Erm... I'm afriad the above is incorrect. The daily alternation is changed every Monday morning. So week 1 would be 27L landing until 3pm local then 27R for landing after that. The next week will be 27R for landing in the morning until 3pm then 27L in the afternoon.

27L is not always used when there are strong south westerly winds. The runway used for landing will be in accordance with the weekly alternation plan. The ATIS will warn pilots of turbulence on short final during certian wind conditions.

Just to clear up the inaccuracies.

What we are saying is that in line with the weekly rotations it should have been 27R for landings before 3pm. It was changed to 27L out of sequence due to the winds.

Behind the second BMI ;) I agree with you that on the day in question we did "de-alternate" due to the crosswind. However Del Prado does not seem to know what he is talking about I am afraid.

With regard to the last 200' wind, if you can when busy just give a call of "200ft wind 220/45" may be of help to the one following? However it is a very high workload situation I would expect so maybe not possible? Out of interest how helpful are our windchecks we give when you are in the final stages of approach after being given landing clearance.

G.I.B

Double Decker bus? I didn't know the A380 was ground testing on the M4?:D

Just wondering... at a typical flare att, what is the AoB req for an outboard engine contact on the 744's.
Thks

Jon Lei,
As little as 5° to 6° angle of bank can result in a pod strike with the struts fully compressed.

JW411,
Not really true. I've yet to see any swept wing aircraft that will remain wings level if you 'KICK' off the drift. Gently 'PUSHING' off the drift while applying enough into wind aileron to maintain wings level is a different thing. Even having said that, have a look at a cross-wind autoland in the aircraft sometime.... It lands wing down every time. BOTH methods work, and from experience I can tell you that wing down generally results in a less 'agricultural' landing. A firm touchdown will only rapidly compress the oleo's reducing your pod/ ground clearance....Just my 2cents worth.

>Out of interest how helpful are our windchecks we give when you are in the final stages of approach after being given landing clearance<

GT3 - Speaking for myself, if it's right on limits I'm working so damn hard the chance of me working out the sin/cos of the crosswind component is remote!
There's always the possibility of course that the wind you give me at 100' will be outside the limit, which raises the possibility of a G/A.
A change from 200/25 to 190/23 frankly isn't worth mentioning. But an instantaneous 180/50 would be worth a shout :eek:
However, I suspect it's one of those things 100 pilots would have 100 different views on.

Fair enough 28L, more a case of reading off the wind display in the flightdeck, or is that inhibited below certian heights?

banana head:

I thank you for your explanation. Perhaps you missed the inverted commas around "kick-off drift"? It is, as you say, a combination of the two.

What I was trying to impart is that you simply cannot touch down in a 747 with 10° of wing down like you can happily do in a DC-10 which is a truly wing-down technique aeroplane.

You cannot scrape a pod in a DC-10 - you get the wingtip first!

I expect to be shot down for this however -
I am a wing down for x-wind landing person. After 31 years from instructing on Piper Cubs, flying Twin Otters, Shorts 360 and Islander to over 12000 hours on Boeings B737, B747 and B777. Got into trouble a few times from trainers on the B737 and also intitially on the B747 Classic. Then came the B747-400 and hey it uses wing down in autoland. More so on the B777. So I have pretty much stuck to this and so far it has worked or I have I just been lucky?

JL, BH......

touchdown geometry for the B744 is shown in TBC's FCTM.
Unfortunately the values are based on rigid geometry for various cases of oleo extension/roll/pitch. Wing behavior and resultant engine pod relative movement is a result of dynamic interactions of oleo rebound, spoiler, aileron input and attitude, with both feedforward and feedback. I wrote an inhouse paper based on a (limited) FEA analysis of wing behavior and it indicated pod touch was possible outside of the margins provided by the manufacturer by up to roughly 1.5 degrees.

BTW, the certification criteria encompassed by CFR14 part 25.473 and methodologically expanded by the applicable AC's/TSO's & orders such as:

AC 25-7A Flight Test Guide for Certification of Transport Category
Airplanes

AC No. 25.723-1SHOCK ABSORPTION TESTS Date: 5/25/01

¡× 25.125 Landing
AC 25.735-1 4/10/02 2
¡× 25.301 Loads
¡× 25.303 Factor of safety
¡× 25.733 Tires

¡× 25.1501 General: Systems and equipment limitations (JAR25x1524)

¡× 21.101 Designation of applicable regulations
¡× 25.943 Negative acceleration (JAR 25x1315)

AC 25.1309-1A System Design and Analysis

TSO-C26c Aircraft Wheels and Wheel-Brake Assemblies with
Addendum I
TSO-C135 Transport Airplane Wheel and Wheel and Brake Assemblies
TSO-C62d Tires

