What do you think about this airline vs 5G brouhaha?

Mark Tinka mark at tinka.africa
Thu Jan 20 08:49:05 UTC 2022

On 1/19/22 23:57, nanog08 at mulligan.org wrote:

> Scott - a side note to clarify things...
> The 737 Max8 problem was NOT due to lack of testing or non-incremental 
> changes.  The system was well tested and put through it's paces.  It 
> was a lack of proper pilot training in the aircraft and its systems 
> and some carriers choosing to NOT purchase specific flight control 
> options.

IIRC, one glaring bug in how MCAS received data in the -MAX was that it 
could only take it from one AoA (angle of attack) sensor, despite the 
aircraft actually having two physical ones onboard. That was a massive 
break in Boeing's previous culture of "backup for backup for backup".

Add to that, Boeing's assumption that an AoA failure in the -MAX would 
be backed up by the pilots, who had not been informed about the 
existence of MCAS on the -MAX, to begin with... never mind the lack of 
training on how to deal with it. Despite more than 200 incident reports 
of an AoA sensor failure sent to the FAA, even prior to the -MAX 
shipping, Boeing did not flight-test this scenario.

Furthermore, the AoA "Disagree Alert" message that would need to appear 
on the pilot's display in the case of an AoA sensor failure, was an 
"optional extra", which most airlines elected not to add to the purchase 
order, e.g., Air Canada, American Airlines and Westjet all bought the 
extra feature, but Lion Air didn't.

After the Ethiopia crash, Boeing made "Disagree Alert" a standard 
feature on the -MAX, and would be retrofitted on previously delivered 

Boeing had made the decision that the AoA indicator, as well as the 
Disagree Alert" feature were not necessary for the safe operation of the 

I still won't board any flight being operated with a -MAX.


More information about the NANOG mailing list