The European Union Aviation Safety Agency (EASA) on Wednesday cleared the Boeing 737 Max to return to service in the EU under the terms of an airworthiness directive mandating a package of software upgrades, electrical wiring rework, maintenance checks, operations manual updates, and crew training. EASA’s approval follows that of the U.S. FAA, Transport Canada, and Brazil’s ANAC, leaving China’s CAA as the last major authority not to have issued clearance. Meanwhile, some EASA member states that issued their own bans last year still haven’t approved the Max to return to service in their sovereign airspace. EASA said it is working closely with those national authorities to do so.
“We have reached a significant milestone on a long road,” said EASA executive director Patrick Ky. “Following extensive analysis by EASA, we have determined that the 737 Max can safely return to service. This assessment was carried out in full independence of Boeing or the Federal Aviation Administration and without any economic or political pressure—we asked difficult questions until we got answers and pushed for solutions that satisfied our exacting safety requirements. We carried out our own flight tests and simulator sessions and did not rely on others to do this for us.”
Speaking to the European Parliament's transport committee on Monday, Ky said a bilateral safety agreement between the EU and the U.S. in place since May 2011 resulted in progressively less involvement of EASA on FAA-approved projects and that European authority would now assert a more independent role in determining the airworthiness of U.S. products.
“Let me be quite clear that this journey does not end here,” he added. “We have every confidence that the aircraft is safe, which is the precondition for giving our approval. But we will continue to monitor 737 Max operations closely as the aircraft resumes service. In parallel, and at our insistence, Boeing has also committed to work to enhance the aircraft still further in the medium term, in order to reach an even higher level of safety.”
Global aviation authorities grounded the 737 Max in March 2019 following the second of two accidents within six months that together claimed 346 lives. Investigators traced the root cause to flight control software known as the maneuvering characteristics augmentation system (MCAS), which Boeing engineers developed to overcome handling deficiencies caused by changes to the Max from the 737NG, most notably the engines. However, the MCAS, guided by only one angle-of-attack (AoA) sensor, activated repeatedly if the sensor malfunctioned, pushing the nose of the aircraft downward multiple times. In both accidents, pilots finally lost control of their airplane, resulting in the crashes.
The EASA airworthiness directive mandates software updates for the flight control computer; software updates to display an alert in case of disagreement between the two angle-of-attack sensors; physical separation of wires routed from the cockpit to the stabilizer trim motor; updates to flight manuals citing operational limitations and improved procedures to equip pilots to understand and manage all relevant failure scenarios; updates to initial and recurrent pilot training; tests of systems including the AoA sensor system; and an operational readiness flight.
“The mandated actions need to be seen as a complete package which together ensures the aircraft’s safety,” said Ky. “This is not just about changes to the design of the aircraft: every individual 737 Max pilot needs to undergo a once-off special training, including simulator training, to ensure that they are fully familiar with the redesigned 737 Max and trained to handle specific scenarios which may arise in flight. This will be reinforced by recurrent training to ensure the knowledge is kept fresh.”
In a statement, EASA noted that Boeing has agreed to work to further increase the resilience of the aircraft systems to AoA sensor failures. The manufacturer will also conduct a complementary human factors assessment of its crew alerting system within the next 12 months to identify the need for longer-term improvements, said EASA.