Boeing stops new plane testing days before first delivery

Boeing had said that it would make its first deliveries of the 737 later this month, with clients including American Airlines and Southwest.

Tests of the aircraft have been ongoing for several months, using engines that have been provided by a joint venture between General Electric and French firm Safran.

Boeing’s share price fell 1.2% on Wednesday after Boeing revealed the engine issues.

"Out of an abundance of caution, we decided to temporarily suspend MAX flights," Boeing said. "The step is consistent with our priority focus on safety for all who use and fly our products."

The company insisted that it has no plans to deliver the aircraft to clients, saying that the production of jets would not be majorly affected. It was first informed of the issue last week.

Boeing MAX versions of its planes have been designed in order to make its fleet more fuel efficient. The planemaker said a possible quality defect in the Leap engine’s low-pressure turbine discs was found during the testing, but had not unduly affected the flight tests.

The 737 MAX is the fastest-selling airplane in Boeing history, adding more than 3,700 orders from 87 customers worldwide since it was first offered.

On Thursday Boeing announced an order for eight 737 MAX 9 airplanes from Primera Air, valued at more than $950m at list prices, including an agreement to purchase four additional 737 MAX 9s and a lease agreement for eight more airplanes from Air Lease Corporation.