I don't know what the big deal is when it comes to a landing minima in Canada.
To continue an approach below a specified DH or MDA for that approach in Canada the visual requirements are "black and white" and very clear as follows...
Landing Minima (TC AIM October 12, 2017)…
CAR 602.128 specifies that landings are governed by published DH/MDAs.
Pilots of aircraft on instrument approaches are prohibited from continuing the final approach descent below DH or descending below MDA, as applicable, unless the required visual reference (see requirements below) has been established and maintained in order to complete a safe landing.
When the required visual reference is not established or maintained, a missed approach must be initiated. Pilots must be cautioned that the missed approach segment that provides for obstacle clearance originates at the published MAP. The published MAP on a precision approach is coincidental with the DH. Obstacle clearance will not be assured for missed approaches initiated beyond the MAP.
Certain published approaches that contain multiple lines of minima may have step-down altitudes that are lower than a published line of minima. Pilots should not descend to a stepdown altitude that is lower than the altitude on their selected line of minima.
The visual references required by the pilot to continue the approach to a safe landing should include at least one of the following references for the intended runway, and should be distinctly visible and identifiable to the pilot by:
(a) the runway or runway markings;
(b) the runway threshold or threshold markings;
(c) the touchdown zone or touchdown zone markings;
(d) the approach lights;
(e) the approach slope indicator system;
(f) the runway identification lights;
(g) the threshold and runway end lights;
(h) the touchdown zone light;
(i) the parallel runway edge lights; or
(j) the runway centreline lights.
So just seeing the ground or some lights while on the approach is a non starter.
It is of my opinion that the crew of that Air Canada flight saw "something" and decided to continue their descent below MDA without meeting any of the above requirements or did not control their aircraft and allowed it to descend below the MDA into the ground.
Last edited by Jet Jockey A4; 29th Oct 2017 at 18:41.