Originally Posted by
oggers
Why does it not add up? It does not say that the FAA determined the aircraft should be grounded. It says:
”The analysis determined that the underlying risks from the MCAS design were unacceptably high without at least some FAA action". My bold.
Some action was taken. The Emergency AD 2018-23-51 was issued straight away.
If you reread the WSJ piece:-
July 31, 2019 5:32 am ET An internal risk analysis after the first of two Boeing 737 MAX airliner crashes showed the likelihood was high of a similar cockpit emergency within months, according to a Federal Aviation Administration official familiar with the details and others briefed on the matter.The regulator’s analysis, not previously reported, showed that it “didn’t take that much” for a malfunction like the one confronted by the pilots of the Lion Air flight that
crashed into the Java Sea last year to occur, one of the people briefed on the analysis said.
Based on the findings, the regulator decided it was sufficient to inform pilots about the hazards of an onboard sensor malfunction that led to
a flight-control system pushing down the plane’s nose. The belief was that if pilots were aware of the risk and knew how to respond, it was acceptable to give Boeing and regulators time to design and approve a permanent software fix to
MCAS, the flight-control system
implicated in the crash, according to the agency official and people briefed on the findings.The FAA’s early goal, one of these people added, was: “Get something out immediately and then mandate something more permanent.”Specifically, the FAA’s analysis suggested that a warning to pilots would be enough to provide Boeing about 10 months to design and implement changes to MCAS, according to a person close to the manufacturer. Boeing had been planning to complete the changes by April, within the 10-month period, this person said.Boeing and the FAA’s risk projections faced a real-world crisis in less than five months. Ethiopian Airlines Flight 302
went down on March 10 in a similar nosedive prompted by the same type of automated MCAS commands pilots couldn’t overcome. The dual crashes took a total of 346 lives.
This is the response :-
This AD was prompted by analysis performed by the manufacturer showing that if an erroneously high single angle of attack (AOA) sensor input is received by the flight control system, there is a potential for repeated nose-down trim commands of the horizontal stabilizer. We are issuing this AD to address this potential resulting nose-down trim, which could cause the flight crew to have difficulty controlling the airplane, and lead to excessive nose-down attitude, significant altitude loss, and possible impact with terrain.
* Take out the standard/similar text of most AD's and it hardly reads as a critical thing that is of a very high priority.