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Heavy Cross Wind Landings  
User currently offlineTOGA From Ireland, joined Jul 2001, 31 posts, RR: 0
Posted (12 years 5 months 2 weeks 2 days 10 hours ago) and read 4213 times:

How difficult to perform are heavy cross wind approaches in poor visibility. Are lower flap settings along with faster approach speeds used to stay centered along the approach ?.

25 replies: All unread, showing first 25:
 
User currently offlineGWB From United Kingdom, joined Mar 2002, 56 posts, RR: 0
Reply 1, posted (12 years 5 months 2 weeks 2 days 9 hours ago) and read 4059 times:

The greater the flap setting, the better stability you get (generally!). It's always more 'challenging' shall we say, but the main concern is sudden downblasts or upblasts, resulting in sudden changes in airspeed. I'm always happy when we're firmly on the ground...

User currently offlineMr.BA From Singapore, joined Sep 2000, 3423 posts, RR: 22
Reply 2, posted (12 years 5 months 2 weeks 2 days 9 hours ago) and read 4039 times:

Higher speeds gives you more control on the ailerons too.


Boeing747 万岁!
User currently offlineThirtyEcho From United States of America, joined Dec 2001, 1649 posts, RR: 1
Reply 3, posted (12 years 5 months 2 weeks 2 days 9 hours ago) and read 4024 times:

All control inputs are more effective at higher speeds. The procedure would be to use less flap deflection and to keep the speed up. In lots of GA aircraft, that would mean no flap at all. Visibility has nothing to do with the issue unless your tendency is to fly sloppy visual approaches and only be on profile if you are in IMC. In general, a steady crosswind isn't nearly as much of a problem as erratic, variable gusts.

User currently offlineTAA_Airbus From Australia, joined Nov 1999, 726 posts, RR: 0
Reply 4, posted (12 years 5 months 2 weeks 1 day 18 hours ago) and read 3951 times:

If the wind is variable and gusting, it always nicer to have a little extra speed, which makes it easier for you to go round if you dont like how it all is.

If its steady, as long as your technique is correct, landings can be really good.

Theres only thing better than nailing a perfect cross wind landing........

......having someone with you to see you do it  Smile


User currently offlineAJ From Australia, joined Nov 1999, 2389 posts, RR: 24
Reply 5, posted (12 years 5 months 2 weeks 1 day 16 hours ago) and read 3950 times:

Generally airliner crosswind approaches are flown according to company SOPs. Ours calls for normal landing flap, a gust allowance for wind and a de-crabbed landing with wings level to avoid pod scrape. These carriers do it differently:
Wow  Smile/happy/getting dizzy :

Click for large version
Click here for full size photo!

Photo © Garry Lewis


Dropping the into wind wing to maintain centreline:

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Photo © Guido Potters


Most heavy aircraft san land still crabbed, although it isn't comfortable:

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Photo © Craig Murray




User currently offlineTAA_Airbus From Australia, joined Nov 1999, 726 posts, RR: 0
Reply 6, posted (12 years 5 months 2 weeks 1 day 16 hours ago) and read 3922 times:

B-52s are good.......you can land crabbed and roll down the runway still in a crab  Smile

User currently offlineThirtyEcho From United States of America, joined Dec 2001, 1649 posts, RR: 1
Reply 7, posted (12 years 5 months 2 weeks 1 day 16 hours ago) and read 3918 times:

LOL, TAA_Airbus. The same thing was true for the Cessna 185 taildragger. Wierdest looking thing you ever saw.


User currently offlineNotar From , joined Dec 1969, posts, RR:
Reply 8, posted (12 years 5 months 2 weeks 1 day 14 hours ago) and read 3916 times:

In Light aircraft No flaps And faster speed

And The landing gear that gets the cross wind first touches down first. useing flaps in heavy wind will throw you back up in the air And in heavy turbulence durring cruise you want to go meaneuver speed So you can prevent damage to the aircraft .

Helicopter nice too Because it gets half the turbulence a aircraft would get. Plus it increases perfomance


User currently offlineNotar From , joined Dec 1969, posts, RR:
Reply 9, posted (12 years 5 months 2 weeks 10 hours ago) and read 3875 times:


Click for large version
Click here for full size photo!

