最近，有些机场的导航台不工作。大家都在讨论是否可以飞的时候。经人介绍，发现FAA曾经发现一个AC，标题是《Use of Suitable Area Navigation (RNAV) Systems on Conventional  Routes and Procedures》。主要的目的是：

(1)Use of a suitable RNAV system as a Substitute Means of Navigation when a very high frequency (VHF) Omni-directional Range (VOR), Distance Measuring Equipment (DME), Tactical Air Navigation (TACAN), VOR/TACAN (VORTAC), VOR/DME, non-directional radio beacon (NDB), or compass locator facility including Locator Outer Marker (LOM) and Locator Middle Marker (LMM) is out-of-service, i.e., the Navigation Aid (NAVAID) information is not available; an aircraft is not equipped with an automatic direction finder (ADF) or DME; or the installed ADF or DME on an aircraft is not operational. For example, if equipped with a suitable RNAV system, a pilot may hold over an out-of-service NDB.
(2)Use of a suitable RNAV system as an Alternate Means of Navigation when a VOR, DME, VORTAC, VOR/DME, TACAN, NDB, or compass locator facility including LOM and LMM is operational, and the respective aircraft is equipped with operational navigation equipment that is compatible with conventional NAVAIDs. For example, if equipped with a suitable RNAV system, a pilot may fly a procedure or route based on operational VOR using that RNAV system without monitoring the VOR.

简单说来就是有了RNAV设备，基本上可以无视地面导航的情况了。为此，我还在丹佛的时候，找了Jeppesen教员核实了一下此咨询通告的目的，我怕我英文理解有偏差。Joe很直接地说，是啊，有了GPS就是随便飞，反正导航台在飞机数据库里就是个坐标。

对他的说法，我还是有些怀疑，我觉得他有点过分乐观了。不过，至少此文的目的和我理解的没错。