Emirates B777 gear collapse @ DXB?
Originally Posted by Underfire
The winds are usually measured at only one location per airport. What can be worse if they are measured at multiple locations and then averaged together.
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-3/5 degrees and a few knots will make little difference. It was a 777 that was involved and not a light single.
DXB has cup anemometers and the exact location of each of them can be found in the UAE AIP if you wish to look.
-3/5 degrees and a few knots will make little difference. It was a 777 that was involved and not a light single.
DXB has cup anemometers and the exact location of each of them can be found in the UAE AIP if you wish to look.
Landing at Philadelphia one day, the wind was given at threshold, mid-point, and far end of the runway. All were different, the far end being 180 deg. removed from the headwind at the threshold. A 727 awaiting clearance was given permission for immediate take-off, no delay. No, said the 727 pilot, I'm going to stay here and watch this 747 land. Barsteward.
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It might be that the way many major airports are measuring wind is NO LONGER GOOD ENOUGH..especially given their propensity to also develop the associated land up to the legal limits imposed by the Obstacle Limitation Surface (OLS). These limits may not be suitable when it comes to certain combination of wind speed/direction (vector) and the proposed or existing location of large (width, height and length) buildings..
I believe many major airports globally, are using far more sophisticated AWS than those which utilise cup anemometers. I think you'll find that Dubai, and many FAA Major airports use more modern measuring equipment. See the internet links in my previous posts.
10 Minute Mean Winds have VERY LIMITED application to Flying Operations.. Note, that most aircraft crosswind limits refer to total crosswind (inclusive of GUST).. Gust Wind or a 1 Minute Maximum Sustained Wind would be far more applicable..
Aviation and Non-Aviation Infrastructure can significantly impact on an airport's wind environment, particularly when structures are adjacent to operational runways.. Note that visibility is measured at three different sections of the Runway for Low Vis Operations. It may transpire that the Aviation community should be measuring wind at multiple points around an airport..including on the roof of very large hangars or terminal buildings?..
Building Induced Turbulence and Windshear becomes a more significant issue when aircraft are limited to certain Runways due to performance issues (thrust, TODR, weight, PCN to name a few)...which may not be ideal given the prevailing wind at the time, regardless of whether the wind is a Mean Wind, Gust Wind, Total Wind...and/or whether it is measured at 10m or 35m..
All I'm suggesting is that IMHO, this issue should be EXAMINED IN DETAIL by the accident investigation team..
Further, all pilots need to educate themselves about building induced turbulence/windshear and should remain vigilant as to its presence in certain adverse wind conditions..
I believe many major airports globally, are using far more sophisticated AWS than those which utilise cup anemometers. I think you'll find that Dubai, and many FAA Major airports use more modern measuring equipment. See the internet links in my previous posts.
10 Minute Mean Winds have VERY LIMITED application to Flying Operations.. Note, that most aircraft crosswind limits refer to total crosswind (inclusive of GUST).. Gust Wind or a 1 Minute Maximum Sustained Wind would be far more applicable..
Aviation and Non-Aviation Infrastructure can significantly impact on an airport's wind environment, particularly when structures are adjacent to operational runways.. Note that visibility is measured at three different sections of the Runway for Low Vis Operations. It may transpire that the Aviation community should be measuring wind at multiple points around an airport..including on the roof of very large hangars or terminal buildings?..
Building Induced Turbulence and Windshear becomes a more significant issue when aircraft are limited to certain Runways due to performance issues (thrust, TODR, weight, PCN to name a few)...which may not be ideal given the prevailing wind at the time, regardless of whether the wind is a Mean Wind, Gust Wind, Total Wind...and/or whether it is measured at 10m or 35m..
All I'm suggesting is that IMHO, this issue should be EXAMINED IN DETAIL by the accident investigation team..
Further, all pilots need to educate themselves about building induced turbulence/windshear and should remain vigilant as to its presence in certain adverse wind conditions..
