ATC Question

[Longhaul]

Sometimes while communicating with approach control, an aircraft will say something like: "Chicago Approach, United 1714 heavy, Wilks, 240 on the heading". My question is what does heavy mean and what is it's significance to ATC?

[ready2fly]

"Heavy" refers to the size of the aircraft - like a 757 would be a "heavy". Anything over a certain weight (I don't know what that specific weight is though).

[avi8tor]

An aircraft is considered to be a "heavy" if it is capable of weighing 255,000 MGTOW.It is significant to ATC because "heavy" aircraft require more seperation on departure, and arrival because of wake turbulance.

[Mavmb]

MGTOW Maximum Gross something??????? What does that stand for?

[mikek123]

Maximum Gross Take-off Weight

[AirborneMedic_ANGa10]

[ QUOTE ]
"Heavy" refers to the size of the aircraft - like a 757 would be a "heavy". Anything over a certain weight (I don't know what that specific weight is though).

[/ QUOTE ]

I believe only some 75s are considered 'heavy'.

[I_Money]

The 757-300's and ATA's 757-200's are considered heavy

[Ophir]

Oh boy, here we go with a long answer. Hold on tight.


A heavy is determined by weight, as mentioned before. This puts the aircraft into a category. There are several different scenarios that a controller will keep aircraft separated by minima standards. These are Same Runway Separation (landing and departing), parallel runway separation, visual approach separation, and radar approach separation. Just to note a B757 is always considered a heavy because of its design. Another interesting note is that the 767’s used to be heavies and now they are in the Large category.

Same Runway Separation (SRS)
1. When only Category I aircraft are involved- 3,000 feet.

2. When a Category I aircraft is trailing a Category II aircraft- 3,000 feet.

3. When the second aircraft or both are Category II aircraft- 4,500 feet.

4. When either is a category III aircraft- 6,000 feet.

If this separation doesn't exist by the time the arriving aircraft crosses the landing threshold, the controller must issue a go-around. It is not the pilot’s responsibility to decide if there is enough separation.

However, if radar separation is being applied, only the following minimum separation must exist before the trailing aircraft is airborne.

1. A heavy behind a heavy- 4 miles.

2. A large/heavy aircraft behind a B757- 4 miles.

3. A small behind a B757- 5 miles.

4. A small/large behind a heavy- 5 miles.

If an aircraft is taking off behind a heavy/B757 on the same runway that has a displaced landing threshold and the projected flight paths will cross, the separation must be two minutes. The reduced radar separation doesn't apply in this case. Also, ATC shall not approve pilots’ requests to deviate from the required wake turbulence separation if the preceding aircraft is a heavy/B757.

Terminal Procedures (this gets detailed)

- For an aircraft that is less than 40 miles from the antenna that provides a facility with their radar information, 3 miles separation is provided.

- For an aircraft that is 40 miles or more from the facility radar antenna, 5 miles separation will be used.

However, it must be noted that greater separation may need to be provided if wake turbulence is involved. Wake turbulence separation minima are as follows:

1) 4 miles for a heavy operating behind a heavy.

2) 5 miles for a small or large behind a heavy.

3) 4 miles for a large or heavy behind a B757.

4) 5 miles for a small behind a B757.

Now for the exceptions. (Come on, you had to know there would be exceptions.)

Aircraft operating in the terminal area will be provided the same separation as in the en route environment, with a few minor adjustments. They are:

1) 4 miles for a small behind a large.

2) 5 miles for a small behind a B757.

3) 6 miles for a small behind a heavy.

This separation must exist when the preceding aircraft crosses the landing threshold. For example, you are vectored to the final approach course in your C172 and are 5 miles in trail of a heavy aircraft. This is legal, but your speed must be such that during the approach the separation increases to the required 6 miles by the time the heavy aircraft crosses the landing threshold.

This information was copied from a UVSC lecture, without permission.

[Longhaul]

Great responses. Thank you! One more piece of the puzzle in place.

[Doug Taylor]

You know what's interesting that I got less wake turbulence from a 777 than I got from a 757.

The 757's will rock your world, pardon the pun!

[MikeD]

[ QUOTE ]
Oh boy, here we go with a long answer. Hold on tight.


A heavy is determined by weight, as mentioned before. This puts the aircraft into a category. There are several different scenarios that a controller will keep aircraft separated by minima standards. These are Same Runway Separation (landing and departing), parallel runway separation, visual approach separation, and radar approach separation. Just to note a B757 is always considered a heavy because of its design. Another interesting note is that the 767’s used to be heavies and now they are in the Large category.

Same Runway Separation (SRS)
1. When only Category I aircraft are involved- 3,000 feet.