Order 8110.4A Type Certification Process
Order 8110.8 Engineering Flight Test Guide For Transport Category Airplanes :ugh:

don't account for isolated wheel loads. To consider the consequences of that look at the Mega Death 2 deal at HK-CLK (not just the deteriorating ROD[18-20FPS @ TD, enough to exceed limit and result in deformation] but the roll instability, resulting in RHW touch and catastrophic overload of the RH MLG aft bearing mount), and some sundry other deals (EWK MD11 report, P40...).

may be worthwhile being gentle with bank...or be as perfect as 411A.

did the VS guys do good? no one here is likely to know without the DFDR/QAR data, but they don't have to be incompetent to have a bad day, just like the rest of us. The eye witness report appears to be of a good operation, which is what the rest of the world generally expects, yet purveyors of the PPrune forum appear satisfied to besmirtch at the least opportunity.



cheers ;)

Works fine in a Piper Cub and maybe even an ATR 42, but in my opinion, this is definitely NOT the best technique to employ in a 200 tonne aeroplane like a 777 or an A340.

The last minute kick straight is basically turning a stable crabbed approach into a horribly unstable approach at the very worst moment – a nanosecond (or hopefully only a nanosecond) before touchdown. If you judge is absolutely right, you’re the ace of the base and the pax will think you’re wonderful.

However, the magic word is ‘if’…

If you misjudge it, particularly in a strong crosswind, you end up with, at best, a not very neat touchdown, and at worst, a potential disaster of crossed arms and legs and a very big aeroplane still airborne but with a lot of momentum heading off in God knows what direction – but usually towards the downwind side of the runway at an increasingly rapid rate because your last minute “kick it off and plant it says I!” has left the aircraft pointing downwind.

In an aeroplane as big as a 777 or an A340, you run out of runway width very, very quickly, (remembering that your seating position is a very long way away from your main gear, [on the 777, around 100 feet or 30 metres]). If things start gyrating, you might stil be not too far off the runway centreline. There's no guarantee your MLG is still on (or over) the runway.

I’m definitely in the same camp as Witraz on this point. Look at the way the 777 autopilot does it – exactly as flown it accuses ex-mil non RAF types (that’s me) of doing it.

The 777 manual says that technique shouldn’t be used in crosswinds exceeding 31 knots. Boeing recommends simply flying it on while still crabbed. The enormous momentum of the aircraft sorts it out quite nicely, although obviously most pilots help it along by instinctively kicking it straight after touchdown.

Don’t believe me? Take a look at these landings by Boeing test pilots. http://www.leathermans.net/content/view/25/39/
http://www.leathermans.net/gallery/m...09c4bf51024a51

Under 31 knots, the wing down, crossed control technique, (as the autopilot does), and aided by the track bar on the PFD, will almost always guarantee the aeroplane will roll on smoothly and stable – and that last word, in my opinion, is the most important one in the equation in big aeroplanes.

GT3

I did pass on the turb <200' after landing.

As for wind checks, fine up to about 200' then as long as the last one is in limits no more ;)

Can't remember exactly but our wind read outs work until touchdown at least.

They are inhibited <80kts on take off.

On ths subject of x winds, I ahve always been a little confused.

Our Flying manual (757/767) states we can use either technique, or a combination of the two.

Now, don't all x-wind landings use a combination of the two in the end?

I crab in and then feed cross rudder and aileron in in the latter stages, but you will ALWAYS land cross controlled with aileron into wind, or the wing will rise even in a modest x-wind.

the difference really is at which point on the approach you cross the controls.

Exactly so and it is nice when the aircraft configuration allows you to do it earlier rather than later!

After 10 years of operating the 747-400 I always found the tricky bit was after touchdown.
The upwind wing just wanted to keep flying and postive use of aileron, but carefully, was necessary .
I always used kick off drift and it worked for me.
The aircraft did use wingdown for autoland but its limit was only 15kts!

Flyer 1-11,

Agree with your remarks re "kicking off drift"" but would point out that the 15kt x/w autopilot limit is in fact only for LWMO ops. A/P can land with a/c limit x/w.

Are you seriously suggesting that on a day when the wings are clapping hands with windshear possible on finals and 35 knots across the runway that you would leave the automatics in to deal with it all on an autoland?

If so, then I am seriously glad that I am getting close to retiring!

JW411,

I'm glad too!

BusyB

The 747-400 that I fly has a crosswind limit of 25kts for an autoland. This is a limit on the autoland system, whether or not it is in low vis. I agree with JW411 in that I wouldn't dream of attempting an autoland with a 35kt crosswind.

