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-   -   Thrust on during flare...Q for AIRBUS test pilots... (https://www.pprune.org/tech-log/536616-thrust-during-flare-q-airbus-test-pilots.html)

nitpicker330 30th Mar 2014 09:00

Ha ha ha ha ha ha

So funny I laughed my a** off.

2 hours ago I landed in HK on 07L with tower reported surface wind about 180/18 gusting 20, Mechanical turbulence off Lantau, Windshear forecast AND reported.

Quite a sporting approach, ended up with about -8 ( back to VLS ) to +15 FROM about 100' down to 50'. Kept under control and guess what:--

I used THRUST to manage the IAS. Only after giving it a big boot full for a few seconds did the IAS return to VAPP at 80'.

I'd like to have seen you control that with Pitch only!!!!!!!

Yes a Jet has a lot of inertia but I can tell you that 100' ain't the place to hope the speed comes back by itself, so those saying it will stabilize all by itself don't know what they are talking about.
God you'd be dead after hitting the sea wall whilst waiting for IAS to return using only Pitch...

Yes for small changes you could control IAS with Pitch if you felt so inclined but not today boys and girls...

737Jock 30th Mar 2014 09:08

So why did your speed change in the first place nitpicker?

InSoMnIaC 30th Mar 2014 09:10

I give up. Thrust for Glide path, Rudder for Roll, and Ailerons for Yaw

nitpicker330 30th Mar 2014 09:15

Well gee whizz Jock why do you think?????

Maybe the Wind velocity and direction changing around after interference from the hills and the Heaco Hangar might be a reason. They call it mechanical turbulence my friend, they even talk about it in the Jepps for HK 07L if you'd like to look.

What's your point? Are you going to mention energy levels, path management and inertia again?

737Jock 30th Mar 2014 09:18


Quite a sporting approach, ended up with about -8 ( back to VLS ) to +15 at about 100' down to 50'. Kept under control and guess what:--

I used THRUST to manage the IAS. Only after giving it a big boot full for a few seconds did the IAS return to VAPP at 80'.
Quite a few contradictions there I would say. Maybe you want to review the values?

I thought you were at +15 from 100' to 50', why did you increase thrust?

737Jock 30th Mar 2014 09:19

No I'm waiting for your explanation why the speed changed. So the wind changed, And you encountered up And downdrafts.

What happened aerodynamically that made your speed change?

nitpicker330 30th Mar 2014 09:28

For gods sake give it up with the aerodynamic mumbo jumbo.

I flew the dam Plane Maverick and at 100' I ain't got time to think about all the aerodynamic reasons for the flight path fluctuations.

When the IAS is heading south at around 100' with a rather long trend vector I'm not sitting on my hands hoping "inertia" will save my ass. Neither would you.

And yes the first post I made describing the events were correct, speed loss corrected by me followed later by a speed gain. ( which was not caused by me leaving the thrust on too long )

Ok I edited the post to include the word FROM to highlight the area from around 100' to 50'

737Jock 30th Mar 2014 09:44

The values are corrrect?

So Lets assume your Vapp = VLS because you are flying manual thrust approach.

You landed on runway 07 with 180/18 maximum 20. (What value is needed to report a gust in the towerwind?) Means you had a 7 kts tailwind.
What was the wind on the approach?

The way I understand your post the way its written:
You ended up with VLS -8 somewhere above 100ft. The speed then increased to VLS+15 from 100 to 50 ft.
You added thrust at 80ft?

Did you mean that:
At 100ft you lost 8kts of airspeed resulting in VLS -8
Then at 80 ft you added a boot full of thrust resulting in the speed increasing passing VLS to VLS + 15?
After which you reduced thrust to settle at VLS?

nitpicker330 30th Mar 2014 09:53

No mate. Tower reported wind was from memory 180 18 gusting to about 23?
Nearly all crosswind and only up to 5kts tailwind, no report of shear from the 748 ahead.

VLS was 134, VAPP 142 as per company policy for gusty conditions and experience on type. I Used managed speed with manual thrust as also recommended by Airbus in gusty conditions.

At around 100' or so the speed dropped quickly to around VLS, so it dropped by about 10 kts from what we had. I corrected quickly and the speed settled back to about VAPP.

Then about 50' the speed shot up to about VAPP +15 or so just as we entered the flare.

We landed safely used full reverse and vacated A9.

Ok?

Isn't that what I said the first time?

737Jock 30th Mar 2014 10:01

Well nitpicker you landed on runway 07L. which is approximately 070 degrees.

Means wind is coming at you at 110 degrees, thus a tailwind component.

At 180/18 that is 7kts tailwind and 17 kts crosswind, at 180/23 its 8kts tail and 22 kts cross.
So yes its mostly cross, but if your tailwind limit is 10kts like on the minibus you were very close to it.

Remember at only 30 degrees off the side you already have half the wind component.

