up and wait" bit Jan. 1.

ATC@ZID · #23 (**permalink**) 08-16-2008, 07:02 PM

Quote:

Originally Posted by Max Power

if your applying VFR sep before and after why bother issuing an instruction to issue it in the middle? would you use it for a departure too?

you: hold for wake turbulence
pilot: we'll waive it
you: preceding 737, maintain visual seperation from that traffic, caution wake turbulence, cleared for takeoff

Max your right but you still have to say report traffic in sight and maintain vis sep between you and that a/c. Trust me I have gotten busted for this.

Roddy_Piper · #24 (**permalink**) 08-16-2008, 09:21 PM

Quote:

Originally Posted by Max Power

if your applying VFR sep before and after why bother issuing an instruction to issue it in the middle? would you use it for a departure too?

you: hold for wake turbulence
pilot: we'll waive it
you: preceding 737, maintain visual seperation from that traffic, caution wake turbulence, cleared for takeoff

in a lot of cases the visual separation on departure is for the radar guy (departure or center, whichever applies). you get pass the 3 minute wake turbulence delay on the runway with the waiver of wake turbulence, but you still owe the radar departure guy the 3 or 5 miles he's required off the runway end. i'd hate to be sitting at the departure scope and have the tower send me two guys so close together that i have to step the back guy up 1000 or 2000 feet at a time because i don't have the required 3 or 5 miles radar separation. if the two departures come to me with the second guy already maintaining visual separation from the first guy than i can use that to get them climbing to at least 17,000 without saying much else.

the visual separation on the runway for a departure is NOT necessarily needed if the departure waives the wake turbulence hold, but it is needed in the radar world.

bravo zulu · #25 (**permalink**) 08-17-2008, 11:24 AM

even VFR vs VFR... say you have a Heavy doing a touch and go in front of a C172 BOTH in the pattern. You must issue the C172 traffic on the Heavy and he must call it in sight. THEN... you must tell him to maintain visual separation and issue the cautionary advisory and clearance. Its clearly printed and thats how its done.

from earlier:

Quote:

Originally Posted by Max Power

if your applying VFR sep before and after why bother issuing an instruction to issue it in the middle? would you use it for a departure too?

you: hold for wake turbulence
pilot: we'll waive it
you: preceding 737, maintain visual seperation from that traffic, caution wake turbulence, cleared for takeoff

...because the smaller aircraft can adjust his pattern/base turn to compensate.

**Towerboss** · #26 (**permalink**) 08-17-2008, 12:58 PM

Quote:

Originally Posted by bravo zulu

even VFR vs VFR... say you have a Heavy doing a touch and go in front of a C172 BOTH in the pattern. You must issue the C172 traffic on the Heavy and he must call it in sight. THEN... you must tell him to maintain visual separation and issue the cautionary advisory and clearance. Its clearly printed and thats how its done.

I disagree, the AIM and .65 state that aircraft in the tower VFR pattern are required to maintain their own wake turbulence / visual separation. All that you are required to do in the above situation is say "Caution wake turbulence" and issue the traffic.

bravo zulu · #27 (**permalink**) 08-17-2008, 03:03 PM

again, from an earlier post...

Quote:

3-9-7 b:

b. The 3-minute interval is not required when:

1. A pilot has initiated a request to deviate from that interval unless the preceding departing aircraft is a heavy aircraft/B757.

NOTE-
A request for takeoff does not initiate a waiver request; the request for takeoff must be accomplished by a request to deviate from the 3-minute interval.

2. USA NOT APPLICABLE. The intersection is 500 feet or less from the departure point of the preceding aircraft and both aircraft are taking off in the same direction.

3. Successive touch-and-go and stop-and-go operations are conducted with a small aircraft following another small aircraft weighing more than 12,500 lbs. or a large aircraft in the pattern, or a small aircraft weighing more than 12,500 lbs. or a large aircraft departing the same runway, provided the pilot of the small aircraft is maintaining visual separation/spacing behind the preceding large aircraft. Issue a wake turbulence cautionary advisory and the position of the large aircraft.

Since the paragraph states "provided the pilot of the small aircraft is maintaining visual separation/spacing behind the preceding large aircraft" we need to use the rules in Visual Separation.

7-2-1 a:

a. TERMINAL. Visual separation may be applied between aircraft under the control of the same facility within the terminal area up to but not including FL 180, provided:

1. Communication is maintained with at least one of the aircraft involved or the capability to communicate immediately as prescribed in para 3-9-3, Departure Control Instructions, subpara a2 is available, and:

2. The aircraft are visually observed by the tower and visual separation is maintained between the aircraft by the tower. The tower shall not provide visual separation between aircraft when wake turbulence separation is required or when the lead aircraft is a B757.

*The tower in our example is not providing the visual separation, the pilot is.*

3. A pilot sees another aircraft and is instructed to maintain visual separation from the aircraft as follows:

(a) Tell the pilot about the other aircraft including position, direction and, unless it is obvious, the other aircraft's intention.

(b) Obtain acknowledgment from the pilot that the other aircraft is in sight.

(c) Instruct the pilot to maintain visual separation from that aircraft.

(d) Advise the pilot if the radar targets appear likely to converge.

So all this being said, the phraseology would be:

"N12345 traffic C-130 departing runway 1."

{N345 traffic in sight}

"N345 maintain visual separation, caution wake turbulence C-130 departing runway 1, runway 1 cleared T/G."

If you arent doing it then I hope for your sake your recorders arent working properly.

**LawnGnome** · #28 (**permalink**) 08-17-2008, 04:43 PM

Quote:

Originally Posted by Towerboss

I disagree, the AIM and .65 state that aircraft in the tower VFR pattern are required to maintain their own wake turbulence / visual separation. All that you are required to do in the above situation is say "Caution wake turbulence" and issue the traffic.

I agree with you Towerboss...we have had that discussion up in our tower and none of us think you should say "maintain visual separation." Who knows...should've asked those eval guys when they were up here...but they never hit us on it at all...I would just issue traffic and caution!

atcbrownie · #29 (**permalink**) 08-17-2008, 04:59 PM

Why would anyone tell a VFR aircraft to "maintain visual separation"? They are already required to do so. I say issue traffic and a cautionary advisory and you are good to go.

Just my opinion
AW

Roddy_Piper · #30 (**permalink**) 08-17-2008, 07:33 PM

Quote:

Originally Posted by atcbrownie

Why would anyone tell a VFR aircraft to "maintain visual separation"? They are already required to do so. I say issue traffic and a cautionary advisory and you are good to go.

I humbly disagree. VFR aircraft are not required to "maintain visual separation". They are only required to see and avoid. Look at the definition and application of visual separation and you will see that it is completely different than see and avoid.

The visual separation is used in lieu of 3 minutes wake turbulence for a C172 touch and go (small, intersection departure) behind a C130 departure (large, full length departure). If you are not applying wake turbulence in this manner you are not doing it correctly.

This may not be applicable at military bases. I know when I was in the base flying reg (AFFTC 11-1 i think) clearly stated that base assigned aircraft are required to maintain their own wake turbulence separation while in the tower pattern. This blurb is NOT in the .65. If it is, I stand corrected and would really like to see the reference. Therefore, you need to provide wake turbulence separation.