JackZ
PILOTE DE DRONE
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Bonjour à tous.
Suite à une question posée sur un forum d’utilisateurs du Fenix, j’ai fait un texte de réponse qui est assez long mais complet et je me suis dit que ça pourrait intéresser du monde. Il est hélas en anglais, et j’ai la flemme de traduire. Enjoy.
Jacques
Approach speed and Flaps
—-——-
In nearly every major airport, there are speed constraints during the approach, due to traffic and sequencing for ATC purposes.
These speed constraints are found either directly on the approach plate OR in the REF section of the approach plates for the field.
The STAR often includes some additional speed restriction/constraints at specific points.
Do not forget also the main constraint of max 250 kts below 10000 ft. At this altitude you should be around 30Nm away of the field.
The typical speeds to reach and maintain during approach are:
1- 220-210 kts on the closing heading to intercept the LOC. According to that, F1 would have to be selected around 20-15 Nm from the threshold and speed reduced from 250 to 220 kts (it takes between 3 to 4 Nm for the speed to bleed off, so plan accordingly)
2- 180 kts when established on the LOC until 10-12 Nm (can be up to 8 Nm) from the threshold. In order not to accelerate during the the glide intercept, it is a good advice to select F2
3- 160 kts from 10 to 6-4Nm meaning you are on the Glide slope.
Between 4 and 3.3Nm at the latest you should be on your current final approach speed (around +/- 140 kts ) in order to be fully stabilized at 1000ft AGL.
Some additional remarks:
———///———-
- The gear should be down around 2500 ft and 2000ft at the latest (roughly around 6Nm), still at 160kts and the rest of the flaps (F3 and FF) deployed around 6 and 5Nm in sequence after the gear.
This in order to be fully configured around 4Nm (1000ft and 3.3Nm at the latest) and the speed back to managed in order to benefit from the ground speed mini function up to the landing.
- Your goal is to be stabilized at 1000ft (Conf Full and final approach speed) at the latest. If not, GO AROUND is mandatory unless in VMC conditions (in that case the stabilized criteria is reduced to 500 ft)
- Of course you mileage may vary, and an earlier configuration might be needed if the conditions are non standard (ie glide slope > 3 degrees, tailwind, heavy aircraft…)
- To reduce you workload, it is recommended to manually activate the approach phase in the MCDU/PERF page at around 15-25 Nm from the Threshold, and be in managed speed initially to start reducing from 250 to 220 kts, and then manually select the speeds as described.
- Don’t forget to go back to managed speed after the final flaps selection to benefit fully from the Autothrottle GS Mini function and reduce your speed further from 160 to final approach speed. The speed reduction is automatic in managed.
- The speed reductions are not instant so you should select the next speed a bit before reaching the required distance in order to let the aircraft decelerate.
Remember also that decelerating is kinda impossible if you are descending like crazy (v/s > -800/-1000ft per min) so plan accordingly.
You cannot descend AND decelerate at the same time. If needed, dropping the gear earlier can save your day.
Suite à une question posée sur un forum d’utilisateurs du Fenix, j’ai fait un texte de réponse qui est assez long mais complet et je me suis dit que ça pourrait intéresser du monde. Il est hélas en anglais, et j’ai la flemme de traduire. Enjoy.
Jacques
Approach speed and Flaps
—-——-
In nearly every major airport, there are speed constraints during the approach, due to traffic and sequencing for ATC purposes.
These speed constraints are found either directly on the approach plate OR in the REF section of the approach plates for the field.
The STAR often includes some additional speed restriction/constraints at specific points.
Do not forget also the main constraint of max 250 kts below 10000 ft. At this altitude you should be around 30Nm away of the field.
The typical speeds to reach and maintain during approach are:
1- 220-210 kts on the closing heading to intercept the LOC. According to that, F1 would have to be selected around 20-15 Nm from the threshold and speed reduced from 250 to 220 kts (it takes between 3 to 4 Nm for the speed to bleed off, so plan accordingly)
2- 180 kts when established on the LOC until 10-12 Nm (can be up to 8 Nm) from the threshold. In order not to accelerate during the the glide intercept, it is a good advice to select F2
3- 160 kts from 10 to 6-4Nm meaning you are on the Glide slope.
Between 4 and 3.3Nm at the latest you should be on your current final approach speed (around +/- 140 kts ) in order to be fully stabilized at 1000ft AGL.
Some additional remarks:
———///———-
- The gear should be down around 2500 ft and 2000ft at the latest (roughly around 6Nm), still at 160kts and the rest of the flaps (F3 and FF) deployed around 6 and 5Nm in sequence after the gear.
This in order to be fully configured around 4Nm (1000ft and 3.3Nm at the latest) and the speed back to managed in order to benefit from the ground speed mini function up to the landing.
- Your goal is to be stabilized at 1000ft (Conf Full and final approach speed) at the latest. If not, GO AROUND is mandatory unless in VMC conditions (in that case the stabilized criteria is reduced to 500 ft)
- Of course you mileage may vary, and an earlier configuration might be needed if the conditions are non standard (ie glide slope > 3 degrees, tailwind, heavy aircraft…)
- To reduce you workload, it is recommended to manually activate the approach phase in the MCDU/PERF page at around 15-25 Nm from the Threshold, and be in managed speed initially to start reducing from 250 to 220 kts, and then manually select the speeds as described.
- Don’t forget to go back to managed speed after the final flaps selection to benefit fully from the Autothrottle GS Mini function and reduce your speed further from 160 to final approach speed. The speed reduction is automatic in managed.
- The speed reductions are not instant so you should select the next speed a bit before reaching the required distance in order to let the aircraft decelerate.
Remember also that decelerating is kinda impossible if you are descending like crazy (v/s > -800/-1000ft per min) so plan accordingly.
You cannot descend AND decelerate at the same time. If needed, dropping the gear earlier can save your day.
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