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Ron Rosenfeld wrote
Are you of the opinion that the IFR charts suggest that when on a random route and NE of ALIKE (but south of the BJC 090 radial) that 7300 is a perfectly OK altitude to use? My teaching has been that when not on a "solid black line" or receiving radar vectors from ATC, to not go below the MSA, OROCA, etc., for that area. The relevant regulation is 91.177 - other than when on approach, 1000 ft above any obstacles within 4 nm of course, or 2000 in designated mountainous areas. If you meet that, you're complying with 91.177. The question is how to best comply with this? On a solid black line, the altitude is published. On vectors, it's ATC's responsibility. On a random route, it's your responsibility - sort of. It is relatively common (at least in my neck of the woods) to have approaches where the FAC is not depicted on the controller's scope. In this situation, RADAR services are available, but vectors to final are not. It's fairly common (in my experience) to get a clearance direct to the IAF (NOT a vector) at an altitude lower than anything published - OROCA, MSA, or even the published minimum altitude for crossing the FAF. Clearly the controller is using his MVA for this. Are you suggesting that accepting such a clearance is improper? Even without RADAR services, it's not all that clearcut. Certainly if you maintain OROCA or MSA, you're complying, and in many cases this is the way to go. However, this is often not practical. For example, in my next of the woods there are tethered balloons going to 15000 ft, and that makes OROCA just over 16000 for the sector. This would make direct routings impossible for anyone without turbos. In reality, the minimum altitudes for direct routings in most of that sector are in the 2000-4000 range. I've seen a similar situation apply to the MSA, where an entire sector had an MSA about 1500 ft higher than it would have been had it not been for ONE tower, about 23 nm away from the fix. I have to believe that in mountainous terrain, this is even more common, since airports tend to be in valleys. Under Part 91, there is really no defined requirement for where the data you use to comply with 91.177 should come from. However, I have to believe that any FAA-recognized chart is fair game. I have no idea if 7300 is OK in the area you describe, because I have not seen the relevant VFR chart. It might be. If the obstructions that make the MSA in the sector 10,500 are 20 miles away, and the local terrain is much lower, then maybe it is. However, with only the infomation on the approach plate, I sure wouldn't try it. Michael |
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