The crux of the problem involves alerting.
The FAA has to consider its own research findings and associated regulations.
and, although the “
The United States Government assumes no liability for the contents or use thereof.” Congress could reflect on the ethical, moral aspects of any dispensation from the requirements.
”Human Factors Considerations in the Design and Evaluation of Flight Deck Displays and Controls”
https://www.volpe.dot.gov/sites/volp...ontrols_V2.pdf
Other certification agencies could throw the whole book back at the FAA / Boeing; your book, your rules, … you comply.
Page 113 onwards:
Warning: For conditions that require immediate flightcrew awareness and immediate flightcrew response.
Red - if immediate action required
Flightcrew alerts must: [14 CFR 25.1322 (a)]
(1) Provide the flightcrew with the information needed to:
(i) Identify non-normal operation or airplane system conditions, and
(ii) Determine the appropriate actions, if any.
(2) Be readily and easily detectable and intelligible by the flightcrew under all foreseeable operating conditions, including conditions where multiple alerts are provided.
The absence of the words - MCAS or TRIM
Prioritize alerts so that the most urgent alert is presented first to the flightcrew. [AC 25.1322-1, 8]
Warning information must be provided to alert the crew to unsafe system operating conditions, and to enable them to take appropriate corrective action. Systems, controls, and associated monitoring and warning means must be designed to minimize crew errors which could create additional hazards. [14 CFR 23.1309(b)(3), 25.1309(c), 29.1309(c)]
Time-Critical Warnings
Some warnings may be so time-critical for the safe operation of the airplane that general alerts such as a master visual alert and a master aural alert may not provide the flightcrew with immediate awareness of the specific alerting condition that is commensurate with the level of urgency of flightcrew response necessary. In such cases, warning elements dedicated to specific alerting conditions should be provided that give the flightcrew immediate awareness without further reference to other flight deck indications. [AC 25.1322-1, 6.b]
Documentation should include the results of analyses and tests that show that any delayed or inhibited alerts do not adversely impact safety. [AC 25.1322-1, 8.a(5)]
When following the guidance in AC 25.1322-1, document any divergence, and provide the rationale for decisions regarding novel or unusual features used in the design of the alerting system. This will facilitate the certification evaluation because it will enable the FAA to focus on areas where the proposed system diverges from the AC and has new or novel features. [AC 25.1322-1, 13.b]
and finally, but not least; Workload
(c) Operationally-relevant behavior of the installed equipment must be:
(1) Predictable and unambiguous, and
(2) Designed to enable the flightcrew to intervene in a manner appropriate to the task.
(d) To the extent practicable, installed equipment must incorporate means to enable the flightcrew to manage errors resulting from the kinds of flightcrew interactions with the equipment that can be reasonably expected in service.
Relying on a requirement of “train to proficiency” may be unforeseeable, economically impracticable, or unachievable by some pilots without excessive mental workload as compensation. [AC 27-1B, AC 27.1303b(4)(ii)(B)(1); AC 29-2C, AC 29.1303b(4)(ii)(B)(1)]