I was checking out this online content. https://en.wikipedia.org/wiki/Crosswind_landing (Refer the image for De-Crab)
Is there a more detailed content online that explains the effects of CROSSWINDS during the APPROACH and how counter/overcome (maneuvers like YAW and ROLL required) such forces and remain on TRACK till the touch down.
Here is my situation, 7-8NM from Touchdown (28R - KORD); 2500 Feet above. At about this point, I disengage A/P and A/T with full flaps deployed and landing gear down. The crosswind of 16 Kts is from SOUTHWEST. I have been using a combination of YAW and ROLL as I start noticing deviation in the LOCALIZER pointer, but have been drifting and unable to remain on the extended CENTERLINE
https://www.youtube.com/watch?v=ib9QNebjqQ8&feature=youtu.be
Don't touch the rudders unless you have an engine out.
If you use the flight director, it will give you nice hints.
Did I say don't touch the rudders?
Only just before touchdown, kick the rudders to align the fuselage with the runway. Or even a bit later if the runway is wet. Or not at all if it is iced :-)
Hoppie
PS. Don't touch the rudders.
Practice makes perfect. :) I often practice with the SITU file in which you land at runway 25C in Frankfurt with real weather.
I find it sometimes tricky to make good crosswind landings, especially if the sidewind component is greater than 8-10 kts.
It is important to use ailerons only (as Jeroen pointed out, don't use rudder) and make small corrections. That's the difficult thing: you have to make small but consequent corrections, but avoid chasing the flight director. When the wind velocity or direction is changing close to the ground, it can get really nasty.
I find it very useful to use the track indicator (the small grey "hair" in the outside view) to align the aircraft with the runway. Keep the wind correction angle as long as possible. I usually initiate the flare at 30-40 ft and wait until the "10" callout. Then I kick in the rudder and try to align the aircraft.
Sometimes I manage to land on the centerline, but often I find myself 10 ft to the right or left. I think that's acceptable.
What I find difficult is to coordinate everything because it all happens within 2 or 3 seconds:
- initiating flare
- thrust reduction
- nose up command to compensate for thrust reduction
- rudder application just before touchdown
Best regards,
Dirk
And yes, I have seen professional pilots, in a sim running PS1.3 and a mediocre yoke, flying a crosswind approach with one hand on the yoke almost without visibly moving it. Tiny bit left. Tiny bit right. Tiny bit up. Repeat. It's not even noticeable that their FD deviates.
Grrrrr.
Hoppie
During the approach the flight deck will have to be offset slightly upwind of the centreline in order to allow for the main wheels to touch down on the centreline.
As others have said, the preferred method generally is to use the 'crab' method, laying off the drift by selecting a heading in to the wind as you come down the approach, then 'de-crabbing' in the flare, just before touchdown, using the rudder to align the nose with the centreline.
I'm personally not a fan of the term 'kick' as that implies a violent/rapid movement. A smooth squeeze of the rudder pedal is all that is necessary -- in the flare, look at the end of the runway (you should be anyway!) and gently squeeze the rudder to smoothly bring the nose of the aeroplane around in to line with the centreline. As you do so, you will need to smoothly feed in opposite aileron (in to the wind) in coordination with the rudder input to keep the wings level (because the yaw induces a rolling moment) which is really quite critical in an aeroplane like the B747 as if too much roll is allowed to develop it is very easy to scrape an outboard pod! Keeping the rudder input smooth and progressive will aid in properly coordinating the aileron input.
Note that obviously as soon as you start to remove the crab the aircraft will drift downwind (as you no longer have a force opposing the drift) so it is important to do so at the latest stage just before main gear touchdown.
Equally important not to stop flying the aeroplane after touchdown either - again in to wind aileron will be necessary to keep the wings level during the rollout.
Quote from: Jeroen Hoppenbrouwers on Fri, 31 Jul 2020 15:31
And yes, .... Tiny bit left. Tiny bit right. Tiny bit up. Repeat. It's not even noticeable that their FD deviates.
Hoppie
Quote from: Dirk Schepmann on Fri, 31 Jul 2020 13:16
Practice makes perfect. :) I often practice with the SITU file in which you land at runway 25C in Frankfurt with real weather.
I find it sometimes tricky to make good crosswind landings, especially if the sidewind component is greater than 8-10 kts.
It is important to use ailerons only (as Jeroen pointed out, don't use rudder) and make small corrections. That's the difficult thing: you have to make small but consequent corrections.
I find it very useful to use the track indicator (the small grey "hair" in the outside view) to align the aircraft with the runway. Keep the wind correction angle as long as possible. I usually initiate the flare at 30-40 ft and wait until the "10" callout. Then I kick in the rudder and try to align the aircraft.
