Flare Mode on A320

[FLEXPWR]

Hello there,

Anyone here who can describe when the flare mode would NOT be active during a manual landing (normal law)?

I am referring to a normal landing with no failures, and no CB's pulled.

I was told recently that the 320 flare mode (2 deg nose down over 8 seconds input) was not operative when the FD's were switched off for the approach, but I struggle to find any reference in FCOM's (mind you, info could be there anyways, Airbus has a talent for hiding stuff in hard to find places!).

The FCOM 1.17.20 only describes the flare mode, but does not give any exceptions for its operation.

Any help appreciated, thanks.

Flex

[rudderrudderrat]

Hi Flex,

I've never heard of that one.

I'm sure Airbus would have written that in big bold print somewhere if the handling was going to be so different between a manual landing from an ILS (with FD on) and a manual landing from every other sort of approach with the FD off.

[FLEXPWR]

That would be my guess, but considering where I heard it from, I would like the opinion of a few collegues/experienced pilots/instructors etc...

I am usually quite thorough in finding the information in FCOM's and other docs...but this one I'd like to check before coming forward and start to debate the veracity of the statements coming from my Yoda Master...:}

Any other mode/situation that could have been interpreted as such?

Thanks

Flex

[fredgrav]

Hi FLEXPWR,
the only thing I know is that sometimes while flying manually (no NAV course or NAV path active) it would be better to turn FD's off in order to revert from THRUST mode to SPEED mode: this may avoid abrupt and uncommanded thrust changes ... but, as far as I know, there ain't any flight mode reversion with FD's engaged !

Best,
fredgrav

[pensador]

Hi! the FLARE mode can never be disengaged in normal law because of the pilot will be rob of the instinctive reaction that needs for flare.

[pensador]

Hi,fredgrav, if I don't mistake whenever you intend to fly manually you MUST turn off FDs. Correct me If not, please!

[Dan Winterland]

I wouldn't use the imperative "must". It's down to your SOPs. My company specifies for visual approaches and the visual part of any non precision approaches.

Not heard that switching the FDs off changes the Flare Law, but that's not to say it doesn't happen. For instance, the rate of change of Rad Alt readings changes Flare Law, if the rate of change increases or decreases rapidly, then the feel is different - apparently. It's not mentioned in the books except for a paragraph which alludes to it in the FCOM bulletins.

It certainly makes for a good excuse for a cruncher at some of our trickier destinations!

[rudderrudderrat]

Hi Flex,

Any other mode/situation that could have been interpreted as such?

During manual Flight, with FD's on, coupled to the ILS - just after 400 radio "Land" annunciates (which has always struck me as being very tricky since both APs are disengaged).

Maybe Yoda Master was saying the "Flare" Mode won't annunciate if the FDs are turned off?

I've never been "looking in" at that stage - so I can't tell you if it does or not with the FDs on.

[NigelOnDraft]

IMHO Airbus have confused us here by having 2 Flare Modes :{

First is the Normal Law stick v pitch effect noted above from 30R - by itself this actually lowers the nose. This is a "Flight Control Law" mode. AFAIK this mode was removed in the A330/340 i.e. the effect of the pilot "needing" the pull this mode requires seems to have been judged unnecessary.

Second is the Autoland FLARE FMA from ~40R - also called in places 'Flare Mode' - this unsurprisingly raises the nose. This is an AP/FD mode. The manual does state that this mode "disengages" when the AP/FDs are disengaged, which might equate to being turned off.