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in regards to PHL:
Here is the map of the data sources used for the MET at PHL, of which, there is but a single MET location for wind measurement...how the estimate the winds at each end is generated, well...
EDIT:
Your link was a Vaisala WM30, a cup anemometer. I believe you will find that most still use the cup anemometer system. While the FAA wanted replacement back in 2010, I think you will find most have not.
Bloggs..I stand corrected on YMML
They have added a second anemometer north of RW9/27 How these gives one TCH info is a bit of a stretch..
MLW1 and MLW2 shown
Here is the map of the data sources used for the MET at PHL, of which, there is but a single MET location for wind measurement...how the estimate the winds at each end is generated, well...
EDIT:
I believe many major airports globally, are using far more sophisticated AWS than those which utilise cup anemometers. I think you'll find that Dubai, and many FAA Major airports use more modern measuring equipment. See the internet links in my previous posts.
Bloggs..I stand corrected on YMML
They have added a second anemometer north of RW9/27 How these gives one TCH info is a bit of a stretch..
MLW1 and MLW2 shown
Last edited by underfire; 31st Aug 2016 at 04:24.
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Is it safe to assume pros/public being prepped to accept WS as the prime reason for this operational incident? Contemplating between intense technical discussion or being brainwashed.
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Presumably you mean to prevent or reduce mechanical turbulence? -you could ask yourself if "airport/hangar infrastructure" has been wind tunnel tested for this anywhere on earth; I think the answer will be no, no-one does this. Having trees and buildings near a runway is a fact of life for pilots.
If airports do not do this then they should. A long time ago in a previous existence when doing talkdown controllers learned where there would be significant changes in wind in certain conditions over some ground features.
Before airports make use of their real estate to put up hangars in addition to the impact on the obstacle clearance surface and thus DAs, they should really confirm that winds would not result in rotor streaming or concentrated straight line winds from or between the buildings across the runways and their approach paths.
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I am pretty sure the UAE authorities monitor this forum and would be prepared to bet that since the general trend recently has been to talk about wind and even wind shear, the final report will include some phrases verbatim from this forum. After all, it could not possibly be a lack of training, complacency or pilot error for relying entirely on the AUTO button could it..?
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The only times I saw the hands of the anemometer dials rock steady was when there was a dead calm. Despite the damping mechanisms they generally fluctuated about mean indications of direction and strength (speed) which is what you passed on to pilots. There were rules about rapidly notifying defined changes. Thinking back ( a long way) I believe our indicators were driven mechanically direct from anemometer on tower roof few feet above. 75ft agl. Pilots are better served today but wind and rain hasnt changed much.
One of my tasks as a P Met O was airfield inspection re. siting and maintenance of instruments. I can vouch that on RAF airfields there was great care taken to site the anemometer well within the known rules, and many anemos were extremely well sited. Civil UK was a very different matter. One was so bad that I refused to sign off the inspection as satisfactory.
Whatever and however "wind" is measured: vertical motion, many sites, gusts, algorithms ........, I find it difficult to understand what use ever finer detail will be to a landing captain. I think the answer may be education rather than instrumentation.
The wind it bloweth where it listeth, and no observation[s] are infallible predictors.
Whatever and however "wind" is measured: vertical motion, many sites, gusts, algorithms ........, I find it difficult to understand what use ever finer detail will be to a landing captain. I think the answer may be education rather than instrumentation.
The wind it bloweth where it listeth, and no observation[s] are infallible predictors.
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langleybaston,
Far more can be done...
More accurate measuring equipment has been developed, tested and is now available Commercial Off the Shelf (COTS)..
The cost of new AWS/ASOS is NEGLIGIBLE when compared to the cost of a B777 hull loss..
If Airport Operators can afford to build large terminals, hangars, car parks and office buildings they surely can afford the costs associated with fully investigating and monitoring the impact of this infrastructure on the ongoing safety of flying operations..
