Datum. Look at ruserious' post above yours. They were pretty much STANDARD summer midday conditions at DXB. The windshear that comes with that is the type that may destabilise an approach leading to a Go-Around but it is NOT like a microburst windshear that can bring down a large twin jet!

Yep..understood.

I'm simply suggesting the combination of adverse environmental conditions at the time of the accident (DA and Wind-shear) are VERY LIKELY to have been 'contributing factors'... As you correctly outline, other aircraft operated 'safely' just prior to the accident.. However, the ACTUAL 'recorded' winds in the immediate time window (15 seconds to 2 mins) prior to 521 crossing the runway threshold MAY have been MORE adverse (actual direction and actual strength) than the winds experienced by preceding aircraft.. Immediately following the accident, aircraft would have been limited/re-cleared to the parallel runway, which is also likely to have been subjected to LESS ADVERSE wind/turbulence conditions.. Note that Dubai Airport accommodates some of the largest aircraft maintenance facilities in the world..located immediately adjacent to the runway touchdown zone..

The airport was closed immediately following the accident.

Out of all the runways at DXB, you are probably least likely to encounter mechanical turbulence on 12L. The big hangars that you mention are down near the 30L/R end.

The 'big hangars' are immediately adjacent to where 521 came to rest...

How many Automated Weather Stations (AWS) does Dubai Airport utilise?.. Where are they actually located?.. What is the accuracy or resolution of these systems?.. What is the accuracy/resolution of what is actually reported to pilots by ATC or via ATIS etc?.. Note, the Wind Direction is LIKELY to be reported +/-5 to10 deg, wind speed +/- 2 to 5 knots, depending on the AWS hardware/software used..and the wind speed.

The wind COULD have been 100-105 deg at close to 25 knots?..

Has the airport/hangar infrastructure been wind tunnel tested, in order to ensure the preservation of safe operational margins in wind conditions such as those characteristic to flight 521?..

These are some of the things I would be keen to clarify during the investigation..

Vilas 1042
 

Global Express fulfills all the criteria of your modern automated machine and we did use automation where appropriate .

This is not always fulltime and that is where manual flying skills remain as important as ever; starting with the Wright brothers through 2 world wars into the present.

If you do not accept that basic premise then I suggest that you should keep your feet firmly on the ground.

I may be old and old - fashioned but that does not mean I am stupid !

Datum. The 'big hangars' are nowhere near the threshold or touchdown zone of 12L!

Very true but surely of insignificance since that is where the aircraft came to rest which is the opposite end to where events unfolded. The actual wind closer to the 12L threshold is bound to be of more interest.

The wind speed given in the wind check with the landing clearance was 11 knots.

immediately above the threshold of Runway 12L is the position at which the crew's problems regarding the go-around will have compounded.. From that position up to where the hull came to rest...which is the MAJORITY of the Runway, the aircraft is likely to have encountered changeable/adverse wind conditions (wind speed, wind direction, possible vertical windshear late in the approach/flare, and possibly building induced windshear)...

How accurate is the 'reported wind' (Tower - landing clearance)?.. Where is that wind measured exactly...for aircraft landing on Runway 12L?... Did the 'reported wind' of 11 knots accurately represent the wind conditions at the time 521 initiated the flare?... Was the 11 knot wind an Average (mean wind) or was it a Gust?.. What averaging (time) period was used to calculate this landing wind speed/direction; was it a 3 sec / 10 sec / 1 min / 2 min or 10 min Wind?..

I'm not suggesting that other factors where not involved..such as possible incorrect GA technique, or the possibility of an unstable approach.. However, I do hope the investigation team are examining the impact of the local conditions at the time..

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.

Datum, have you ever landed in Dubai, you are looking for smoking guns, where there are none. Mechanical turbulence caused by hangars, dream on

Dangerous to be so confident you are correct without fully investigating and/or understanding what I'm suggesting.. The cost associated with wind tunnel testing is NEGLIGIBLE when compared to the cost of a Boeing 777 hull loss and the other costs directly/indirectly attributable to an accident!... As with most aviation mishaps, it is likely that MULTIPLE factors will have contributed..