Our manuals quote a 3rd "Flare Mode" in Altn Law when the gear is lowered (direct stick to elevator relationship). Commonly understood to be "Direct Law"... but then knowing Airbus, maybe it is not quite that :ugh:

Summary: IMHO landing with the FDs off does not alter the Normal Control Laws / feel / pull required in the flare. One might understand otherwise from the Airbus manuals, but what's new :oh:

NoD

[FCeng84]

I wish the Airbus control law were more clearly defined. For the 777 (and identical for the 787) a Flare Compensation function is always active for manual flare and landing. As main gear altitude decreases from 50 feet to zero (i.e., touchdown) an increasing nose down command bias is added that requires the pilot to hold aft column to counter. Flare is accomplished with a monotonic pull until main gear touchdown (target of 15 to 20 pounds at touchdown). Nose let-down is accomplished by relaxing the column thus allowing the flare compensation bias to command negative pitch rate.

[Microburst2002]

Yes.

Maybe they are referring to the case where G/S and LOC are active but at 350 ft LAND does not come green. Then neither FLARE nor ROLL OUT are armed and you land manually (no autoland) and disregarding the FD.

But I don't know the conditions required by the FMGS to give the green light to the LAND mode or the red one.

[FLEXPWR]

Thanks to all of you for your inputs, it leaves a big question mark still, but in a way seems to confirm no change in the flare law with FD's off.

I have to insist the example given to me was relating to the law during flare being different the FD's on or off, not any other flight phase, nor any call out, and focused only on the manual landing.

But again thanks, I am looking forward to see other replies as well.

Note: not a rethorical question, but genuine interest to get a better understanding of what the beast is doing.

Flex

[fredgrav]

Hi,fredgrav, if I don't mistake whenever you intend to fly manually you MUST turn off FDs. Correct me If not, please!

Hi Pensador,
the MUST depends on your company's SOP ... however it would advisable to turn FD's OFF whenever you're flying manually, with ATHR active, an off route segment or an interception course (eg. HDH/TRK to intercept, radar vectors, visual approac etc.), this just to avoid unexpected thrust excursions.

;)

[TyroPicard]

FLEXPWR
There is nothing in FCOM or FCTM that backs up your Yoda Master statement. I suggest you ask him/her to show you the reference .. I don't believe there is any difference with FD ON or OFF - that would be a ridiculous design feature. (AP ON or OFF is different!).
With FD OFF the FLARE mode is not annunciated, but it still works the same.

Re Manual flight - of course you can fly with FD ON. It is recommended to turn it off and use the bird in certain circumstances.

I am hoping your YM is not an instructor - his/her info comes from beyond the dark side...

fredgrav
however it would advisable to turn FD's OFF whenever you're flying manually, with ATHR active, an off route segment or an interception course (eg. HDH/TRK to intercept, radar vectors, visual approac etc.), this just to avoid unexpected thrust excursions. Can you explain further? I am mystified by this statement. How can you use HDH(sic)/TRK to intercept with FD OFF? Radar vectors are easier with FD ON....

[mcdhu]

The jiggery pokery called Flare Law that goes on beneath your feet below 50' in Normal Law in the A320 Family is there simply to make it behave like a non FBW aeroplane in the flare. Therefore, it matters not whether the FDs are on or off, whether the FPV is on or off or anything else for that matter.

The 'Flare' FMA is nothing to do with this and becomes active only during an Autoland ie AP1/2 engaged and 'Land' annunciated.

Cheers
mcdhu

[fredgrav]

Can you explain further? I am mystified by this statement. How can you use HDH(sic)/TRK to intercept with FD OFF? Radar vectors are easier with FD ON....

Hi Tyro,
I'm sorry, HDG not HDH ... just a typing error ! :}
I was referring to an AP OFF + FD + ATHR ON condition: here the A/THR is still in THRUST mode. In THRUST mode the AP pitch mode maintains speed, but as it is not ACTIVE, unwanted thrust excursions may verify while flying manually. It is advisable at this purpose to turn FD's OFF in order to revert from THRUST MODE to SPEED mode, where ATHR maintains a constant speed (selected). Surely radar vectors are easier with FD ON, but if you are being vectored, and flying with AP OFF, FD should also be selected OFF, and FPV alone might help you keeping the path ...

fredgrav

[tom775257]

fredgrav <<but if you are being vectored, and flying with AP OFF, FD should also be selected OFF, and FPV alone might help you keeping the path>>

No! The time you have to worry about taking the FD off (with regards to this) is if you are not following them. You can perfectly happily fly the aircraft around AP off FD/Athr on in thrust or speed mode during vectoring, or most other stages of flight.

