Procedural Longitudinal Separation

Question 1

In a non-radar environment (Procedural) are we using exact or estimated positions of aircraft?

Answer 1

Estimated

Question 2

How can longitudinal separation be achieved in a procedural environment?

Answer 2

Ensuring aircraft depart at a specified time
Getting aircraft to arrive over a geographical location at a specified time
Holding aircraft over a geographical location until a specified time

Question 3

What is the time based departure separation required between aircraft flying on tracks diverging by at least 45 degrees in a procedural environment?

Answer 3

1 minute

Subject to wake turbulence

Question 4

What is the time based departure separation required when two aircraft are following the same track and the preceding aircraft is 40 kts faster than the following in a procedural environment?

Answer 4

2 minutes

Subject to wake turbulence

Question 5

When can the departing aircraft separation be reduced in a procedural environment?

Answer 5

When aircraft are using parallel or non-crossing runways, when it has been approved by the authority and lateral separation is effected immediately after takeoff.

Question 6

What separation is required if a following aircraft will fly through the level of a preceding aircraft while flying the same track in a procedural environment?

Answer 6

5 minutes

This must be maintained or increased while vertical separation does not exist.

Question 7

What must ATCOs be cautious of when applying just time or distance-based longitudinal separation between aircraft on the same track in a procedural environment?

Answer 7

If the following aircraft is maintaining a higher airspeed than the preceding.

Question 8

Other than level, how can longitudinal separation be achieved between aircraft following the same track or diverging track in a procedural environment?

Answer 8

By the application of speed control, including the Mach number technique.

Question 9

Define Same Track

Answer 9

Same direction tracks where the angular difference is less than 45 Degrees and the protection areas overlap

Question 10

Define Reciprocal Track

Answer 10

Opposite direction tracks where the angular difference is more than 135 Degrees or less than 225 degrees and the protection areas overlap

Question 11

Define crossing tracks

Answer 11

Intersecting tracks where the angular difference is not Same and Reciprocal.

Question 12

What is the standard time based longitudinal separation to be used for aircraft on the same level and track in a procedural environment?

Answer 12

15 minutes while vertical separation does not exist

Question 13

If navaids permit frequent determination of position and speed, what time based longitudinal separation must be used for aircraft on the same level and track in a procedural environment?

Answer 13

10 minutes while vertical separation does not exist

Question 14

If two aircraft have reported the same point, or departed the same aerodrome and the preceding aircraft has a TAS of 20kts higher, what time based longitudinal separation must be used for aircraft on the same level and track in a procedural environment?

Answer 14

5 minutes while vertical separation does not exist

Question 15

If departing aircraft is joining an en-route, what time based longitudinal separation must be used for aircraft on the same level and track in a procedural environment?

Answer 15

5 minutes if the preceding aircraft has a 20kt higher TAS, while vertical separation does not exist

Question 16

When can the 5 minute time based longitudinal separations for aircraft on the same track and level be reduced?

Answer 16

When the preceding aircraft has a 40kt higher TAS the separation can be reduced to 3 minutes, while vertical separation does not exist

Question 17

What is the standard time based longitudinal separation to be used for aircraft on a crossing track at the same level in a procedural environment?

Answer 17

15 minutes, while vertical separation does not exist

Question 18

What is the European time based longitudinal separation to be used for aircraft on a crossing track at the same level in a procedural environment?

Answer 18

10 minutes, as Navaids allow frequent determination of position and speed, while vertical separation does not exist

Question 19

What is the standard distance based longitudinal separation to be used for aircraft on the same track and level in a procedural environment?

Answer 19

20nm provided both aircraft use “on-track” DME stations, or both use GNSS

Or 10nm if the lead aircraft is flying a TAS 20kts or more faster

Question 20

What is the standard distance based longitudinal separation to be used for aircraft on a crossing track and same level in a procedural environment?

Answer 20

20nm provided both aircraft use “on-track” DME stations, or both use GNSS

Or 10nm if the lead aircraft is flying a TAS 20kts or more faster

Question 21

What is the standard distance based longitudinal separation to be used for aircraft on the same track but climbing/descending in a procedural environment?

Answer 21

10nm while vertical separation does not exist provided one aircraft is maintaining a level and both aircraft use “on-track” DME stations, or both use GNSS

Question 22

What is the standard distance based longitudinal separation to be used for aircraft on a reciprocal track but climbing/descending in a procedural environment?

Answer 22

10nm while vertical separation does not exist provided one aircraft is maintaining a level and both aircraft use “on-track” DME stations, or both use GNSS

Question 23

When are Mach numbers normally used?

Answer 23

For fairly high level, FL250 and above

Question 24

If two aircraft are using the same Mach number at the same level, will they have the same TAS?

Answer 24

Yes. Two aircraft at the same level with the same Mach will have the same TAS.

Question 25

What is the standard time based longitudinal separation for aircraft on the same track and level using the Mach Number Technique

Answer 25

10 minutes, unless 98765, 23456.