2. When a Category I aircraft is trailing a Category II aircraft- 3,000 feet.

3. When the second aircraft or both are Category II aircraft- 4,500 feet.

4. When either is a category III aircraft- 6,000 feet.

If this separation doesn't exist by the time the arriving aircraft crosses the landing threshold, the controller must issue a go-around. It is not the pilot’s responsibility to decide if there is enough separation.

However, if radar separation is being applied, only the following minimum separation must exist before the trailing aircraft is airborne.

1. A heavy behind a heavy- 4 miles.

2. A large/heavy aircraft behind a B757- 4 miles.

3. A small behind a B757- 5 miles.

4. A small/large behind a heavy- 5 miles.

If an aircraft is taking off behind a heavy/B757 on the same runway that has a displaced landing threshold and the projected flight paths will cross, the separation must be two minutes. The reduced radar separation doesn't apply in this case. Also, ATC shall not approve pilots’ requests to deviate from the required wake turbulence separation if the preceding aircraft is a heavy/B757.

Terminal Procedures (this gets detailed)

- For an aircraft that is less than 40 miles from the antenna that provides a facility with their radar information, 3 miles separation is provided.

- For an aircraft that is 40 miles or more from the facility radar antenna, 5 miles separation will be used.

However, it must be noted that greater separation may need to be provided if wake turbulence is involved. Wake turbulence separation minima are as follows:

1) 4 miles for a heavy operating behind a heavy.

2) 5 miles for a small or large behind a heavy.

3) 4 miles for a large or heavy behind a B757.

4) 5 miles for a small behind a B757.

Now for the exceptions. (Come on, you had to know there would be exceptions.)

Aircraft operating in the terminal area will be provided the same separation as in the en route environment, with a few minor adjustments. They are:

1) 4 miles for a small behind a large.

2) 5 miles for a small behind a B757.

3) 6 miles for a small behind a heavy.

This separation must exist when the preceding aircraft crosses the landing threshold. For example, you are vectored to the final approach course in your C172 and are 5 miles in trail of a heavy aircraft. This is legal, but your speed must be such that during the approach the separation increases to the required 6 miles by the time the heavy aircraft crosses the landing threshold.

This information was copied from a UVSC lecture, without permission.


[/ QUOTE ]

In the AF, we've also got RRS or Reduced Runway Separation. 3000' between similiar aircraft, 6000' between disimiliar. That means that F-16s on landing need only be 3000' apart, so on a 12,500' runway, you can have 3 aircraft rolling out with another touching down so long as the rollouts are on the "cold" side of the runway.

MD

[Ophir]

What are the regs on taking off or landing in formation? I have seen taking off, but not landing. Do they do that?

I have taken off in formation, with my instructor behind me, in two 182's. FUN

[MikeD]

[ QUOTE ]
What are the regs on taking off or landing in formation? I have seen taking off, but not landing. Do they do that?

I have taken off in formation, with my instructor behind me, in two 182's. FUN

[/ QUOTE ]

Formation takeoffs/landings are authorized unless specific fields don't allow them. In the USAF, each aircraft type has it's own specific rules for formation takeoff/landings (wx, winds, runway width, etc) as well as each command and wing having their own specific procedures.

From a flight safety standpoint, what concerns me is someone that has performed formation takeoffs, then asks "what are the regs governing that?"

Word of caution, I DO NOT reccomend pilots that HAVEN'T been trained in formation flight to undertake this endeavor; it's VERY risky. There are specific items/procedures that those undertaking form flying, especially takeoffs and landings, MUST understand, both from a lead and wing perspective. These items MUST be briefed and clear prior to stepping to the aircraft.

Items such as when taking the runway for departure, where does the leader place the wingman and why? What procedures should be followed in the event of lead/wing needing to abort prior to, or during, takeoff roll? What formation references does the wingman use to remain in position? Why is the runway centerline considered a "brick wall" and what happens if either aircraft violates said wall? For form flying: What are lead/wing responsibilities for effecting rejoins? What are the clues for detecting an overshoot? What are the procedures for performing an overshoot?

These are just but a few, among many questions that pilots undertaking formation flight MUST know, at a minimum. If ANY incident arises from pilots performing formation flight who haven't been trained in same, the FAA will have an easy case to justify suspending, or possibly revoking, the pilot's certificate under the 14 CFR 91.13, Careless and Reckless Operation.

MD

[Snow]

[ QUOTE ]
You know what's interesting that I got less wake turbulence from a 777 than I got from a 757.

The 757's will rock your world, pardon the pun!

[/ QUOTE ]

Yeah I read a safety review on 757 wake turb, they are also allowed to fly steeper approaches or somthing?

They said a 737 behind a 757 had a breif uncontrolable rolling moment and that ain a small plane.