<<I was referring to an AP OFF + FD + ATHR ON condition: here the A/THR is still in THRUST mode>> No, it depends on the vertical mode selected, you could easily have a VS selected and a heading to intercept the ILS, hand flying it, FD + AThr on, selected or managed speed, the aircraft will be in Speed, V/S mode HDG and LOC blue AP off Athr on 1FD2



The time it is very important to bring FD's off to get speed mode is really either a visual approach where the flight directors will offer no guidance obviously, or continuing visually after a non-precision approach or a TCAS RA when you will ignore the flight directors hence you need to turn them off to get speed mode.

I take it you have never flown the aircraft?

[Chris Scott]

Quote from fredgrav:
I was referring to an AP OFF + FD + ATHR ON condition: here the A/THR is still in THRUST mode. In THRUST mode the AP pitch mode maintains speed, but as it is not ACTIVE, unwanted thrust excursions may verify while flying manually. It is advisable at this purpose to turn FD's OFF in order to revert from THRUST MODE to SPEED mode, where ATHR maintains a constant speed (selected). Surely radar vectors are easier with FD ON, but if you are being vectored, and flying with AP OFF, FD should also be selected OFF, and FPV alone might help you keeping the path ...


Can an old fart be permitted a few remarks, to challenge statements that are admittedly off the original topic? As a long-retired A320 driver (Jan1988 - Nov2001) I've been trying to keep my oar out of this thread, but the above remarks seem to betray a big misunderstanding of the A/THR modes. What exactly do you mean by "THRUST MODE"?

On the initial approach, the only thing that will prevent the A/THR being in "SPD" mode is if the FD has been left in "DES" mode or "OP DES" mode. The A/THR mode will then be "IDLE". If at this stage the pilot goes visual, ignores the FD commands (while leaving the FD on), [U]and sooner or later starts to reduce the rate of descent, the A/THR will continue to command idle thrust. This was the prime reason for the Indian Airlines Lahore (?) accident circa-1989, but others had previously fallen (nearly) into the trap. THAT is the scenario in which you MUST turn the FDs off (although improved low-speed protections were installed after that accident).

With AP off, I agree that – any time you are not on radar vectors or flying an ILS – the FD should be switched off, and "SPD" mode of the A/THR verified (assuming you are using it). The "bird" is to be recommended.

On final approach, using auto-thrust, some of the commanded thrust changes can be unnecessary, particularly in gusts. On a single-engine approach, in particular, unexpected thrust changes make smooth yaw-control difficult. A stickler for SOPs, I hope nevertheless that there are still some A320 fleets sufficiently enlightened to permit their pilots the choice of manual thrust, on short-final at least? The A320 manual throttle is the best of the six jet types I flew. But in auto-thrust, the absence of tactile information (throttle movement) is a drawback, as we tried to convince Bernard Ziegler in 1986...

Chris

PS:
tom775257, see you got in first!
fredgrav, I have just looked at your personal profile. I hope the above is helpful, and that you soon enjoy flying Airbus FBW.

[pensador]

fredgrav
and
Dan Winterland
how often do you fly AP-off with FDs-on (I mean do not follow FDs commands) and in what cases?

[fredgrav]

Thanx ChrisScott it more than helpful !
I fully agree with both you (Chris and Tom775) ... though the situation I was thinking for radar vectors was a really basic one: AP OFF + FD OFF + ATHR ON, without any FCU HDG or ALT selection -> (eg. the controller instructs you to fly heading 050 climbing to FL90, then you fly heading 050 manually with NO FCU selection, while starting a climb, to FL90 manually). In that situation, a FD left ON on a previous heading or ALT might also lead to unwanted thrust excursions, that's what I meant ... if wrong, could anyone explain the why ?!

