Advanced ATC Techniques Procedural Separation Part 1 – Controlled Airspace (CTA)

Topics we’ll be covering … Separation Standards. Navigation Tolerance. RNAV, DME and VOR separation techniques. Examples.

Disclaimer ~ words of warning ~ don’t try this in real life, even with strict supervision! All rules, suggestions, methodology & separation standards etc are specifically for online aviation simulation only. They have been modified &/or simplified for the online environment & are not to be used in the real world under any circumstances.

Separation Standards you already know. The Enroute Rating competencies set out by VATSIM include: Provide Separation in radar environment: 5nm Enroute 3nm TMA Provide time separation of aircraft in non-radar (procedural) environment: 10min (same track) 15min (crossing track)

Surveillance Tolerance - Radar Where do the 3nm and 5nm radar standards come from? Enroute Radar 5nm standard takes into account all possible errors (including operator error) associated with the radar surveillance equipment. Let’s refer to this error as “Surveillance Tolerance”. 5nm minimum VOZ886 314100 B737 360GS REX3458 210 210 S34 230GS Track error – accounts for aircraft’s possible position

Surveillance Tolerance - Radar You may reduce the lateral separation standard to 3nm, provided that aircraft are in communication with and under the control of a Terminal Control Unit (TCU) providing Class C services and are within 100nm of the radar sensor. The aircraft are now closer to the radar sensor, and the equipment is better (eg. Rotates/refreshes faster). Therefore the error is reduced and the separation standard can also be reduced. 3nm minimum VOZ886 122100 B737 280GS REX3458 105 090 S34 200GS Track error – accounts for aircraft’s possible position

Summary so far... Radar separation standards are based on the errors associated with the radar surveillance system. These standards have built in buffers that allow for the accuracy of the position of the radar paint plus a margin. Within the TMA, the radar standard is reduced to 3nm due to the reduced errors associated with the surveillance system at reduced range and increased refresh rate.

Australian radar coverage Let’s step out of our comfort zone and look at procedural standards to be used – EVERYWHERE ELSE. Current radar coverage areas (at F330). [ADSB coverage not shown and outside the scope of this presentation]

Procedural Standards Complicated? YES. Let’s simplify. Real life procedural standards are of course many. Real Air Traffic Controllers take 4 months to learn procedural control techniques and separation standards. As online controllers enjoying your hobby, you are not expected to be familiar with all of them. Time – T1a-e, T2, T3, T4, T5, T6, T7a-d, T7, T8a-b. Distance (DME) – D1, D2, D3, D4a-e, D5, D6, D7,D8a-c. RNAV – R1, R2, R3, R4, R5, R6, R7, R8. A free online source for these standards is the CASA Manual of Standards – Section 10. Standard in green are most commonly used online. Standards in orange are those introduced in the Enroute Rating moodle. Complicated? YES. Let’s simplify.

Assumptions The more complicated standards have many conditions that must be met to apply that standard. When operating online, we make some assumptions about the nav performance and equipment of aircraft to simplify the standards we apply: Time 10min time standard for same track. (T2) 15min time standard for crossing tracks. (T8a-b) Distance 20nm by DME. (D1, D2, D3) 30RNAV. (R3)

Longitudinal Standards Longitudinal standards are used to separate traffic on same, crossing or converging tracks. VATPAC uses just a few of these standards to simplify procedural control. To learn all procedural standards, enrol in ATC College.

Longitudinal Standards Time (Same Track):

Longitudinal Standards Time (Crossing Tracks):

Longitudinal Standards Distance (DME): 20nm for aircraft climbing, cruising or descending. Distance reports must be provided with enough frequency to ensure the minima is maintained. For aircraft at or above F290, both aircraft must be on the same side of the DME station. When aircraft are climbing to non vertically separated levels, both aircraft must report reaching their cruising levels.

Longitudinal Standards Distance (RNAV): Useful when time separation is no longer achieved. 30nm by RNAV derived distance reports. Not to be used in Oceanic Airspace. When aircraft are climbing to non vertically separated levels, both aircraft must report reaching their cruising levels. Example dialogue: ML-CTR: “Go-Cat 522 and Qantas 861, in turn report RNAV distance to RUSAD.” Go-Cat 522: “RNAV 110nm to run RUSAD. Go-Cat 522.” Qantas 861: “RNAV distance RUSAD 65nm. Qantas 861.”

