Airbus A/C flaring on landing
Only half a speed-brake
No, Vs1g is deemed (by certification authorities) equivalent to Vs. Vref is locked at 1,3 Vs1g. Typical Vapp is Vref+5 kt.
Yours,
FD (the un-real)
Yours,
FD (the un-real)
Join Date: Feb 2005
Location: India
Age: 68
Posts: 23
Likes: 0
Received 0 Likes
on
0 Posts
maths
Looking at it as a simple Maths problem. If descent angle is 3 deg, you need to change body angle by 3 deg to get a level flight path IF the speed was constant. Wind additives to V Approach would have the effect of giving you a virtually constant body angle (for an unadjusted V App, you would have a higher body angle due to a lower rate of descent.)
at the COMPLETION of the flare, the body angle would be higher than required to fly level, because you would have been using additional lift coefficient (angle of attack) to change flight path from descent to level. If you had a speed vector which you could point at the aimpoint during approach and then at the horizon on completion of flare, you would get a perfect touchdown every time, regardless of speed. Every landing technique aims at this trajectory, with different ways of briefing for it, with the addition of the speed decay from V App to a few knots below.
Just my two bit worth
at the COMPLETION of the flare, the body angle would be higher than required to fly level, because you would have been using additional lift coefficient (angle of attack) to change flight path from descent to level. If you had a speed vector which you could point at the aimpoint during approach and then at the horizon on completion of flare, you would get a perfect touchdown every time, regardless of speed. Every landing technique aims at this trajectory, with different ways of briefing for it, with the addition of the speed decay from V App to a few knots below.
Just my two bit worth
Join Date: Jul 2006
Location: USA
Posts: 451
Likes: 0
Received 0 Likes
on
0 Posts
Captain Turbo...Where have you been?????
Captain Turbo,
I wish I had had a copy of this post years ago to describe to others the correct way to land this plane! (I'm retired, now. Too late!)
Obviously, you read the manuals.
Well said!
Fly safe,
PantLoad
I wish I had had a copy of this post years ago to describe to others the correct way to land this plane! (I'm retired, now. Too late!)
Obviously, you read the manuals.
Well said!
Fly safe,
PantLoad
Join Date: Apr 2005
Location: Southeast USA
Posts: 801
Likes: 0
Received 0 Likes
on
0 Posts
Generally, I agree with all that Capt Turbo has said – but I would add the following … every airplane lands from the level flight attitude for the established configuration – supersonic fighters, light general airplanes, transport category airplanes from the smallest to the largest, regardless of the manufacturer. In other words if you were to level off at a height of 3 to 4 feet above the runway (that should be about 1 foot in a Cessna 152) and maintain that height all the way down the runway – without climbing or descending and without accelerating or decelerating (airspeed approximately 1.10 to 1.50 Vs for the existing configuration in ground effect) – you would have been at the proper attitude to land. It is THIS attitude that you should reach at the end of your flare – and your height above the runway should be down close to the runway – of course the higher you are when reaching this attitude, the longer you’ll take to get the wheels on the surface … not too good, particularly on shorter runways.
The other thing is that you should most assuredly have the throttle(s) at idle when the mains contact the surface – where you start to retard those throttles and how quickly you do it depends a lot on technique and individual airplane characteristics. Generally, if you cross the threshold at the proper height, at the proper speed, and begin a very gradual throttle reduction at that point – rotate to the proper flare attitude, taking no more than 3 seconds to reach that level flight attitude (3 – 4 feet) from the time you begin the flare, getting there at a speed of 1.10 to 1.50 Vs – continuing to retard the throttles – hold the airplane in that flared attitude for no more than 3 seconds, making sure the throttles hit the idle stop at touchdown – you will have made the “perfect” landing (contrary to those “know-it-alls” to say perfect landings don’t exist). This procedure will allow you to land at the proper distance down the runway, at the proper attitude, with sufficient airspeed to maintain directional control until you get the nose on the ground. I won’t tell you it will be the “grease job” landing everyone thinks is the mark of a good landing. No. It will be somewhat firm – but not at all unpleasant – and it works with headwind, tailwind, crosswind, light weights, heavy weights, and with any flap configuration. You’ll have enough vertical force to put the wheels on the runway – through any precipitation activity, but not so hard that the little old lady in 2A will have a coronary. However, it does take some knowledge of level flight attitudes at those conditions and some practice to achieve the proper attitude at the proper speed. Try it the next time you have a simulator session - and let us know how it works out.
