Nonsense! There is a reason why it is called the World Geodetic System.

In this case I suspect it actually could well be the cause!

If you're not working at EK then that's something you wouldn't really know about... The procedures are very well documented and if briefed and followed don't actually require a lot of 'training' as such. The procedures aren't that difficult; however I will agree that FATIGUE is also part of the cause!

Daily or double daily flights to UUDD for about 13/14 years from OMDB means most of the guys/gals (at least the left seaters) have been many times over the years...

The issue I submit to you ATC Watcher is not having the time to recharge the batteries between trips... ULR over the pole to LAX one day and a few days later doing a DXB/BKK/SYD trip for example!

India 4 2 : Don't be fool by the name , marketing , it is a US DoD baby, developed by them for their GPS , derived from WGS60, itself from an earlier one started when they launched satellites in the 50's . WGS84 still uses their old North American reference of 85W centered in middle of USA.

White Knight : I am not talking about EK in particular, just looking at incident/accident reports . The recent TK A330 in KTM, or the SFO 777 are good examples to start with.

I think you perhaps mix up causes and contributing factors. For instance fog or Cb are not causes . Like QNH/QFE or m/feet conversion. Contributing factors maybe ( as we do not yet know yet what happened here , just Internet speculation ) but not causes. That was my point.

WK and his reference to fatigue, speaks very true words.

Wow, really. It is not a reference point, WGS84 appoximates the Earths Ellipsoid. It has been adopted by ICAO as the worldwide standard for aviation.

The grid is based on UTM, with 60 zones. Each gridline is its own unique reference line, and is ultimately accurate.
Zone 1 and 60, moving from West to East, and letters from South to North., and does not relate to the Prime Meridian, nor 85W.

Max difference between geoid and ellipsoid is 105m. IF you have a GPS on the aircraft, or wherever, the system calcs the difference between the Geiod (MSL) and the Ellipsoid (GPS alt) by means of the lat/long and corrects, so you dont have to.
It does not give you AGL, it gives you altitude based on MSL.

Back-up (pressure) altimeters would have local sea level air pressure value sent to them automatically by data link (with a readout of this figure available for cross-checking against forecast values). In commercial aircraft a discrepancy between the GPS and pressure altimeter indications exceeding pre-determined limits would generate a crew alert. Development of this sort of kit is within the bounds of current technology.

The Cub pilot would be responsible for manually setting LSLAP on his or her old tech altimeter.

As Underfire stated, WGS84 is a worldwide system adopted by ICAO around 1989.

In the early days of RNAV, but later than 1989, many countries were not WGS84 compliant. More and more complied as the years passed. Several years ago if I would select an airway or terminal procedure in a country that was not WGS84 compliant, I would get an advisory message "X Country not WGS84 Compliant."

I believe most countries are WGS84 compliant in 2017. I tested Russia at UUDD with a current database. UUDD has several RNAV approaches. I did not receive a WGS84 noncompliance advisory alert for a UUDD RNAV IAP that I selected.

As to China, Hong Kong has RNP AR procedures. So, at least that portion of China is WGS84 compliant. So is Tibet as it has a very sophisticated RNP AR approach procedure developed some years ago for China Airlines by Naverous.

I selected ZUCK in China that has some ILS procedures with RNAV transitions and some without. I wasn't able to select the RNAV/ILS procedures. I'm not sure what that means.

I can confirm that 'underfire' and 'aterpster' are right. Many years ago I was involved in updating an airline's charting and in work on GPS and Galileo compatibility.

Then I stand corrected.

I was in an ICAO meeting in the early 1990's where all this was explained, the earth being a " potatoid" (I remember that term !) therefore every major State used a different reference point/system fitting their Country or continent surface. Since GPS was going to be used worldwide , the USA GPS standard was chosen to the the ICAO standard for their GNSS. ( The then USSR fiercely opposed this , but since they dissolved around that time , they lost the argument )
To be fair in those days we were looking at 2D ( Lat/long positions maps, etc..) , not altitude at all.

ATC WATCHER,

It was an interesting time when WGS 84 was being introduced and we found that all the individual country's surveys did not quite connect - sometimes by a few metres and sometimes by many miles!

The confusion probably stems from the fact that, for all intents and purposes, WGS84 and NAD83 (North American Datum 1983) are virtually the same over North America and evolve together. That is why the US did not care if it was WGS84.

Now lets start talking vertical datum, ellipsoids and geoids, h and H, that is hours of fun!

aa,

A man after my own heart! Hours of fun indeed, trying to explain the difference between h and H to people who have never heard the term ‘geoid’ and who think lat/long values can never change.

underfire,

A small clarification. Universal Transverse Mercator (UTM) is a widely-used and very useful map projection, but it has nothing to do with the definition of WGS84.