Airclues

Captain Airclues,

I can only assume that is an operators restriction. Both -400 and 777 in my company have an LWMO restriction (because of reduced visual ref) and the a/c restriction. Whether you use it or not is up to the individual. Having sampled it I am much happier with a 777 max x/w autoland than a -400 one although that was still satis.

JW411, Capt Airclues & co,
While you may well have your reservations regarding autoland capability, I can assure you it is well able to cope with 35kts across on the -400....
Having said that, I too would tend towards a man landing in such weather, but I've long thought that was just because I was old fashioned!!!
:)

Incedently Busy B, why are Cathay the only company on the planet to refer to what ICAO call LVP as LWMO? Is life not complicated enough without individual companys creating there own TLC (three letter codes... or four letter codes for that matter!!!):hmm:

and fdr.... kudos! I'm very much impressed.......

We can autotoland 757/767 up to max x-wind limits now (40 kts), providing its CAT 1.

CAT2/3 remains 15 kts xwind.

Wiley

Thanks for posting the link to the Boeing x-wind landing video. I have been carrying that movie around on a flash drive for a while wondering how to post it. The soundtrack ain't too bad either.

As a humble flight dispatcher, and not a pilot, it looks like that on Boeing a/c a wings level approach then kick it straight is the way to go.

I remember a conversation many years ago with one of our drivers about cross wind landings and I'm sure he said the same thing.

Whatever the correct technique is, my condolences to the drivers of this flight and I am happy that everybody was able to walk away from it.

H

The aspect that I prefer about the wing down technique is that, once you have it stabilised, (well before the threshold), there is not much else to do other than make a normal landing. Naturally, it can get tricky at night when the w/v has a habit of changing rapidly during the last 150ft but you get the same problems crabbing it in as well.
One thing is for sure though - for these reasons a x/wind landing is far more difficult at night than during daylight (unless you are near the tropics but let's not go into that).
My understanding (just a pilot's working knowledge) of the Boeing autoland in x/winds is that it ignores up to 5deg of crab and then uses forward slip (i.e. wing down) to deal with the rest; but only up to 2 deg of slip max. Up to the 25kt x/wind maximum therefore there cannot be a risk of scraping.
The only problem with wing down is that you can apply more forward slip than necessary and not know it - which is where many pilots go wrong - arriving at the runway with too much wing down. You should never require more than 3 or 4 deg of slip (bank) even for max x/winds.
I would add though, that I have never flown 747's so what would I know about it? Bad luck to the crew involved though - could happen to any of us.

Cheers
BS

As a single engine pilot with modest experience, I am reading this thread with interest. I NORMALLY look to learn from the professionals on this form.

BUT. I see a lack of concensus on this one.

My takeaway so far is that x/w landings are a black art, and pilots expercise a variety of technique from crab to wing-down and all shades inbetween. This surprises me, for most other aspects of aviation have standard procedures. If this is the case then it must be due to a large extent on the "relatively" broad handling tolerance across a range of commerical aircraft.

Some more structured comments would help to diminish my view that x/w is a black-art....

:D :D

Not necessarily a black art, AirScrew, but strong cross wind landings in swept wing jet transports do require skill, and basic knowledge of the geometry of the particular aircraft that you are flying.

For many years I operated the good 'ole B707, and the engine pods on this aircraft were a darn sight closer to the ground than the 747, yet in all those years of operating this, what could at times be a very limiting aircraft in adverse situations, never scrapped an engine pod and, oddly enough, neither did any of the First Officers that I trained/flew with did either.

I maintain that, with all the 'automatics' in more modern day designs, rather basic flying skills have been neglected to a large degree.

A very good FMS/FMC in a jet aeroplane might make the navigation/thrust management a breeze, but that same box has limitations, and pilots find out their true abilities when the chips are down, and the winds are a blowin'....:}

Some simply don't measure up to expectations.
And likely never will.

Dont kick off drift too early...
 

Hi GT3,

I don't know about your watch but on my watch we always de-alternate when there's a strong SW'erly.
That's borne out by the fact Heathrow did de-alternate on the day in question due to the strong wind and associated turbulence from the hangers.

I felt a few posters on the thread were concluding the de-alternation was due to the pod scrape. I was trying to give the correct reason and thought I'd managed to explain that to BTSM, didn't think you needed to jump in with both feet about the runway alternation plan and alleging I don't know what I'm talking about.

Can you clarify for me that 27L was indeed the landing runway (against the weekly alternation) and the aircraft in question landed on the departure runway after 7am? (as I was out on a break when it happened.)




Ratarsedagain, re the other incident- thanks for clearing that up.

