Rta

Required Time Of Arrival (RTA)

The criteria for determining that an RTA will be matched ( and this a magenta constraint circle /astrix are :

The flight crew may assign a time constraint (RTA) to any down path waypoint in the flight plan. The RTA may be AT, AT or BEFORE (-), or AT or AFTER (+).

The FMGC computes at managed speed between green dot speed and VMO-10/MMO-0.02 in order to achieve a 30 second time difference for the waypoint.

When the constrained waypoint is sequenced, the ECON SPD/MACH is resumed.

The time constraints (RTA) is enterd on the RTA page. The RTA pages is accessed from the Flight plan page, vertical revision for the required waypoint.

As with the other constraints, Altitude and speed a magenta value is displayed until performance predictions are available. Thereafter, a magenta or amber astrix is shown to the left of the time value.

Entry is of the format +/-HHMMSS

Distance < 2000 nm

Distance > 2000 nm

RTA match within 30 seconds

RTA match within 30 seconds + 60 seconds for every 1000 nm

Eg 150 seconds for a RTA of a waypoint at 4000 nm away.

An RTA will be automatically cleared if :

Engine out condition exists

Holding pattern entered

Go-arround mode activated

RTA exists at another waypoint

MANAGED

Displays blue brackets if no RTA exits. Otherwise it shows the waypoint at which the RTA exits.

Shows the actual FMGS managed sped mode value

ACT MODE

Shows the current FMGS speed mode either MANAGED or SELECTED

RTA

The RTA value in HH MM SS with an optional +/- in front

ETA

The value of the Estimated Time of Arrival over the waypoint

RTA ERROR

The difference between RTA and ETA, if RTA is determined as being missed, else blank

ETT

The Estimated Time of Takeoff. Available only in the Pre Flight phase . This entry is manual and appears in Magenta. If the Takeoff phase has not started before the ETT has been reached then a MCDU message of “CLOCK IS TAKEOFF” appears in the scratchpad, indicating that the ETT is now the clock time.

UTC

The UTC Available after the Pre Flight phase. It is shown in Green.

An Asterix on the Flight Plan page shows the RTA constrained waypoint

+ is AT or After the RTA time

- is AT or Before the RTA time

Neither +/- is AT the RTA time

All the times used in the simulation are UTC and should take into account day light savings times. Local time is not shown in the cockpit.

An RTA may be cleared in a similar manner to that of a sped or altitude constraint.

Using the CLR button on the MCDU and selecting the appropriate Right Hand LSK on the flight plan page.

Note clearing constraints this way, clears all the constraints for the waypoint.