I take it you have never flown the aircraft?

Tom775, haven't flown the bus yet, cause I'm yet a "pilot in the making" ... :)

Pensador, while flying with AP OFF, it would be best to turn the FD OFF whenever you're not going to follow it ... even if the example I made above is a bit uncommon to be sincere !

[charlies angel]

Pensador
Dont confuse flying the aircraft with the autopilot off..... with not following the flight directors demands.
It is perfectly permissible to use the pnf(pm) to select alt/hdgs/speed etc and the pf to follow the "programmed" settings especially if the (now overloaded!!) pnf is a slightly smug or overconfident low hours pay to fly cadet:E who needs putting back in their box:ok:
Threads like this prove that the Airbus takes a looong time to really thoroughly understand despite all of our best efforts.

[Microburst2002]

Fredgrav

AP/FD OFF, A/THR ON: SPEED mode is active.
If, inadvertently, it is not in speed (because one pilot pushes the LS button instead of the FD, or does not push it at all when commanded), you can be in deep **** (in approach with the A/THR still in THR IDLE or during a TCAS RA "descend descend" and THR CLB still active, for instance).

This condition is very easy to go unnoticed, believe me. You can have a full FMA and the FPD and just ignore it, when workload is high.

always check and callout "speed" after selecting "FDs OFF". My advise

[shortfuel]

It seems to be lots of confusion about FLARE MODE...and that's normal because the manufacturer gave the same name to two different functions in this flight phase:

1/ FLARE MODE related to flight controls NORMAL LAW (pitch control)
That's the one you describe in your initial post. This mode is available with FDs ON and OFF.

2/ FLARE MODE related to Auto Flight System (AP/FD common modes) during AUTOLAND.
This mode will align, flare and retard (if A/THR ON) the bus automatically.
For obvious reason, this common mode is not available if AP/FDs are OFF (1.22.30 p52).


fredgrav: in normal situations, when FDs are ON, you follow them. If for any reason you don't want to follow them, you turn them OFF.

[CONF iture]

Shortfuel,
your post inspires me a question, silly maybe but still a question, something I've never thought experimenting in a simulator :

During automatic landing, the A/THR will go in RETARD mode, commanding IDLE thrust during the flare. But what would happen at the end of the landing roll when the crew disconnects AP in order to exit the active runway and, if despite the ''RETARD'' callout, the crew forgot the thrust levers in the CLB detent ?

My presumption would be that the engines would go to climb thrust ... ?

[Dan Winterland]

Pensador - how often do I fly with FDs on in manual flight? Quite often. Our SOPs don't allow for flight with FDs off except in the circumstances mentioned and then the FPV is always used. But we always follow the FDs with the PM setting the ACP as directed by the PF. Why? It's because the SOPs are designed with commonality accross the company in mind and the Boeing side has a big influence.

It's not the Airbus way and not somthing I necessarily agree with. We used to be pure Airbus but since being absorbed into a bigger company which took us over we are using their SOPs. However, they do encourage manual flight when the conditions allow and I take the opportunity to do that when I can - and nearly always with manual thrust. They do also not provide for a situation where the FDs could be ignored - and there should be very few. Chris Scott has very aptly highlighted the danger of asking the aircraft to tell you what to do and then ignoring what it is saying.

[fredgrav]

Thanx MicroBurst, a very helpful example ! :ok:
_______________________________

fredgrav: in normal situations, when FDs are ON, you follow them. If for any reason you don't want to follow them, you turn them OFF.

Hi shortfuel,
that's what I said, though I was referring to a situation where FD is indavertently left ON ... by the way, fully agree with you ! :ok:

2/ FLARE MODE related to Auto Flight System (AP/FD common modes) during AUTOLAND.

