Airbus Crosswind... "White Knuckled Landing"
Thread Starter
Airbus Crosswind... "White Knuckled Landing"
OK, It's CNN, so that puts it in perspective, however, the Airbus has a rudder installed on it for various reasons, it is not only decorative.
https://www.cnn.com/videos/world/201...ngham-orig.cnn
The control laws for elevators change as a function of radio altitude, and emulate a normal aircraft.
The ailerons are rate commands, no input no roll
The rudder is a rudder, it will give a yaw rate and when stabilised a sideslip angle. It also gives a roll moment the the aileron logic nulls out (mainly).
The rudder is there for aligning the nose of the plane, (the bit where the professionals sit...) down the runway at an appropriate and well considered point in the approach to landing.
The FBW is different, but it is still a C-150 underneath it all.
https://www.cnn.com/videos/world/201...ngham-orig.cnn
The control laws for elevators change as a function of radio altitude, and emulate a normal aircraft.
The ailerons are rate commands, no input no roll
The rudder is a rudder, it will give a yaw rate and when stabilised a sideslip angle. It also gives a roll moment the the aileron logic nulls out (mainly).
The rudder is there for aligning the nose of the plane, (the bit where the professionals sit...) down the runway at an appropriate and well considered point in the approach to landing.
The FBW is different, but it is still a C-150 underneath it all.
Only half a speed-brake
Some people do a strict crab technique, and only put the rudder for the landing. I was trained similar initially (pre-Airbus) by what was an ex-anhedral instructor group.
The video shows them a bit on the downwind side at the threshold markers, correcting back to center line. The G/A is initiated about 2 sec before the climb out (my guess).
They never reached the point when the rudder would had been put in. For a strict crab technique.
Maybe not the best choice in such a gale.
The video shows them a bit on the downwind side at the threshold markers, correcting back to center line. The G/A is initiated about 2 sec before the climb out (my guess).
They never reached the point when the rudder would had been put in. For a strict crab technique.
Maybe not the best choice in such a gale.
Thread Starter
Some people do a strict crab technique, and only put the rudder for the landing. I was trained similar initially (pre-Airbus) by what was an ex-anhedral instructor group.
The video shows them a bit on the downwind side at the threshold markers, correcting back to center line. The G/A is initiated about 2 sec before the climb out (my guess).
They never reached the point when the rudder would had been put in. For a strict crab technique.
Maybe not the best choice in such a gale.
The video shows them a bit on the downwind side at the threshold markers, correcting back to center line. The G/A is initiated about 2 sec before the climb out (my guess).
They never reached the point when the rudder would had been put in. For a strict crab technique.
Maybe not the best choice in such a gale.
FD: Reasonable points. I raise this image just following the number of weird crosswind images that come into the public domain. The Airbus seems to be in a world of its own with being either plonked on the ground going sideways with the decorative tail, which exerts high loads on the beam on bogie gear sets, or we see the plane exhibiting PIOs from flying slip on final which is not a great match with AI FBW logic.
Nothing wrong with a go around.
Nothing wrong with that approach or go around with 40 kts of crosswind, no PIO as claimed.
The 737 with direct control to flight control surface and connected yokes produces better results.....
The 737 with direct control to flight control surface and connected yokes produces better results.....
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If I remember correctly you have to be below 50ft for the FBW to allow cross controls. This thread might also be a timely reminder in that on touch down any aeleron input you have applied is halved.
Originally Posted by arketip
BS .
Without going into the B vs. A discussion, could someone with airbus experience clarify something for me? ...Since I have exactly 0 minutes flight hours on an airbus.
We were lining up behind a departing A340 in a strong crosswind. There was NO aileron input at all into the wind during their takeoff roll. The plane was clearly begging for it, as the upwind wing was higher than the downwind wing. When it lifted off the runway, only THEN was aileron input introduced. My colleague said that this was normal in an airbus because of design/control law etc.
To me it seems consistent with this landing of this airbus in Birmingham, above. No cross control in the way I have been doing the past 3 decades on boeings.
We were lining up behind a departing A340 in a strong crosswind. There was NO aileron input at all into the wind during their takeoff roll. The plane was clearly begging for it, as the upwind wing was higher than the downwind wing. When it lifted off the runway, only THEN was aileron input introduced. My colleague said that this was normal in an airbus because of design/control law etc.
To me it seems consistent with this landing of this airbus in Birmingham, above. No cross control in the way I have been doing the past 3 decades on boeings.
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Without going into the B vs. A discussion, could someone with airbus experience clarify something for me? ...Since I have exactly 0 minutes flight hours on an airbus.
