Just some quick pointers. I presume it is the first interview of the process you are attending based on the information on your thread
1.) The interview is designed to eliminate the very weak candidates from the process. ie. People they feel will not make competent officers in the Defence Forces.
2.) Have a thorough knowledge of the Air Corps and the entire Defence Forces in general. YOU WILL BE ASKED ABOUT THIS!
3.) Try and overcome your nerves and show excellent maturity and confidence. Convince them that you will make an excellent officer and pilot with them.
4.) You will be interviewed by two current serving Air Corps personnel, although only one of them will probably be a pilot. Expect that member to ask you questions about aviation eg how does an airplane fly, Describe how one would go about flying a circuit.
5.) You will be asked about the fleet of aircraft the Air Corps operate. Make sure you have a thorough knowledge of this, as it shows interest. Basically, these are the questions they want to see if you can answer. They are not going to hire someone who dosen't even know what aircraft they fly etc.
6.) Make sure you are up to date with current affairs. Even if you read the paper between now and the interview on Thursday, you should have sufficient knowledge of the main headlines.
7.) Should you get through this stage, you will progress onto the Aptitude testing stage with PARC aviation. These test are exactly the same as the Aer Lingus ones and you can find details of these by doing a search on this site.
8.) Lastly, should you become successful be prepared to spend the thoughest eight months of your life doing pre flying military training in Cadet school. You will be pushed to your physical and mental limits. They will ask you if you know about the training involved. Make sure you do and let them understand that you realise it will very tough. They appreciate honesty because I can gaurantee you that they will not have enjoyed one minute of theirs.
9.) Place a reply with your e-mail address on this thread if you want any further information. I will gladly expand on any issues or questions you may have.
Finally, best of luck and remember portray confidence and maturity on the day. Let us know how you got on!