![\"RNAV](\"images\/RNAV_GPS_36.jpg\")
<\/p>\n<\/p>\n
When we layer on a non-precision approach coupled to our FMS ability to VNAV down a VDP from the FAF to the runway, the plot really thickens.\u00a0 If you have been flying lots of VNAV VDPs down to near the pavement without any problem, you are definitely in the danger zone.\u00a0 Add an approach briefing Lite where you fail, for example, to notice that there is no VASI or PAPI serving runway 36 and that the approach is not authorized at night, and your insurance rates are definitely going to go up.<\/p>\n
Lee\u2019s article does a good job of explaining a complex, TERPS-based subject.\u00a0 Many will not take the time to sort through the technical details, and that is understandable. Not many of us are or want to be TERPS techies.\u00a0 So here is the bottom line \u2013 on any non-precision approach it is possible to have obstacles that do not penetrate the surveyed Obstacle Clearance Surface (OCS) but can penetrate the VDP line between the FAF and the pavement.\u00a0 When this happens, you will not be able to tell it from the information on the published chart, although, as Lee explains, there may be clues.\u00a0 No VASI or PAPI, may be one of them.<\/p>\n
We and everybody else in the training world preaches that you are visual below the MDA, but Lee Smith\u2019s article puts some clothes on the concept.\u00a0 The risks are real \u2013 don\u2019t get bit.\u00a0<\/span><\/p>\n","protected":false},"excerpt":{"rendered":" Runway 36 at KBHM (Birmingham AL) is Lee\u2019s Poster Child and if you have ever flown an approach to it you will connect with this article in a personal way. For starters you are already in an environment of hills and low mountains, weather of one kind or another is often a factor, and there are plenty of man-made obstacles around to keep you interested. If you don\u2019t fly in there and to that specific runway frequently, you have just added another risk factor.<\/p>\n","protected":false},"author":19,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[143],"class_list":["post-239","post","type-post","status-publish","format-standard","hentry","category-blog","tag-obstaclesbelow-the-mdanon-precision-approachesadvanced-aircrew-academy-instrument-procedureslee-smithifr-magazineavwebfmsvnavvdpfafvasipapiterpsobstacle-clearance-surfaceocs"],"_links":{"self":[{"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/posts\/239","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/users\/19"}],"replies":[{"embeddable":true,"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/comments?post=239"}],"version-history":[{"count":1,"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/posts\/239\/revisions"}],"predecessor-version":[{"id":642,"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/posts\/239\/revisions\/642"}],"wp:attachment":[{"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/media?parent=239"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/categories?post=239"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/tags?post=239"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"iStock](\"images\/iStock_000008257473_Medium.jpg\")
We have written in the past about the dangers of obstacles below the MDA of non-precision approaches and our Advanced Aircrew Academy Instrument Procedures training also addresses this issue. More recently Lee Smith has written a piece that does a good job of explaining how the environment below the MDA can bite you. Originally published in IFR magazine, Lee\u2019s article was republished in March 2015 on AVweb. It is recommended reading and you will find it via this link<\/a>.<\/p>\n