View Full Version : approach trick question?


Ajax 28
23rd Aug 2008, 17:10
Am I not understanding the concept right, or was i given wrong info..

the question is: What is the difference between a VMC approach and a visual approach?

I know that a visual approach is done in VMC conditions while on a IFR flight plan, so the answer should be, there is no difference, right??

The only difference i can see is that under a VMC approach, the crew must keep own separation, whereas with a visual approach you are afforded traffic separation..

any comments??



adz1616
23rd Aug 2008, 17:59
there is no such thing as VMC approach. VMC is only a condition

saucy jack
23rd Aug 2008, 20:08
Likewise, never heard of a "VMC Approach" as such, but here's my take on it.

It may refer to an Instrument Approach Procedure which happens to be carried out in VMC, in which case you must still comply with the full procedure as regards radials, step downs, speeds etc and you remain under positive ATC control at all times, including traffic separation, with assured terrain clearance.

During a visual approach the flight remains IFR but you are left to your own devices, and this includes traffic/obstacle separation. Hence you may well be asked for confirmation that preceding traffic (if any) is in sight before the visual is approved and will remain so until touchdown, although traffic information may be passed to you subsequently.

Just my thoughts...not sure if this is what they are getting at.

Ajax 28
23rd Aug 2008, 20:15
yeah, i dont know... bit of a weird question... will have to leave it to the guys with 20000hrs to explain that one...

btw... thats an interview question i got from someone..

bArt2
23rd Aug 2008, 20:16
I learned about this in the USAF, I am not aware of it being described in used in civil regulations however:

I copy pasted this out of the AFMAN 11-217 which is the USAF IFR flying manual (formerly known as AFMAN 51-37)



14.3. Visual Approach.
Visual approaches reduce pilot/controller work load and expedite traffic by

shortening flight paths to the airport. A visual approach is conducted on an IFR flight plan and

authorizes the pilot to proceed visually and clear of clouds to the airport. The pilot must have either the
airport or the preceding identified aircraft in sight, and the approach must be authorized and
controlled by the appropriate ATC facility.
14.3.1. Conditions Required to Conduct Visual Approaches.





Before a visual approach can be

authorized, several conditions must be met:

14.3.1.1. 1,000 and 3 at the Airport.




The reported weather at the airport must have a ceiling at

or above 1,000 feet and visibility 3 miles or greater.

14.3.1.2. Operational Benefit.




ATC will authorize visual approaches when it will be

operationally beneficial.

14.3.1.3. Cloud Clearance Requirements.
Visual approaches are IFR procedures conducted
under IFR in visual meteorological conditions (VMC) with one exception -- cloud clearance
requirements described in AFI 11-202, Vol 3, para 7.3, are not applicable. Pilots must be able to
proceed visually while remaining clear of clouds.



14.3.1.4. Airport or Preceding Aircraft in Sight.
ATC will not issue clearance for a visual
approach until the pilot has the airport or the preceding aircraft in sight. If the pilot has the
airport in sight but cannot see the preceding aircraft, ATC may still clear the aircraft for a visual
approach; however, ATC retains both aircraft separation and wake separation responsibility.
When visually following a preceding aircraft, acceptance of the visual approach clearance
constitutes acceptance of pilot responsibility for maintaining a safe approach interval and adequate
wake turbulence separation.



14.3.2. A Visual Approach is an IFR Approach.
Although you are cleared for a “visual”


approach, you are still operating under IFR.
Do not cancel your IFR clearance when cleared for a
visual approach. Be aware that radar service is automatically terminated (without advising the pilot)
when the pilot is instructed to change to advisory frequency.



14.3.3. What ATC Expects You to Do When Cleared for a Visual Approach.
After being
cleared for a visual approach, ATC expects you to proceed visually and clear of clouds to the airport
in the most direct and safe manner to establish the aircraft on a normal straight-in final approach.
Clearance for a visual approach does not authorize you to do an overhead/VFR traffic pattern.



14.3.4. Visual Approaches Have No Missed Approach Segment.
A visual approach is not an
instrument approach procedure and therefore does not have a missed approach segment. If a goaround
is necessary for any reason, aircraft operating at controlled airports will be issued an
appropriate advisory, clearance, or instruction by the tower. At uncontrolled airports, aircraft are
expected to remain clear of clouds and complete a landing as soon as possible. If a landing cannot be
accomplished, the aircraft is expected to remain clear of clouds and contact ATC as soon as possible
for further clearance (separation from other IFR aircraft will be maintained under these
circumstances).



14.3.5. Pilot Responsibilities During Visual Approaches.
When cleared for a visual approach, the
pilot has the following responsibilities:



14.3.5.1.
Advise ATC as soon as possible if a visual approach is not desired.


14.3.5.2.
Comply with controller’s instructions for vectors toward the airport of intended
landing or to a visual position behind a preceding aircraft.



14.3.5.3.
After being cleared for a visual approach, proceed visually and clear of clouds to the
airport in the most direct and safe manner to establish the aircraft on a normal final
approach. You must have the airport or the preceding aircraft in sight.



14.3.5.4.
If instructed by ATC to follow another aircraft, notify the controller if you do not
see it, are unable to maintain visual contact with it, or for any other reason you cannot accept
the responsibility for visual separation under these conditions.



14.4. Contact Approach. An approach where an aircraft on an IFR fight plan, operating clear of clouds
with at least 1 mile flight visibility and having an ATC authorization, may deviate from the instrument
approach procedure and proceed to the airport of destination by visual reference to the ground. This
approach will only be authorized when requested by the pilot and the reported ground visibility at the
destination is at least 1 statute mile.
NOTE: Being cleared for a visual or contact approach does not authorize the pilot to fly a 360°
overhead traffic pattern. An aircraft conducting an overhead maneuver is VFR and the instrument flight
rules (IFR) flight plan is canceled when the aircraft reaches the “initial point.” Aircraft operating at an
airport without a functioning control tower must initiate cancellation of the IFR flight plan prior to
executing the overhead maneuver or after landing.


Bart

bArt2
23rd Aug 2008, 20:32
See also: Weekly Topic (http://bathursted.ccnb.nb.ca/vatcan/fir/moncton/weeklytopics/Archives/20030406/CurrentTopic.html)

Spitoon
23rd Aug 2008, 20:55
When about a VMC approach I think you are referring to what used to be called 'approach maintaining VMC and own separartion'. I don't think this has been used in the UK for several years but ICAO describes it in PANS-ATM para 5.9 as below:

CLEARANCES TO FLY MAINTAINING OWN SEPARATION WHILE IN VISUAL METEOROLOGICAL CONDITIONS
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.So the key difference is that with a visual approach ATC provides sepaarartion whereas during a 'VMC approach', where it is allowed, the pilot provides the separation/collision avoidance.

Ajax 28
23rd Aug 2008, 21:10
spitoon.. i think you are right with that last bit... thats the only difference i can find as well...

thanks to all the guys who replied and helped out