Boeing (BOE, Washington National) has temporarily suspended test flights of its B737 MAX aircraft following the discovery of an issue with its CFM International LEAP-1B engines, reports Reuters.

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

CFM International is a joint venture between General Electric Aviation and Safran Aircraft Engines. According to its website, more than 7,400 LEAP-1B engines have been ordered by 86 customers for around 3,700 aircraft in the 737 MAX family.

Jamie Jewell, spokesperson for CFM, has said that the engine issue pertains to a low pressure turbine disc which CFM discovered during a quality control check.

"We will work closely with CFM to understand the precise scope and root cause of the quality issue," Boeing's statement said. "Our plan remains to begin MAX delivers in May. MAX production will continue, as will production and delivery of our Next-Generation 737 airplanes."

Malindo Air (Kuala Lumpur International), the launch operator of the B737-8, was due to take delivery of its first of four aircraft next week. The Lion Air (JT, Jakarta Soekarno-Hatta) subsidiary has not yet commented on any delay to that schedule.