Re: CONFUSED
zhtm:
"I am confused about the "RWY track" and "whatever track it is" when the TOGA button is pushed! Anyone can clarify this? Is it different between 777, 744 and 737?"
I can only speak for the 747-400.
The question was in regard to a coupled ILS approach. The track followed by the FMS and autopilot on an ILS approach IS the ILS track. When an ILS is tuned, a magnetic track must also be programmed. When the ILS approach is selected from the DEP/ARR page on the CDU, the ILS freq and track are automatically programmed into the radios and FMS. Once the Approach Mode is armed and engaged, the ILS track is followed. That is the same track that will be followed in the TOGA mode, until another roll mode is selected (above 500' HAA, by our FHB).
"Also I've got two more questions here (more straight forward this time):
"1. Will changing the landing runway erase all previously entered altitude constraints (those requested by ATC, not those in the STAR) in the FMS? "
If a VFR Runway is selected on the DEP/ARR page, no waypoints or altitude constraints will be changed or erased; the runway waypoint will be inserted after the last waypoint on the current route.
If an instrument approach procedure (VOR/LOC/ILS) is selected, any previously-selected approach procedure will be erased and overwritten. If a AP (STAR) is already selected, and that AP is also available for the new runway, its waypoints and altitudes will remain intact. However if the same AP is re-selected, any manually-entered altitude constraints will be deleted when the AP is overwritten.
In either case, no waypoints before the AP will be affected.
"2. Is this true that “LVL CH” and “V/S” mode does not honour altitude constraints programmed into the FMS? However “VNAV” has altitude constraint protection. "
FLCH and V/S use MCP-entered altitude only.
VNAV honors FMS-entered altitude constraints, except where the MCP altitude is more restrictive (e.g., descending from FL330, next programmed constraint is 11,000'; if MCP is set at 15,000', VNAV will level at 15,000' until a lower MCP altitude is entered; if MCP is set at 8,000', VNAV will intercept the constraining waypoint at or above 11,000).