B737 3/4/500 FMS Nav accuracy
I'm interested in other operators' experiences with FMS Nav accuracy on B737 3/4/500 (Twin IRS + DME/DME radio update) aircraft. Particularly with the sort of 'errors' that you are seeing when doing a 'raw-data' fix check against FMS position.
Assuming that you are operating in a 'DME rich' area, how does the FMS navigation perform i.e. what are typical displacements of FMS position from radio position (n mls)?
What are typical displacements of FMS position from the IRS positions (n mls) and what would you consider excessive?
If heading into an area where DME support is limited or nil, do you have any SOP to select the most accurate IRS for FMS use to try to avoid spurious EGPWS alerts when the position drifts towards a possibly inaccurate IRS position following loss of 'radio' position?
Lastly, does anyone have any links to sites explaining how FMS nav operates as it 'downgrades'? (I'm aware of the Honeywell site and Chris Brady's)
Last edited by BOAC; 2nd Mar 2003 at 11:37.