And no its not what you said first time. Which is why I asked clarification. Won't hold that against you though, I imagine you are tired after a long flight.

Capn Bloggs 30th Mar 2014 10:04


Originally Posted by hikoushi
We're all right and we're all wrong, depending on who you ask.

I hand-flew an ILS yesterday (with the ATS engaged :eek:); the conditions weren't nice; bouncing around all over the place. I can tell you one thing; I like nitpicker wasn't waiting for the thrust to fix the glideslope: I poled the aeroplane so it stayed put on the glideslope and ATS just controlled the speed for me (as I would have done had it been disengaged).

For the life of me, I cannot understand how 737jock and his mates can think they're best off picking up slope excursions with power.


Originally Posted by St Martin
At this point, further pitch up without thrust addition might produce a greater rate of descent and cause the airplane to sink more below the desired glide path.

This makes clear that path is controlled by thrust.

No it doesn't, it shows that the pilot involved was either stupid or taught by a twit. If you are below slope and going lower at constant speed, of course it's going to slow down/go down if you pitch up to get back without adding power! Attitude + POWER = performance... But fix the slope first and then the speed (if indeed anything needs to be done about the speed at all).


Won't hold that against you though, I imagine you are tired after a long flight.
Aww shicks, that's nice. Picker, lift yer game, lad! Long flight or not, the power-for-slope lawyers won't stand for anything less than the whole truth the first time...

737Jock 30th Mar 2014 10:08

Hey Bloggs is back what a coincidence....:E

Bloggs what I actually said is that both explanations are incorrect or correct, whatever you want to call it.
The problem is actually that you don't want to accept that thrust for speed is only a simplification.
And that you refuse to believe that thrust for path is a similar simplification that holds just as much merit.

Thrust manages energy, and the pitch manages airspeed and vertical speed.

Capn Bloggs 30th Mar 2014 10:12


Hey Bloggs is back what a coincidence....
Yes, mate, I just got back from flying. I got a bit high on final. I said "no you don't", stuffed the nose down, got back on slope and didn't even touch the power (well, ATS didn't move). If I had pulled the power back (override ATS) I would have been there for too long waiting for the machine to first slow down then second drop down onto the slope. I have better things to do.

When was the last time you touched an aeroplane?

737Jock 30th Mar 2014 10:23

8 times in the last 4 days buddy on the minibus, all without autothrust.

Nobody was contesting how the autothrust system is designed. Flying with autothrust is not manual flying. Just saying....

nitpicker330 30th Mar 2014 10:25

Magnetic runway direction for 07L in VHHH is 073
Magnetic tower wind was 180 18 G 23

Giving a xwind component of up to 22 kts and a tailwaind component of up to 5.3 kts ( oh and Max Tailwind for the A330 is 15kts )

I think your pencil is too thick.:D

Me? I used 2 different Apps to check it in the hotel!!

Yes I am a bit tired.

Friend that landed behind me in a 777 did an Autoland!! Slack bugga, I couldn't have even if I wanted to in the blunder bus!!

737Jock 30th Mar 2014 10:38

I used an app as well (airports). I used 070 as I don't know the exact magnetic course.

But if you want to be exact:

5.26 at 18 kts And up to 6.72 at 23 kts

180-73= 107-90 = 17

Sin 17 x 18 (or 23)= 5.26 And 6.72

Good that its 15kts Max tailwind! Wish my boss had paid the money to change some letters in the FCOM of the minibus. Would prevent some of the nasty circlings we sometimes encounter.

nitpicker330 30th Mar 2014 10:46

Either way tailwind component was not my primary concern today!!

Sin this, tan that.......I either use the graph in the QRH which is crap or I use an App designed to make my life a lot easier on the spot.

737Jock 30th Mar 2014 10:50

Don't do tan. Use cos for the xwind.

I'm glad to see you appreciate the science that goed on behind all these things.

nitpicker330 30th Mar 2014 10:58

I do appreciate the theory I learned 25 years ago but at the end of the day I'm just another dumb Pilot that flies the Aircraft the way I'm told to. I don't have the luxury of questioning science while I operate my Airlines 100 million dollar Jet. It's their train set and I'll do it the way I'm told. The Airline in turn does it the way Airbus tell them to do it to minimize litigation against themselves.

It's all about butt saving at the end of the day.!!

Like I said KISS method works for me

737Jock 30th Mar 2014 11:06

Hmmm for me its all about doing a job I enjoy.

If I had to save my butt everyday I come to work, I would do something different.

I think about these things outside the flightdeck, I believe that improving my understanding makes me a better pilot inside the flightdeck especially when confronted with non-normal circumstances that haven't been catered for by the litigation experts.

Obtaining a deeper understanding doesn't make you a danger to safety!

But if you like to see yourself as a dumb pilot, go ahead. I find that description wholly unsatisfactory.


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