Boeing Crosswind Testing Video

[NavyLonghorn]

Id be interested to read how crosswind controls are effected by fly by wire technology. Im thinking it would be more then a casual conversation though.

 

[HAL Pilot]

Since the crosswind limitations are based on rudder effectiveness... does the crab with the kickout increase the crosswind limitation on an aircraft signifigantly?

Yes. This is why the FAA recommends teaching the wing down/opposite rudder to private pilot students. With the wing down/opposite rudder technique, if you can hold centerline on final, you won't get blown off the runway on landing if you maintain the control inputs.

When I was a private pilot student, my instructor was a retired Navy tailhooker/airline pilot. All he taught me was the crab method. I never heard of wing down/opposite rudder. The DE had a fit when I was doing my crosswind landing on my check ride. He taught me wing down/opposite rudder during the check and made me demonstrate my crosswind landing again.

Also, if it does, isn't their a risk of straightening it out with the kickout, and then not having enough rudder to keep the plane on the runway with wheels on the ground?

Yes, that is why there is a maximum demonstrated crosswind. Once on the ground, if the wind is strong, the down aileron input is still applicable.

I think the biggest challenge is the weather vanning effect on the roll out. Plane wants to weather vain into the wind, which requires downwind rudder to track straight, but that's counter intuituve because now you're not counteracting the effect of the cross wind, plus side load restrictions, and rudder effectiveness like you said.

One of the biggest problems I had flying the Twin Otter was getting the FO to maintain his rudder input on landing roll out. The Otter has the biggest f'ing rudder imaginable in comparison to its size. Coupled with the high wing, it weather vaned like a MFer and would come up up on the leeward (like that nautical term Steve?) wheel as the wind lifted the windward wing. The hardest part of landing that plane in a strong crosswind was keeping it on the runway during roll out. But if you went to full aileron deflection and used your rudder it was very manageable. Even though the demonstrated maximum crosswind was 20 knots, I landed with 30 to 35 knots on many occasions. 20 knots was routine at the Grand Canyon and in Vegas during the spring.

We taught our FOs to think of the rudder on landing roll out like they did during V1 cuts. Look at the horizon and use whatever rudder you need to keep the nose straight. Since most of our FOs were low time straight out of general aviation/CFIing, they still associated the rudder pedals with nose wheel steering and always worried about ground looping the aircraft. If fact it was just opposite. If you did not use the rudder, the Otter would ground loop in a heart beat. Once they got it in their heads that the rudder pedals did not connect to the nose wheel, they did better.

Someone smarter than me figures all that out, and I just pay attention to the number.

One thing to note from this discussion is that manufacturers do not publish a maximum crosswind limit. They publish a maximum demonstrated crosswind. That is the point that they demonstrated the plane to during testing and the maximum that they feel it is safe for an experienced pilot to land. If an airline or company desires a limit, it is up to them to set a limit in their operations manual.

 

[MSkinsATC]

747 approach

Good video of showing a crab and then the kickout. Im sure a lot of you have seen this before but still....i am the 'video posting whore'

video

the 747's crab in the video was more of getting back on centerline.....but the same principal of kicking out applies


another video found with a little too much crosswind for landing (look at the tree blowing in the lower corner of the video in the first couple of seconds to get a feel of the wind)

video2

That use to be the normal approach pattern into Tokyo airport, you had to come over these mountains and literally dive down low while turning, and thats what it looked like, if you look to the sock in the back ground there isnt much wind at all...just thought I'd throw a little insite your way

 

[NavyLonghorn]

That use to be the normal approach pattern into Tokyo airport, you had to come over these mountains and literally dive down low while turning, and thats what it looked like, if you look to the sock in the back ground there isnt much wind at all...just thought I'd throw a little insite your way

Thats gotta scare the trash outa the passengers.

 

[wink]

And then kick it out

Ya, and if you get lucky right when you drop the wing, that main mount will kiss the runway. The passengers will not even know you were going into a slip.

I don't know if any of the airliners transition to a slip in the autoland flare. Maybe some of the new electric jets do. The MD-80 series will program in rudder to align the nose with the runway but it doesn't drop the wing to slip. That is proably why the lower autoland x-wind limit. Without a slip or crab the aircraft would blow off the centerline in a high wind.

 

[mules83]

That use to be the normal approach pattern into Tokyo airport, you had to come over these mountains and literally dive down low while turning, and thats what it looked like, if you look to the sock in the back ground there isnt much wind at all...just thought I'd throw a little insite your way

Yeah, i know what airport it was (Kai Tak) and its interesting approach. The guy still overshot his turn to final which made him kick it back at the last second.....which would be the same if there was a crosswind.

