Welcome to the enquiries forum. this is the place to ask questions relating to our books, our courses or the school. If you have a more specific problem relating to aviation theory, check out the Question and Answer forums. That's the best place to post your technical questions.
Carello created the topic: Instrument Rating Study Guide - July 2011
I was flicking through an old “Instrument Rating Study Guide” published July 2011 when I stumbled across a comment you made about descent below the LSALT by day.
More specifically the comment stated: “This does make you wonder a little about the idea of a visual approach. AIP ENR 1.1 par 2.11.8 says that you cannot commence a visual approach by day unless you are within 30nm of the destination aerodrome, but AIP GEN 3.3 p4.4 and CAR 178 says that if you are in VMC by day you can fly the entire trip below LSALT if you want to and you are still classified as an IFR flight. So what is the point of the 30 nm limit imposed by the AIP ENR 1.1 p2.11.8. If you meet anybody that can explain it – please let me know”
By way of an explanation, I would suggest that an IFR visual approach is not an approach in VMC. While IFR flight below the LSALT is allowable in VMC by day, an IFR visual approach permits descent below the LSALT within 30 nm of a controlled destination by day in conditions less than VMC. More specifically an IFR visual approach requires that “the pilot has established and can continue flight to the aerodrome with continuous visual reference to the ground or water; and the visibility along the flight path is not less than 5,000M, or for helicopters 800M, or the aerodrome is in sight”
In summary, by day an IFR flight can fly to the destination aerodrome below LSALT in VMC and once within 30 nm of a controlled aerodrome can continue to the destination in conditions less than VMC provided it is clear of cloud, insight of ground or water with a flight vis of 5000 m or the aerodrome in sight + other condition etc.
With the above in mind, the “30 nm limit” marks the point between VMC and non VMC conditions when an IFR flight is “visual” below the LSALT.
That being said, what are your thoughts? Am I barking up the wrong tree or just barking mad?
Please ignore this post if this question has been resolved since 2011!
bobtait replied the topic: Instrument Rating Study Guide - July 2011
The comment was intended for a pilot making a visual approach to a non-controlled aerodrome. I made that comment because I never could understand the point of the 30nm reference in practice. The definition of a visual approach in AIP ENR 1.5 para 1.15(a) makes no mention of the destination being in CTA so I guess it applies to all destinations. The visibility mentioned is 'in flight visibility' not 'along the intended flight path' so that's the same as VMC. It seems the only difference between the conditions described in the definition and VMC is the 'clear of cloud' rule for flight above 3000ft AMSL or 1000ft AGL. That seems rather pointless to me. Are there any pilots capable of accurately assessing 1000ft vertical and 1500m horizontal separation from cloud in flight anyway? That said, I'm the first to admit that the law is the law.
AIP ENR 1.1 para 2.11.8 details the controller's responsibility when authorizing a visual approach in CTA. In that case, the controller must be satisfied that visibility 'along the flight path' is not less than 5000m, otherwise he/she must not authorize a visual approach. The controller has no way of assessing the 'in flight' visibility since he/she is not in the cockpit - that is left to the pilot.
Carello replied the topic: Instrument Rating Study Guide - July 2011
I take your point that an IFR Visual Approach applies to all destinations - controlled and uncontrolled.
That being said, the point is that at 30 nm from the destination the conditions for visual flight below the LSALT etc... change from VMC to something less than VMC - ie clear of cloud. Given that VMC changes with the class of airspace, the clear of cloud requirement differs from VMC for flight above 3000'/1000' (AMSL/AGL) in uncontrolled airspace and for ALL levels in controlled airspace.
As for the question, "Are there any pilots capable of accurately assessing 1000ft vertical and 1500m horizontal separation from cloud in flight anyway?", the answer is are there any pilots capable of actually assessing VMC for VFR flight. I suppose an IFR pilot is supposed to be more experienced than a VFR private pilot. That being said, I do take your point.
In summary, the requirements for IFR visual flight below the LSALT etc... changes at 30nm - well at least on paper.