RVSM / MNPS

03-01-2003

1 - RVSM - Generalities :

A long time ago, due to reliability of flight instruments lower than now, it was decided to apply a minimum vertical separation of 2000 ft above the FL 290, keeping a 1000 ft spacing below this level. So until now, we had the CVSM (Conventional Vertical Separation Minimum) as follows :

- 1000 ft spacing below FL 290

- 2000 ft spacing above FL 290.

From 02 February, 2002, this rule has changed also changed in South-East Asia with the implementation of the RVSM (Reduced Vertical Separation Minimum). This is due to the quality of flight instruments now installed onboard aircraft. They are more reliable and more accurate that those of the previous decades. Considering this fact, in addition to the necessity of increasing the control capacity in upper airspace sectors, it was decided to reduce the spacing from 2000 to :

- 1000 ft between FL 290 and FL 410.

The semi-circular rule (NEodd-SEeven rule) is then modified as follows :

Hdg  000 -  179 Hdg 180 - 359   Hdg 000 - 179 Hdg 180 - 359
ODD LEVELS

CVSM (old)

EVEN LEVELS

CVSM (old)

  ODD LEVELS

RVSM (new)

EVEN LEVELS

RVSM (new)

FL 50

FL 70

FL 90

FL 110

FL 130

FL 150

FL 170

--USA-CAN-----------

FL 190

FL 210

FL 230

FL 250

FL 270

FL 290

-------------------------

FL 330

FL 370

FL 410

FL 450

FL 490

FL 530

...

FL 40

FL 60

FL 80

FL 100

FL 120

FL 140

FL 160

--USA-CAN-----------

FL 180

FL 200

FL 220

FL 240

FL 260

FL 280

---------------------------

FL 310

FL 350

FL 390

FL 430

FL 470

FL 510

...

 

  FL 50

FL 70

FL 90

FL 110

FL 130

FL 150

FL 170

--USA-CAN------------

FL 190

FL 210

FL 230

FL 250

FL 270

FL 290

----------------------------

FL 310

FL 330

FL 350 

FL 370

FL 390

FL 410

-------------------------

FL 450

FL 490

 

FL 40

FL 60

FL 80

FL 100

FL 120

FL 140

FL 160

--USA-CAN------------

FL 180

FL 200

FL 220

FL 240

FL 260

FL 280

----------------------------

FL 300

FL 320

FL 340

FL 360

FL 380

FL 400

--------------------------

FL 430

FL 470

 

   

6 new even FLs are thus created.

3 even levels in the former system are now odd.

CVSM is still applied above FL 410.

 

Note: Please remember that the transition altitude at most airports in Thailand is 11000ft !

2 - RVSM - Airspaces concerned :

RVSM has been or will be implemented in most areas of the word as the following picture shows:.

It has been introduced in our areas in February, respectively October 2002. We can assume that all airspace adjoining to VTBB-CTR (including Laos, Cambodia and Burma) are RVSM aispaces where the above rules apply.

3 - MNPS - RVSM approval :

MNPS stands for Minimum Navigation Performance Specifications, representing those requested for an aircraft to be RVSM approved. These MNPS are for middle/long range aircraft able to fly above FL 290. 

Being simple, as far as real life is concerned, say those aircraft can fly into RVSM airspace if they are equipped with :

- a redondancy of altitude check devices, with high standards of accuracy and reliability.

- a new generation TCAS.

- an autopilot with advanced altitude hold features.

All aircraft which came out from factories these last 5 or 6 years match with these specifications. Most of other planes have been modified to be RVSM approved, thus bringing to about 94% the rate of aircraft concerned by RVSM which are effectively RVSM approved.

Some old generation aircraft (DC-8, DC-9, B707, some first generation FALCONs...) don't have been updated because their operators found that was too expensive. Also, some military aircraft, and particularly combat aircraft, are not RVSM approved (technical and operational imperatives are different from those requested for commercial aircraft).

So what about RVSM approval for virtual aircraft ?

- The present design of panels doesn't enable the implementation of independent altimeters. Every panel has at least one altimeter. When more than one is available, they all show the same indications.

- The TCAS is integrated in Squawkbox and thus, available for all aircraft. We consider that the one integrated into SB version 2.3 or higher is a new generation TCAS ;-)))

- Only autopilots are really different from one panel to another but they all have a reliable altitude hold feature.

4 - RVSM / MNPS policy of IVAO :

The only MNPS applicable in the sim world are the altimeter and the autopilot to be fully operational.

Therefore we consider that all aircraft capable of flying above FL 290 are RVSM approved.

However an aircraft is considered as NON-RVSM if :

- the pilot wants to play it that way and specifies this into the FP. 

=> NON-RVSM indicated in Remarks field (if not, aircraft will be considered as RVSM approved).

=> RVSM flight levels (300-320-340-360-380-400) may be filed in FP but flying into the RVSM airspace (between FL 290 and 410 inclusive) may be refused by a CTR controller according to his/her workload.

- an autopilot and/or altimeter failure occurs (for those using CH Client or the failure features of FS).

=> to be declared to the CTR controller who will keep the aircraft into RVSM airspace as much as possible and apply a 2000 ft spacing instead of the new 1000 ft standard.

Therefore :

- RVSM aircraft have no restrictions (the large majority of sim aircraft concerned).

- non-RVSM aircraft may be accepted or refused into RVSM airspaces according to the CTR traffic workload.

Into RVSM airspaces, CTR controllers concerned use RVSM levels where applicable as follows :

- according to new RVSM semi-circular system shown above (except otherwise indicated on nav charts).

- 1000 ft spacing for RVSM approved aircraft.

- 2000 ft spacing for :

. non-RVSM aircraft subsequently to a failure.

. non-RVSM aircraft indicated into the FP if traffic permits (if not, aircraft will be asked to remain out of RVSM airspace, that is to say below FL 290 or above FL 410 except for climb/descent phases of the flight).

 

- Handoffs of flights using RVSM FLs must be particularly coordinated (by chat) from one CTR controller to the next.

 

- See national procedures for transitions between RVSM and NON-RVSM airspaces when applicable due to the problems shown below :

 

Odd flightlevels between FL310 and FL390 are heading in opposite
direction and such a situation should be avoided in any case.

5 - SUMMARY :

* Into RVSM countries and areas :

- vertical spacing is 1000 ft below FL 410 except for particular case (see below).

- vertical spacing is 2000 ft above FL 410.

(quite simple, same as before with 410 instead of 290).

- FL 300, 320, 340, 360, 380 and 400 may now be filed in FP.

- Chat coordination between CTRs highly recommended, particularly for transitions with non-RVSM airspaces.

* Particular case :

- controllers apply 2000 ft spacing in RVSM areas between FL 290 and 410 with non-RVSM aircraft if traffic permits.

- pilots of non-RVSM aircraft have to leave (or remain out of) RVSM airspace if requested by the CTR controller.

- an aircraft is non-RVSM if :

. specified in FP - this is a pilot choice.

. failure of autopilot and/or altimeter - to be declared to the controller.

(This document has been taken from the IVAO-training pack and adapted for the use in Thailand)
Even though all frequencies and codes SHOULD be real,
they are only for use with ProController, SquawkBox and Flight Simulators,
and should NOT be used for real life aviation.

2001-2002 - IVAO TH - All Rights Reserved