Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

Some landing advice please. A320

Tech Log The very best in practical technical discussion on the web

Some landing advice please. A320

Old 11th May 2013, 23:27
  #101 (permalink)  
 
Join Date: Apr 2005
Location: Southeast USA
Posts: 802
I'll try this one more time ... I used to be a member of this forum for a very long time ... but due to circumstances beyond my control, I've been unable to participate for quite some time now ... so ... and at the risk of sounding overly borning, I'm going to repost one of my earlier posts that some may consider goes to the heart of this specific question:

I know just how much everyone on this forum likes to have someone come along and “tell them” how it’s to be done. So, for those of you here who are older than ½ of my age – stop reading and go on down to the next post. OK, maybe you don’t know my age, but I was around when dirt was invented – that should give you an approximation. But, for you folks who are less than ½ of my age, listen up – this may be important to you, and, after a little practice, you just may be able to teach those guys who have now stopped reading how to really land an airplane. This procedure is applicable to every airplane from a C-152 to a B-747 (I haven’t flown a B-52 or the A-380, but I’ll bet it works there, too) – it also works in calm conditions, head winds, tail winds, cross winds, CAVU conditions, snow, ice, rain, simple IMC conditions, and even FLIR-aided IMC conditions.

As almost all of the folks above have indicated – the last portion of the final approach should be flown in the configuration in which you plan to land, and flown at a constant speed of 1.3 Vs (computed in that configuration), plus ½ of the steady state wind (not to exceed an additive of 20 knots) plus all of the gust factor. I personally believe that this steady-state condition should be established at 1000 feet AGL, but I know that some operations allow this altitude to be lower – but in the passenger revenue world I’m not aware of any that are below 500 feet AGL.

You should cross the runway threshold at what ever is the minimum threshold crossing height – for most transport category airplanes this should be about 50 feet. And at that point you should have been able to bleed off the airspeed additives you’ve been holding for steady-state wind (only the steady-state wind additives) – you’ll still have the 1.3 Vs plus all the gust factor. This will require you to continue to fly the airplane to the runway. Some operators recommend that you begin to reduce power at this point – if that is the procedure you’ve been taught, fine – but keep the airspeed constant until you begin the flare (that may mean pushing the nose over a bit – hopefully it will only require nose down pressure and not nose down movement. The point to which you should be flying at this point (the “aim” point – that point that doesn’t move up or down in the windscreen) is a point on the runway surface about 2/3 of the way between the threshold and the fixed distance markers (for the C-150 guys, this aim point should be the numbers themselves and for the B-747 guys, the aim point should be the fixed distance markers or just beyond).

OK, now for the flare. The question that always comes up is, “what attitude do I flare to?” When you start to flare is critical. You will want to reach your flare attitude with the main wheels something between 1 and 5 feet from the runway surface (1 foot or so for the C-152 guys and 5 feet for the B-747 guys … yes, I know how difficult it is to imagine the mains at 5 feet above the runway from the B-747 cockpit – but remember, you’re good at your job! – Make it 5 feet!) The change in the attitude from when you initiate the flare to reaching the flare attitude should take just about 3 seconds (no less than 2 for you C-150 guys and no more than 4 for you B-747 guys) and you should wind up with the main wheels “just off the runway surface. The speed you should have when you reach the flare attitude should be just below what you carried from the threshold to this point – between 5 and 15 knots – the smaller number for the smaller airplanes and the larger number for the larger airplanes. The attitude should be just exactly what it would take to maintain level flight from this point all the way down the runway. What I’d have you practice would be, “do not climb, do not descend, do not accelerate, do not decelerate; we’ll go around at the end of the runway.” I’d also have you mentally locate the position on the belly of the airplane exactly between the main gear (the body gear for you B-747 guys) and I’d tell you to fly down the runway (no climb, no descent, no faster, no slower) with that point on the belly of the airplane exactly over the runway centerline – and to do that with whatever crab angle you need to do it. Of course you’d have to add a bit of power – since you had the throttles back but this is OK for practice.

I’d have you do this exercise as many times as was necessary to get you comfortable with when to initiate the flare, how quickly to flare, and to what attitude you need to stop the flare with the main gear just off the runway surface. The key here, getting you to recognize when to start the flare and how quickly to flare, is to get you to recognize what attitude to reach at the end of the flare – THAT attitude is called the LEVEL FLIGHT ATTITUDE.

