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-   -   Vmc Maneuver (https://www.pprune.org/atc-issues/364144-vmc-maneuver.html)

Cash Machine 28th February 2009 11:19

Vmc Maneuver
 
are vmc maneuver and circling approach the same thing ? if not then why ?:)

goatface 28th February 2009 12:51

If I understand your question correctly, they are two entirely different things:

The "circling to land after an instrument approach" is a procedure which can take place within a specified radius of the airfield, (usually within the normal visual circuit pattern), and involves an IFR aircraft making an instument approach to one runway then circling to land on another.
The height of obstacles within that area is taken into account when the visual manouvering height for the procedure is calculated.
If the cloud base is below the published visual manouvering height for the aircraft category at the airfield, then circling to land is not permitted.

If you are thinking of "an approach maintaining VMC", that went out the books many years ago, and is now known as a "Visual Approach".
A visual approach is normally conducted when an a/c flying an IFR approach to a particular runway, wishes to continue visually - usually cutting the corner onto final approach - but still to land on that runway.
The aircraft is still treated as IFR and the clearance to conduct the approach is only given by ATC if the weather minima is suitable and traffic levels permit.

Hope that helps.

bookworm 28th February 2009 14:38


are vmc maneuver and circling approach the same thing ? if not then why ?
"vmc maneuver" as you write it is not a standard phrase and might be interpreted as a "maneuver" in Visual Meteorological Conditions. "Visual Manoeuvring (Circling)" is the standard ICAO phrase used for what is commonly called a "circling approach". Unfortunately, it is sometimes abbreviated to VM(C) which leads to confusion with Visual Meteorological Conditions.

2 sheds 28th February 2009 16:05

Cash Machine

As, according to your profile, you are an ATCO, perhaps you could enlighten us as to where you have seen these terms, particularly the first?

2 s

mad_jock 28th February 2009 16:21

To be honest the way I read it, it said to me procedural.

"slowburd xxx visual with traffic on the nose, request visual climb against"

2 sheds 1st March 2009 11:25

What sort of phraseology/procedure is that?!

niknak 1st March 2009 12:18

Its Scottish for "request VMC climb/descent...." :p;)

mad_jock 1st March 2009 20:32

From my limited pilots side of things.

For you to get a VMC climb/decent against, you have to tell the procedural controller that your visual with the traffic he is separating you against and give him some hint that its the right one. Normally they will have one coming in on an advisory route and one going out. Hence the "on the nose"

If you give it to him in one call, his next call will be to the other aircraft asking if they will accept a VMC climb/decent against you. Unless its another pilot used to operating in and out those types of fields they won't have a clue what the controller is on about. But usually accept it because the controller has offered it.

As you pass each other with a wave the procedural controller then transfers you over to a scottish area controller who is usually abit pissed off because all his separation alarms have gone off because 2 IFR aircraft with a scottish squawk have been within 1 mile of each other at the same altitude.

Does that sound about right Niknak?

Jumbo Driver 1st March 2009 21:06


Originally Posted by Cash Machine (Post 4754155)
are vmc maneuver and circling approach the same thing ? if not then why ?:)

If, by "vmc maneuver", you mean "Visual Manoeuvring (Circling)" as mentioned in CAP493 (MATS Part 1), Section 1 Chapter 6 (page 3) ...

7 Procedures at Aerodromes
7.4 Visual Manoeuvring (Circling)
7.4.1 If an aircraft makes an instrument approach that is to be followed by a visual manoeuvre (circling) to land on another runway, as appropriate, the QFE aerodrome or QFE threshold is to be given.


... then, IMHO, this is the same as a "circling approach".

An IFR Approach to Visual Circling limits is (as goatface describes) an instrument approach to one runway, followed by a break-off at or above Visual Circling limits to enable a fully visual approach to another (usually into wind) runway.

An example would be to use an ILS or VOR/DME approach to R/W 31 at Seychelles (SEZ) as a cloudbreak procedure in a tailwind, followed by a break-off to a visual approach to land into wind on R/W 13.


JD
:)

Spitoon 2nd March 2009 06:21

It's not clear where Cash Machine comes from so rather than confuse things with national/UK procedures, here are some relevant extracts from ICAO:

PANS-OPS
7.2 VISUAL FLIGHT MANOEUVRE

7.2.1 A circling approach is a visual flight manoeuvre. Each circling situation is different because of variables such as runway layout, final approach track, wind velocity and meteorological conditions. Therefore, there can be no single procedure designed that will cater for conducting a circling approach in every situation.

PANS-ATM
5.9 CLEARANCES TO FLY MAINTAINING OWN SEPARATION WHILE IN VISUAL METEOROLOGICAL CONDITIONS

Note 1.— As indicated in this Section, the provision of vertical or horizontal separation by an air traffic control unit is not applicable in respect of any specified portion of a flight cleared subject to maintaining own separation and remaining in visual meteorological conditions. It is for the flight so cleared to ensure, for the duration of the clearance, that it is not operated in such proximity to other flights as to create a collision hazard.