Photo © Colin Parker



User currently offlineIllini_152 From United States of America, joined Jan 2001, 1000 posts, RR: 2
Reply 10, posted (12 years 5 months 1 week 5 days 5 hours ago) and read 3837 times:

Hmm, the way I learned and fly now, if you can't keep the nose pointed down the runway with zero drift at normal approach speed, either pick a differant runway, angle across the runway, or land into the wind anyway.

The rational is that if you need the extra control effectiveness at a higher approach speed to stay lined up with the runway, what happens on rollout as you decelrate from the higher than normal approach speed through normal approach speed and slower? Your aerodynamic controls aren't enough to keep you on the runway, how do you keep the wind from blowing you off? Its more difficult to fly the plane at its proper approach speed, yes. But you use less runway, and tear up the brakes and tires much less. Anything else is sloppy piloting.

Keep in mind, this was in taildraggers, but if you didn't have enough rudder to handle the x-wind at normal approach speeds, you shouldn't be landing there in the first place (granted, this put the x-wind limit way up there; ran out of rudder once while practicing; 35 knot direct crosswind. Even most spam cans will get you at least to 25 knots with full flaps and full rudder. At that speed, I could have landed across the runway though, ended up just angleing across- landing downwind of the centerline and pointing slightly into the wind so you're slightly into the wind.)

Gusting winds is the only time it is acceptable to fly final faster than published approach speed in a GA piston (well, or landing on a 10,000' runway with a Lear behind you...)



Happy contrails - I support B747Skipper and Jetguy
User currently offlineThirtyEcho From United States of America, joined Dec 2001, 1649 posts, RR: 1
Reply 11, posted (12 years 5 months 1 week 5 days 3 hours ago) and read 3828 times:

Illini_152, you must operate onto a lot of iced-over runways at big airports with no traffic and crashwagons right beside the touchdown zone that you are landing across. As to "most spam cans" handling a 25kt direct crosswind, I think not. As I recall (somebody tell me if I'm wrong) the max direct X-wind component for a 172 is about 17kts.
I soloed in a very treacherous taildragger, the Luscombe 8-E, and used the combination method of X-wind technique into a wheel landing to keep speed and control effectiveness up. I sure wouldn't want to be in one of those older Cessnas, with max 40-degree flaps, floating at 35kts right above the runway and get smacked by a 25kt X-wind, even if I was landing "across" the runway rather than straight down it.
I think part of sound X-wind technique is to use as little flap as possible, keep speed and control effectiveness up, and kill the flaps immediately after the nosewheel touches down.


User currently offlineIllini_152 From United States of America, joined Jan 2001, 1000 posts, RR: 2
Reply 12, posted (12 years 5 months 1 week 5 days 1 hour ago) and read 3811 times:

Yeah, max demonstrated x-wind in a 172 is 17 knots. However, its not a limitation; thats just the strongest winds they could find that day. I can tell you for a fact that an Archer will run out of rudder at around 25 knots with full flaps, and a 152 can be landed in a 28 knot x-wind flaps up.

Actually, I learned out of a 2500x30 strip with no x-wind runway; I guess I should have clarified my post a little. Partial flap landings do work better in a heavy x-wind. But the practice I've seen of "adding 5 knots for the x-wind" then "adding 5 knots to make it easier to go around", before you know it, you're flying final at10-15 knots above final approach speed, and then floating down the entire runway, or as I've also seen done, forcing the plane onto the pavement before its ready. Neither is an acceptable way of dealing with a crosswind. Its either a sign of sloppy piloting, or a sign that you're trying to make the airplane do something its not supposed to do.

BTW, I wasn't refering to landing 90 degrees to the runway (though I've seen that done too). Its kind of hard to explain without pictures, but imagine a 9/27 with a wind from 010 at 35. Flying final and landing on a the southwest corner of 9 with a heading of roughly 070 reduces the x-wind compenent by roughly 16%, give you roughly 3x the runway's width to land, and increase your headwind by 14 knots. Certianly manageable in an emergency.