We were lining up behind a departing A340 in a strong crosswind. There was NO aileron input at all into the wind during their takeoff roll. The plane was clearly begging for it, as the upwind wing was higher than the downwind wing. When it lifted off the runway, only THEN was aileron input introduced. My colleague said that this was normal in an airbus because of design/control law etc.
To me it seems consistent with this landing of this airbus in Birmingham, above. No cross control in the way I have been doing the past 3 decades on boeings.
We were lining up behind a departing A340 in a strong crosswind. There was NO aileron input at all into the wind during their takeoff roll. The plane was clearly begging for it, as the upwind wing was higher than the downwind wing. When it lifted off the runway, only THEN was aileron input introduced. My colleague said that this was normal in an airbus because of design/control law etc.
To me it seems consistent with this landing of this airbus in Birmingham, above. No cross control in the way I have been doing the past 3 decades on boeings.
Half forward stick is used at the commencement of the take-off run. For crosswind take-off, routine
use of into-wind aileron is not recommended. In strong crosswind conditions, small amounts of lateral control may be used to maintain wings level, but the pilot should avoid using excessive amounts. This causes excessive spoiler deployment, which increases the aircraft tendency to turn into wind. A two stage power application to TOGA or FLEX is made and the aircraft is kept straight by use of the rudder.
use of into-wind aileron is not recommended. In strong crosswind conditions, small amounts of lateral control may be used to maintain wings level, but the pilot should avoid using excessive amounts. This causes excessive spoiler deployment, which increases the aircraft tendency to turn into wind. A two stage power application to TOGA or FLEX is made and the aircraft is kept straight by use of the rudder.
Thread Starter
Continuing approaches in conditions that are severe may not be what the punters are paying for. That is a peer pressure/normalisation/mission completion item, tied up with the financial needs of the companies. The punters are paying to go from A to B, rather than C, however they are also not paying for disneyland rides, where there is elevated risk of bad outcomes. Not casting nasturtiums, I've looked out the #2 window in a B74 to see the runway, and at 500' decided that there was no way the landing would end up without making a headline. In retrospect, even calling it quits at 500' wasn't that much fun for the people paying our salary on that evening.
Not a fan of the B737, Boeing makes some great flying planes, the B737 makes money for the airlines. Can't argue that. The Airbus down in the flare behaves like a real plane. In both cases, (and not shown in these videos anyway) wing down/slip doesn't work very well, more of a problem on the Airbus than any other, but in both cases, wing down on the approach results in more unstable flight paths than flying with drift until the flare, and then aligning the nose towards the end of the runway.
Mild PIO is not an issue on this approach, it becomes more prevalent with slipping flight. The A320 video is of interest only on the amount of time spent with drift on just above the ground, before the G/A was initiated. The crew are dealign with challenging conditions in the A320 video. My point is that getting down in the weeds and ending up in a position where the rudder isn't applied due to the conditions, probably indicates we are in the wrong place at that point. Back when London's Hyde Park fell over in storms, we drove a B74 into MAN RWY06 with a gusty 35Kt crosswind, which was fun until it wasn't. I got the plane to the runway with a reasonable setup, cockpit slightly upwind of the centerline for the alignment, and eased the power off to land, and was about to put in rudder when we got hit with a 60Kt crosswind gust. The good news is the gust assists align the aircraft into wind through directional stability, but the track went from straight down the runway to a recorded 15 degree downwind track. about a second later we touched down, but in that time I had thought about putting in into wind rudder... pretty ugly, doing a go around... not going to happen without touching down, or planting the aircraft. I planted the aircraft. and spent the next 10 minutes apologising to the rest of the crew who were still in fits of laughter. The passengers weren't. The company was happy we got there for the passengers. I think we should have stayed in bed, and defended the passengers rights more effectively. The B74 is a sweet handling crosswind aircraft. Much nicer than the B762, even the B763. The B777 is also a great crosswind aircraft, with a remarkably effective rudder. (there is one oddity with the B777 however, for the takeoff roll, aircraft will weathervane into wind and need down wind rudder to maintain alignment. The B777 does as well, but only above about 80Kts, below that, the aircraft has an out of wind tendency which can be seen in the data if any crew look at their FDM/QAR output data). Years later, looking at serious incidents on one particular type and airline, the aircraft was tearing up the MLG trunnions. The data analysis showed that the crew were routinely landing with high levels of drift on. In those cases, this was also happening on landings with relatively low crosswinds, but where the crews were flying slip, they were getting out of sorts, such that in a 7kt crosswind, they had full rudder applied, and the aircraft in a forward slip into the flare and touchdown. That was eventually resolved, and the training reinforced to comply with the OEM's TM guidance, de-crab in the flare or after establishing the landing attitude.
