Hi
I am flying to Rio in October and back from Buenos Aires.
I am trying to book a flight between the two cities. When I get to the payment page one of the required fields is a Social Security number.
in the UK we don't have these. The nearest equivalent is a National Insurance Number.
I've never seen a requirement for this type of information before.
Can anyone advise me on what I enter in this field. it won't let me complete the booking otherwise.
Thanks

The SSN is the USA equivalent of your NIN for this purpose. It's a bit odd that you are being asked to supply this by Emirates for a local flight between these two cities. Is it possible that you are trying to book through the US Website? If you aren't, wouldn't the best thing to do be to call?

As someone who lives in the US I was initially outraged that a SSN was being required by an airline, especially since this number is tied into every aspect of ones credit and therefore not to be handed out especially to a airline. But I eschewed venting opting instead for a Google search which seems to suggest that this may be a Brazilian thing. It appears a Brazilian CPF (Social Security Number) may be required for domestic--and Argentina is a neighbor--flights. I did not require this on a US bought ticket (twice) between Sao Paulo and Rio. But I am curious.

I'm Platinum on Emirates and they have never asked me for my SSN. I live in Brazil and TAM or GOL airlines don;t ask for your US SSN. If you're in the Portuguese site, they may ask for your CPF (Brazilian SSN) to validate your credit card. Use the English (USA) website and they will only ask you for your passport number.
Hope this helps!

Just tried the UK and USA sights and both are asking for the Social Security number.

this is a Argentina thing and only applies to Argentinian residents, there were a series of questions that come before that mean if not a resident then you will not have to enter the number to continue.

I have definitely answered the questions correctly and cannot get past the payment stage without entering something. I wonder if entering the UK National Insurance Number will work. Can they validate this? It won't be in the format they require and probably won't have the correct number of digits.

So are you a resident of Argentina, if so then you should have the CUIL number or if finalised a CUIT number to enter? If not then answering that you are not an Argentina resident should allow you to skip this.
Otherwise probably a call is the way to get past this

If it were me I would make one up 123-45-6789 should do. I doubt they check it against anything.

Phoned Emirates. They can make the booking but so far their system won't let them accept payment!! The operator is back on to his supervisor again.

Apparently I can only make payments for a domestic Brazilian flight by going to an Emirates Office but the guy in Dubai asked his supervisor and was told if I phone Manchester they may be willing to make the payment over the phone.
There's no dedicated number for Manchester so I am now told that I need to keep trying the regular number and hope that Manchester pick it up and not India.

What a ridiculous situaiton. 45 minutes on the phone so far.

In the US, when the SS number is not yet available, some Financial institutions sometimes enter 999-99-9999 for temporary solution. why not try the same?

Because he/she might get refused boarding?

I am pretty sure this has to do with certain tax on the ticket.The AR tax applies only to nationals and residents of Argentina and I am assuming for the Argentinian equivalent of an SSN number.Also the ZK tax is a retention income tax:

PLEASE NOTE THE FOLLOWING NEEDED TO COMPLY WITH ARGENTINA
GOVERNMENT RESOLUTION 3450/AFIP;

1. THE TAX PAYER FISCAL NUMBER *(CUIT)/ (CUIT) OR (CDI)
MUST BE INCLUDED IN ALL INTERNATIONAL TICKETS ISSUED IN
ARGENTINA. THE CUIT MUST BE REPORTED IN THE RET FILES IN
THE PXDA FIELD.

2. THE AIRLINES CUIT NUMBER MUST BE INCLUDED AND MUST GO IN
THE RET FILES.

3. THE FOLLOWING TEXT MUST ALWAYS BE DISPLAYED IN THE
PASSENGER ITINERARY : ZK RG3450/AFIP.

While the EK website and call center are having the OP jump through all kinds of hoops why not try a third party booking engine. A search on Kayak yields an EK flight. The ticketing page, purchasing through Kayak itself (actually priceline their partner), lists all the the required detail payment included on one screen and nowhere is an ID number required. I suspect Orbitz/Expedia might offer the same.
Other forums suggest that you will have less luck with Webjet etc. which require the Brazilian CPF.