Last Sunday’s fatal crash of Ethiopian Airlines Flight 302 outside Addis Ababa—the second accident involving a Boeing 737 MAX 8 in just five months—has sent shockwaves across the globe, with President Donald Trump announcing Wednesday that the United States is joining more than 40 other countries in grounding the MAX 8 and MAX 9 models until further notice.

Leading up to the White House’s emergency order, the FAA, Southwest Airlines and American Airlines had all expressed confidence in the MAX 8’s airworthiness despite growing concerns with the airplane’s Maneuvering Characteristics Augmentation System, or MCAS, a new software feature Boeing added to stabilize the reengined 737 during low-speed, nose-up flying conditions in which airplane could potentially stall.

While keeping MAX 8s out of the sky is an effective, albeit extreme, move by regulators to forestall further accidents until Boeing releases an update to the aircraft’s software next month, the unpopular truth is that the MCAS alone did not cause Ethiopian Airlines Flight 302 to crash—nor did it cause Lion Air Flight 610 to nosedive into the Java Sea last October.  Indeed, both flights would have landed safely if their respective civil aviation authorities had made sure that the airlines had adequately trained the pilots to handle standard emergency scenarios.

To be clear, neither of the two flights’ crews are to blame. In most countries around the world, commercial passenger airlines are regulated by civil aviation authorities that, like the FAA, are responsible for overseeing air transport operations and ensuring that airlines comply with worldwide aviation safety standards, such as those set forth by the United Nations’ International Civil Aviation Organization (ICAO).  Airlines are required to administer periodic proficiency checks to retrain pilots on the aircraft they fly and rehearse possible scenarios that could jeopardize safety in flight.  Ultimately, responsibility for seeing that air carriers conduct these checks—as well as for verifying that emergency industry and manufacturer bulletins are promptly incorporated into an airline’s training programs—rests with the civil aviation regulator of the country in which an airline is based.

For example, following the Lion Air accident last October, Boeing issued a worldwide Operations Manual Bulletin telling its MAX 8 customers how to override a “runaway stabilizer” and recover the aircraft from an MCAS-induced nosedive. The next day, the FAA directed U.S. airlines to revise their airplane flight manuals to include this procedure and train their flight crews to override the MCAS by setting the flight controls’ STAB TRIM switches to CUTOUT and manually flying the aircraft for the remainder of the flight.

Likewise, the Ethiopian Civil Aviation Authority should have confirmed that its country’s airlines also trained their pilots on the recovery procedure. It has been reported that Ethiopian Airlines did train its pilots on Boeing’s bulletin in the wake of the Lion Air crash; but the degree to which the regulator was involved in confirming that the training was effectively administered remains unclear. Pilot training oversight continues to be one of the most common areas in need of improvement by foreign civil aviation authorities.

While it is still too early to speculate as to the exact cause of Sunday’s accident, the unsettling similarities between Lion Air Flight 610 and Ethiopian Airlines Flight 302 suggest that a runaway stabilizer contributed to both crashes. If so, Flight 302’s pilots likely did not cut power to the stabilizer and fly by hand when MCAS tilted the MAX 8’s nose downward, instead reacting by pulling back on the yoke in an attempt to bring the nose back up. This appears to be what happened to Lion Air Flight 610, which recorded erratic altitude fluctuations and unstable vertical speeds shortly after taking off, indicating that the pilots struggled repeatedly with the aircraft’s flight controls prior to impact as opposed to switching the STAB TRIM switches to CUTOUT.

It is true that Boeing needs to implement a comprehensive fix to resolve MCAS’s well-known issues.  But the rush to ground the MAX 8 worldwide—while certainly one way to guarantee safety—risks ignoring the systemic breakdowns in regulatory oversight of pilot training that must be fixed in order to prevent tragedies like Flight 610 and Flight 302 from happening again.

Glenn Wicks is the Managing Director of The Wicks Group, a Washington, DC-based international aviation law and consulting firm. Barry Valentine is the former Acting Administrator of the Federal Aviation Administration and Senior Advisor to The Wicks Group. John Waltz is leading expert in flight simulation training device certification and a Senior Technical Consultant at The Wicks Group.