Pod Scrape at LHR
Join Date: Jul 2002
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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!!!)
and fdr.... kudos! I'm very much impressed.......
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!!!)
and fdr.... kudos! I'm very much impressed.......
Join Date: Nov 2003
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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
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
Join Date: Jan 2001
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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
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
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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....
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....
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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.
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.
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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.
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.
Last edited by Del Prado; 7th Nov 2005 at 17:25.
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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.
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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?
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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!
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!
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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.
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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
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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.
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.
semantics, we could, if wanted, like the spellcheckers out there, try and be that clever