Sometimes I manage to land on the centerline, but often I find myself 10 ft to the right or left. I think that's acceptable.
What I find difficult is to coordinate everything because it all happens within 2 or 3 seconds:
- initiating flare
- thrust reduction
- nose up command to compensate for thrust reduction
- rudder application just before touchdown
Best regards,
Dirk
Dirk, you nailed the points for me....Especially, the last four points...But, I am way way behind you...I am not even able get to situation where I am 50feet from touch down and able to meet the last four points you have listed. To get into a little more detail of the situation I am trying to master is explained below
Lets say, I am tracking on the extend centerline till I disengage A/P and A/T. There is crosswind of 16Kts from SOUTHWEST. After disengaging A/T and A/P I keep the throttle position unchanged. I continue for a couple of seconds, I notice the LOCALIZER deviation. This is when I am trying to understand if I should use AILERON and ROLL...When I ROLL and momentarily spot myself on the Extended centerline, I am not able to figure out how to maintain track close to the EXTENDED CENTERLINE...And then I keep drifting LEFT RIGHT.
But your experiences shared is helping me understand my practices better..Positive side is, I am grasping quite a lot..
Remember the localizer is a horizontal position indicator. If you drift left of localizer, you need a bit of roll to the right so your heading moves a bit to the right, then you roll in the opposite direction to get your heading back where it was to maintain the localizer. It is a balancing act.
Switch the FD on (not the AP) and follow the cross hairs. That will teach you. It also has accelleration sensors so it tells you trends before you see them on the localizer.
Hoppie
Quote from: Jeroen Hoppenbrouwers on Fri, 31 Jul 2020 20:28
It is a balancing act.
Hoppie
Seems like there is more practice required from myside...Hoppie, I am very thankful to all the feedback and guidance.
Have a great weekend
Squeeze don't kick. Crab until the flare.
I know that the recommended practice is to crab until flare. (Though, I recall that didn't work out well when I flew in the sim with Jeroen with 25kts of crosswind set by Joerg. *boom*)
When I was in the 747-8i sim three years ago I practiced this technique a lot in PSX and then tried it in the full flight sim. KSFO landing 28L with 25 kts crosswind, and thanks due to the PSX training, I could walk away from that landing and be fairly happy with it.
But then the instructor (apparently, an old-style retired DC10 flight engineer) said: why all this crabbing? Why don't you fly a side slip? So, I tried again, challenge taken, again 25 kts x-winds, now this time with nicely crossed controls all the way in. Guess what? It worked even better. ;) ;D
p.s.
My next approach was the rarely used KSFO Visual 01R right approach (circling from LOC28L). No crosswind (25 kts on the head). Much more fun!
Quotewhy all this crabbing? Why don't you fly a side slip?
why do anything at all? the 747 is certified to land while crabbed up to the crosswind guideline speeds! ;D
Whatever you do, remember: plenty of aileron!
Quote from: Markus Vitzethum on Sat, 1 Aug 2020 13:54
I know that the recommended practice is to crab until flare. (Though, I recall that didn't work out well when I flew in the sim with Jeroen with 25kts of crosswind set by Joerg. *boom*)
No, that was slightly different, for as far as I remember.
We had a failed #4 engine and came in to EHAM 24 and feeling adventurous, we decided NOT to remove the crab. At the moment of touchdown, the sim abruptly froze and displayed LATERAL FORCES EXCEEDED. No satisfying effects except for some noise from "down below" that was sort of alarming.
The real fun came afterwards. We reset the sim for a departure from 24, so basically remove all speeds and settle down. Go! Push all throttles forward, no need to check, we're having fun.
#4 still shut down...
That ended in the ditch in about 8 seconds.
But now I think longer, why crab with a failed engine?
Ah well. We did lots of silly things :-D
Hoppie
(http://www.hoppie.nl/galleries/gppm5/slides/slide_im000096.jpg)
http://www.hoppie.nl/galleries/gppm5/24.html
(I don't have a photo of this sim session with me and Markus in the seats; this left seater is Thorsten)
My question might sound a little silly, but please bear with me...
Okay, my latest challenge is "ROLLing" during crosswind.
I am 2500 feet above, 7NM miles landing on 28R (KORD). At the point of disengaging the A/P and autothrottle, I notice I am not on Extended centerline (I am to the left of the MAGENTA diamond) and there is crosswind (16-18) from the RIGHT. When I apply AILERONs at this point, it seems like I am having a Fishtail effect (excusing me for not using the technical word). Do I still not use RUDDERS at this point?
Quote from: Jeroen Hoppenbrouwers on Thu, 30 Jul 2020 22:43
Don't touch the rudders unless you have an engine out.
If you use the flight director, it will give you nice hints.
Did I say don't touch the rudders?
PS. Don't touch the rudders.
