Boeing remains to be in hot waters. After an unprecedented presentation by European Union Airline Safety Agency (EASA), the head of this organization Patrick Ky expressed skepticism of Boeing/FAA safety standards and pledged a tougher stance on ungrounding the deadly Boeing 737 MAX,
FlyersRight.org was granted an exclusive interview.
FlyersRights: With MCAS (Maneuvering Characteristics Augmentation System), Boeing has apparently added a form of envelope protection to the 737 MAX. We believe that MCAS is implemented in the Rockwell-Collins EDFCS-730 autopilot/flight control computer(s) (FCC). The architecture of the 737 MAX FCC appears to be considerably more primitive and limited when compared to the architecture of the A320neo envelope protection system. Particularly in the areas of sensor redundancy, self-diagnosis and software heterogeneity (we believe the software is single-sourced).
What, if any, effects on EASA’s certification process might the above have?
We believe that the master minimum equipment list for the A320 series does not allow flight if any of the heaters for the three angle of attack sensors are inoperative. The master minimum equipment list for the 737 MAX appears to allow flight if either or both of the two angle of attack sensor heaters is inoperative.
FR: The nature of the 737 MAX’s airframe stability with MCAS disabled is unknown. If EASA determines that the 737 MAX airframe is unacceptably unstable with MCAS disabled what effect could that have on pilot training requirements? In particular, could a MCAS failure in-flight constitute an emergency situation?
What, if any, effects on EASA’s certification process might the above have?
EASA: Aircraft longitudinal stability is subject to airworthiness requirements. Boeing has to demonstrate compliance of the 737 MAX airframe with these requirements. Consequences of failures of systems affecting potentially the aircraft stability need to be assessed using acceptable safety analysis methodology also subject to airworthiness requirements. Pilot training requirements are not meant to compensate for non-acceptable design on the compliance and safety standpoint.
We believe that Boeing largely or entirely self-certified the 737 MAX airframe, including the flight control computer software, under the FAA’s Organization Designation Authorization (ODA) program.
FR: What is EASA’s position on self-certification? Going forward, will EASA view the airworthiness of US aircraft certified under the ODA system as equivalent to aircraft certified by the FAA, using its own personnel?
EASA: Some investigations are ongoing on the certification process followed by the FAA in the case of the B737 MAX. EASA do not wish to comment on the presumable “self-certification” or on the level of delegation to Boeing that the FAA has granted.
FR: Boeing and a US Advisory panel have taken the position that software-only changes are needed. Specifically, that no hardware changes, no aircraft redesign and no pilot retraining on full-motion MAX simulators are necessary to unground the aircraft. Does EASA agree?
EASA: Our design review is not completed yet and we have not reached a conclusion yet on that matter.
Will EASA be flight-testing the MAX using its test pilots with MCAS and flight automation disabled, or rely on Boeing and FAA testing?
Among the next milestones are flight tests performed by EASA on a modified Boeing 737 MAX that will last a full week.
What is the EASA position on pilot simulator training for Emergency conditions?
EASA: Our review of pilot training requirements is not completed yet and we have not reached a conclusion yet on that matter.
What is EASA position, if any, on restrictions of planes in hot weather especially at high altitude airports?
EASA: Investigation of the accident is on-going and we do not wish to comment on this. Airplanes are certified with an operational envelope and with limitations on the weather conditions and airfield altitude for take-off.
Not Reassuring The Flying Public
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- Additionally, the automation philosophy between the 737 and the A320neo appears to differ in that the A320neo system incrementally gives more control to the pilots, through flight control law progression, in response to system fault and/or failure.
- EASA do not wish to comment on the presumable “self-certification” or on the level of delegation to Boeing that the FAA has granted.
- We believe that the master minimum equipment list for the A320 series does not allow flight if any of the heaters for the three angle of attack sensors are inoperative.