Note 2.— It is axiomatic that a VFR flight must remain in visual meteorological conditions at all times. Accordingly, the issuance of a clearance to a VFR flight to fly subject to maintaining own separation and remaining in visual meteorological conditions has no other object than to signify that, for the duration of the clearance, separation from other aircraft by air traffic control is not provided.

Note 3.— The objectives of the air traffic control service as prescribed in Annex 11 do not include prevention of collision with terrain. The procedures prescribed in this document do not relieve pilots of their responsibility to ensure that any clearances issued by air traffic control units are safe in this respect. When an IFR flight is vectored by radar or is given a direct routing which takes the aircraft off an ATS route, the procedures in Chapter 8, 8.6.5.2 apply.

When so requested by an aircraft and provided it is agreed by the pilot of the other aircraft and so authorized by the appropriate ATS authority, an ATC unit may clear a controlled flight, including departing and arriving flights, operating in airspace Classes D and E in visual meteorological conditions during the hours of daylight to fly subject to maintaining own separation to one other aircraft and remaining in visual meteorological conditions.

When a controlled flight is so cleared, the following shall apply:

a) the clearance shall be for a specified portion of the flight at or below 3 050 m (10 000 ft), during climb or descent and subject to further restrictions as and when prescribed on the basis of regional air navigation agreements;

b) if there is a possibility that flight under visual meteorological conditions may become impracticable, an IFR flight shall be provided with alternative instructions to be complied with in the event that flight in visual meteorological conditions (VMC) cannot be maintained for the term of the clearance;

c) the pilot of an IFR flight, on observing that conditions are deteriorating and considering that operation in VMC will become impossible, shall inform ATC before entering instrument meteorological conditions (IMC) and shall proceed in accordance with the alternative instructions given.


6.5.3 Visual approach

6.5.3.1 Subject to the conditions in 6.5.3.3, clearance for an IFR flight to execute a visual approach may be requested by a flight crew or initiated by the controller. In the latter case, the concurrence of the flight crew shall be required.

6.5.3.2 Controllers shall exercise caution in initiating a visual approach when there is reason to believe that the flight crew concerned is not familiar with the aerodrome and its surrounding terrain. Controllers should also take into consideration the prevailing traffic and meteorological conditions when initiating visual approaches.

6.5.3.3 An IFR flight may be cleared to execute a visual approach provided the pilot can maintain visual reference to the terrain and:

a) the reported ceiling is at or above the approved initial approach level for the aircraft so cleared; or

b) the pilot reports at the initial approach level or at any time during the instrument approach procedure that the meteorological conditions are such that with reasonable assurance a visual approach and landing can be completed.

6.5.3.4 Separation shall be provided between an aircraft cleared to execute a visual approach and other arriving and departing aircraft.

6.5.3.5 For successive visual approaches, radar or non-radar separation shall be maintained until the pilot of a succeeding aircraft reports having the preceding aircraft in sight. The aircraft shall then be instructed to follow and maintain own separation from the preceding aircraft. When both aircraft are of a heavy wake turbulence category, or the preceding aircraft is of a heavier wake turbulence category than the following, and the distance between the aircraft is less than the appropriate wake turbulence minimum, the controller shall issue a caution of possible wake turbulence. The pilot-in command of the aircraft concerned shall be responsible for ensuring that the spacing from a preceding aircraft of a heavier wake turbulence category is acceptable. If it is determined that additional spacing is required, the flight crew shall inform the ATC unit accordingly, stating their requirements.

6.5.3.6 Transfer of communications to the aerodrome controller should be effected at such a point or time that information on essential local traffic, if applicable, and clearance to land or alternative instructions can be issued to the aircraft in a timely manner.

8.9.5 Vectoring for visual approach

8.9.5.1 The radar controller may initiate radar vectoring of an aircraft for visual approach provided the reported ceiling is above the minimum altitude applicable to radar vectoring and meteorological conditions are such that, with reasonable assurance, a visual approach and landing can be completed.

8.9.5.2 Clearance for visual approach shall be issued only after the pilot has reported the aerodrome or the preceding aircraft in sight, at which time radar vectoring would normally be terminated.
There's plenty more where that came from. I reccommend PANS-OPS and PANS-ATM for further bedtime reading.

Jumbo Driver 2nd March 2009 07:59

All very interesting, spitoon ...

... but I confess I am confused as to which bits exactly of those rather tedious extracts you are suggesting are relevant to answering Cash Machine's original question ... :confused:

JD
:)

Spitoon 2nd March 2009 16:17

Well.... I thought the first bit that said 'A circling approach is a visual flight manoeuvre.' might be the closest to clarifying Cash Machine's the issue in original question.

And the rest, tedious or otherwise, might have helped to identify some other type of procedure that was relevant.

Just trying to help really.


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