Issue

When altering the Vapp entry or adjusting altitude constraints, the Flight Plan (F-PLN) profile undergoes a re-computation. If the Required Time of Arrival (RTA) function had been utilized prior to these modifications, the MCDU and PFD may unexpectedly present inaccurate speed targets.

In addition, this scenario could occur if the flight crew has initially inserted an RTA but subsequently deleted it, as the FMS may erroneously retain the RTA target, potentially leading to the display of incorrect speed targets.

Solution

RTA (Required Time of Arrival) is a time requirement to be met over a specified waypoint of the lateral flight plan Speed monitoring becomes more important if RTA function is used. If an erroneous speed target is displayed, flight crew should manually select a speed to continue (Take action if things do not go as expected – Airbus Golden Rule).