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-   -   Landing A320 on very wet runway (https://www.pprune.org/tech-log/623058-landing-a320-very-wet-runway.html)

slate100 30th Jun 2019 14:38
Landing A320 on very wet runway
 
So the runway is very wet, and you want to plant the 320 firmly onto the runway to avoid hydroplanning.

What's your technique for planting the 320 firmly on runway? Flare less? Thrust to idle earlier?

B2N2 30th Jun 2019 14:46
What does the manual say?

Johnny F@rt Pants 30th Jun 2019 15:14
All landings should be the same, right place, right speed with a firm positive contact. It makes no difference whether it is wet or dry.

vilas 30th Jun 2019 16:31
All landings should be the same, right place, right speed with a firm positive contact.
observing all that still on dry runway possible to give a personal touch. But on wet runway just flare to break descent, close thrust, let the aircraft touch down then forward pressure on the stick.

Fursty Ferret 30th Jun 2019 17:01
. then forward pressure on the stick.
As far as I know there is no requirement to maintain forward pressure on the stick after touchdown. A nose-down input on the ground will reduce the weight on the main gear (thus the effectiveness of the brakes).

sonicbum 30th Jun 2019 18:45
How wet is very wet ?

Jonty 30th Jun 2019 19:02
I suppose the OP must mean contaminated type of wet. More than 3mm of standing water.

MD83FO 1st Jul 2019 01:52
if you're using auto-brakes, scheduled deceleration rate is not commanded until the nose is below a certain point, so a nose down command can increase braking.

compressor stall 1st Jul 2019 06:02
Originally Posted by MD83FO (Post 10506638)
if you're using auto-brakes, scheduled deceleration rate is not commanded until the nose is below a certain point, so a nose down command can increase braking.
Do you have a reference for this pls?

sonicbum 1st Jul 2019 07:38
Originally Posted by compressor stall (Post 10506684)
Do you have a reference for this pls?
He might be referring to this article.
  • Perform early and firm touchdown (early as runway behind you is no use, firm to ensure no delay in ground spoiler extension, brake physical onset, and reverse extension by sluggish wheel spin-up and/or delayed flight to ground transition of the gear squat switches)
  • Decelerate as much as you can as soon as you can: aerodynamic drag and reverse thrust are most effective at high speed, then moderate braking only at low taxi speed after a safe stop on the runway is assured
  • Do not delay lowering the nose wheel onto the runway (it increases weight on braked wheels and may activate aircraft systems, such as auto-brake)
Originally Posted by slate100 (Post 10506274)

What's your technique for planting the 320 firmly on runway? Flare less? Thrust to idle earlier?
A normal touchdown that ensures ground spoilers deployment.


compressor stall 1st Jul 2019 08:20
Thanks sonic. Coincidentally I’d actually read that today re the latest FCOM change to wet ice.

Yes the ground spoiler extension triggers the auto brake cycle - just the above post seemed to imply an alpha that would trigger it. The article is ambiguously worded. I don’t remember that in the GS logic diagram but I don’t know everything and always curious...

Nightstop 1st Jul 2019 08:33
REV IDLE is the norm in our outfit, so much so that many F/O’s have NEVER used REV MAX. If nose down sidestick isn’t held after selection of REV MAX, the nose will rear upwards like an angry horse!

Goldenrivett 1st Jul 2019 08:44
Originally Posted by compressor stall (Post 10506739)
....just the above post seemed to imply an alpha that would trigger it. The article is ambiguously worded. I don’t remember that in the GS logic diagram but I don’t know everything and always curious...
There may be confusion with some of the words in FCOM regarding Ground Spoiler logic.
The 2.5 degree condition applies when "Speed brake lever in the retracted position but ground spoilers not armed and:"

"Ground Spoiler Control..
FULL EXTENSION - LANDING PHASEThe ground spoilers will automatically extend when the following conditions are met:
  • Speed brake lever not in the retracted position or ground spoilers armed and:
    • Both main landing gears on ground,
    • Both thrust levers at or below Idle position, or Reverse selected on at least one engine (and the other thrust lever below MCT position).
  • Speed brake lever in the retracted position but ground spoilers not armed and:
    • Both main landing gears on ground,
    • Reverse selected on at least one engine (and the other thrust lever below MCTposition).
The ailerons are fully-extended (Aileron Anti Droop@ ), provided one aileron servocontrol is available on each side, when:
  • The ground spoilers are fully extended
  • Flaps are not in clean CONF
  • Pitch attitude is lower than 2.5 °
  • Flying manually
  • In normal law only."

compressor stall 1st Jul 2019 08:52
Possibly, but the aileron extent is only triggered after GS extension, by which time the AB cycle will be running (or counting down).

MD83FO 2nd Jul 2019 02:34
i cant remember where it is, but I understand the purpose of the pitch inhibited auto braking is to prevent a hard nose down up on activation.

AerocatS2A 2nd Jul 2019 03:46
Originally Posted by Nightstop (Post 10506755)
REV IDLE is the norm in our outfit, so much so that many F/O’s have NEVER used REV MAX. If nose down sidestick isn’t held after selection of REV MAX, the nose will rear upwards like an angry horse!
Will it? Where I work we use rev max for every landing and I’ve never been conscious of the nose rearing up but I might be applying nose down without thinking about it.

bill fly 3rd Jul 2019 06:12
Originally Posted by Goldenrivett (Post 10506768)
There may be confusion with some of the words in FCOM regarding Ground Spoiler logic.
The 2.5 degree condition applies when "Speed brake lever in the retracted position but ground spoilers not armed and:"

"Ground Spoiler Control..
FULL EXTENSION - LANDING PHASEThe ground spoilers will automatically extend when the following conditions are met:
  • Speed brake lever not in the retracted position or ground spoilers armed and:
    • Both main landing gears on ground,
    • Both thrust levers at or below Idle position, or Reverse selected on at least one engine (and the other thrust lever below MCT position).
  • Speed brake lever in the retracted position but ground spoilers not armed and:
    • Both main landing gears on ground,
    • Reverse selected on at least one engine (and the other thrust lever below MCTposition).
The ailerons are fully-extended (Aileron Anti Droop@ ), provided one aileron servocontrol is available on each side, when:
  • The ground spoilers are fully extended
  • Flaps are not in clean CONF
  • Pitch attitude is lower than 2.5 °
  • Flying manually
  • In normal law only."
Shortly after introduction of the 320(1) in our airline, Lufthansa had an accident on landing at Warsaw.
Our 320 TP asked the rest of us what the spoiler logic was on our aircraft - as at that time at least one mainwheel on each side had to have spin up. Airbus had canvassed the airline TPs.
On the MD, which was “my” ship, any two main wheels - both one the same side - or one on each side - or more, would trigger the spoiler. I believe shortly after this, the same logic was employed on the 320.


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