If you care to go further- Take a 50' wide runway and a 80 degree x-wind at 35 knots. Landing 45 degrees to the runway gives you 70' of pavement to stop on, a 20 knot x-wind, and a 30 knot headwind. Lets say you're flying your 172 that stalls at 44 knots (with flaps 40; flaps up its 50). Landing full stall, you only have to reduce your speed by 14 knots.

The approach and landing wouldn't be pretty, but neither would screaming in clean at 80 knots and planting her on the runway, then hoping that you don't get blown off or lose control, or run out of pavement.

But the only time this sort of thing should ever be needed is if you've botched you planning so badly that there is just nowhere else to land within your range.

Just some things I've learned by hanger flying with the elder pilots I've met...
Mike



Happy contrails - I support B747Skipper and Jetguy
User currently offlineThirtyEcho From United States of America, joined Dec 2001, 1649 posts, RR: 1
Reply 13, posted (12 years 5 months 1 week 5 days 1 hour ago) and read 3805 times:

2500x30? Wow, you are a big airport guy. I routinely flew a C140 into 1500x25, and the 1500 was interrupted by a hump in the middle that sent many a plane right back in the air if they floated and didn't "plant" it.
Just to settle this for good, I saw a J-3 take off across a 200' runway once. He cheated by having the tailwheel off in the grass before he started.


User currently offlineLY744 From Canada, joined Feb 2001, 5536 posts, RR: 10
Reply 14, posted (12 years 5 months 1 week 5 days 1 hour ago) and read 3803 times:

"the max direct X-wind component for a 172 is about 17kts"

When someone says something like that, what do they mean? I hear a lot of talking about a certain max crosswind component for a certain a/c in knots, but what is the angle of the wind in relation to the direction of the a/c's flight?

LY744.



Pacifism only works if EVERYBODY practices it
User currently offlineThirtyEcho From United States of America, joined Dec 2001, 1649 posts, RR: 1
Reply 15, posted (12 years 5 months 1 week 4 days 22 hours ago) and read 3790 times:

No doubt, someone is about to post an X-wind component graph and a formula for computing the X-wind component as a factor of wing aspect ratio but here's the simpleminded explanation:

Let's say that flight test and engineering data shows that an airborne C172 can stay on the runway centerline, at touchdown speed and configuration, with a wind blowing directly from the side of up to 17kts. That means that at 18kts, despite full control deflection, the wind will begin to push the 172 off the runway centerline. If the wind was on the nose at 18kts, it wouldn't push the 172 sideways at all (though it might make it hover). So that means that at intermediate points off the nose, the wind will have intermediate effect. If there is no effect with the wind at 12 o'clock and the airplane begins to drift with the wind over 17kts at 9 o'clock, how much wind can the plane handle with the wind coming from 10:30? The simple arithmetical answer is twice the max 9 o'clock speed, or 34kts. Now, this isn't the REAL answer, speedwise, but it IS the theory. Obviously, by the time you works this arithmetical answer around to the nose, the 172 could handle an INFINTE wind on the nose, which we know it can't. Hope this helps; now go read the crosswind component graphs.


User currently offlineIllini_152 From United States of America, joined Jan 2001, 1000 posts, RR: 2
Reply 16, posted (12 years 5 months 1 week 4 days 21 hours ago) and read 3787 times:

LY744:
<< >>>

The maximum demonstrated x-wind component is just that. During the certification of the aircraft, that was the strongest crosswind component that they flew the plane in.

Think of wind as a vector; say you are heading 090, and the wind is 045 at 20. You can break that 45 degree vector down into 2 components- the one acting as the headwind (in line with your flight path) and one acting as the x-wind (perpendicular to your flight path).

Pilots can figure these out with tables, charts, slide rules and even trig if they want (W * sin theta = x-wind where theta = angle between flight path and wind direction) <- I think that's right; its been a while, its either sin or cos...) As a rule of thumb though, a 30 degree x-wind gives you 90% as the headwind, 45% as the x-wind, a 45 degree x-wind will give you 2/3's headwind and 2/3's x-wind, and a 60 degree x-wind is the opposite of a 30 degree...)

And ThirtyEcho,

Its nice to see someone else out here that knows how to fly out of real airports.



Happy contrails - I support B747Skipper and Jetguy
User currently offlineJetguy From , joined Dec 1969, posts, RR:
Reply 17, posted (12 years 5 months 1 week 4 days 18 hours ago) and read 3762 times:

Personally, I've noticed that I make my best landings when the weather is really foul. The stronger the x-wind (up to a point of course) and the gustier the conditions the better landing. I think that it's due to paying more attention to what's going on. Now if I want to really clang one on, all it takes is a warm sunny Saturday afternoon, calm winds, and a bunch of people watching. It's guaranteed to result in an "arrival"!

User currently offlineKAUSpilot From United States of America, joined Jan 2002, 1958 posts, RR: 33
Reply 18, posted (12 years 5 months 1 week 4 days 17 hours ago) and read 3764 times:

I don't think it's necessarily required that you use less flaps in a crosswind landing.

The primary concern is too keep your airspeed about 10% higher than normal if you expect to be experiencing a direct crosswind component greater than 5 knots (in a 172). For me that translates to a stabilized airspeed of 70-72 KIAS on final for the skyhawk.

Instead of using less flaps, just keep in mind that you will lose altitude faster by pitching for the higher airspeed and adjust your approach accordingly (this will yeild a steeper approach than normal; a good thing as long as you stabilize your airspeed; lack of flaps = higher airspeed for a given sink rate).

The side slip is sometimes awkward, and I usually only go into one if the direct x-wind component is less than 5 knots. Otherwise the crab required is so slight that it is not a problem to touch down crabbed. As long as I turn the alerions into the wind immediately upont touchdown, everything goes smoothly.


User currently offlineThirtyEcho From United States of America, joined Dec 2001, 1649 posts, RR: 1
Reply 19, posted (12 years 5 months 1 week 4 days 16 hours ago) and read 3760 times:

KAUSpilot...ACK! I hope that you know that the 172 is big, bad placarded against intentional slips with the flaps down! Snap rolls right into the ground aren't pretty.

User currently offlineIllini_152 From United States of America, joined Jan 2001, 1000 posts, RR: 2
Reply 20, posted (12 years 5 months 1 week 4 days 14 hours ago) and read 3756 times:

KAUSpilot, you are abusing that airplane needlessly. I hope this isn't how your instructor is teaching you (though I have seen/heard worse). If he/she is telling you to land in a crab because its "easier" then get yourself a new instructor. Think of the side loads you're putting on that landing gear. Guess what happens if you try and land in a crab with a retractable gear bird? I know of two friends that did $60,000 in damage to a 310 by landing in a slight crab. Main gear folded up, tip caught, props dug in, and she settled on her tail nicely. New prop, new tip tank, 3 cracked ribs, repaired spar, rebuild landing gear, rebuild motor, repaired the skin damage to the tail... The only place I've ever heard of landing a GA plane in a crab is in the Ercoupe, which couldn't be slipped in as it had no rudder pedals. Either lower your wing into the wind and keep the nose down the runway with rudder, or for god's sake, kick that crab out in the flare so you're at least pointing down the runway when you land. There's a differance between piloting an aircraft, and driving a cessna.

BTW- the book lists final approach speed for a 172 as 55-65 flaps down and 60-70 flaps up. Now tell me; what is the advantage of that extra speed? Unless the winds are gusty (or you have traffic following), there is no need to fly faster on final. All you'll do is eat up valuble runway, and accelerate wear on the tires and brakes. If you're flying as PIC, you should be comfortable and competent to operate the ship thru the performance envelope. That means landing too. If in doubt; look at the bottem of the white arc, a good rule of thumb is add 15 knots to that; in most GA singles that will get you 1.3 Vs0; if you're going into a short field, add 10 knots, that will get you 1.2. That is at max gross and most forward CG. So now you have that safety margin thrown in there too; you cannot possibly land at maximum gross takeoff weight (unless you already took off above it...) and how often are you at the forward limit. The only changes to this should be for 1/2 the gust factor.

