A spokesman for the Aircraft Division of the Hong Kong Institute of Engineering on Friday said he suspects a Rolls-Royce engine fire on a Zurich-bound Cathay Pacific plane earlier this month might have been caused by maintenance procedures.

Warren Chim was speaking on RTHK's Hong Kong Today programme, a day after the Air Accident Investigation Authority said the defect on Flight CX383 could have sparked a more serious fire, potentially causing extensive damage to the aircraft.

"The fuel hoses may be required to be removed so the removal procedures or the cleaning method prescribed by Rolls-Royce may have some problem but it is only a hint based on the emergency air worthiness," Chim said referring to ruptured fuel hoses found in the fuel manifold and a European Union Aviation Safety Agency (EASA) emergency air worthiness directive.

On September 19, EASA issued an airworthiness directive for Rolls-Royce Trent XWB engines fitted on Airbus A350 aircraft. It superseded a September 2 directive, issued in response to the incident on CX383 which departed from Hong Kong on September 2.

"In-service and in-shop inspections since then have identified that a specific cleaning process available during engine refurbishment may lead to fuel manifold main fuel hose degradation," the new directive said.

After the incident, Cathay cancelled dozens of flights and grounded its A350 fleet for inspection.