The other thing is that you should most assuredly have the throttle(s) at idle when the mains contact the surface – where you start to retard those throttles and how quickly you do it depends a lot on technique and individual airplane characteristics. Generally, if you cross the threshold at the proper height, at the proper speed, and begin a very gradual throttle reduction at that point – rotate to the proper flare attitude, taking no more than 3 seconds to reach that level flight attitude (3 – 4 feet) from the time you begin the flare, getting there at a speed of 1.10 to 1.50 Vs – continuing to retard the throttles – hold the airplane in that flared attitude for no more than 3 seconds, making sure the throttles hit the idle stop at touchdown – you will have made the “perfect” landing (contrary to those “know-it-alls” to say perfect landings don’t exist). This procedure will allow you to land at the proper distance down the runway, at the proper attitude, with sufficient airspeed to maintain directional control until you get the nose on the ground. I won’t tell you it will be the “grease job” landing everyone thinks is the mark of a good landing. No. It will be somewhat firm – but not at all unpleasant – and it works with headwind, tailwind, crosswind, light weights, heavy weights, and with any flap configuration. You’ll have enough vertical force to put the wheels on the runway – through any precipitation activity, but not so hard that the little old lady in 2A will have a coronary. However, it does take some knowledge of level flight attitudes at those conditions and some practice to achieve the proper attitude at the proper speed. Try it the next time you have a simulator session - and let us know how it works out.
Join Date: Jul 2008
Location: Gone to my "Happy Place".
Posts: 157
Likes: 0
Received 0 Likes
on
0 Posts
I am showing my age here a bit but on the A-300 (B4) the smoothest landings were achieved by easing forward on the controls after the flair had been established
For the "Fly by Wire" ignorant, landing in the FBW Airbus series is in a "Control Law" that makes landings feel "...like any other aicraft..." sort of!
Vapp. Vapp ALWAYS includes an additional margin of speed to compensate for, lazy auto-thrust, Severe Icing, etc. Any other additions will be at the discretion of the pilots (For whatever reason) or a inputted as a result of a failure affecting aerodynamics (Flaps, etc).
In 15 years on FBW Airbus, I've seen more people get into trouble with landings (Pitch) when they didn't understand what Ground Speed Mini (GS Mini) did, or how it actually functioned. In fact, yesterday I had a guy want to REDUCE Vapp because GS Mini was doing EXACTLY what it was designed to do. In this case - had I allowed that reduction - the aircraft would have landed with a fairly high pitch attitude and - incidently -increased thrust. As a result, tail strike more probable.
Flaps Full or Flaps 3 is the same. The difference will be the approach speed (sometimes only a marginal difference) and a flatter pitch attitude at the commencement of Flare. Nonetheless, it's still a better landing (and according to the FCOM / FCTM) if you arrest the sink, then derotate the aircraft.
Generally, if you cross the threshold at the proper height, at the proper speed, and begin a very gradual throttle reduction at that point
I wish I had had a copy of this post years ago to describe to others the correct way to land this plane!
All of that said, no matter what you do during a landing, Airbus will always call you a "Retard, Retard, Retard".
Last edited by Jimmy Do Little; 3rd Aug 2009 at 12:51.
I won’t tell you it will be the “grease job” landing everyone thinks is the mark of a good landing. No. It will be somewhat firm – but not at all unpleasant
I have heard many passengers comment on both smooth (grease job) and firm/hard/rough landings, but none ever made any comment at all about the touch down zone
You might say that the passengers of the flight which ran off the end of the runway did not have the opportunity to complain. However I do not think there will be much risk of this happening in fine weather conditions on a runway more than twice as long as legally required (which is already factored).
Argue against this point as much as you like, but just ask the passengers, who pay our wages / salary. Some are very fearful of flying want the overall experience to be as smooth as possible.
Sure, a greaser within the zone is ideal if you can do it everytime
Last edited by John Citizen; 4th Aug 2009 at 09:06.
Join Date: Jul 2008
Location: Gone to my "Happy Place".
Posts: 157
Likes: 0
Received 0 Likes
on
0 Posts
[QUOTEbut none ever made any comment at all about the touch down zone 
[/QUOTE] I beg to differ....
Air France 358
Luftansa 2904
Southwest 1455
TACA 390
China 605
Qantas 1
Garuda 200
Lion Air 538
US Air 5050
Southwest 1248
All those passengers had comments about it!