DP, check your PMs.

The plane in question did land on 27R at about 07.30am. Not sure what went on that day in terms of runway alternation, but for the rest of the day (at least till late afternoon) the landing runway was 27L and did not change over at 3pm for whatever reason.

I think the landing runway on the morning in question was against the alternation. However I felt it necessary to make it clear that it does not always mean de-alternation in strong winds. Remember the days of 23?

My personal preference on the 757 was to try to push off about 2 thirds of the drift at 400ft or so. This way you were less cross controlled which made it easier to handle and anyway the wind nearly always drops off in the last couple of hudred feet so you mostly ended up with the nose pointing straight down the rwy once you'd flared.

Hmm, I see that TEMPO 1316 21020G35KT is forecast for London Airport today. Shame that RW23 is no longer available.....

On the ancient Vickers Super FunBus, one's man (the flight engineer) did the throttles on the approach in response to the pilot's calls. Rather nautical, e.g. "Eng, 83% please". That meant you had both hands on the control column to wrestle with the beast in strongish (up to 28 kt) crosswinds rather than the Piper Cherokee one hand for control, one hand for throttle method used by the airlines of today. We used the wing-level 'crab' technique all the way to the flare, then yawed to align the a/c with the runway at the same rate the a/c was held off in the flare, ideally touching down gently with zero drift. Any swept wing roll-with-yaw characteristic was countered with opposite aileron/spoiler.

It took a fair bit of practice to fly the thing in strong crosswinds - an ILS on a gusty wet night was always rather a challenge!

B744 Autoland in crosswind
 

The B744 localizer antenna is located in the radome with the weather radar so the whole aircraft is downwind of the centreline in a crosswind. The only way the autopilot can align the body gear with the runway centreline is to use the sideslip, wing low method. Boeing recommend the De-Crab during flare method for manual landings to maintain the wings level throughout the approach, flare and touchdown. This works well if you don't float...in which case you have to resort to the sideslip wing low method to maintain the centreline. Hopefully, Boeing will locate the localizer antenna near the body gear on the B747-400 Advanced.

In sporting x-wind I agree that a bigger problem is created by taking off the drift too early and thereby establishing a flightpath towards the down-wind side of the runway. Whilst it is entirely possible to land with full drift on I think that the best solution lies between the two. By starting to ease the drift off you establsh a momentum which, if you touch down at the right time, will assist in letting the aircraft "centre". If you do not get the timing quite right and find that the aircraft is starting to move down-wind, then if you still have a bit of drift on, then it is easier to maintain the centreline with a degree or two (certainly not more than a smidgin!) of bank.

Are you sure? I seem to remember my manual says that the antenna is in the tail and switches to one on the gear when the gear is selected down. It specifically cautions against selecting the gear down immediately prior to localiser capture to prevent the autopilot missing the intercept due to switching between the antennas.

Carnage Matey!, it's the glideslope you're talking about. :ok:

Just to set the record straight, from the 744 MM:

VOR/LOC Antenna
A.
One dual-channel VOR/LOC antenna is used to provide rf signals to the ILS when the airplane is in the air prior to approach, and to the VOR system(SUBJECT 34-51-00).
B.
The VOR/LOC antenna is located on the vertical stabilizer tip. The left channel of the VOR/LOC antenna provides signals to the left ILS via the left VOR/LOC rf power divider. The right channel provides signals to the right and center ILS via the right VOR/LOC rf power divider and the right/center LOC rf power divider.
4.
Localizer Antenna
A.
Two dual-channel LOC antennas are used to provide localizer information to the receivers when the airplane is in approach mode.
B.
The LOC antennas are located on the forward pressure bulkhead inside the nose radome. One LOC antenna is located above and one below the weather radar antenna. The lower LOC antenna provides signals to the left and right ILS receivers. The upper LOC antenna provides signals to the center receiver. One channel of the upper antenna is not used.
5.
Glide Slope Capture Antenna
A.
Two dual-channel G/S capture antennas are used to provide glide slope information to the receivers before the nose landing gear is down and locked.
B.
The G/S capture antennas are located on the forward pressure bulkhead inside the nose radome below the weather radar antenna. The lower G/S capture antenna provides signals to the left and right ILS receivers.
The upper G/S capture antenna provides signals to the center receiver.

One channel of the upper antenna is not used.

B T S M... one of your first posts refers to 'My' First Officer. Don't you mean 'THE' First Officer or are you the owner?

sr jumbo:ooh: semantics, we could, if wanted, like the spellcheckers out there, try and be that clever:yuk: :yuk: but it does get boring:*

B T S M most of us know what your saying:ok: