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-   -   "Pitch" auto callout in the 320 (https://www.pprune.org/tech-log/421024-pitch-auto-callout-320-a.html)

Microburst2002 14th Jul 2010 18:01

"Pitch" auto callout in the 320
 
this one is for experts, since, as usual, the FCOM explais little about this auto callout.

When is it exactly triggered?
Which computer is in charge of doing it?

Why on earth so many things in this airplane have to be transparent to us?

And something related with the above: according to the FCOM bulletin 806/1 p5 (Avoiding Tailstrikes) it says that, during a typical flare, pitch "will increase by approximately 4.5º".
Does it mean that pitch at touch down will be 4.5º approx or that it will be increased 4.5º, that is, approximately 2.5º + 4.5º = 7º?

I think 7º is quite a nose up attitude. Sometimes I reach 7º, but when I do what I consider perfect landings, pitch will rarely exceed 5º.

Thanks

rudderrudderrat 14th Jul 2010 19:26

Hi MB2002,

Our new A320s have this Pitch Attitude warning fitted. A new display appears on the PFD round about 300 agl. If your pitch & rate of change of pitch on landing is such that you'll get to 10 degs (in about 1 seconds time) then it shouts "Pitch Pitch" at you.

I've had it a couple of times when doing Flaps 3 Landings - but the subsequent trace analysis showed I hadn't exceeded 8 degs on touch down.

That bulletin 806/1 assumes you'll bleed off 10 kts during the flare to touch down. So 3 degs pitch change to fly level (from a 3 deg slope) + 1 degree more for the loss of speed, and you'll probably still have a slight sink rate.

Edit: Info from Airbus.
"A synthetic voice "PITCH PITCH" should be emitted by FWC if the FAC (since FAC P/N B397BAM0619) detects a risk of Tail Strike at landing. FAC indicates that such a risk is reached when:

* "Tail strike protection" pin programming is activated

* TLAs are not on Take off thrust

* APs are not engaged

* Predictive pitch (pitch value reaches one second later if last pitch rate is maintained = Pitch + Pitch rate) is below a Pitch threshold

* Radio height is below 20ft

* Radio height is not loss

* Radio height is not "No Computed Data" since more than 1 second

In addition, we can indicate that Pitch threshold value is:

* 8.25° for A321,

* 9.25° for A320 if "Lift Improvement Package " (LIP) is not installed,

* 10° for A320 if "Lift Improvement Package " is installed.



As a consequence, since "Tail strike protection" is pin programmed on A320 (?Airline? spec) while LIP function is not activated, Airbus can inform ?Airline? that "PITCH PITCH" auto call out might trig if predictive pitch overshoots 9.25°. Thus, "PITCH PITCH" auto call out might have triggered while pitch reached 7.5° if pitch rate was higher than 1.75°/sec at that time."

Microburst2002 15th Jul 2010 19:08

Many thanks, RRR

I got the damned "pitch" voice a week ago but I would swear I didn't even reach 8º.

What puzzles me is that a 7º pitch touch down is considered typical by airbus, so why "pitch"a t 8º?
Anyway, your info is good. It is probably due to a trend in the pitch rate, that the voice is triggered.

thanks

Slasher 18th Jul 2010 01:35


I got the damned "pitch" voice a week ago but I would swear I didn't even reach 8º.
Micro you know youve probabley been QAR'd over it.

dannypc 3rd Feb 2011 10:57

hi, thanks for the information.

could you please tell use where to find the source of the information and how it is called or tell the right chapter in the FCOM?

regards

dream747 10th Jul 2013 05:06

Anyone knows if this information has been introduced into the FCOM? I still can't find anywhere in the manuals for the conditions for the Pitch callout.

The closest I come across is in the FCOM normal procedures where it says monitor the pitch and a callout is available if the pitch hits 10 degrees; but like many others I have witnessed calls when the pitch is nowhere near 10.

HazelNuts39 10th Jul 2013 07:13


* Predictive pitch (pitch value reaches one second later if last pitch rate is maintained = Pitch + Pitch rate) is below a Pitch threshold
Exceeds threshold would be more logical

*Lancer* 10th Jul 2013 10:14

Practical application of what rudderrudderrat posted (my understanding anyway):

If current pitch + pitch change in last second > 9.25 deg (depending on type), you'll get the alert.

So if you snatch flare for some reason, and reach a pitch of 7 deg in one second (4.5 deg change from 2.5 deg approach attitude): 7 + 4.5 = 11.5 and "pitch pitch"...

pilot-737 10th Jul 2013 13:16

The FWC triggers The "pitch pitch" auto callout when the predicted pitch exceeds a specific threshold.
The predicted pitch is the estimate Pitch that will be reached after 1 sec if the PF maintains the current pitch rate.
Predicted pitch = current pitch + pitch rate (d/s) *1sec

Predicted pitch threshold a320 :9.25 or 10 (mod34041) a321: 8.25

Valmont 10th Jul 2013 22:35

Do you have any reference for that ? Can't find it in the FCOM. :ugh:

*Lancer* 12th Jul 2013 02:14

It's not in FCOM... My reference came from some Airbus tech newsletter / FAST etc that I printed out.

Valmont 13th Jul 2013 01:23

Thanks Lancer ?
If I may ask you, do you remember which issue of the FAST does it come from ?

The only place where i've found something about the "pitch" auto callout in the FCOM was in the PRO-NOR-SOP Landing.

Oxidant 13th Jul 2013 01:31

New version with the sharklets call "pitch" at 7.5 degrees.

IXUXU 13th Jul 2013 06:25

The "Pitch Pitch" auto callout, if available, will depend on type.

While on the A321 you´ll get the "Pitch" at 7.5º ( tailstrike occurs at 11º), in the A320 the auto callout is triggered at 10º (tailstrike occurs at 13.5º).
If the "Pitch" auto callout is not available, it should be done by the PNF.

PRO-NOR-SOP Landing (Flare), if available.

flyboyike 13th Jul 2013 13:41

It would be better if the word pitch were replaced by another similar one, especially if said word were to either precede or follow the "RETARD...RETARD" callout. By similar I mean with a different first letter, otherwise the same.

IFLY_INDIGO 5th Aug 2013 12:25

yesterday, I had this callout on landing with config 3 in a non-sharklet aircraft. PM reported that pitch never exceeded 10 deg. I have asked the flight data monitoring dept to find out the max value of pitch during flare and touchdown.

My instant reaction was : lower the pitch! which I guess saved us from trouble. so I would say the callout ' pitch pitch' is meaningful.

Cough 5th Aug 2013 21:40

Ifly - Check pilot 737's post above. Its not just the achieved pitch value, but it also looks at pitch rate - If it thinks you will exceed the threshold you will get a shout. As you say - it achieves the aim quite well...

Fursty Ferret 6th Aug 2013 15:37

For some reason it always used to trigger for me at TFS, even if pitch never exceeded 5 degrees. So it's not the be-all and end-all.


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