E-Jet flaps level positions

[leon737]

Gentlemen,

Does anyone know the reason that Embraer E-Jet family aircrafts have flaps positions 4 and 5 with same flaps/slats deployment?

When on final, the usual flaps selection is Flaps 3 at GS intercept, next Flaps 5 before 1000' AGL. So, Flaps 4 position is always skipped.
When on Go Around with Flaps Full, then Flaps 4 will be selected, but it has same slat/flap deployment as in Flaps 5 lever position.

Why does E-Jet have this extra flaps lever position? Reserved for future generation?

[KingKoopa]

Flap 4 is a takeoff setting, flap 5 is a landing setting.

That's the difference.

[Piltdown Man]

You are right, Flap 4 is the same as Flap 5. The reason is that this slat/flap position can be used for take-off and landing. But each has different protection rules. For take-off, you want the config warning system to detect that the correct flap position has been chosen and for a landing, you want the EGPWS and Flight Warning computer to determine that a valid landing flap position has been selected.

As for flaps usage, I'll normally pop onto the glide with Flaps 1 with Green Dot plus 10 or so. At five miles select gear down and Flaps 3. At Flaps 3, re-select Green Dot and at three miles, Flaps 5 or Full and Vfas. It keeps the noise down, you are easily stabilised by 500' and works nicely. But when ATC demands something different or on horrible days a different schedule may have to be followed.

[leon737]

Thank you, KingKoopa and Piltdown Man! Now it's clear.

2 Piltdown Man:
Can you please clear up your flaps usage technique: what is your IAS with Flaps 1 on the glide with typical weight and does this comply to '160 knots before 4nm' rule?

[FE Hoppy]

Leon 737

I know a top notch training school who can teach you everything you need to know about the Ejet. ;-)

Different company procedures may well deviate from the Embraer standard SOP and flap selections are different depending on EASA or FAA AFM.

[AtomKraft]

If asked for '160 to 4', do it flap 3, gear down.

You can drop the gear at 5d, or earlier if you wish.

At 4d, go flap 5, speed on approach, landing checklist. ;)

[Onceapilot]

If the flap/slat positions are the same, surely the systems logic could be designed to recognise the aircraft situation? Could this be a certification issue with the limitation of not being possible to select from a flap+slat config to a flap only config without a baulk or a double selection? Just asking?

[leon737]

Thanks, AtomKraft!

Your words fully match with what I've used.
I'm feeling safe when using mental 'milestones' - 180 up to 10 nm, then 160 up to 4 nm, then decelerate and go in landing conf. Even when not asked by ATC :)
(but gears down only at 5 nm, then immediately the landing flaps selection; all completed before 1000' AFE)

Just was slightly astonished why E-Jet has the special 'duplicate Flap 4' position, not like Bus. Now it's clear - just the procedures issue, not a bug, just a feature :)

[AtomKraft]

Leon
Flap 4 take offs are routine in the E-jet, but not all operators need to do them.

Flap 4 is usually used from performance limited runways. The TO config sys needs to know what you plan to do, thus flap 4. Trying to leave with flap 2, from an airfield where you've calculated flap 4 performance could end quite badly.