How would lining up on the extended centerline be achieved, strictly with ROLL and when there is a crosswind?
Quote from: vnangli on Thu, 6 Aug 2020 20:45
I am 2500 feet above, 7NM miles landing on 28R (KORD). At the point of disengaging the A/P and autothrottle, I notice I am not on Extended centerline (I am to the left of the MAGENTA diamond) and there is crosswind (16-18) from the RIGHT. When I apply AILERONs at this point, it seems like I am having a Fishtail effect (excusing me for not using the technical word). Do I still not use RUDDERS at this point?
How would lining up on the extended centerline be achieved, strictly with ROLL and when there is a crosswind?
Not sure, what you mean with fishtail effect... but basically you have to fly an angle into the wind (the crab angle).
So when the localizer starts to drift away from the center, you'll initiate a slight turn into the wind. When the localizer starts to move back, you'll change the heading back towards the runway heading, but just a little bit. Enough to keep the localizer centered. Often you have to repeat this a few times until you find the necessary Wind correction angle.
The stronger the crosswind is, the greater the correction angle is... it might even look scary at strong crosswinds. But under most circumstances it will be a small correction angle which can be easily corrected with the rudder at or immediately after touchdown.
I'd suggest to create a training scenario with constant crosswind with 10-15 kts. Fly it often, get a feel for the sim and your hardware. And be gentle with the controls, make frequent small corrections instead of big corrections.
Good luck!
QuoteHow would lining up on the extended centerline be achieved, strictly with ROLL and when there is a crosswind?
No need for the rudders. When you smoothly bank with the ailerons, the heading will change, and that will eventually put the aircraft on a different track. When it is on a track that leads to the runway, roll the wings smoothly back to level. You don't need to use the rudder to roll into a bank, hold the bank until you are on the desired track, and roll the wings level again.
Remember that with a crosswind, the nose of the aircraft won't be pointed at the runway itself, because you'll be flying in a crab.
Quote from: Dirk Schepmann on Thu, 6 Aug 2020 22:40
Not sure, what you mean with fishtail effect... but basically you have to fly an angle into the wind (the crab angle).
Good luck!
CRAB angle is the term I should have used...
Try it this way.
Fly 10 nm out and let the AP intercept and track the localizer. Then closely monitor what it does to remain on the localizer.
Note the crab angle. Your nose points not at the runway, but left or right of it, this is your heading. Your over the ground track should be dead center on the runway. The difference is the wind correction. No bank required! Just your heading.
To make small heading corrections, keeping the track aligned with the runway, the AP makes small bank corrections, left and right. But almost invisible. Look at the FD and the aileron positions or the yoke. It's small. Your track and heading stay almost static and the plane only wobbles a bit.
Then once you know the numbers, disconnect the AP and do it yourself. Just the localizer. Forget the glideslope.
Fly 99.99% of the approach just using this technique, crab into wind. You can as well use a VOR radial or any other straight line over the ground with wind from the side.
Only just just just before touchdown, you have to do something to avoid touching down with too much crab. You're not a B52. One smooth squeeze of rudder to align the aircraft with the runway, and onto the tarmac. Flying without a crab means drifting aside, so you want to basically not do that. Go from plane to car and become a car just at touchdown, simply stated.
https://www.youtube.com/watch?v=A1lpoZDjt00 <-- B52
Hoppie
Quote from: Jeroen Hoppenbrouwers on Thu, 6 Aug 2020 23:48
Try it this way.
Fly 10 nm out and let the AP intercept and track the localizer. Then closely monitor what it does to remain on the localizer.
Hoppie
I am going to do this exercise and will have to put the screen recording in my PC to work and record the values to repeat it when I will disengage AP.
Now, I will record the values (approximate values) of the CRAB angle from the Heading and Track indicator (PFD) or from ND. How can I get (record) the Bank angle values apart from observing the Flight Director bar in the PFD?? You have given me a good home assignment :)
Further advice: Let's say you see you are on the localizer but drifting to the right. So you want to turn left to stop the drift.
1. Apply left aileron and roll gently to a 5 degree bank. No rudder required.
2. Hold the 5 degree bank until you see the CDI stop drifting away and then ever-so-slightly start to drift back.
3. Roll the wings level, watching the CDI move back on course.
4. Then when the CDI is just about centered, roll gently to a 5 degree bank to the right to freeze the CDI.
5. Now roll wings level, and you are tracking the localizer.
6. Repeat as necessary, with smaller motions as you get closer to the station.
Quote from: Will on Fri, 7 Aug 2020 02:33
Further advice: Let's say you see you are on the localizer but drifting to the right. So you want to turn left to stop the drift.
These points are going on my cheat sheet...Thank you.
Over these last 20 - 25 days that I have been practicing manual landing, I have to thank this forum. Every landing attempt has added something to what I have learnt..