Airbus calls this RETARD MODE just not to confuse it with FLARE mode in conjuction with a FLT/CTL law ...
__________________________________

During automatic landing, the A/THR will go in RETARD mode, commanding IDLE thrust during the flare. But what would happen at the end of the landing roll when the crew disconnects AP in order to exit the active runway and, if despite the ''RETARD'' callout, the crew forgot the thrust levers in the CLB detent ?

Hi CONF Iture,
how would you deploy THR RVRS and GND SPLRS with a thrust lever left in CLB detent ???! :confused:

fredgrav

[pensador]

Hi, charlies angel! I didnt confuse. whenever someone is going to drill his handling skill he disengage the AP an FDs as well. What is exactly I mentioned about
con respecto!

[Microburst2002]

After 4,000 hours on the bus, I still learn things and change my habits. I have learnt that managed is often a bad way of flying this airplane.
If you know the 320 AFS, you can fly it better, more efficiently and more confortably for the pax if you use selected modes rather than managed ones. And it greatly improves your situational awareness.

I will always defend the practice of hand flying skills, but I also think that the most important ATA chapter in eny airplane's FCOM is Autoflight.

We are too used to automation. Try to do a NO FD TAKE OFF. The first time I didn't "like" to see the FMA totally blank. I hesitated for a second as there was not any call out after take off thurst selection. So after a few seconds wondering what should I check I remembered to at least check that the thrust effectively was on FLEX (there is not even a MAN FLEX white FMA, since A/THR does not arm). After that I always say "FMA BLANK". You can even find "challenging" a low altitude level off (when the ATC has cleared you to 3000 thousand and instead of clearing you higher as usually they say "maintain"). It should be not, right?
That is why I highly recommend to practice such take offs every once in a while when circumstances are ok. I also highly recommend not to forget selecting V2 and once airborne not to push again the A/THR (the automation element that most pilots wish to recover in the first place, in my experience) before selecting a higher speed!

[shortfuel]

fredgrav,
-I don't know exactly what's your background on this A/C but let's try not to spread inaccurate info or try to make yourself clear:
FLARE MODE (AP/FD) is one thing and RETARD MODE another (A/THR).
-[content deleted]

Salut CONFiture,
Your presumption is correct :ok:
Have a look to this related thread:
http://www.pprune.org/tech-log/402922-a320-family-autoland.html

MicroB,
I cannot agree more :D. There is nothing like flying raw data from 10,000' on a perfect continuous descent approach without levelling-off...

[indeed rudderrudderrat... :oh:]

[rudderrudderrat]

Hi shortfuel,

During Autoland and on certain A/C (depends on MSN and type), speedbrakes will deploy shortly after MLG touchdown whatever the TL position.

Just to clarify - I presume you mean "Ground Spoilers" will deploy ... etc

[CONF iture]

Shortfuel,
Thanks for the link, there is more than I expected.
Great reading !

[fredgrav]

Hi shortfuel,
I'm neither trying to spread inaccurate info or just to make myself clear ...
My background is related to a 4 years study on the aircraft even though didn't fly the bus yet, cause I'm just about to end my ATPL training. Every time I write on this forum is either cause I'm quite sure about what I say (ie. reference to FCOM) or just cause wanna learn from what others say. I got wrong about the FLARE/RETARD mode, but everyone makes mistakes, and above all, is important to learn from them.

During Autoland and on certain A/C (depends on MSN and type), speedbrakes will deploy shortly after MLG touchdown whatever the TL position

Could you please quote a reference to the FCOM (or an official document) ?

Thanks in advance, :ok:
fredgrav

[shortfuel]

fredgrav, I was just about to give you the ref. (FCOM 1.27.10 p12 in "note" for A320/321 only) when I realised that I wrote a wrong statement myself :} !

Allow me to correct it: in autoland, gnd spoilers will extend only if you move back the TL to Idle like in any other landing!