Once you’ve got it, as you begin the flare, you begin the throttle reduction. The idea is to get the throttles to the idle position as the mains touch the runway. As you pull the throttles back, you will notice the nose getting heavier – don’t let it move down. Increase the back pressure on the elevator controls – not to move the nose up – rather to just keep it from moving down. Over that 3 seconds, the airspeed continues to decelerate, while the airplane continues to descend, going from just above the runway to ON the runway. Level Flight Attitude is the attitude from which you want to land the airplane. Your touchdown should be firm but not hard, the kinetic energy of the airplane should be moving in the right direction, the nose should be able to be flown to the runway rather quickly as it is not unnecessarily high to arrest a high sink rate. You should be over the center of the runway, with the controls already properly positioned for the landing run.

If you had been carrying a crab angle to counter a crosswind, the crab should be removed in exactly the same time as the flare takes – 3 seconds. The pressure applied to the rudder pedal to pressure the nose around to line up with the centerline of the runway should start with the back pressure on the control column to flare. As you probably know, this may take some “into-the-wind” aileron to counter the tendency of the forward sweeping wing to rise … but, unless the wind is quite strong, you won’t be in the air long enough to have the wind blow you downwind off the centerline. Of course, if the wind IS quite strong, you may have to add a bit more aileron to slightly (very slightly) dip the wing tip in the up-wind direction.

I offer just one caveat. If you discuss this with your chief pilot or fleet captain and they absolutely forbid you to fly and land this way – pay attention to your company and forget what I’ve said. This is not an attempt to thwart the way your company procedures require you to operate. If this is different from the way you normally approach and land, I do not recommend that you do it without everyone in the cockpit knowing what you are going to do, no matter what position you are flying – if you can swing it, I’d recommend practicing it in the simulator with someone who knows what they are doing. I think you’ll be surprised at how easy this becomes, and how consistent your landings will become as well – night, day, rain, snow, clear, no matter. Consistent landings are good things to cultivate. Also, if you try this and just simply think it is the epitome of wrong-headedness, let me know and I’ll buy you a beer. However, if you think it is the correct way to land, let me know and I’ll buy you two!
AirRabbit is offline  
Old 12th May 2013, 14:42
  #102 (permalink)  
 
Join Date: Jul 2007
Location: uk
Posts: 653
737Jock: I think you will find that if the Thrust Levers are quickly closed prior to the RA trigger point then you will NOT get a "Retard" call. Works for me these last 17 years!
Meikleour is offline  
Old 13th May 2013, 16:02
  #103 (permalink)  
 
Join Date: Sep 2012
Location: Nowhere near Shinbone Waterhole
Posts: 201
One old thread I recall yonks ago asked for 737 landing advice - total 1 1/2 pages.

This thread asks for landing advice on the 320 suck-squirt....6 PAGES so far!

I have a bet going with a 727 mate of mine that this thread will reach at least 10
full pages or until the wheel is fully reinvented.
mikedreamer787 is offline  
Old 13th May 2013, 16:17
  #104 (permalink)  
 
Join Date: Jan 2012
Location: Not far from the edge of the Milky Way Galaxy in the Orion Arm.
Posts: 510
Well the autopilot starts reducing the thrust at 30ft RA, not at 20! So how does that relate to the old man? It doesn't.
No, you are right - it doesn`t. (after revision) I was wrong. the thrust levers are closed at 30` (subject to conditions)

..also, to flare by 20` not at 20` (subject to conditions) (however I got away with it so far, but like you said, the objective is to nail it 10/10, not 9/10, which is what I am going to do) -

AirRabbit`s post was well cool I thought, so were your comments, much appreciated.
Natstrackalpha is offline  
Old 13th May 2013, 17:15
  #105 (permalink)  
 