Confusion can arise because the projection formulae use the parameters of a spheroid to convert lat/longs to eastings/northings. The spheroid used is usually the same spheroid that is specified in the geodetic datum that was used to calculate the lat/longs, but it doesn’t have to be.

As a consequence, a properly labeled map will have not only the geodetic datum parameters, but also the parameters used for the projection, including the spheroid.

Rather than expand at length, I offer the following Wiki links, for further reading:

https://en.m.wikipedia.org/wiki/World_Geodetic_System

https://en.m.wikipedia.org/wiki/North_American_Datum

https://en.m.wikipedia.org/wiki/Univ...rdinate_system

On a final note, the US DOD were the initiators of the work that led finally to WGS84 and they did this because they needed a world-wide, earth-centred datum, to help in targeting ICBMs.

Crazy enough, when the Collins FMS-800 was installed in the C-5, we could select the datum to be used with WGS-84 as the default. If wanted the Argentine 1926, if was there and everything shifted. Not sure who thought that up.

Was involved in hydrographic survey in '73 and sections had not been surveyed since the time of discovery by Captain Cook in 1770. What surprised was generally how accurate he was given the technology of the time. Also spent time chasing errors in the national data base. Know nothing of the subject, I was just the means of transport and dogsbody carrying equipment.

Bingo!

Then remember selective availability, which Bill Clinton finally turned off.

It's likely as you read this that there are several aircraft around the world flying with mis-set or mis-read altimeters. Some pilots will have omitted to change from QNH to standard when climbing through transition, others the opposite during descent. Some will be reading altitude on QFE and others height on QNH, which may result in level busts or airspace violations. Some will have incorrectly converted feet to metres or vice versa.

In Europe the problem is compounded by low Transition Altitudes. Every time a deep low pressure weather system crosses the UK a Notam has to be issued to remind pilots to be vigilant in setting standard when climbing through TA to avoid traffic conflicts. Of course, in such weather turbulence and wind shear are more likely to be encountered, distracting crews from essential tasks (such as resetting altimeters) at this critical time.

The consequences of altimeter mis-sets or mis-reads will usually be limited to red faces when the error is discovered. But now and again . . .

Yep, I agree, the wheel has been invented in most other parts of the world. :ugh:

Why put the transition altitude/level down low where things are busy and traffic is most congested? :confused:

Fortunately QFE, like ADF holding, is almost extinct at large international airports in my experience. :ok:

Yes, I can confirm that the procedures for China use WGS84. The terrain model is WGS84 and based on SRTM data. Getting a survey on local terrain/vegetation, controlling obstacles, and the airport data was all created from scratch.

Yes India24, the UTM was comment rushed, I was thinking about the current project I am working on where the land based mapping is UTM.
WGS 84 is based on the prime meridian. A straight path across the surface is one thing to calculate, but a curve path on the surface is quite the other...the regulatory agencies were using the Helmert Formula, but that is not accurate enough for curves, so we use Vincenty's Formula which is far better.

In the end, the aircraft system understands WGS 84...

From Jeppeson. WGS84 Compliance worldwide...

https://i.imgur.com/GpE3qhw.jpg

http://ww1.jeppesen.com/company/publications/wgs-84.jsp

From WK--

Here's a chap who manages to sort the wheat from the chaff in PP discourses these days . Metric/feet conversions , while an inconvenience, should never be an issue for a competent (i.e well disciplined , well trained crew ) and I am sure this is the case with pretty well all major operators these days, including those supposedly in "The Third World".

However, the point about time zone change and subsequent effects is the one that strikes me . I have always wondered why it was not possible for a roster to avoid this mix of Far West , followed by Far East . I always felt it should be a case of one or the other, with a North/South rotation filling in the rest of the month , (although in this case a Moscow trip would be following that philosophy ) . But then, bidding software perhaps makes that wish "mission impossible" . I don't know , but I do have a lot of sympathy for the rostering departments ; an unenviable job , as you could never satisfy everybody. , especially with the top floor guys coming in at short notice to make their own requests for favorite destinations ( usually combined with favorite seasonal weather---westbound in summer, eastbound in winter,---" no typhoons approaching; no Cat 3 approaches, please...).

In a previous gentlemanly life, (744 cargo) , we had a great route structure; set off eastbound and arrived back at base 2 weeks later, having traveled round the world in one direction (with multi day layovers), followed by a week off to "recover". 60 hours a month, if you were lucky.

Sadly, it seems those days are long gone.....

Rather long missive published to all Pilots by EK Training Management. Reference all the recent accidents incidents etc. Shake up in training and including introducing regular unannounced spot checks on route sectors by Route Check Capts.