How to claim compensation from Norwegian for cancelled flights, overbooking, or delays under EU261.
If Norwegian cancels your flight less than 14 days before departure, you are entitled to compensation (250-600 EUR) PLUS rebooking or a refund of the ticket. If they cancel due to technical issues, you are almost always entitled to compensation.
No, technical issues generally do not qualify as extraordinary circumstances under EU law. Maintaining aircraft is part of the airline's normal operations.