Thrust on during flare...Q for AIRBUS test pilots...
 

Any Airbus test pilots out there?

I've noticed quite a few pilots in my company who, when flying a manual thrust approach, will leave thrust on during the flare after noticing sink or turbulence approaching the flare…sometimes resulting in either floating, or a firm landing.

Is there ANY reason to leave thrust on during the flare? Can you confirm that correct technique is to use thrust to compensate (aggressively if required) for a sudden sink approaching the flare, but not to maintain thrust on during the entire flare maneuver? This results in 3 or 4 "RETARD" calls.

You'll feel it in your bum and see it out the window, if you feel that you need thrust in the flare then do it.

Remember that in a Jet Pitch controls Sink rate and thrust controls Speed.

So, if the A/C is sinking too much at say 100' you will need to pull back to arrest the sink and THEN add thrust to stop the speed decay. If it's big enough you will need to keep the thrust on all the way to touchdown and then close the thrust.

One problem, not adding thrust will require the pitch attitude to be higher than normal to arrest the sink thus a tail strike is possible in extreme situations. Watch out. Sometimes in extreme undershoot shears it could require a lot of thrust to arrest the sink, in that case I'd strongly suggest a missed approach be conducted even if you touch down.

In a A/THR approach the A/THR will obviously add the thrust for you, all be it a little slowly for some!! ( another story )

On a normal stabilized landing in the A330 you'll need to close the thrust levers as you commence the flare otherwise it won't land!!

Glad we final have the answer to the whole thrust vs pitch discussion.

Question - on the descent today I increased the thrust. Speed remain constant but our rate of descent was reduced. Should we have written the jet up?

Don't think he has heard of CFS...................:)

See the Habsheim discussion about thrust and AoA and speed for controlling flight path.

CFS…Country Fire Service or Central Flying School??:} (I've been to one of them)

String through the ears…one hand goes forward, one hand goes back…right!!??!

I'm not referring to making adjustments to flight path for sink…I'm referring to maintaining thrust on during the flare. There seems to be a tendency to avoid seeing VLS at all costs. (Which incidentally, is maybe why many will choose manual thrust when landing in turbulence…Airbus auto thrust is designed to maintain speed from -5 to +10kts, but if some guys see VLS, they seem to think the jet is about to fall out of the sky!).

The A330 flies like a glider compared to other jets I've flown, so I don't see any reason to deviate from the tried and true technique of closing the thrust levers as the flare is commenced, unless compensating for very late sink (string through the ears). If correct landing technique is used (look to the far end of the runway at the commencement of the flare), any unusual sink can be picked up (unless you are in Hong Kong and can't see the other end of the runway!) and compensated for with slightly higher flare attitude and a slight delay in closing the thrust levers.


Again…any LONG COURSE TEST PILOTS who can confirm if there is a reason to keep thrust on during flare in an A330?

There is not one single recipe for every situation. Your question needs some serious rethinking.

For a trainee pilot: do what the FCTM tells you to do, and finetune it as you get more experienced.
For experienced pilots: fly the aircraft

Most of jets have the main landing gear well behind the center of gravity, thus the landing gear is behind the pivoting point. So you can easily drive the landing gear onto the runway when pitching up close to the ground.

Even with autothrust you will need to vary the height at which you put the thrust levers to idle.

Oh Yeah and Vapp with manual thrust = Vls according to airbus in zero wind.

Hot and/or high ops with a gusty head wind. Just to have enough energy to have THREE smooth touch downs. If not, then you might want to watch your nose.

misd again--- very appropriate user name my friend.

Yes you increased thrust on descent? Mmmmm and the relevance is?

Well I'll tell you AGAIN..

Yes normally on a stabilized landing you will need to close the thrust at the beginning of the flare, that's normal and sometimes the speed may decay to VLS before touchdown.....ok I think we are agreed on that.

There are times during a late low level undershoot sinking shear you may need to leave the thrust on until touchdown to prevent speed decay, especially below VLS.......ok

That's the ONLY time I leave thrust on late in the flare......ok

It's not rocket science.....

Go the Picker!
 

Got a job for you. Take over our jet induction course and teach them properly! :D

"Always remember and forever take heed: left hand for glidepath and right hand for speed!" (Reverse for first officers).

Hey he asked, don't have a cheap shot at me for trying to answer him by using pretty basic stuff.

One wonders why he had to ask but if I take him at face value it was apparently about why do some guys get upset if the speed falls in the flare and insist on delaying idle thrust......

My answer was correct and inferred basic handling abilities and seat of the pants instinct.......

Not having a shot, I'm agreeing with you 100%. :ok:

Fair enough.....all good

I thought proper thrust at proper place was part of a stabilised approach..
Sink sink thrust thrust bounce bounce go around.:E

Yes that's where the "aviate" part comes in, you decide how bad it is........before it gets to bounce bounce go around...:ok:

On the wrong foot….
 

Quote
"Remember that in a Jet Pitch controls Sink rate and thrust controls Speed."

Maybe I've been through all the wrong trainings, instructors, career, everything…

But last time I checked, IN JET AIRCRAFT, pitch controls speed, then we control flightpath with thrust.
I dont recall any Boeing manuals (or Airbus for the sake of this thread) teaching it differently. Our military background friends with AoA experience will certainly confirm the same.

This can be a VERY long discussion of course (Pitch or power etc etc) but regarding your specific question relative to flare, your experience will prove that in order to arrest descent, you add thrust. The reason you pitch up is to bleed off excess speed during flare.

If you are coming down fast (on VS rates that is) and you pitch up without adding thrust, you'll probably have an unpleasant experience.

Anyway, thats the way I've seen it happening, medium and heavy jets for 20 years +, but as always, I just might have been lucky, doing it the wrong way all this time and getting away with it.

Personal advice, keeping some thrust in, or adding a short burst during flare if needed, decreases the required pitch and you touch down smoother (because of the angle of the landing gear compression strut in relation to the horizontal).

There even used to be a term called "the Boeing flare" in the older days (before Airbus), where the pilot would pitch the nose over momentarily during flare in order to "grease it". Different wings too, I know.

Nowadays of course, pilots care too much about flying the numbers, making a big fuss for keeping 1 knot over Vref+5. I still keep Vref+10 min and fly a manual approach almost always, so flare is hardly ever an issue.
Nobody got hurt for carrying 5 extra knots, remind yourself to remain a pilot and refuse to become an accountant.

I know there will be comments but at my age, I can take them. Fire on…..

So next time I want to takeoff I should line up and lower the nose to accelerate down the runway? :}

It's no different for prop driven aeroplanes, either. :8

Is Pitch+Thrust=Performance ok for everyone?:p

Are you "flying" when you are accelerating down the runway mate?

Tell us about your experience without any childish comments. Unless you are only an armchair pilot.

I admire your sense of humor…….. you must be a very popular guy:}