Has the airport/hangar infrastructure been wind tunnel tested ? Before they decide where runways and buildings should be in the next 40 years ? get real-

If 10kts to 25kts of wind ends up with a smoking hull on the RWY, then Id suggest they're ATO will be doing some explaining. However combine that with the PF's apparent lack of real flying experience and it may be a different discussion. As for the temp and QNH, seriously.. a B773 on two engines at or under MLW .... please.

Im looking forward to reading (or at least anecdotally hearing) about the cockpit gradient/CRM issues with this event!

Hangers most def create mechanical turb. But usually only to the extent of an uncomfortable ride. Would have thought being their home port they'd have considered this.

Datum, winds reported are at 10m AGL, so other than "windshear' there is no other reporting (currently) of the level of the windshear or the defining change.
When a pilot tells ATC they encountered windshear, usually as the reason for a GA, ATC broadcasts that until someone says they did not encounter windshear. In reporting winds, the 2min average based on 1 min readings is what is reported. Gusts are on a 10min average, unless the gust exceeds the average, then 5 minutes is used. I have no idea why gusts are reported this way. It should be understood that these measure the horizontal winds only, not the vertical winds, so a vertical windshear component cannot be measured.

Wind profilers show the winds aloft, providing details of the windspeed/direction (horizontally and vertically) and can be used to report exactly what the level and shear conditions are. How to use this information is under development.

As noted by several others, RW12L is about the least likely to encounter a wake. The conditions were right for a dry microburst.

In regards to structures, the low level ground turbulence is usually so scrambled, that structures contribute little, terrain has far more influence.

Dubai Airport integrated weather forecasting/reporting system:

http://radiometrics.com/data/uploads/2012/11/Dubai_AWDSS.pdf

Technical Spec for Viasala Automated Weather Sensor (AWS):

http://www.vaisala.com/en/products/windsensors/Pages/WM30.aspx

Wind should be +/- 3 deg?.. However, this is rounded to nearest 10 deg for METAR purposes and possibly for tower/approach reports to pilots.. The height of the A380 capable hangars is at least 25m..more like 30m.. Distance from runway is approx 420m..

What was the wind speed and direction (vector) at the top of those hangars, moments prior to the aircraft crossing the threshold, initiating the flare, initiating the go-around, settling on to the Runway?.. Was the wind measured at 10m, different at various positions along Runway 12L?.. The geometry of the airport suggests to me that if the wind had ANY easterly component, Runway 12L is more likely to experience mechanical turbulence associated with the maintenance infrastructure?.. The question is, how much Turbuelence/Windshear based on the direction and wind speed (momentary gust wind speed/total wind at 35m, NOT 10m...) This possibility is in addition to; the elevated DA and the vertical windshear characteristic to the airport environment at the time..

Anyone think a truthful and prompt report is likely from the UAE authorities?

I for one do not. Not in a month of Sundays.

This is a region where face-saving is more important than truth. So conjecture may as well continue.

OMDB 030900Z 11021KT 3000 BLDU NSC 49/07 Q0993 WS ALL RWY TEMPO 35015KT 1500

The wind could have been rounded from 105 deg up to 110 deg for METAR or Tower Reported Wind.. The accuracy of the wind sensor is approximately +/- 3-5 deg.. This means the wind direction could have been in the range 100-102 deg..

The total wind speed (including momentary gust) at 10m may have been closer to 25 knots +/- error.. However, at 35m, the height of the hangar roof, the wind speed is likely to have been higher than 25 knots..

I seem to remember RJTT (Tokyo Haneda) 34L and mechanical turbulence from close proximity hangars, but these are much closer to the runway touchdown area than the location of the DXB hangars to 12L.

Datum, the standard for aviation winds is 10m, winds are standard at this location for takeoff and braking performance. 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.

Cup anemometers only measure the horizontal component of the wind. When it is gusting, the cups tend to overspeed and keep running past the gust, hence the 10 minute average.

As you are alluding to, winds do not always blow completely horizontally, affected by structures and terrain. The Ekman spiral is typically used in aviation (procedure design) to estimate winds aloft and the direction rotation at altitude due to the influence of terrain drag and the Coriolis effect.
Wind seldom is completely horizontal, following a Kelvin Helmholtz type pattern
http://www.brockmann-consult.de/Clou...k-w-system.gif
so it is important that the vertical wind component be measured due to uplift/downdraft components that are typical in winds.

http://i67.tinypic.com/x2p92w.jpg