Europe's aviation security guard will not accept a US verdict on whether Boeing's troubled 737 Max is safe.
Instead, the European Aviation Safety Agency (Easa) will run its own tests on the aircraft before approving a return to commercial flights.
737 Max has been grounded since March after two fatal accidents.
However, Easa told the US Federal Aviation Administration (FAA) that there would be "no delegation" on security clearance in a letter sent April 1
Patrick Ky, CEO of Easa, revealed a list of four matters that were given to US authorities in a presentation to the European Parliament's Committee on Transport and Tourism on Monday.
Europe's tough attitude is a blow to Boese's hope of a speedy return to service for the 737 Max, and is also a significant breach of the established international practice of aviation regulators accepting each other's standards.
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737 Max aircraft has not flown commercially since an Ethiopian Airlines plane crashed shortly after takeoff March 10, killing 157.  There followed a Lion Air crash on October 28 last year that killed 189.
In both incidents, investigators have focused on the role of a software system called the Maneuvering Characteristics Augmentation System (MCAS), which was designed to make the aircraft easier to fly.
Probes have shown the software – and the failure of sensors – helped pilots not be able to control the aircraft.
Ky & # 39; s presentation showed that refusing to accept delegation was the first of the four conditions that had to be met before flights in Europe could be resumed.
The other three were:
- an "additional and broader independent design review" by Easa
- that the two fatal crashes were "considered sufficiently understood"
- and that flight crews had been adequately trained in modifications to plane.
Easa's work on the 737 Max had resulted in "a unique level of effort", with 20 aviation experts and two to three web meetings a week with Boeing engineers.
There was plans for a full week of test flights with a modified aircraft at the Boeing Flight Test Center in Seattle.
Boeing has been working on modifications to 737 Max's flight control systems to avoid the MCAS problem. In addition to changes in the aircraft, it has proposed changes in the way pilots are trained.
Reports in the United States have suggested that Boeing had hoped for the FAA's security clearance next month, with airlines free to fly the aircraft later this year.
FAA approval would allow US airlines to fly the aircraft, but European operators – including Norwegian Air – would need Easa approval before returning to commercial service.