Iata has urged the world’s aviation regulators to align certification requirements and timelines for the return to service of the grounded Boeing 737 Max.

Airline association Iata suggested restoring public confidence in the 737 Max “demands” that regulators agree on the timing of the aircraft’s return.

Iata’s call came after the US Federal Aviation Administration (FFA) confirmed it had identified an unspecified new flaw in the 737 Max which will delay recertification.

The FAA said in a statement on Wednesday that it “recently found a potential risk that Boeing must mitigate”.

It noted: “The FAA will lift the aircraft’s prohibition order when we deem it is safe.”

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The 737 Max was grounded in March after an Ethiopian Airlines flight crashed soon after take-off – the second disaster involving the aircraft in five months.

A Lion Air 737 Max crashed in late October. More than 340 passengers and crew were killed in the two disasters.

Global aviation regulators acted separately in grounding the aircraft and both the European Aviation Safety Agency and China’s Civil Aviation Administration now plan their own certification of the 737 Max which was originally certified solely by the FAA.

The MCAS stall-prevention system on the aircraft was implicated in both crashes. Boeing has engineered a software fix for the system which the FAA has been testing.

The new problem was discovered during simulator testing when it is reported it took too long for test pilots to regain control of the aircraft after the MCAS system kicked in.

It remains unclear whether the latest issue requires work on the software or more time-consuming changes to hardware.

In a statement, the aircraft manufacturer said: “Boeing will not offer the 737 Max for certification by the FAA until we have satisfied all requirements for certification of the Max and its safe return to service.”

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Iata director general and chief executive Alexandre de Juniac said: “We respect the duty of regulators around the world to make independent decisions on FAA recommendations.”

However, he said: “Aviation is a globally integrated system that relies on global standards, including mutual recognition, trust and reciprocity among safety regulators.

“Aviation cannot function efficiently without this coordinated effort. Restoring public confidence demands it.”

Iata also called for consistency on “additional training requirements for Boeing 737 Max flight crew”.

The FAA announced this week: “We are still developing necessary training requirements.”

Travel Weekly reported a leading analyst’s view last week that the 737 Max would not return before December “and it could be later”.

Surveys of both US corporate travellers and leisure air passengers have suggested significant unease among passengers about flying on the aircraft.

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