On the lion air the sensor was non-operable from the start of the flight; so yes on both flights the AoA sensor was in a non-flightworthy condition.
One point of clarification: on the 737 and most other airplanes the airspeed is unreliable if the AoA sensor becomes damaged. This occurred on both the ET302 and the lion air flight. In such a state, it is up to the pilot to place the plane in safe flying state that does not depend on access to the airspeed. The pilot should by memory, ideally, set the thrust and nose up attitude of the plane along with other control surfaces. Failure to do this is what indirectly caused the AF447 disaster and it seems the the crew didn't execute this procedure on the ET302 flight. At the very least, attempting to engage the autopilot and disengaging flaps were contrary to standard procedure. Not executing this procedure dramatically increases the workload on the pilot and increases the risk that either airspeed wall outside of the safe operating range of the aircraft or the pilot will have to take drastic action to maintain airspeed in a safe range. Both are dangerous and even an experienced pilot can fail to take appropriate action especially in an emergency with the flight crew attending to other anomalies.
With that caveat stated, there is nothing inherently unsafe about flying with the combination of unreliable airspeed and an uncommanded MCAS activation in theory. The previous flight of the lion air flight was able to counteract 20+ instances of MCAS activation by simply trimming the aircraft using manual trim before they tried disengaging electrical power to the stabilizer motors. After disengaging trim the pilots felt comfortable continuing the flight and adjusting trim using the manual cockpit trim wheels. With all that being said, no aviation regulator would certify a plane that couldn't fly safely with an unreliable airspeed and manual trim turned off.
I think the question about why the 737 MAX's haven't crashed more is two fold. First, a birdstrike that takes out an AoA sensor is very rare. In that sense, Boeing got very unlucky in that they had a birdstrike that knocked out the specific AoA sensor tied to MCAS a month before they planned on rolling out the software update. Additionally, flight sensors are usually maintained very well as they are a critical item. You would never expect standard maintenance procedure not to fix an unreliable airspeed. When it has happened before though, the outcome can be tragic just as it was on the lion air flights regardless of any issues with MCAS.
One point of clarification: on the 737 and most other airplanes the airspeed is unreliable if the AoA sensor becomes damaged. This occurred on both the ET302 and the lion air flight. In such a state, it is up to the pilot to place the plane in safe flying state that does not depend on access to the airspeed. The pilot should by memory, ideally, set the thrust and nose up attitude of the plane along with other control surfaces. Failure to do this is what indirectly caused the AF447 disaster and it seems the the crew didn't execute this procedure on the ET302 flight. At the very least, attempting to engage the autopilot and disengaging flaps were contrary to standard procedure. Not executing this procedure dramatically increases the workload on the pilot and increases the risk that either airspeed wall outside of the safe operating range of the aircraft or the pilot will have to take drastic action to maintain airspeed in a safe range. Both are dangerous and even an experienced pilot can fail to take appropriate action especially in an emergency with the flight crew attending to other anomalies.
With that caveat stated, there is nothing inherently unsafe about flying with the combination of unreliable airspeed and an uncommanded MCAS activation in theory. The previous flight of the lion air flight was able to counteract 20+ instances of MCAS activation by simply trimming the aircraft using manual trim before they tried disengaging electrical power to the stabilizer motors. After disengaging trim the pilots felt comfortable continuing the flight and adjusting trim using the manual cockpit trim wheels. With all that being said, no aviation regulator would certify a plane that couldn't fly safely with an unreliable airspeed and manual trim turned off.
I think the question about why the 737 MAX's haven't crashed more is two fold. First, a birdstrike that takes out an AoA sensor is very rare. In that sense, Boeing got very unlucky in that they had a birdstrike that knocked out the specific AoA sensor tied to MCAS a month before they planned on rolling out the software update. Additionally, flight sensors are usually maintained very well as they are a critical item. You would never expect standard maintenance procedure not to fix an unreliable airspeed. When it has happened before though, the outcome can be tragic just as it was on the lion air flights regardless of any issues with MCAS.