Join Date: Apr 2005
Location: Southeast USA
Posts: 802
The last time I checked, an airplane was an airplane. They all use the same principles and comply with the same aerodynamic rules. The difference between the A320 and the B737 is the amount of electrons to which pilots (albeit because of the engineers involved) have abdicated their decision making abilities. As I am able to recognize from my somewhat limited experience in flying the Airbus Family of airplanes, we still have a collection of parts and pieces (making up the airframe) that remain subject to the same forces and results that the air through which it travels demands. Yes, there are some electrons whose duty it is to prevent you (the pilot) from doing things that are not authorized in that electron's programming ... like bringing (or leaving) the engines in an idle thrust position (particularly when getting close to the ground and getting the nose to an attitude not acceptable to those electrons' programming) ... or continuing to raise the nose to a higher angle of attack that is also beyond the level of acceptability programmed into those "electron" memory banks (as Capt Sullenburger began to recognize at the very end of his "miracle landing" on the Hudson River). However, with those notable exceptions, the A320 can land, and, in my not-so-humble-opinion, should be landed, in exactly the same way as any other airplane. I know it can be done because I've done it, more than a few times, in a rather wide variety of conditions, weights, and specific Airbus equipment types. It comes back to the point that the pilot is (or at least SHOULD BE) in command of the airplane. Airbus has not taken that issue out of consideration ... they've simply made the boundaries within which the pilot remains in command, a bit smaller ... and, some would say too much so ... but I'm not intending to post a criticism of Airbus or their very fine equipment. If the pilot knows his/her equipment, and knows the boundaries of where his/her exercise of command authority over that equipment starts and stops, I'll be a "happy camper" regardless of the manufacturer of that equipment. Therefore - I'll stand by my previous post and again point out that the landing attitude is the "level flight" attitude, and should occur at an airspeed that is somewhat below (the exact number is not "specific" and is deliberately variable to allow the pilot to make adjustments when necessary) a margin of 30% above the projected aerodynamic stall airspeed for the configuration, weight, and location (leaving in place the wind gust factor should any exist - and that only for safety purposes), on the center-line of the runway, tracking to remain on that centerline, and should occur at a point between the threshold and not further down the runway than 3000 feet or 1/3 of the runway available, which ever is shorter. This only becomes a "real" issue when landing on runways less than 9000 feet (where these two distance maximums are equal) and provides specifics to improve the probability of NOT departing the end of the runway during the landing roll-out. I'll say it again ... an airplane is an airplane.

Last edited by AirRabbit; 13th May 2013 at 17:19.
AirRabbit is offline  
Old 20th May 2013, 02:09
  #106 (permalink)  
 
Join Date: Oct 2007
Location: America
Posts: 91
http://www.airbus.com/fileadmin/medi...LAND-SEQ08.pdf
junebug172 is offline  
Old 20th May 2013, 02:15
  #107 (permalink)  
 
Join Date: Mar 2002
Location: Seat 0A
Posts: 7,807
Originally Posted by Airbus
tailstrike occurrence is directly related to pitch attitude
versus aircraft geometry, and the status of main landing gear extension.
Correct. If status=retracted = tailstrike!
Capn Bloggs is offline  
Old 20th May 2013, 02:44
  #108 (permalink)  
Person Of Interest
 
Join Date: Jan 2000
Location: Floral City, Florida, USA
Age: 64
Posts: 835
There's our buddy NATSTRACKALPHA awakening from his 3 month hibernation at Thule BGTL Greenland...Reminds me of a reggaee song..."Stir It Up"....
DownIn3Green is offline  
Old 20th May 2013, 02:53
  #109 (permalink)  
 
Join Date: Mar 2002
Location: Seat 0A
Posts: 7,807
Well, I learn something every day...

Originally Posted by Airbus
Crosswinds Not Handled Correctly
When the aircraft is close to the ground, the wind velocity tends to decrease, and the wind direction tends to turn (direction in degrees decreasing in northern latitudes).
The flight crew must be aware that during the approach phase, and especially during the flare, a crosswind effect could suddenly increase the pitch of the aircraft, and result in tailstrike.
Coriolus?
Capn Bloggs is offline  
Old 20th May 2013, 14:41
  #110 (permalink)  
 
Join Date: Jan 2006
Location: US
Posts: 2,088
Seriously? How much does the pitch increase with a wind shift? Half a pitch? A third of a degree? 1/8? 20,000+ hrs, two crosswind landings, and neither one had a noticeable pitch up.

Based on my experience it's the 'marking with a [email protected] and cutting with an axe' detail. In other words, more nonsense that some new guy will get confused about, worry about, or get questioned about.
misd-agin is offline  
Old 20th May 2013, 15:16
  #111 (permalink)  
 
Join Date: Mar 2007
Location: Another Planet.
Posts: 562
FBW Steel Variants.