[/QUOTE] I beg to differ....Air France 358
Luftansa 2904
Southwest 1455
TACA 390
China 605
Qantas 1
Garuda 200
Lion Air 538
US Air 5050
Southwest 1248
All those passengers had comments about it!
Let me say this again :
I, my own ears, have not ever heard any passengers comment (speak directly to me) at all about the touch down zone.
I have had a look at those accidents you mention. I agree the passengers would have a lot to comment about.
However, these accidents involve other factors :
- adverse weather / windshear / storms / snow
- wet runway
- short runway / displaced threshold
- excessive approach speed / unstable approach
- speed brake retraction after touchdown
- idle reverse only / late deployment of reverse
- not in ideal landing configuration (flap setting)
Lion air 386 and US Air 5050 were both takeoff accidents Please explain how these are relevant to the discussion here.
For 2 of those accidents, Southwest 1248 and TACA 390, the aircraft actually did touch down in the zone but still crashed
A touchdown in the zone does not necessarily mean that you will never run off the runway and a long landing beyond the zone (as you see all the time) does not necessarily mean you will run off the runway and all die.
Let me say this again (assuming you fly a stable approach) :
Can you please find any examples where such has happened ?
Such conditions were not present in all those mentioned accidents above.
Don't get me wrong, I still believe you should attempt to touchdown in the zone every time but a smooth landing (to me) is also important.
However, in adverse conditions on a short runway, getting down in the zone suddenly becomes far more important now.
I, my own ears, have not ever heard any passengers comment (speak directly to me) at all about the touch down zone.
I have had a look at those accidents you mention. I agree the passengers would have a lot to comment about.
However, these accidents involve other factors :
- adverse weather / windshear / storms / snow
- wet runway
- short runway / displaced threshold
- excessive approach speed / unstable approach
- speed brake retraction after touchdown
- idle reverse only / late deployment of reverse
- not in ideal landing configuration (flap setting)
Lion air 386 and US Air 5050 were both takeoff accidents
Please explain how these are relevant to the discussion here. For 2 of those accidents, Southwest 1248 and TACA 390, the aircraft actually did touch down in the zone but still crashed
A touchdown in the zone does not necessarily mean that you will never run off the runway and a long landing beyond the zone (as you see all the time) does not necessarily mean you will run off the runway and all die.
Let me say this again (assuming you fly a stable approach) :
I do not think there will be much risk of this happening (runway over run) in fine weather conditions on a runway more than twice as long as legally required if you land slightly beyond the zone.
Such conditions were not present in all those mentioned accidents above.
Don't get me wrong, I still believe you should attempt to touchdown in the zone every time but a smooth landing (to me) is also important.
However, in adverse conditions on a short runway, getting down in the zone suddenly becomes far more important now.
Last edited by John Citizen; 5th Aug 2009 at 02:17.
Join Date: Jun 2008
Location: 31000FR
Posts: 60
Likes: 0
Received 0 Likes
on
0 Posts
Dear PantLoad.
Where I was? In Toulouse with the old factory trying to teach a lot of guys how to do just these things ( between testing, delivering and manuals...).
Never left South Western France - people, food, wine, wx etc too good - but too old to see the fantastic 350 into service. Back out in the real world flying airline style for some of my old customers, retirement lurking round the corner.
You have a good one yourself..... T.
Ops, thought I send u a PM, anyway
(and I fly pushbuttons.....)
Never left South Western France - people, food, wine, wx etc too good - but too old to see the fantastic 350 into service. Back out in the real world flying airline style for some of my old customers, retirement lurking round the corner.
You have a good one yourself..... T.
Ops, thought I send u a PM, anyway
(and I fly pushbuttons.....)
Passengers are where the revenue for our wages come from but we work for the Chief Pilot and he wants me to put the wheels on the runway in the TDZ. He also looks at the FOQA data to make sure thats what his pilots are doing. Of course pax don't comment about the TDZ because they have no idea what it is. Even the manufacturers don't want "greasers" as it can lead to tailstrike if you try and "hold-off". They also want you on the runway dumping lift bringing it to a stop and their figures are based on putting it on the runway at the 300m mark. If you are happy to land "slightly beyond the TDZ" then you are in test pilot territory.
If affirmation of your flying skills by people unkown to you is important then what about the professional at the holding point who is going to be taking points off for a long landing?
If affirmation of your flying skills by people unkown to you is important then what about the professional at the holding point who is going to be taking points off for a long landing?