Sincere thanks
try putting these parameters into any airport you wish to experiment on
these are the windiest and gustiest places today for pilots
Station
Wind
Gust
Vis(SM)
Temp/Dew
Baro
K2WX 33 47 25/13 29.78
K2WX 070214Z AUTO 22033G47KT SQ 26/13 A2978 RMK AO1 PK WND 20047/0211 WSHFT 0200 PRESRR T02560133
PAVC 31 42 10 11/8 29.45
PAVC 070156Z AUTO 26031G42KT 10SM OVC015 11/08 A2945 RMK AO2 PK WND 25044/0057 SLP972 T01110083
K1HW 30 42 10 21/12 29.98
K1HW 070158Z AUTO 18030G42KT 10SM -SHRA FEW085 BKN100 22/13 A2998 RMK AO2 PK WND 19043/37 LTG DSNT E-SE SHRAE0057RAB19E30SHRAB30 TSB15E30 SLP114 T02170126 $
YCNM 30 42 11/11 29.70
YCNM 070200Z AUTO 07030G42KT //// // ////// 11/11 Q1006
RJCA 28 41 6.21 27/18 29.32
RJC
Station
Wind
Gust
Vis(SM)
Temp/Dew
Baro
K2WX 33 47 25/13 29.78
K2WX 070214Z AUTO 22033G47KT SQ 26/13 A2978 RMK AO1 PK WND 20047/0211 WSHFT 0200 PRESRR T02560133
PAVC 31 42 10 11/8 29.45
PAVC 070156Z AUTO 26031G42KT 10SM OVC015 11/08 A2945 RMK AO2 PK WND 25044/0057 SLP972 T01110083
PACD 30 40 7 10/8 29.43
PACD 070153Z AUTO 26030G40KT 7SM OVC012 11/09 A2943 RMK AO2 PK WND 26043/0127 SLP966 T01060089 TSNO
K1HW 30 42 10 21/12 29.98
K1HW 070158Z AUTO 18030G42KT 10SM -SHRA FEW085 BKN100 22/13 A2998 RMK AO2 PK WND 19043/37 LTG DSNT E-SE SHRAE0057RAB19E30SHRAB30 TSB15E30 SLP114 T02170126 $
YCNM 30 42 11/11 29.70
YCNM 070200Z AUTO 07030G42KT //// // ////// 11/11 Q1006
A 070121Z 20028G41KT 9999 FEW020 BKN040 BKN070 27/18 Q0993 RMK 1CU020 5CU040 7AC070 A2932
Adelaide International Airport (Adelaide, AU-SA)
WX MAP UNAVAILABLE Nearest METAR:
YPAD 070200Z 15008KT 9999 FEW018 BKN072 OVC096 09/04 Q1013 TEMPO 0300/0500 5000 RA BKN020 FM0200 MOD TURB BLW 5000FT FM0300 SEV TURB BLW 5000FT
YSCB App/Dep Canberra International Airport (Canberra, AU-ACT)
WX MAP UNAVAILABLE Nearest METAR:
YSCB 070200Z AUTO 16007KT 9999 -RA SCT029 BKN035 OVC044 07/07 Q1020 TEMPO 0200/0500 5000 RA BKN020 FM0200 SEV TURB BLW 5000FT
Metropolitan Oakland International Airport (Oakland, US-CA)
ksfo Nearest METAR:
KSFO 070156Z 27022G31KT 10SM FEW006 18/13 A2987 RMK AO2 PK WND 27034/0123 SLP113 T01830128
Crossed-controls! Not many people can do it which is why it is vilified.
It seems that PIC in this incident used / followed wrong procedure, resulting in an engine pot strike.
And one more interesting quote:
"To deal with the crosswind, the PIC opted to use the 'touchdown-in-a-crab' technique. However, while he was aware that the FCTM had stipulated that pilots should aim at having the main landing gears touch down on the centre of the runway, he decided that he should aim at having the main landing gears touch down slightly to the right of the runway centreline. He believed this would allow a greater margin of safety from an excursion off the left edge of the runway should the aircraft be forced downwind during touchdown."
Emphasis are mine. As stated several times, de-crabbing method is preferred one.
Despite the fact that the wind was not very strong (7 kts), result was unnecessary. Could this be PIC's last flight with SIA or would he go to re-training?
https://avherald.com/h?article=4d07791d&opt=0 (https://avherald.com/h?article=4d07791d&opt=0)
Cheers,
Apparently, the captain landed in a crab and then got disoriented, incorrectly thinking the aircraft had bounced and was airborne again, and then initiated a go around. In the go around, he used aileron to align the aircraft with the runway, resulting in the pod strike.
This probably wouldn't have become an incident if he had used rudder instead.