Just thought i would throw that back at ya....


as sub guys in movies would say.....DIVE DIVE DIVE!

or the crew in the 777 would say.....OH SH!T

got to love kai tak...too bad its closed

 

[NavyLonghorn]

If I was in a plane with 200 people, and I was that ****ed.. id think about givin it another shot.

 

[Fly Navy]

Yeah, i know what airport it was (Kai Tak) and its interesting approach. The guy still overshot his turn to final which made him kick it back at the last second.....which would be the same if there was a crosswind.

Just thought i would throw that back at ya....

Kai Tak is the old Hong Kong Airport, not Tokyo.

 

[Lawman]

If I was in a plane with 200 people, and I was that ****ed.. id think about givin it another shot.

Aww C'mon Vance, Real men dont go around.

***Went around on my Checkride because there was no way I was gonna try that much cross wind with full flaps on 7R at Daytona.***

 

[NavyLonghorn]

Aww C'mon Vance, Real men dont go around.

***Went around on my Checkride because there was no way I was gonna try that much cross wind with full flaps on 7R at Daytona.***

Never read the story bout the dude that went around. Just the dude that didn't.

 

[mules83]

Kai Tak is the old Hong Kong Airport, not Tokyo.

that video is from kai tak (closed now)....just making sure we are on the same page

 

[Lawman]

Never read the story bout the dude that went around. Just the dude that didn't.

Yeah I had a video before my last Reformat that showed an Air Italia Jet almost completely blow it. Like landed and put enough sideload on the plane that it rocked and nearly touched the right wing into the dirt. That had to have been fun to explain to the 200 people screaming when all the air masks dropped out of the ceiling and some flight attendent goes rolling down the isle.

 

[A4sForever]

I posted most of this a long time ago ... update follows F.Y.I.:

B747 "Whale": If anyone cares----but someday you might.



"We" do it both ways. I've taught it and been taught both ways; i.e., crab or wing down/top rudder -- when flying Boeing's or Douglas products, but especially when flying the "big iron", a.k.a. "heavy metal", a.k.a. "eighteen wheeler".

For me, it usually depends on the actual wind/WX conditions--i.e., how strong is the X-wind?, am I IFR?, did I just cross the Pacific = and am I tired?, is it day or night?, what day of the week is it (?), blah, blah, blah ,etc....... in other words, no one-size-fits-all.

Wing down/top rudder (WDTR)---that's (usually) my friend for the touchdown transition from @ 500'AGL ......until @ 50' AGL (actual altitudes will vary with the conditions) when you make your transition to landing flare ----then after touchdown put the aileron back in to keep the upwind wing from rising. You're a busy boy .....

You also have to steer with the rudders/nose wheel steering during roll out --- obviously. In some limits X-wind conditions I could not really keep centerline with ailerons, NWS, and rudder-effectiveness all working --- you just minimize the drift. You also must be very judicious with your ailerons on touchdown so as not skag #1 or #4 engine pod on the ground --- as some have, much to their dismay.

Some guys--myself included--favor a slight, repeat: SLIGHT upwind lineup orientation if we are going to "crab" all the way down glide slope. Makes the workload a little less on approach. We are on the end of a long "moment arm" way out there in the B747 cockpit. If you visually put the cockpit on centerline in a crab---you will be offset on the downwind side when you take the crab out to line up in close. And that could be hazardous to your health when landing in a heavy crosswind.

Sooooooooo ..... a typical Whale high X-wind approach & landing (for yours truly) might be:

Crab for most the approach ('cause it's easier and allows for a short nap :sleep_125 ) ...
to a WDTR (to finesse the CL and flare) from an in-close to at-the-ramp position ...
to a wings level touchdown (don't skag those outboard engines) ...
to an immediate aileron into the wind, with reversers, & steer with rudder while effective then hold centerline with NWS ...
to go to the hotel ...
to change underwear ...
to debrief approach with beer and chips ..... :icon_rast

GRADE: O.K. 3 Wire ..... :icon_wink ... then go do it again tomorrow.

 

[A4sForever]

KaiTak (circle) in its death throes ... circa 2004. Kowloon in the center ... HK island on the left.

 

[Fly Navy]

that video is from kai tak (closed now)....just making sure we are on the same page

Sorry, yeah you and I are, I quoted the wrong guy.