Diplomatic concerns come into play when an aircraft is owned by a foreign state, writes Conor Lally
While gardaí have all their normal powers in the investigation of crimes taking place on board aircraft, their position is greatly weakened if, like CIA rendition flights, one is being used to carry out the official business of a foreign government.
Domestic laws governing searches, including searching aircraft, bestow strong powers on members of the Garda.
An aircraft is defined as a "place" under Irish law. As such, it does not enjoy the same protections from unsanctioned search as afforded to a "dwelling" under the Constitution.
However, other diplomatic considerations come into play when aaircraft is owned or controlled by a foreign state.
If gardaí wanted to search a civilian or commercial aircraft, which they suspected was being used for the commission of a crime, they would need to be in receipt of strong specific intelligence. As one senior garda put it: "Whether you are investigating road traffic offences or very serious crimes, you can only use your powers if you have good reason."
In the case of a commercial or civilian flight, gardaí could board it without a search warrant if they believed the life or safety of anybody on board was at risk.
Indeed, they be would obliged to act if they had information to this effect. In the event they were searching for drugs, firearms, people being smuggled or any other illicit cargo, they would in most cases apply to the courts for a search warrant.
If a warrant is not sought, there is no guarantee that a judge at a trial would accept any evidence found during such a search. Admitting evidence obtained without a warrant is completely at the discretion of a trial judge.
Security sources who spoke to The Irish Times yesterday said they believed the power to search aircraft or investigate their activities is greatly curtailed if one is owned by a foreign state or is merely passing through an Irish airport en route to another country.
One source said he believed US government flights, such as rendition flights, might even be completely immune from investigation here under international protocols that afford sovereign protection to property owned by foreign states. However, this had not been tested in the courts, he stressed. A number of sources said Irish aircraft enjoyed similar protections when abroad and this had to be reciprocated.
One senior Garda officer who spoke to The Irish Times said the diplomatic dimension to the current controversy created a range of difficulties.
"Even if you went to court and got a search warrant, you would be making a very big leap indeed in searching a plane owned by another government. We are talking about the relationship between two sovereign states here.
"The US government has given assurances to the Irish Government that there is nobody being transported through Shannon for the purposes of torture and our Government has accepted that."
Another senior Garda source said despite the intense media speculation about the US rendition flights, no evidence whatsoever had been presented to gardaí indicating prisoners were being, or had been, transported through Ireland for torture.
The Department of Foreign Affairs is responsible for granting permission to foreign government or military aircraft to use Irish airports. It is provided with a manifest of what persons and cargo are on board such flights.
These details are passed on to the Irish airports being used by the aircraft. However, like the assurances being offered on rendition flights, manifests provided by the US government are accepted in good faith.
The Revenue's customs and excise service also has a role in investigating aircraft, cargo and people moving through Irish airports. However, because rendition flights are simply stopping to refuel on their way to their final third-state destination, there is no obligation on their crews to make a declaration to customs.