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Old 15th Aug 2015, 00:44
  #64 (permalink)  
7478ti
 
Join Date: Sep 2011
Location: Mercer Island WA
Posts: 139
@CM reference your questions

Sir, ANP level alone matters little, as long as it's less than the needed RNP with adequate FTE margin (e.g., the reason for having features like NPS), and is predicted to stay less than RNP for any relevant non-normal conditions. Instead, it is the low RNP capability that really matters for an aircraft, and having it able to support RNP based LNAV and VNAV suitably, for any leg type combination needed, including for RF legs down low, while fully satisfying all the rare-normal, and non normal conditions that must be addressed in the FHA and FMEA. Yes, I am intimately familiar with that particular autoflight system, including even for the pending E2 design, and have seen no evidence whatsoever that so far it is capable, or will be capable of safely flying the real RNP procedures that I cited earlier, even for normal operations, let alone for rare-normal, or non-normal operations down to the TDZ and back out, even in the event of a first E/O, and first Nav failure, or any relevant system failure, such as a lightening strike bus trip back to stby power, while maintaining RNP capability (per relevant criteria such as in AC120-29A, which was the basis for RNP approvals for aircraft and airlines now doing [real] RNP).

Last edited by 7478ti; 15th Aug 2015 at 00:54.
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