Wing down during final approach.

[Chuck Ellsworth]

With regard to the time frame between the flare and the touch down the shorter the time frame the less exposure one has to both drift caused by X/wind and height above the runway variations caused by wind gusts and thermal activity due to temperature changes.

I am cursed with the habit of using logic to help solve problems and thus have come to the conclusion that carrying power through the flare and hold off portion of any landing just exposes me to higher risk of destabilizing the flight path of the device I am flying at the time.

So I almost always reduce power to zero once the runway touch down point is assured.......generally between two hundred feet above touch down to fifty feet above touch down.....

....I find I have better control of the device using inertia as my power source rather than extending the process by using power as a crutch for poor aircraft handling skills......

If I can recall any aircraft fixed wing or rotary wing that I could not land safely and under control power off I will get back to you......

[riverrock83]

Originally Posted by david viewing

The PA-28 could not have held off that ferocious crosswind wing low, because there is just not the control authority, but in the crab it can defy (almost) any wind. Of course in the last few feet the wind gradient usually falls off, meaning that the 'kicking' straight is normally a gradual adjustment, not the violent manoevre described by some. Just be ready to keep straight during the roll out!

I'm surprised that that. I'd have thought to get the max possible cross wind (lets ignore demonstrated) you would need to use a combinations of both techniques (crabbed and wing down). I haven't quite got it right in my head, but if you have enough rudder authority to "kick" straight, why wouldn't you have enough authority to have a wing down approach?

I'm not sure if this helps, but this is Airbus' advice:
http://www.airbus.com/fileadmin/medi...LAND-SEQ05.pdf

At the top crosswind limits, it talks about crabbing on the approach, but using wing down by around 5 degrees and 5 degree crab angle when touching down.

At the moment I normally crab until not far off the runway, then transition to wing low, stabilise, then flare with wing low. This works.

I had a problem in training when I had myself sorted for a certain cross wind, then would apply the same rudder input when I had a lesser crosswind and ended up crabbed the wrong direction (low enough that was still on the centre line but the tyres didn't like it...). 2nd time - no problems as I'd learnt, that is until the next time I flew, when the crosswind component would be different and I'd have the same problem again.
Transitioning higher I found considerably easier and more stable. Over time I've transitioned lower and lower as I've gained experience, but it takes experience to know how much rudder input is needed to get yourself straight without labouring the transition so you end up drifting.

My instructors were happy to teach both techniques and discuss the advantages of each.

Yes - I was training in a 20kt crosswind at times and in a Bulldog which has a v. powerful rudder (max demonstrated = 35kt!) so lack of technique is / was magnified.

[riverrock83]

Originally Posted by Chuck Ellsworth

I am cursed with the habit of using logic to help solve problems and thus have come to the conclusion that carrying power through the flare and hold off portion of any landing just exposes me to higher risk of destabilizing the flight path of the device I am flying at the time.

So I almost always reduce power to zero once the runway touch down point is assured.......generally between two hundred feet above touch down to fifty feet above touch down.....

Interesting with the Airbus, that a higher approach speed reduces risk (see doc linked to above). I'm quoting airbus as I've not seen the equivalent for smaller aircraft documented like this.

No issues though in having a steeper approach with lower power settings in a small GA aircraft. 3 degree glideslopes were not designed for PA28s!

[Chuck Ellsworth]

but it takes experience to know how much rudder input is needed to get yourself straight without labouring the transition so you end up drifting.

Yes, experience is vital in performing any physical exercise accurately, however if we look at this in its most simple context we use the picture we see at the moment to determine how much control input we need to point the airplane in the correct position for touch down.

Control input is easier to determine if you have been properly taught attitudes and movements at the start of your flight training.

[Chuck Ellsworth]

Interesting with the Airbus, that a higher approach speed reduces risk (see doc linked to above). I'm quoting airbus as I've not seen the equivalent for smaller aircraft documented like this.

Hi Riverrock, time dims the memory for recalling numbers etc. of different airplanes it has been a long time since I did the simulator training at Airbus and I never had the opportunity to fly the Bus in commercial operations......but as I recall in normal law, rudder input was cancelled by the flight computers above floor alpha during the landing approach so side slipping way back in the final approach was not possible in normal law.....

.......is my recall wrong?

[riverrock83]

Chuck
As you'll know from my profile - I'm a low hours PPL. I don't pretend to be anything different. No willie waving required!

However, I understand that certainly on the newest Airbus aircraft (A380) you can command a side slip angle using the rudder pedals, with help from three vanes mounted on the nose which calculate the sideslip angle. The system will automatically put in the correct bank angle to maintain the heading. At least one article has been written which includes testing this during a simulated approach.

