When a go-around is initiated, and the SRS pitch mode is active, the target speed is initially set to the current speed (with a minimum of VAPP and a maximum of VLS +15). Selecting OP CLB, or reaching the FCU altitude, terminates the SRS go-around pitch mode and the managed speed changes to Green Dot. The airplane wants to speed up to Green Dot and the autothrust will command the power accordingly until reaching it. This allows acceleration through the climb and flap retraction.
Green Dot allows acceleration and flap retraction with continuous climb power, and is a reasonable speed for flying in the terminal area, since you will probably be returning for another approach, there is no point to accelerate to 250 knots.
Now you’re in the traffic pattern again, flying at Green Dot just like the first approach. If you extend the flaps with the magenta bug at green dot, will the airplane slow down? NO, because the target speed is still Green Dot. you must activate the approach once again.
Once the flaps are retracted and you’re established at Green Dot airspeed, you’ll need to activate the approach again. It won’t immediately change your speed, but by activating the approach it will change the target (bug) speed, which will again reduce to VAPP. Of course Since the flaps are still up, so the auto thrust will continue to maintain Green Dot until the flaps are extended. and you get the corresponding automatic speed reductions.
Here’s what can happen if the approach is not reactivated but the speed is manually selected instead. The airplane will, of course, fly the selected speed. Once established on final, when the speed knob is pushed for managed speed, with the go-around phase is still active, Green Dot will still be the default target speed. The autothrust will add power to try to meet the target speed (Green Dot). The The quick resolution is to quickly pull the speed knob again and select the desired speed. Another option is to or manually pull command the the thrust levers back and manage your speed, and then ask for the approach to be activated so that the managed speed will be correct.
After selecting Flaps 1, it’s a good idea to:
- Review and clear the ECAM STATUS page (if displayed).
- Ensure the Approach Phase has been activated.
- Rotate the ENG START selector to IGN/START if required.
- Ensuring the approach phase is active can be done by observing the magenta target speed (is it at VAPP?), or looking at the MCDU PERF or PROG pages and seeing the active flight phase in the page’s title in green. Therefore, getting to final approach with the go-around phase still active is an error on both the PF and the PM.
Tomorrow, more to come on another situation that could occur while flying your Airbus, and how to get out of it.