MADRID – Boeing Co’s efforts to return the grounded 737 MAX airliner to the sky after two fatal crashes face another hurdle after the head of the European Union Aviation Safety Agency said it will give extra scrutiny to the plane before clearing it to fly.
Boeing is working on a fix to a stall-prevention system on the MAX known as MCAS to address problems that caused it to misfire when one of the plane’s operated by Lion Air crashed in Indonesia in October, killing all 189 people aboard.
The stall-prevention system activated when a sensor on the plane fed erroneous data into the flight-control system.
Investigators into the March 10 crash of the same plane model operated by Ethiopian Airlines have said they see similarities between the two accidents.
On Tuesday, EASA Executive Director Patrick Ky, in a hearing before the European Parliament’s Transport and Tourism Committee said: “I can guarantee to you that, on our side, we will not allow the aircraft to fly if we have not found an acceptable answer to all our questions whatever the FAA does.”
On Monday, Canadian Transport Minister Marc Garneau said the government would conduct its own certification of Boeing’s promised software modification to the stall-prevention system, even if it is certified by the US Federal Aviation Administration.
Both EASA, as the European Union Aviation Safety Agency is known, and Canada last week grounded the Boeing 737 MAX fleet because of safety concerns before the FAA, the principal regulator for Boeing planes, took the same action.
Under international agreements, EASA and Canada generally follow the safety judgment of the FAA on Boeing planes.
The regulators have tried in recent years to more closely avoid duplicative and expensive checks.
The FAA has said that the software updates Boeing is working on should be ready before the end of April.
Ky said “we will look at them very deeply, very closely and we will even go back to the architecture of the MCAS to look at all the failure modes and how they are treated.”
In the run-up to granting its safety approval to the MAX plane in 2017, EASA hadn’t separately checked the flight-control issues that the FAA had declared safe, Ky said.
The FAA and Boeing in February approached EASA about changes to the MCAS system and a month later, just days before the Ethiopian Airlines plane went down, changes in the training for the system.
At the time, EASA viewed the changes as sufficiently to cover safety risks found after the Lion Air crash, Ky said.
Boeing Chief Executive Dennis Muilenburg, in his first public statement since the crash of Ethiopian Airlines Flight 302 that killed 157 people, on Monday said “as the facts from the accident become available, and we understand the necessary next steps, we are taking action to fully reassure airlines and their passengers of the safety of the 737 MAX.”
The enhanced regulatory scrutiny comes as the US Transportation and Justice Departments are probing how Boeing developed the plane. The probes were first reported by The Wall Street Journal. Lawmakers in the US have said they will scrutinize whether pilots were given adequate training about the system.
EASA’s Ky said that as part of the approval process for the MAX fix, training would also be examined.
“We intend to make sure that the software upgrades which are going to be proposed by Boeing will not only be safe in terms of architecture, design and validation, but also will be accompanied by the proper training requirements,” he said.
The two accident probes in Indonesia and Ethiopia also continue. Ky said EASA has asked Ethiopia to be an observer in the Flight 302 crash probe to learn if it needs to take more action related to the MAX.
Ky also said that EASA scrutinized data to check for other instances where the MCAS misfired and couldn’t find any.