Not quite sure what alpha floor has got to do with it. If you hit alpha floor protection you are going around...

However, back on topic I quoted the airbus doc as it includes graphs of bank angle vs crab angle for different crosswind speeds with geometry limitations. The numbers aren't going to work for your average PA28 but it shows how these relate to approach speed and how you can reduce extremes of bank or crab angle by combining them.

[Chuck Ellsworth]

I had no idea of your real background Riverrock, I thought maybe you were an airline pilot flying the Bus because you brought the Airbus into the discussion.

Alpha floor protection in normal law is to prevent the pilots from stalling the airplane in the low speed segment of flight....remember what happened to that crew over the Atlantic in the ITCZ turbulence...the airplane was in law alternate and they stalled it.

No willie waving required!

For sure I understand that can sometimes enter these conversations and it can be difficult to separate willie wagging from someone speaking from practical experience...........quite often I get my willie slapped by posters accusing me of ego....but somewhere there has to be a benchmark from which ones opinions can be measured ...so I often use my past qualifications to reinforce an opinion on the subject under discussion.

It would not be socially acceptable for me to have to post proof of the size of my willie...but I can post proof of my qualifications without fear of the moderators binning it. .

[VP-F__]

speaking from a fair amount of personal experience flying the Islander in a number of years of continual crosswinds I always used the crab approach up until the last hundred meters or so when I would go wing down. The reason for switching was simple, passenger comfort for most of the approach followed by a controlled touchdown where you want with little unwanted drift at the speed I desired pretty much every time.

Forgetting demonstrated limits on the aircraft this always means that ahead of touch down you know if the aircraft is handling the crosswind OK and that you are not going to get an undue sideways load on the gear on landing.

If your runway is nice and long then it probably doesn't matter which method you are using............however if it is 300 meters of grass with 20 kts across there is only one method for me.

[Pace]

VP-F

Yours would not be my chosen way but it obviously works for you and that is important
Also you have a high wing aircraft which suits that method better.

Pace

[Desert185]

...and the asymmetric power of a wing mounted twin assists in controlling weathervaning during touchdown and rollout.

[mad_jock]

however if it is 300 meters of grass with 20 kts across there is only one method for me.

Land into wind across the runway?

[IFMU]

I have landed into the wind across the runway before. It was over 30kts though.
Bryan

[India Four Two]

IFMU,

I had to do that once in a towplane after a downwind cross-country tow with an IAS of 50 kts and a 50kt tailwind.

After landing, I parked on the runway, facing into wind and hoped the glider pilot (non-radio) would see me and look at the windsock. He did.

[piperboy84]

Quote:
however if it is 300 meters of grass with 20 kts across there is only one method for me.
Land into wind across the runway?

That's exactly what I do right up to 90 degrees across the runway, it's a blast pulling It up in a 150 feet right before the side fence

[Maoraigh1]

FAA on Crosswind take-off and landing.

[IFMU]

My cross the runway landing was in a Schweizer 2-33. There were some small cells in the area and the lift was good. One of the small ones got large at a rate which was hard to comprehend. It was a "good judgement comes from experience, experience comes from bad judgement" moment. I had a hard time getting down at redline and dive brakes out until I was able to fly out of the lift. I thought it would be fine once I was on downwind but then I realized the gust front from the storm had set up a major crosswind. I had to fly clean, 70MPH until I crossed the side threshold of the field in order to penetrate. I landed on the taxiway to the hangar, the crew grabbed us before we stopped and shoved us in the hangar before we even unstrapped.

Often when towing there (Harris Hill) the crosswind would have us at such an extreme crab on final that it was discouraging. It always seemed better near the ground.
Bryan

[foxmoth]

Interesting that even the FAA is advising what I would say is the consensus here - wing down on landing even if your approach has been crab, so to me NOT the true crab landing which is crab/kick straight and touch wings level before the drift gets chance to take you. Sorry Pace, even the FAA are against you!!

[Chuck Ellsworth]

Judging from the advice to transition from the crabbed approach to a side slip to correct for drift before the flair that video was intended for ab-initio training.

[abgd]

The water-skiing pilots I've heard of coming to grief have all been flying tricycle aircraft, where it's frankly obviously not a great idea. Have there been lots of conventional gear accidents also?

I have seen videos of bush aircraft waterskiing onto spits and the like, so there does seem to be some genuine utility to the technique though it's not something I personally hanker to learn.

[Pace]

I would like to see the FAA recommendation to start with a crab and then change to wing down / X control ? Or even suggesting wing down over crab?

Pace