A Boeing 737 Max has flown for the first time since the fleet was grounded globally after two total-loss crashes – on the same day a European airline cancelled its order for almost 100 examples of the controversial aircraft and sued its US manufacturer over the debacle.
The Monday test flight flew between America’s Seattle Tacoma airport and Grant County International Airport in Moses Lake, which has an unusually long runway of 4,100 metres. It was one of the alternate landing sites for the Space Shuttle for this reason, and Boeing regularly uses it for testing. The 737 landed safely and uneventfully after two hours aloft.
It's the start of an unusually long road ahead to get the 737 Max airworthy again. Once it passes American certification tests – possibly as early as the autumn if all goes well – Boeing will face separate scrutiny from other regulators around the world. In the past, US Federal Aviation Administration certifications were accepted at face value by other countries, but that is no longer the case, in part due to serious failings highlighted by the 737 Max testing process.
Industry blog The Air Current went into some detail a few weeks ago about the then status of 737 Max flight control software revisions and certification challenges ahead of Boeing.
Author Jon Ostrower noted: “EASA [the EU Aviation Safety Agency] is conducting its own Integrated System Safety Analysis on the 737 Max and its new software, effectively applying a regulatory template intended for Airbus aircraft on top of Boeing,” and repeated Boeing fears that the Max might fail the EU analysis.
If you're wondering what that's all about, bear in mind some years ago Airbus’ mainstay A320 airliner had a potentially serious flaw where if angle-of-attack (AoA) probes became blocked, the aircraft’s control software assumed it had entered a stall (too little speed to maintain height) and automatically applied nose-down trim plus full engine power, a response known as “alpha protection." That trim input pointed the aircraft downwards so it would safely pick up speed and allow the pilots to recover from the stall.
In 2014, an Airbus A321 (an A320 sub-variant) suffered an unexpected alpha protection activation after its AoA probes became blocked. Airbus bulletin OEB48 was issued shortly afterwards, with a similar bulletin, OEB49, issued for A330 and A340 long-range airliners. EASA issued a safety directive, known in its final form as AD-2018-0007R1, which ordered the installation of a software update that (among other things) stopped Airbuses from applying nose-down trim when alpha protection kicked in. No Airbuses have crashed as a result of alpha protection inappropriately being activated.
Nice test flight, you can keep your planes though
On the same day as the 737 Max test flight took place, Norwegian, a Scandinavian airline, announced it was cancelling its order for 97 737 Maxes and would claim compensation from the airframe maker for the extended grounding of the type.
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“Norwegian has in addition filed a legal claim seeking the return of pre-delivery payments related to the aircraft and compensation for the company’s losses related to the grounding of the 737 MAX and engine issues on the 787,” the airline said in a statement to financial newswire Reuters.
As the whole world knows, the 737 Max series of airliners was grounded worldwide after two fatal crashes that killed 346 people. Investigations discovered that the Max contained software features that its pilots hadn’t been sufficiently briefed about, including the infamous MCAS automatic trim system.
In desperation to compete with Airbus’ market-share-gobbling A320 Neo, a direct competitor of the 737, Boeing assured airlines that pilots who flew previous 737 models could swap to the new Max with minimal training. This turned out to be a lethal cost-saving shortcut that left pilots unaware of how to shut off MCAS when it kicked in and forced their airplanes to point at the ground instead of the sky.
The entire project has gone down in history as an example of how not to do high-stakes software development: MCAS was a bodge to compensate for changed handling characteristics caused by fitting bigger engines to the 737 airframe as part of the Max design. Rather than pay to recertify the aircraft design from scratch, Boeing hoped the software would compensate for hardware changes and keep it within the existing 737 certification.
Boeing recently announced layoffs of 6,700 employees. ®