Airbus A330 MCDU
Joined: Apr 2006
Posts: 529
Likes: 0
From: Asia
Hi Farid, the takeoff shift is derived from the takeoff performance calculation when using a shifted departure point. ie. Intersection takeoff.
Its purpose is to provide a final FM position update at takeoff thrust when GPS PRIMARY is not available. It also gives you more accurate climb predictions based on you new departure point, which are only for advisory.
It is commonly used at long runways were it can be advantagous in saving time and fuel, and even sugested by atc for traffic sequencing.
Its purpose is to provide a final FM position update at takeoff thrust when GPS PRIMARY is not available. It also gives you more accurate climb predictions based on you new departure point, which are only for advisory.
It is commonly used at long runways were it can be advantagous in saving time and fuel, and even sugested by atc for traffic sequencing.
The Bumblebee
Joined: Jul 1999
Posts: 333
Likes: 1
From: Inside the shiny tube.
Guiones,
You are right, it updates regardless of GPS primary, but with GPS primary it is not necessary to insert the TO Shift as the system will take the GPIRS coordinates at the application of FLEX/TOGA. Whereas, if you are flying without GPS primary you are giving FMGS your exact location of take off (by inserting take off shift) at the time when you move thrust levers to FLEX/TOGA.
Our company policy is if GPS primary no need to insert TO Shift, otherwise you do.
You are right, it updates regardless of GPS primary, but with GPS primary it is not necessary to insert the TO Shift as the system will take the GPIRS coordinates at the application of FLEX/TOGA. Whereas, if you are flying without GPS primary you are giving FMGS your exact location of take off (by inserting take off shift) at the time when you move thrust levers to FLEX/TOGA.
Our company policy is if GPS primary no need to insert TO Shift, otherwise you do.
