Air New Zealand grounded its fleet of Beech 1900D aircraft Tuesday after a hairline crack was found on an aircraft. 

The aircraft was undergoing a routine inspection when the authorities noticed the crack on the tail of the aircraft.

"Aircraft engineers are currently inspecting the Beech 1900D fleet of 18 aircraft, which are operated by Eagle Air," the airline told Reuters in a statement. "Inspections have already been completed on four aircraft, three have been found to be affected."

Eagle Air General Manager Carrie Hurihanganui said that they are going to cancel the flights for precautionary measures and further inspection on the fleet.

"We apologise to customers for the inevitable inconvenience caused by undertaking a full check of our fleet. However, the safety of our customers, our staff and our aircraft is paramount and non-negotiable for the airline," Hurihanganui said.

Around 800 customers were affected due to this incident. The airline has advised the customers to check the flight status on Air Newzealand website.

Eagle Air is operating since Oct. 2001. The 19-seat aircraft caters 20 destinations across New Zealand.