I like that statement because as a non pilot I understand that pilots make a big deal about the Angle of Attack and so if you are going to give them information on the AOA it should be practically foolproof, and NOT just one opinion, with a second opinion being optional and costing more money.
AOA External sensors can be damaged by ice, runway debris, bird strikes, so you need a backup of some sort.
Of course you can get it from Boeing if you want to pay extra. - Tom
There was some confusion about that in the media. There has always been two AOA sensors on the aircraft, and they are connected to the redundant flight control computers.
What was optional was to display the angle of attack on the electronic flight display screens. From what I've read, it was an option that was only purchased by some U.S. airlines with lots of ex-military pilots who are used to having that instrument in the cockpit, but was not purchased by overseas airlines with pilots who were trained on civilian aircraft that does not have an AOA instrument on board.
Then the option was that if you purchased the AOA cockpit display option, then you also got an "AOA Disagree" warning on the cockpit display. If you did not get the option, you also do not get the AOA disagree warning.
The dual flight control computers still flagged the AOA disagree for its own internal use (except for MCAS, which was a big problem) but the pilots were not told that the two AOA sensors disagreed.
So as part of the software fix for MCAS, all displays will have the AOA disagree alert regardless of whether they have the AOA display option.
>>>Of course you can get it from Boeing if you want to pay extra<<<
Therein lies the problem. Optional Multiple Sensors and Redundancy should never be viewed as a cost saving opportunity for the Customer. Safety is safety and should always be the first consideration.
We aren’t talking Corinthian Leather here. Nobody died because they chose a Fabric Car Interior.