4 ms·

I suspect the most interesting part of this is why, precisely: If this is a known bug, incorrect setting of the throttle and subsequent disconnect of the auto

by K0balt 2y ago

I suspect the most interesting part of this is why, precisely: If this is a known bug, incorrect setting of the throttle and subsequent disconnect of the auto throttle system, why is the aircraft still deemed airworthy while using the auto throttle during takeoff? How was using defective equipment critical to flight safety if engaged not specifically prohibited in an addendum to the POH? Because that would require additional training and be a bad look, that’s why, I suspect. If a FAR23 (light) aircraft had a defective throttle cable that sometimes failed to effect the commanded throttle setting under certain conditions, it would be grounded immediately pending remedial service or, if impossible, at least placarding of the prohibited configuration and modification to the POH to specified prohibit that configuration, as well as implicating changes into training materials if the aircraft fell into the high performance category. That Boeing is operating at a lower standard of flight safety than is typically required of SLA regulations is an indication of a deeply broken relationship with regulators.

kayodelycaon 2y ago
There was nothing wrong with the throttle controls or the engines. The engines were at commanded thrust. What happened was the autopilot (autothrottle) failed to engage. Pilots set manual thrust and rearmed the system. It didn’t engage. Then the pilots failed to verify engine performance or throttle position twice during takeoff. This is dangerously negligent because engine performance may not match throttle setting due to mechanical fault. The computers may or may not detect this. See: https://en.m.wikipedia.org/wiki/Air_Florida_Flight_90 https://en.m.wikipedia.org/wiki/Air_Florida_Flight_90
- K0balt 2y ago
  Exactly. The procedure of taking off with the auto throttles rather than manually controlling the engines should be prohibited in the POH if the software governing the flow of that procedure is unreliable. Sure, double checking it is a really great and necessary step, but you don’t throw down marbles on the floor in front of the aircrew, even if they should be able to step around them. Mistakes get made. Procedures botched, steps overlooked or conditioned by habit to be checked ok when they are not. Aviation safety is the result of defense in depth, layered mechanisms and procedures that make loss of life highly improbable. An aircraft that is faulty in a way that defeats these layers of safety is by definition not airworthy. Often, it can be made airworthy by a change of procedure, a change in operational regimes, or even by a placard on the dash. In this case, prohibiting the use of autothrottle takeofff until the software is reliable is probably indicated. Something that fails once in a while but usually works is often much more dangerous than something that just doesn’t work at all or is tagged out.

by K0balt 2y ago

kayodelycaon 2y ago

There was nothing wrong with the throttle controls or the engines. The engines were at commanded thrust. What happened was the autopilot (autothrottle) failed to engage. Pilots set manual thrust and rearmed the system. It didn’t engage. Then the pilots failed to verify engine performance or throttle position twice during takeoff. This is dangerously negligent because engine performance may not match throttle setting due to mechanical fault. The computers may or may not detect this. See: https://en.m.wikipedia.org/wiki/Air_Florida_Flight_90 https://en.m.wikipedia.org/wiki/Air_Florida_Flight_90

K0balt 2y ago
Exactly. The procedure of taking off with the auto throttles rather than manually controlling the engines should be prohibited in the POH if the software governing the flow of that procedure is unreliable. Sure, double checking it is a really great and necessary step, but you don’t throw down marbles on the floor in front of the aircrew, even if they should be able to step around them. Mistakes get made. Procedures botched, steps overlooked or conditioned by habit to be checked ok when they are not. Aviation safety is the result of defense in depth, layered mechanisms and procedures that make loss of life highly improbable. An aircraft that is faulty in a way that defeats these layers of safety is by definition not airworthy. Often, it can be made airworthy by a change of procedure, a change in operational regimes, or even by a placard on the dash. In this case, prohibiting the use of autothrottle takeofff until the software is reliable is probably indicated. Something that fails once in a while but usually works is often much more dangerous than something that just doesn’t work at all or is tagged out.