(And FWIW, the placard in the 'hawks says "AVOID SLIPS WITH FLAPS EXTENDED" nothing about prohibited. Big differance; problem with slipping with flaps was in older 172's with 40 degrees, the flaps COULD blanket the horizontal stab at certian weight/cg conditions. This would cause either a buffetting in the yoke, or a nose down pitch. New models with 30 degrees only seem to have the mild buffett (and occasional fuel tank unporting in prolonged slips)

Mike



Happy contrails - I support B747Skipper and Jetguy
User currently offlineLY744 From Canada, joined Feb 2001, 5536 posts, RR: 10
Reply 21, posted (12 years 5 months 1 week 3 days 1 hour ago) and read 3715 times:

Thanks, ThirtyEcho, Illini_152.  Smile

LY744.



Pacifism only works if EVERYBODY practices it
User currently offlineSkyguy11 From , joined Dec 1969, posts, RR:
Reply 22, posted (12 years 5 months 1 week 2 days 18 hours ago) and read 3700 times:

Notar said:
"And in heavy turbulence durring cruise you want to go meaneuver speed So you can prevent damage to the aircraft."

Just keep in mind that you want to go at or below maneuvering speed, not only at it. The slower you go, the less turbulence you will experience and the less G loading you will get on the plane.

As for slips in a 172 with flaps extended, I've done it plenty of times and have had no adverse effects from it. The idea is that the airflow to the tail will be reduced due to the interuption caused by the flaps, but I really don't see a problem with it. The placard is a recommendation, not a limitation. And if I ever did find myself nosing down uncontroabally during a slip I would simply stop the slip and recover.

Has anyone flown and slipped a Katana? I fly one a lot now and it's great fun, but every time I slip it on final the plane feel extremely nose heavy and starts to pitch down. Has anyone experienced this? What is the cause? I was thinking it might have something to do with the bulbus cockpit and the T-tail / low wing design.


User currently offlineA330 From Belgium, joined May 1999, 649 posts, RR: 7
Reply 23, posted (12 years 5 months 3 days 6 hours ago) and read 3632 times:

Skyguy, May I strongly recommend you to STOP immediately this dangerous manoeuvre! I am only saying this for your own health. As an experienced pilot on C172, Slips with more than 10 degrees flap can cause loss of control, unable to recover when you are on final. Believe me, I have done them at altitude to see the effects, and you will not like it.


Shiek!
User currently offlineSkyguy11 From , joined Dec 1969, posts, RR:
Reply 24, posted (12 years 5 months 2 days 14 hours ago) and read 3590 times:

Hey A330, can you please elaborate on this? What were you doing? What kind of experience do you have? Note that I am not trying to challenge you but rather am trying to figure out where you are coming from and learn something from it. Thanks. I have slipped with full flaps and never have I had any problems. I have also talked to other pilots including instructors and they have said the same. Also, you said that slipping with more than 10* of flaps can lead to an unrecoverable situation when on final. What would make it unrecoverable? The altitude loss in taking out the slip? I don't think I'd slip that low to the ground anyways. One more thing: What about landing in a cross wind with 20* of flaps? You are slipping then, weather its a sideslip vs forward slip is irrelevent.

User currently offlineIllini_152 From United States of America, joined Jan 2001, 1000 posts, RR: 2
Reply 25, posted (12 years 5 months 2 days 1 hour ago) and read 3568 times:

I too would like some details on this. The only effects I've heard of with new Skyhawks was with certian CG locations and full flaps with a maximum deflection slip was a minor buffetting of the tail, similar to a prestall buffett, but not a severe.

In older 'hawks with 40 degrees of flaps I have heard of loss of elevator effectiveness due to the blanketing of the tail, but this was recoverable when the slip was taken out even slightly or the flaps retracted.

This corresponds to what I've heard from Cessna test pilots also. And this is why, the manual says "Avoid slips with flaps extended" not "Slips wiht flaps extended prohibited". Believe me, if the condition was unrecoverable, it would be prohibited.

BTW, I'd also like to know how he manages to land in a x-wind.

Mike



Happy contrails - I support B747Skipper and Jetguy
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