The note I am referring to is actually only detailing the extension moment and rate of the spoilers, nothing else:
http://nsa14.casimages.com/img/2010/04/08/100408111052964690.jpg (http://www.casimages.com)

This statement "one second after both MLG touch down" misled me.
It is only one condition for spoilers extension, not the only condition as I wrongly said previously.

I found out with this:

http://nsa14.casimages.com/img/2010/04/08/100408111552324277.jpg (http://www.casimages.com)

We drifted big time from the subject though...
Cheers

[fredgrav]

Don't worry shortfuel, as said before, everybody makes mistakes ! ;)

In the Safety Magazine that Airbus mailed to me last month (February 2010) there's a big item on the topic, titled "A320 Family/ Evolution of ground spoiler logic". I've just posted it and can be now downloaded by the following link:

RapidShare: 1-CLICK Web hosting - Easy Filehosting (http://rapidshare.com/files/373732349/20100055_SafetyFirst-9-ToConsult.pdf.html)

To summarize the whole item:

Runway excursion and hard landing events have prompted Airbus to develop a new standard of Spoiler Elevator Computer, the SEC 120. Expansion of the ground spoiler extension conditions means that the spoilers will extend even when the speed brake and/or thrust levers are in inappropriate positions, thereby improving the aircraft’s deceleration on ground. In addition, a new ground spoiler partial extension logic has been developed to limit bounces that may lead to hard landings.

To summarize, the SEC standard 120 provides means to reduce:

- Runway excursions by enabling:

• Arming of the ground spoilers even when the speed brake lever is not retracted.

• Extension of the ground spoilers even with a thrust lever above the Idle position.

- Hard landings by minimizing:

• The number and amplitude of bounces by triggering partial spoiler extension at touchdown even with both thrust levers in the ATHR position.

Note: In autoland, the ground spoilers fully extend at half speed one second after both main landing gear touch down.

I noticed that some FCOM's include the note and some do not: at that point, I'm left to think that, as you previously said, the A/LND GND SPLRS logic may change on some MSN's ... :ok:

Cheers,

fredgrav

[pensador]

Hi, Microburst2002! I am fully with you!!!! Any chance for practice I just use it for handling. As for me it will expand pilot's attention.

[pensador]

shortfuel.
Let me pay attention on the THR leavers idle position.
FCOM 1.27.10 p13 clarifies us that the THR idle condition does not meat the THR idle detent.
con respecto!

[pensador]

fredgrav, thanks for the link!

[CONF iture]

Fredgrav,
Excuse my curiosity, you say you have not flown the Airbus yet, but have been studying it for the last 4 years. You personally receive an interesting magazine that is only forwarded to professional addresses and is usually restricted to flight and ground crew members. What kind of formation are you following, and when do you expect to be the RHS of a 320 ?
Do you have already access to a flight simulator or a kind of 2D trainer ?
Anyway, it all looks promising and you demonstrate a real positive attitude.
Good luck in your training.

[fredgrav]

Hi CONF Iture,
first of all thanx a million for your really kind wishes ! ;)
I do love both planes and computers, and I think Airbus groups them all together ... so 4 years ago I started studying the bus because of my "terrific" love for it ! I do have loads of useful stuff for studying like FCOM's, AOM's, AOPM's, FCTM's, CBT's, Briefing Notes, Diagrams, Trainers, Guides, Safety Magazines, Questionnaires etc., either printed or electronic. I'm supposed to take my final (Frozen) ATPL's exam within the next 1/2 months. PPRuNe is both a great place where to learn and confront with others. My final thought is that this "early study" on the aircraft, may/will help me right away or in a very near future ... :)

Best, :ok:
fredgrav

p.s. in order to receive a free copy of Airbus Safety Magazine, you can either contact Airbus by phone or mail, so that they can register you in their digital distribution list.

[captain_adel]

Hello sir
i am A320 first officer with 700hrs
please tell me the best way to get kiss landing with A320 AND 319 i want to know the key for me some times i made good landing kiss one and some times no so how can i sure that my landing will be kiss
thank you
you can email me ([email protected])