Lateral Separation Lateral Separation techniques are used to determine when two aircraft - that are not on the same track – need to be separated using longitudinal or vertical means. Using a specific lateral navigational tolerance depending on the type of navigation in use by the aircraft, we apply the basic lateral separation minima. If two aircraft are separated by less than this minima, longitudinal or vertical separation must be applied.

The Basic Lateral Separation Standard. The Lateral Separation Standard is 1nm between the possible positions of two aircraft. 1nm? How is that so? In procedural airspace, all aircraft have a lateral tracking tolerance (or “cross-track error”) applied to ascertain the aircraft’s possible position. This tolerance accounts for all the possible variations and errors associated with the aircraft’s navigational equipment and the flight crew’s use of that equipment.

VOR Radial Tracking Tolerance VOR radials can be used to laterally separate aircraft. The lateral tracking tolerance for a VOR radial is 5.5°. Eg. An aircraft tracking outbound the 010 radial could in fact be anywhere between the 004 or 016 radial. The 15-16 rule (up to F290): Two aircraft tracking on radials separated by 15° will enter/leave lateral conflict at 16nm from the navaid.

RNAV Cross-Track Error 30nm RNAV lateral tolerance. The aircraft may be anywhere within 30nm either side of it’s reported track. Aircraft’s possible track This aircraft could be anywhere across 60nm! 30nm Aircraft’s reported track 30nm Aircraft’s possible track

RNAV Cross-Track Error We must apply a 30nm tolerance to determine if any two aircraft are to come into lateral conflict. Whilst in lateral conflict, any two aircraft MUST be separated by either longitudinal or vertical means. “ETA AS 0302z” “ETA AS 0301z” Current Time 0245z VOZ987 370 370 48 B737 Alice Springs VOR DME/RNAV Distance from AS ATC Instruction: “VOZ987, for separation climb and maintain non- standard F380. Requirement to reach F380 by XXnm from Alice Springs. Report Maintaining.” 30nm Tolerance Confliction Point! Where 1nm no longer exists between the two possible tracks. QFA123 370 370 49 B767

RNAV Cross-Track Error The following table can be used to determine the distance from a common point, two converging or diverging tracks enter or leave lateral conflict. RNAV Lateral Separation Tolerance - 30nm for use in CTA only. Angle Distance 10 354 30 116 50 66 70 44 11 322 31 112 51 65 71 43 12 295 32 108 52 64 72 13 272 33 105 53 62 73 42 14 252 34 101 54 61 74 41 15 235 35 98 55 60 75 40 16 221 36 95 56 58 76 17 207 37 93 57 77 39 18 196 38 90 78 19 185 88 59 79 20 176 85 80 21 167 83 81 22 159 82 23 152 63 24 146 84 25 140 45 49 26 134 46 48 86 27 129 47 67 87 28 124 68 29 120 69 89  

What we’ve covered … Longitudinal Separation Standards Lateral Separation Navigation Tolerance Cross-Track Error

Practical Examples VOR Radial – Alice Springs Override QFA1939 180090 28 B738 355 Radial Override CTR: “Co-ord, to you Qantas 1939, 737 inbound 355 radial, assigned 9000.” TWR: “Qantas 1939.” HVM: “16DME, HVM.” TWR: “HVM, contact CTR 134.2.” CTR: “HVM, climb and maintain flight level 340, report maintaining.” VHHVM 080 080 22 C500 TWR: “HVM, for separation turn left track outbound the 340 radial, report 16DME.” 340 Radial 350 Radial Recall 15-16 Rule! 15°-16nm VHHVM 036080 14 C500 AS VOR/DME

Practical Examples RNAV 30nm Cross Track Prior to entering lateral conflict, these aircraft require no separation standard to be applied. 30nm QFA1939 390 390 48 B738 Area of Conflict + Lateral Separation buffer (1nm) ANZAC 30° 124nm HVM: “ML-CTR, HVM request flight level 430.” ML-CTR: “HVM climb and maintain F430. Requirement to reach F400 by 124nm to run ANZAC.” VHHVM 380T430 44 C500

Caution re presentation content: Please bear in mind that this presentation grossly over-summarises all the real life separation standards & rules. There are many many more rules, hence the real ATC course being over 12 months, amazingly not just 40 minutes!  Naturally then, application of the previous standards would at times be not legally correct, & are just a general guideline for online controllers.

Questions ???