Further, airports don't just cater for HEAVY jets.. The impact of development needs to be examined with regard to ALL AIRCRAFT that use, or are forecast to use an airfield..including light aircraft, medium aircraft and helicopters..
Far more can be done...
More accurate measuring equipment has been developed, tested and is now available Commercial Off the Shelf (COTS)..
The cost of new AWS/ASOS is NEGLIGIBLE when compared to the cost of a B777 hull loss..
If Airport Operators can afford to build large terminals, hangars, car parks and office buildings they surely can afford the costs associated with fully investigating and monitoring the impact of this infrastructure on the ongoing safety of flying operations..
Further, airports don't just cater for HEAVY jets.. The impact of development needs to be examined with regard to ALL AIRCRAFT that use, or are forecast to use an airfield..including light aircraft, medium aircraft and helicopters..
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I find it difficult to understand what use ever finer detail will be to a landing captain.
I noted at locations known for windshear that there were several GA in a row, but on second attempt, all landed. That was due to the situational awareness, so if you had that information to begin with, would there be less chance of a GA?
Other than simply windshear from ATC, would not the details and flight level of the windshear be of value?
Same for DEP, what if surface winds are calm, but at 100m you have a strong headwind, ATC says windshear, but what are you set for, calm winds? Would that not help?
If you are on final with a slight tailwind or crosswind, and at 120m, the winds shift to a strong headwind? Would you find that information useful if it could be provided?
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The ND shows the wind component you are flying through as a component of the flightpath based on several factors. The ATC winds may not have anything to do with the windshear, nor the actual level. Nothing, not even the aircraft, shows the vertical wind component.
If this was so easy, why are there so many go arounds and FOQA busts?
What does the ND say when you are on the ground, ready to depart?
Flight deck displays of ‘instant’ wind velocity based upon on board computations are now quite accurate when instant variation is not required. This is especially true when the aircraft is away from the ground, but their usefulness for assisting the execution of a safe touchdown, landing roll or take off roll is often very limited, both for practical and computational reasons. Updating of on-board readouts of wind velocity depends on the system which generates them. FMS wind is the most accurate, because it is based upon changes of GPS or DME/DME position, but it may only be re-calculated every 30 seconds. Wind Velocity based upon an INS is often calculated as many as 10 times per second but the result is less precise. The net effect is that neither have real value near or on the ground.
If this was so easy, why are there so many go arounds and FOQA busts?
What does the ND say when you are on the ground, ready to depart?
Flight deck displays of ‘instant’ wind velocity based upon on board computations are now quite accurate when instant variation is not required. This is especially true when the aircraft is away from the ground, but their usefulness for assisting the execution of a safe touchdown, landing roll or take off roll is often very limited, both for practical and computational reasons. Updating of on-board readouts of wind velocity depends on the system which generates them. FMS wind is the most accurate, because it is based upon changes of GPS or DME/DME position, but it may only be re-calculated every 30 seconds. Wind Velocity based upon an INS is often calculated as many as 10 times per second but the result is less precise. The net effect is that neither have real value near or on the ground.
Last edited by underfire; 1st Sep 2016 at 00:59.
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The current wind is not displayed on the ND.
Next time you are flying along, gently add a little rudder input.
If you aren't that brave, try it in the simulator.
Next time you are flying along, gently add a little rudder input.
If you aren't that brave, try it in the simulator.
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Yep, confirmed. I am nuts. Let me try a bit of rudder therapy...
Please explain how the ac determines the winds? Crosswinds?
Airspeed, groundspeed and rudder? What happens in a turn? The vertical windspeed component with uplift and downdraft? Your aircraft and skills are amazing!
Please enlighten all of us. All of these GA from windshear would be eliminated!
A bit curious on your Perth destination now that you know that have one weather station and a bunch of windsocks, that they provide threshold wind measurements? (and change them when an ac cannot rotate?) You are so good that you get the winds and check the windsocks on final?
