If the media did you know about the collapse of the liner and I suspect that the Board could be your friends or relatives, immediately contact the airline. In this case, to deny you have no right, moreover, specifically created hotlines that you can call around the clock. Later, when the initial excitement calms down, it will be possible to Refine the list of passengers on the Internet. It will be posted on a special website.
If we are not talking about life and death, to access data on passengers will be very difficult. Try to contact the airline staff and honestly tell us what it is you need. If you, for example, due to sudden outbreak of love at first sight want to know the name of the companion and will be able to convince the representatives of the airline in their honest intentions, may be they will help you. But they are not obliged to do so, but if we are talking about some business matters, do not have the right to disclose such information.
Use ties to law enforcement, if you have some friends there. Databases of airports have access to the FSB, the police and tax authorities. Using their powers, they might Suss what you need.
Do not try to find data online. Although there are dozens of sites offering similar services, rely on them impossible, and their services are very expensive. A skilled hacker can hack into the database of the airline, but it is a criminal offence, and it is better not to use them.
Hire a private investigator. If he has a license to search, he may request information at the airport. In any case, its capabilities are much more than your.