Finnair is preparing to restore services to the Estonian city of Tartu, following a reinforcement of ground navigation equipment that will serve as an alternative to GPS.

The carrier had suspended the route from Helsinki on 29 April after incidents in which ATRs – operated by its regional partner carrier Norra – encountered GPS interference.

Finnair states that it will resume Tartu flights on 2 June.

Vice-president of operations control says the Estonian air navigation service EANS has “done an excellent job” by implementing an alternative system, which is based on distance-measuring DMEs.

Finnair ATR-c-ATR

Source: ATR

Finnair has been using ATRs to serve Tartu

EANS chief Ivar Vark says the organisation has received confirmation that the DME signals provide “sufficient coverage” in lower airspace.

“This means that we have found a solution that enables us…to continue serving these flights for which GPS or another conventional navigation solution is a necessary prerequisite,” he adds.

“During validation we found that the signal sent from the DMEs works very well at an altitude range where the additional coverage was needed.

“Flights can [travel], in Tartu’s case, from controlled airspace to the [ILS]. Now we need to add this solution to the procedures and then the pilots can start using it.”

Finnair will operate twice-daily to Tartu, six days per week.

EANS says DME has served as an alternative for higher-altitude traffic, above 10,000ft, since March. It adds that no other flights, besides Finnair’s, have turned back or been cancelled as a result of the GPS disturbances.