Technical Round Trip Delay
From WikiLink
The Technical Round Trip Delay (TRTD) is one of the general performance measures that are published. It is the time taken by the system to uplink a CPDLC message and receive its application level acknowledgement.
Technical Round-Trip Delay is measured using ground initiated transactions that require a LACK response. Only ground initiated transactions are considered to ensure that a common time source is used for both time measurements.
TRTD = First LACK response reception time – Uplink message transmission time |
Note: For FANS aircraft the gateway in the ground system generates a LACK when it receives a message delivery assurance report from the ACARS data services processor.