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#11
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Ron Rosenfeld wrote:
On Sat, 10 Sep 2005 17:30:27 GMT, Tim wrote: The new RNAV (RNP) criteria presume a complete loss of GPS for the missed approach. If the airspace/obstacle environment will permit a heading or track to a VOR missed approach in the event of loss of GPS, then no backup is required. If the missed approach areas are too tight then dual or triple IRUs are required. Where is that requirement spelled out for Part 91 operators using GPS (single-sensor)? I don't see it in AC90-100, but that does not deal with missed approaches. Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA) First, you can't use the new procedures at all unless you receive a letter of authorization from your FSDO. That is a requirement of "SAAAR." Part of that qualification requirement is to understand the requirements of each RNAV (RNP) SAAAR SIAP. There is currently in coordination such a "dual-thread" IAP for KSUN. The missed approach reads in part, "RNP required." Implicit in that is the ability to maintain RNP with loss of GPS. That can only be done with an IRU platform. |
#12
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#14
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Ron Rosenfeld wrote:
On Mon, 12 Sep 2005 11:49:41 GMT, wrote: Ron Rosenfeld wrote: On Sat, 10 Sep 2005 17:30:27 GMT, Tim wrote: The new RNAV (RNP) criteria presume a complete loss of GPS for the missed approach. If the airspace/obstacle environment will permit a heading or track to a VOR missed approach in the event of loss of GPS, then no backup is required. If the missed approach areas are too tight then dual or triple IRUs are required. Where is that requirement spelled out for Part 91 operators using GPS (single-sensor)? I don't see it in AC90-100, but that does not deal with missed approaches. Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA) First, you can't use the new procedures at all unless you receive a letter of authorization from your FSDO. That is a requirement of "SAAAR." Part of that qualification requirement is to understand the requirements of each RNAV (RNP) SAAAR SIAP. There is currently in coordination such a "dual-thread" IAP for KSUN. The missed approach reads in part, "RNP required." Implicit in that is the ability to maintain RNP with loss of GPS. That can only be done with an IRU platform. Ah, I think we are talking two different things. I've been thinking, and reading about, the RNAV SID's and STAR's. You're writing about SIAP's. I can maintain the RNP with GPS, but don't have any backup for that. Where can I read about these new RNAV S There is an 90 series AC in final draft phase. IAP's? Will they also require radius-to-fix legs? Not always. The KSUN procedure presently on the FAA coordination site does not use RF legs but it requires RNP for the missed/extraction. What is "SAAAR"? Special Aircraft and Aircrew Authorization Required, same as CAT II/III Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA) |
#15
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The draft language that will likely become official: This is one (of many) reasons these RNP procedures are SAAAR. This will be addressed in the aircrew training. AC 90-RNP SAAAR (still up for approval signature and number assignment), Appendix 1, paragraph 2c, does start the ball rolling with: c. RNP missed approach. At designated locations, the airspace or obstacle environment will require precise RNP capability during a missed approach from anywhere on the procedure. At these designated locations the reliability of the navigation system has to be very high to conduct the approach. Operation on these designated approaches typically requires redundant equipment, as no single point of failure can cause loss of RNP capability. An example of a missed approach requiring RNP is shown in Figure 5, as indicated in the notes section of the chart. Then in Appendix 5, Operational Considerations, paragraph 2o, you have the "Go-Around or Missed Approach" guidance: o. Go-Around or Missed Approach. (1) Procedures that do not require RNP Missed Approach. Where possible, the missed approach does not require precise RNP guidance. The missed approach portion of these procedures is similar to a missed approach of an RNAV (GPS) approach. (2) Procedures that require RNP missed approach. Where necessary, RNP values less than RNP-1 will be used in the missed approach or precise RNP capability may be necessary in the event of a go-around before the decision altitude. Since not all aircraft have this capability, flight crews must be aware of whether or not they can conduct these procedures. For those that can conduct it, a different set of equipment or procedures may be required. In many aircraft a change in lateral navigation capability may exist upon actuation of Take-off/Go-around (TOGA). In most aircraft, the autopilot and flight director disengage from the LNAV guidance, and the flight director reverts to track-hold derived from the inertial system. Flight crew procedures and training must address the need to minimize the lateral deviation from the published missed approach procedure. LNAV guidance to the autopilot and flight director should be re-engaged as quickly as possible. (3) The flight crew procedures and training must address the impact on navigation capability and flight guidance if the pilot initiates a go-around while the aircraft is in a turn. |
#16
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