PPRuNe Forums - A320 family autoland

PPRuNe Forums (https://www.pprune.org/)

- Tech Log (https://www.pprune.org/tech-log-15/)

- - A320 family autoland (https://www.pprune.org/tech-log/402922-a320-family-autoland.html)

A320 family autoland

Just curious - what happens on an autoland on the A320 family if at the "Retard, Retard" call the thrust levers remain in the climb gate ?

The "RETARD" is as a reminder only. The trust is at idle already, as long the autopilot remains engaged. ROLL OUT will follow, but no spoiler deployment hence no AUTO BRK function (and obviously no reverse as the levers are in CL detent)

You better retard the levers before you disconnect the AP, as A/THR is still active and will increase the trust conform the lever position.

Thats why it says "RETARD" leave it long enough and you are...:}

Hey ZONNAIR Just tried looking in the FCOM regarding spoilers activation, in an auto land, in case one does not bring the thrust levers back from CL gate to idle and FMA shows idle, after touch down ground spoilers would not activate???
As the book says "IF THE GROUND SPOILERS ARE ARMED AND THRUST LEVERS ARE AT IDLE GROUND SPOILERS WILL ACTIVATE AS SOON AS LANDING GEAR TOUCH"

Hotrod, are you mixing up Thrust Lever position and FMA?

Are you sure TP. If the thrust levers are not @ idle position then the ground spoilers and thus autobrake cannot activate.

In a full autoland you are merely putting the thrust levers to where they should be as a confirmation of what the autothrust has already done for you ie its already at idle ...

Yes Dragstrut that is correct. But the ground spoiler function is based on thrust lever position.

Quote:

Full extension - Landing phase

If the ground spoilers are armed and all thrust levers are at idle, the ground spoilers will automatically extend as soon as both main landing gears have touched down.

If the ground spoilers are not armed and both main landing gears have touched down, the ground spoilers will automatically extend as soon as reverse is selected on one engine (the other thrust lever remains at idle).

Note : The spoiler roll function is inhibited when spoilers are used for the ground spoiler function.
Partial extension

The ground spoilers partially extend (10°) when reverse is selected on at least one engine (other engine at idle), and one main landing gear strut is compressed. This partial extension, by decreasing the lift, eases the compression of the second main landing gear strut, and consequently leads to full ground spoiler extension.

Retraction

The ground spoilers retract :

After landing, or after a rejected takeoff, when the ground spoilers are disarmed.

Note : If ground spoilers are not armed, they extend at the reverse selection and retract when idle is selected.

During a touch and go, when at least one thrust lever is advanced above 20°.

Note : After an aircraft bounce, the ground spoilers remain extended with the thrust levers at idle.
FOR INFO

The landing gear touchdown condition is triggered for both main landing gear, either when their wheel speed is greater than 72 knots, or when their landing gear struts are, confirmed to be compressed by the radio altitude (RA < 6 feet).

The thrust levers are considered to be at idle when they are :

Below 4°, when the RA is above 10 feet,

Below 15°, when the RA is below 10 feet.

Thus although thrust will be at idle the logic will not. Try it in the sim if you have a chance!

HOTROD wrote

Quote:

after touch down ground spoilers would not activate???

I say again, HOTROD is correct!

TP,

I have probably misunderstood but the question marks and last sentence in Hotrods post make me think he believes ground spoilers will deploy with thrust levers in the CLB gate.

I only read what he wrote - what he believes is not mine to guess. And what he wrote makes perfect sense.

Spoilers will deploy in the following modes.

Ground spoilers automatically extend when armed:
- both thrust levers at forward idle and both MLG touch down (Flight /
Ground transition),
-during Take Off (TO) run at speed greater than 72 knots (kts) and
both thrust levers retarded at forward idle.

Ground spoilers automatically extended (not armed):
- when both MLG touch down and reverse is selected on at least one
engine (remaining engine at idle),
- or during TO run speed greater than 72 kts and reverse is selected on
at least one engine (remaining engine at idle).

Ground spoilers partially extend:
- when reverse is selected on at least one engine (remaining engine at
idle) and one MLG is compressed.
This partial extension (10degrees) by decreasing the lift, will ease

compression of the second MLG, and consequently will lead to the normal
ground spoiler extension.

Thrust Reversers
SECs and EEC must have TLA below -3degrees for thrust reverser deployment and RA <6ft, this data is from the potentiometers of the throttle control unit and Rad alts respectively.

Regards
Beeline

Hotrod and Tyro are absolutely correct. If someone does not close the TLs after touchdown on an autoland, you will drift off the end of the r/w doing somewhere around 100KIAS with Pierre shouting ''(you) RETARD''.

Done regularly in the sim to prove to disbelievers who don't know their tech.

mcdhu

Thanks Guys. Just read the FCOM 1.27.10 there's a NOTE which says " IN AUTOLAND, GROUND SPOILERS FULLY EXTEND AT HALF SPEED ONE SECOND AFTER BOTH MAIN LANDING GEARS TOUCH DOWN"

Very clearly as per this, in autoland TLA position has no meaning. Correct me if i am wrong.

I don't have access to the FCOM at the moment, but I am telling you what actually happens in 4 different A320 sims.

mcdhu

Hotrod,

Can you confirm you are reading from the A320 series FCOMs, as I concur with MCDHU. In the last 12 years on the A320 I have never seen this line. I also have this view backed up by 4 different sims although they might well be the same ones MCDHU uses.

Interesting debate guys...

Just checked my FCOM 1 and that note is included, but of interest is that the note appears applicable to only the A320, but not the A319 or A321!

T'Bug:ok:

Thunderbug is correct. The difference is whether we are talking about the 319 or 320 (sry I don't fly the 321).

On the 319, spoilers do not come out until you retard the thrustlevers on an autoland (although engines are already at idle). The 320 does as earlier mentioned, come out slowly when both landing gears have touched down.

Thanks for that Hotrod.