.
FM/GPS POSITION DISAGREE
.
FMS1/FMS2 POS DIFF
.
Loss of FINAL APP mode
. Loss of both FMGC or severe dual reset require the flight crew to initiate a missed approach procedure. After the loss of GPS FMS position update, the FMS position will drift with the IRS position. But the drift rate is sufficiently low to ensure safe navigation the time necessary to reach the MSA. For the FM/GPS POSITION DISAGREE and FMS1/FMS2 POS DIFF alerts, the flight crew must continue the missed approach or departure procedure using mitigations means (e.g. conventional radio navaids EGPWS, adequate procedure charts with all the relevant information, …)
The loss of NAV or FINAL APP mode will require the PF to disconnect the AP, fly manually using the L/DEV indication (disregarding the FD orders) until the PNF can re-engage NAV and the opposite AP.
Following the loss of both AP the crew will continue the procedure using FD and the L/DEV indications. In approach with RNP<0.3, as the FTE with FD has not been demonstrated during certification, the airline procedure may be to require a go around. The same situation may also occur following engine failure for SA aircraft with an FMGC standard, for which the AP must be disconnected in approach with OEI. For RNP<0.3, the airline has the option to demonstrate that the pilots have been trained to continue an approach using FD and can meet the expected RNP level.
In case of loss of both FMGC or severe dual reset, the flight crew will revert to mitigations means (e.g. conventional radio navaids, EGPWS, adequate procedure charts with all the relevant information, …). Both FMGC failure means total loss of RNAV capability and may also include loss of AP and/or A/THR. The crew procedures to deal with such a situation should be based on the mitigations means available for each individual approach or departure. This evaluation should be part of the operational approval. Specific procedures must be established and trained when use of TAWS/EGPWS terrain display is considered following loss of both FMGC.
7. RNP AR Operations and Training
Getting to grips with RNP AR
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7.2.6 RNP MONITORING PROGRAM
The airline are required to implement an RNP Monitoring Program, which has some
similarities with what is usually required for CAT II/III operations.
This program must ensure continued compliance with the guidance of AC 90-101 and to
identify any negative trends in performance.
Statistics on the number of RNP AR successful and unsuccessful procedure should be kept.
The reasons of unsuccessful procedures such as: 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：getting to grips with RNP AR Required Navigation Performance(32)
