A321: tail clearance Flap 3 versus Full

[applecrumble]

Did we ever get the the bottom of this. Is flap 3 slightly better for tail clearance on a 321?

[misd-agin]

It's either F3, or F4, that gives more tail clearance. The difference is minimal.


If you're that concerned about tail clearance it's time to freeze your pitch attitude or go-around.

[applecrumble]

I completely agree. It's all a bit academic.
I was wondering if anyone could check the next time they fly on an A321 what the pitch attitude is flap 3.
Flap full is 2.5/3 degrees. At my airline we vary rarely do a flap 3 so I can't check.
If anyone could take a picture on the PFD flap 3 That would be grand!

[FlightDetent]

Applecrumble: yes, there is a note somewhere in official AB docs, that F3 give more tail clearance on A321. Please do not make me go look for it.

[autoflight]

The question is possibly more academic and not really about go around or flare technique. If there was an appreciable body angle difference, wouldn't there be a caution in the manual? However the thread drift is appropriate.
I recall that with an uncomfortable sinking feeling in the flare, selecting a lower rather than increased body angle was sometimes appropriate on a B727-200 and also on A320 & A321, to reduce the rod of the main gear. Not encouraging this as SOP.

[applecrumble]

Thinking about this (purely academically).
The tail strike limit (oleo's compressed) doesn't change and for an A321 is 9.7 degrees.
The clearance is the 9.7 minus pitch attitude after flare.
Since the flare in flap 3 is more of a check and the final pitch attitude from memory slightly lower. I think there is the answer. A tiny bit more clearance. Marginal though.

[FlightDetent]

On a practical note, there is a technical paper from the manufacturer saying that on A321 landing flap 3 gives the biggest tailstrike margin. Who are we not to believe that?

[Lantirn]

Hi FD,

Do you have a ref please?

[FlightDetent]

I cannot find it, I really wish. It does not sound right at all, does it?

It is NOT mentioned:
FCTM 32S edition 2017
FCTM 32S edition 2013
FCTM 32S edition 2006
A320 Family Instructor Support edition 2001
this OLV presentation: http://www.smartcockpit.com/docs/Avo..._by_Airbus.pdf
Safety First issue 6: A320/ Prevention of tailstrikes

FCOM 32S edition 2017
FCOM 32S edition 2015
FCOM 32S edition 2010

Flight Operations Briefing Notes: Landing Techniques - Preventing Tailstrike at Landing
FCOM Bulletin 806/1 JUL 2004: Avoiding Tail-Strikes

I do not have access to check
. A318/A319/A320/A321 and A330/A340 e-briefings – Tailstrike Avoidance
. the type rating course PDP package - A321 familiarization briefing
. (old) blue FCOM Bulletin 22/3

[FlightDetent]

Circumstantial evidence found: Landing in CONF 3 - Use of reversers [April 2007] p20: Operational Consequences - Approach in CONF 3

"... Tailstrike margins are reduced (except for the A321 aircraft) but, ..."

[tubby linton]

CLEARANCE AT TOUCHDOWN fcom806/1
The following table provides the ground clearance in degrees for the A318, the A319, the A320, and the A321 at landing (all numbers are mean values).
Aircraft Geometry limit at Touchdown Pitch attitude at Vapp(Vref + 5) (1) Pitch attitude at Touchdown(Vapp - 8) (2) Clearance(3)

A318 17.3° 3.2° 7.8° 9.5°
A319 15.5° 3.4° 7.7° 7.8°
A320 13.5° 3.3° 7.6° 5.9°
A321 11.2° 2.4° 6.6° 4.6°

Notes:
Flight path in approach = -3°
Mean value of pitch attitude at touchdown, assuming a deceleration of 8 knots during flare (Vapp - 8), and a flight path of - 1° at touchdown (approximately 3 feet/second).
Clearance = Geometry limit - Pitch attitude at touchdown.
When the approach speed is decreased by 5 knots, clearance decreases by approximately 1.3° (attitude at touchdown increases by 1.3°).


It doesn"t give values for F3 unfortunately