As it turns out, AC 90-108, in Paragraph 8 b, specifically prohibits the use of the FMS\/RNAV system as a substitute for the lateral guidance provided by the ground based nav-aid during the final approach segment. It seems pretty clear to this reader, and to others with knowledge of the subject with whom we have spoken.<\/span><\/p>\n So what\u2019s the problem? If there is a problem, it may be that very few of us are actually observing that prohibition. Let\u2019s face it, which procedure is easier to use, more accurate, and arguably safer\u2014flying a raw data VOR approach to a manually calculated VDP or flying it as an FMS approach with VNAV to the MDA? The answer to that is a no-brainer.<\/span><\/p>\n While the AC prohibition was established with TERPS-related issues in mind, it seems today a lonely beacon from the past in a world moving rapidly towards all things PBN. So here we have one of those interesting dichotomies between the regs and what\u2019s happening in the real world of operations, similar, let\u2019s say, to the regulatory requirement for a pilot to wear a truly painful and unsuitable piece of emergency equipment (oxygen mask) during normal operations (above specified altitudes). In both these cases, some would observe that it ain\u2019t happenin\u2019.<\/span><\/p>\n Meanwhile, the FAA has been alerted to the FMS approach issue and is looking at it. The easy fix will be to include the prohibition from AC 90-108 in the AIM. Hhmm. Stay tuned.<\/span><\/p>\n","protected":false},"excerpt":{"rendered":" In theory, you have a range of choices. On the one end of the spectrum, you can fly the approach the old fashioned way\u2014completely \u2018raw-data\u2019. Tune and check the VOR, dial in the final approach course in the HSI or equivalent, and maybe hack a watch somewhere along the way, just like you did when you were working on your instrument rating way back when. <\/span>On the other hand, you select the approach from the FMS menu and fly it as an \u2018FMS approach\u2019 without ever tuning in the VOR or displaying any VOR raw-data information. In between is the option of flying the FMS version, but having some or all of the VOR info up somewhere on the panel, maybe on the Pilot Monitoring side, or vice-versa. Is there regulation and\/or guidance on all this?<\/span><\/p>\n","protected":false},"author":19,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[141],"class_list":["post-236","post","type-post","status-publish","format-standard","hentry","category-blog","tag-fmsvorndbraw-datafinal-approach-coursehsifms-approachac-90-108use-of-suitable-area-navigation-rnav-systems-on-conventional-routes-and-proceduresvdpvnavmdaterpsaim"],"_links":{"self":[{"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/posts\/236","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=236"}],"version-history":[{"count":1,"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/posts\/236\/revisions"}],"predecessor-version":[{"id":645,"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/posts\/236\/revisions\/645"}],"wp:attachment":[{"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/media?parent=236"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/categories?post=236"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.aircrewacademy.com\/blog\/wp-json\/wp\/v2\/tags?post=236"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"FMS](\"images\/FMS_Approaches.jpg\")
Here is the scenario: You are airborne in your typically equipped modern day biz-jet, meaning that you are equipped with some form of glass on the instrument panel and at least one FMS. You are going to be flying a VOR (or NDB) approach into your destination airport. The question is, how are you going to set up the approach in your avionics\/nav system? And, however you do it, why are you doing it that way? Is there a regulatory requirement on this? What are you training?<\/span><\/p>\n