IATA say's the standard format for transmitting passenger messages is UN/Edifact. Somewhere else it says the standard is type B format.

what are the differences between these two? Or are they a same format?

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    $\begingroup$ "IATA says..." can you link the document and cite the page? Also "Somewhere else it says..." Again, link the document and cite the page so we can read this in context. $\endgroup$
    – Ron Beyer
    Oct 19, 2017 at 15:02

2 Answers 2


There are many types of messages which are used very specifically within the aviation Industry and TypeA and Type B are the most notorious ones.

Its not the message format that differentiates them , its the characteristic message delivery and response that does.

Type A - Expect immediate application response, have timeout handling in place at the application level, delivery is not guaranteed and could expect loss of messages. EDIFACT is one of the well known industry accepted and following TYPE A message formats..

Type B - Guaranteed delivery and will make anything and everything possible to deliver the message . Does not expect an immediate response back.

Regarding the format of the messages, the type A message formats are governed by PADIS ( PASSENGER AND AIRPORT DATA INTERCHANGE STANDARDS MESSAGE STANDARDS DOCUMENT). It does differ for each applicaiton( reservation, ticketing, DCS etc). Here is a sample one for PNRGOV standards.


For TYPE B , always refer to the AIRIMP documents which governs the TYPE B mesasge formatting..

Here is a sample of the same.. ftp://ns.tais.ru/pub/doc/AIRIMP34.pdf

Thanks, Jothi

  • $\begingroup$ Unfortunately, the first link is now gone, while the second is there, but contains nothing $\endgroup$
    – userfuser
    Nov 5, 2020 at 16:58

I have searching the matter on basic definitional difference between the two type of messages. After a lot of research, my understanding of the two is given below:

1.) Type A: Transactional interchange of data between airline and the travel agent for seat reservation and ticketing. The data used is stored on single central system through data network. As you might have observed, it requires real-time query/response due to nature of job at hand i.e. reservation/ticketing, and hence, quick response. Security is not a concern though and there is high level of possibility for duplication.

2.) Type B: It is messaging between airline and service providers i.e. airports, baggage handlers, cargo handlers, immigration; and follows standardized formats as well as standardized/secure networks (SITA). Query/response is not required, however, due to nature of job, delivery of message is ensured. There are 4 levels of priorities assigned in order to ensure timely delivery. One other matter which differentiates it from the Type-A is the cost. Due to specialized networks and organization involved during type-b messaging, costs of type-b messages is high.


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