Good points
OzExpat, but more emphasis is still required on how non precision approaches should be flown.
Captain Smiley asked for information on stabilized approaches
and constant angle non precision approaches. The critical issue is that both must go together as one in the same procedure. There have been many accidents where crew have flown NPAs with an ILS type of operation; configuring the aircraft and decelerating whilst descending, and then forgetting that they are responsible for judging / controlling the ‘glidepath’. If an NPA is flown in VS mode (FD, autopilot, or crew computation) then as the aircraft decelerates the required vertical speed reduces. Simple, obvious, basic … but so often forgotten; an error, which allows the aircraft to descend below the optimum glidepath.
A NPA requires special briefing with respect to the method of controlling the aircraft to achieve a constant angle approach
and to achieve speed / configuration stability on which to judge corrections to the approach. Without these the approach is like a moving target, the crew may loose position awareness, or lack knowledge of distance or time to go; all of which add to workload and increase the operating risk. And do not forget that an ILS with GS inop is a NPA.
All NPA charts should have a range / altitude table so that crews can judge how the accurately the glidepath is being followed; crews should always estimate the required vertical speed and time to visual descent point or MAP. Charts should also show the VDP on the profile or the distance to go table.
Re European stabilized approaches and constant angle non precision approaches; the JAA Ops / all-weather ops groups were drafting new information for JAR-OPS 1 subpart D/E to be published as an ACJ. When I last viewed the information it was an awful mess mixing up constant angle with stabilized parameters. It also suggested that crews would have to have extensive training and yearly practices / assessments of how to fly a stabilized approach; if this isn’t basic every day flying, controlling speed, altitude, and VS, then what standard of crew expertise is the JAA using? Has this new information reached JAR-OPS 1 yet? Has anyone any update on the so-called harmonization of CANPA with the FAA?
Edit:
More links:
Other Articles - Constant Angle Non-Precision Approach this document also has other links, some pro CANPA and some cons, read these carefully and relate them to GA / commercial operations as appropriate.
An Alternative to Dive and Drive
An interesting view from virtual reality
CANPA JAA RNAV info including approaches: see
Day Three