FDR, yet another fascinating post of yours; thank you.
These are interesting comments. When we started on our "Boeing" (not really a Boeing; inherited from McD), the FCOM (written by Boeing) had nothing much to say about crosswind landings. Then, in 2010, there was a major rewrite, with a completely new section devoted crosswind landings which introduced the Forward Slip technique, at "approx. 200ft AGL". Later revisions changed that to "below 200ft AGL", but it was still the full forward slip. Whether this applied to all Boeings, I don't know, but I think was an acknowledgement that kicking it straight at the last second and dropping it on was getting beyond the capabilities of some pilots. See my comment above. It feels bl@@dy awful to sit through, but that's what Boeing now wants...
You seem to be into the FDM; an analysis of bank/angle pod strike risk verses landing with the wing down in a juicy crosswind using the forward slip technique is interesting!
wing down on the approach results in more unstable flight paths than flying with drift until the flare, and then aligning the nose towards the end of the runway.
Years later, looking at serious incidents on one particular type and airline, the aircraft was tearing up the MLG trunnions. The data analysis showed that the crew were routinely landing with high levels of drift on. In those cases, this was also happening on landings with relatively low crosswinds, but where the crews were flying slip, they were getting out of sorts, such that in a 7kt crosswind, they had full rudder applied, and the aircraft in a forward slip into the flare and touchdown. That was eventually resolved, and the training reinforced to comply with the OEM's TM guidance, de-crab in the flare or after establishing the landing attitude.
You seem to be into the FDM; an analysis of bank/angle pod strike risk verses landing with the wing down in a juicy crosswind using the forward slip technique is interesting!
Reading the B737 Classic FCTM it says "The airplane can land using crab only (zero sideslip) up to the crosswind limit guideline speeds. On dry runways upon touch down the airplane tracks toward the upwind edge of the runway while de-crabbing to align with the runway."
To me that implies you can safely touch down sideways without removing drift.
Perhaps Boeing should have added with a sly wink "And the Devil take the hindmost." To those who have seen this happening and shuddered at the thought, remember the old adage "Neat but not gaudy - like an elephant's arse sown up with a bicycle chain," might humour the frightened.
To me that implies you can safely touch down sideways without removing drift.
Perhaps Boeing should have added with a sly wink "And the Devil take the hindmost." To those who have seen this happening and shuddered at the thought, remember the old adage "Neat but not gaudy - like an elephant's arse sown up with a bicycle chain," might humour the frightened.
Well Said
The reason I made that comment was because these scenarios are where stick and rudder skills are the only thing that will result in a good landing. You can be the best button-pusher of all time but if you can't hand-fly very well, then you will have a reduced chance of a successful outcome, either landing in the zone or having the presence of mind to GA. Another Prune thread commented on the rough-controlling that sometimes occurs as soon as the AP is disconnected. That's because increasingly, people can't "fly" any more.
OBD.
Stick and Rudder skills
Not overtly disagreeing with the underlying need for skills, but consider how and when modern pilots gain those necessary to manage the situations encountered today. What is the experience base in crosswinds, and in what range of circumstances; are we now required to fly closer to the limit ?
How many operators restrict crosswind exposure to Captains only, or severely restrict FO to mild conditions.
How often do Capts really get tested; oh the simulator, but how realistic is that. Simulations cannot adequately stress-test limiting skills because like pilots they lack programming for the complete range of situations, or the finesse to replicate them.
For the average line pilot, how many exposures, what range of conditions - every crosswind is different - particularly for turbulence, and then at what point in their career is a sufficient standard achieved.
The likelihood is that many pilots have yet to fly to the limits of the aircraft, and probably haven’t as yet defined the limit of their judgement or skill level.
And even for those who have flown at the limit, and are aware of their flying capability, there is always one more crosswind on a dark rainy night with a short runway.
“Don’t criticise them; they are just what we would be under similar circumstances.”
– Abraham Lincoln
How many operators restrict crosswind exposure to Captains only, or severely restrict FO to mild conditions.
How often do Capts really get tested; oh the simulator, but how realistic is that. Simulations cannot adequately stress-test limiting skills because like pilots they lack programming for the complete range of situations, or the finesse to replicate them.
For the average line pilot, how many exposures, what range of conditions - every crosswind is different - particularly for turbulence, and then at what point in their career is a sufficient standard achieved.
The likelihood is that many pilots have yet to fly to the limits of the aircraft, and probably haven’t as yet defined the limit of their judgement or skill level.
And even for those who have flown at the limit, and are aware of their flying capability, there is always one more crosswind on a dark rainy night with a short runway.
“Don’t criticise them; they are just what we would be under similar circumstances.”
– Abraham Lincoln