Can anyone explain to an old codger who's only ever flown steel FBW, why does one design and certificate a public transport aircraft which changes its handling qualities @ 50' radio and starts to LOWER the pitch @ 30' radio, just when the evolved baboon (we're all one of those!) who's driving, is trying to alight in a fairly precise manner on the tarmac??!!

No wonder the OP has asked the question, how do I land this bl**dy thing?


BARKINGMAD is offline  
Old 20th May 2013, 17:26
  #112 (permalink)  
 
Join Date: Oct 2007
Location: America
Posts: 91
You guys are over-thinking this thing.

You don't notice any of those changes at all. Land the airplane like you would any other airplane - using your aviator skills. It works just fine and is very intuitive.
junebug172 is offline  
Old 20th May 2013, 20:20
  #113 (permalink)  
 
Join Date: Aug 2005
Location: fl
Posts: 2,561
All airplanes land about the same. No need to sort them out. If you have a crosswind just add a few knots because you need some lift to counteract the slip you are in to make the wheels roll straight down the runway. Why land in a crab and look like a student pilot? Try that in a tail dragger some day.

Last edited by bubbers44; 20th May 2013 at 20:23.
bubbers44 is offline  
Old 20th May 2013, 21:05
  #114 (permalink)  
 
Join Date: Jan 2006
Location: US
Posts: 2,088
Some a/c are designed to land in a crab. Most aren't. Fly them as recommended. Airbus and Boeing recommend cross-controlled landings.
misd-agin is offline  
Old 20th May 2013, 21:17
  #115 (permalink)  
 
Join Date: Aug 2005
Location: fl
Posts: 2,561
Isn't that hard on the main landing gear tires landing in a skidding situation? Why would you do that? Try that in a DC3. Guess that is not a problem any more, is it?
bubbers44 is offline  
Old 21st May 2013, 04:03
  #116 (permalink)  
 
Join Date: Oct 2007
Location: America
Posts: 91
Some aircraft, because of the engines, won't let you bank into the wind so you're really limited as to how much bank angle you can put into the upwind side.

Airbus does a decrab, or kick out, where you flare and add downwind rudder. Hopefully, you're not holding it off to where drift becomes an issue.
junebug172 is offline  
Old 21st May 2013, 04:39
  #117 (permalink)  
 
Join Date: Aug 2005
Location: fl
Posts: 2,561
No Boeing has this problem of landing straight. Who makes an airplane that you have to land in a crab?
bubbers44 is offline  
Old 21st May 2013, 05:21
  #118 (permalink)  
 
Join Date: Oct 2007
Location: America
Posts: 91
Boeing.

Don't they recommend for the 737 landing with a crab in winds of about 20kts or more with more than 15 degrees of flaps?

From the Boeing 747 Flight Crew Training Manual:

"It is not necessary to eliminate the crosswind crab angle prior to touchdown on wet runways. Allowing the airplane to touch down without removing the crab angle will reduce drift toward the downwind side of the runway".

And as you can see by this vid, you can land perfectly well in a crab. And some aircraft, especially those with very low nacelles (737) or engines that are far outboard (747) will sometimes require you to land in a crab.

Crosswinds - Video

Last edited by junebug172; 21st May 2013 at 05:30.
junebug172 is offline  
Old 21st May 2013, 06:56
  #119 (permalink)  
 
Join Date: Jun 2007
Location: Wanderlust
Posts: 2,334
junebug172
"It is not necessary to eliminate the crosswind crab angle prior to touchdown on wet runways"
The reason to decrab before touch down is undercarriage is not designed to take high side stress. By design nose wheel aircrft CG swings the aircraft straight but at the point of touch down side stress is imposed on the gear. In your quote about 747 FCTM the word wet is important because on wet RW the a/c at the point of touch down skids straight on which reduces the side stress and then when it grips the surface it swings straight ahead. It is not recommended on dry surface.
vilas is online now  
Old 21st May 2013, 07:55
  #120 (permalink)  
 
Join Date: Oct 2007
Location: America
Posts: 91
Crosswind Landings of 21 Airplanes at OSAKA Airport - YouTube

Last edited by junebug172; 21st May 2013 at 08:01.
junebug172 is offline  

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.