On a IFR flight to a small airport, the FMC function to select an approach, had "NDB-A" shown. What does that stand for? Where could I learn more about this type of approach?Thanks,jim

An NDB approach uses a non-directional beacon for guidance to the runway. The suffix means the final approach course is not aligned with the runway. They are becoming more and more obsolete. More here: http://www.flightsimbooks.com/learning/flight23.php

If I recall correctly, approaches that have a letter next to them, like VOR-A or GPS-A or NDB-A, are approaches that do not have straight-in landing minimums to any specific runway. This means that the only way to land using a -A approach is to circle to land on the active runway. Note that the name of the approach has no runway mentioned, unlike some that do.Example: The VOR-A approach is commonly used at KTEB with many corporate jets. The approach brings them over mid-field, where they can then join various downwind legs for landing.Obviously this approach is used when it is VFR. When IFR an ILS runway would be used or, if available, a VOR approach dedicated to a specific runway, in which case straight in landing minimums would be available.Regards,http://www.dreamfleet2000.com/gfx/images/F...R_FORUM_LOU.jpg

Yup, NDB-A and -B approaches are used in Beef Island, here's the chart of the NDB-B to illustrate what was said above.http://forums.avsim.net/user_files/144183.jpgDaniel P.http://www.precisionmanuals.com/images/forum/supporter.jpgMember of SJU Photography. [A HREF=http://www.jetphotos.net/showphotos.php?userid=9004]Click Here[/A] to view my aircraft photos at JetPhotos.Net!The official psychotic AA painter. :)

CIRCLING ONLY PROCEDURESApproaches that do not have straight-in landingminimums are identified by the type of approachfollowed by a letter. Examples in figure 5-6 showfour procedure titles at the same airport that haveonly circling minimums.As can be seen from the example, the first approach ofthis type created at the airport will be labeled with theletter A, and the lettering will continue in alphabeticalorder. Circling-only approaches are normally designedfor one of the following reasons:

Thanks. This is exactly what I wanted to know.Jim

Jim, What aircraft are you using, can you post a link to it, I'd like to have a look at that FMS.Thanks

Lou Betti wrote:>Obviously this approach is used when it is VFR. When IFR an>ILS runway would be used or, if available, a VOR approach>dedicated to a specific runway, in which case straight in>landing minimums would be available.Circling approaches are not restricted to VFR-only conditions. The minima are typically (but not always) higher than straight-in approaches, but circling is an approved IFR procedure. Certainly a straight-in, if available, might be preferred, but again not always. It might be that the only available straight-in would require landing with tailwinds or crosswinds out of limits, for example.San Bernardino International (KSBD) for example, does not have straight in approaches to rwy 24 due to mountainous terrain to the northeast...so if there are 700 ft ceilings, 2.5 miles vis, winds 240/25G35, the localizer to rwy 6 circle to rwy 24 is the only IFR approach option.CheersBob ScottATP IMEL Gulfstream II-III-IV-V L-300Santiago de Chile

>Circling approaches are not restricted to VFR-only conditions.>Bob, very good point. If conditions were VFR you would not need an IFR approach in the first place ;)Michael J.http://www.precisionmanuals.com/images/forum/pmdg_744F.jpghttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg

Bob,At KTEB the VOR A IS flown under VFR conditions- period. As there are two ILS approaches to 6 and 19, and those are the only two runways.I am well aware that a circling approach can be flown under IFR conditions, but do not want to mislead folks to think that such would be flown when the weather is the same as the minimums for an ILS approach.I too have circled to land on a VOR A under IFR conditions, however, the weather was not 300 and 1/2 either. ;-)Regards,http://www.dreamfleet2000.com/gfx/images/F...R_FORUM_LOU.jpg