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> And, "hopelessly intertwined"? Is that your viewpoint as a software developer, or are you an aircraft designer? Because I'm sure that an outsider would see my

> And, "hopelessly intertwined"? Is that your viewpoint as a software developer, or are you an aircraft designer? Because I'm sure that an outsider would see my code as "hopelessly intertwined" even when it isn't. Even with modern aircraft, even with the A380, when a fan lets go or the engine grenades bad things happen. Qantas Flight 32, an A380, suffered a UCE and everyone was very lucky that there were additional, experienced pilots on board. Take a look at the ATSB report. Pretty much everything that could fail, did. Engine control for the #1 (IIRC) engine had been destroyed and it took the firefighters three hours to pump enough water to shut down the engine. Without the extra crew things could have gone very differently. British Airways 2276, a 777 -- a plane that has an excellent safety record, suffered a UCE and the plane caught fire. Luckily the pilots were able to abort the takeoff, but fire on a plane is about the worst possible failure mode. AA #383, a 767, also suffered a UCE on takeoff that resulted in a massive fire. Cameroon Airlines Flight 786, same deal. UCE, punctured fuel tank, fire. So, yes, things have almost certainly gotten better but given how much energy is released when a high bypass turbofan lets go, it's pretty damn hard to design something that's completely failsafe.

eesmith 9y ago
Sure. But do all those correct statements mean that the A380 hydraulic control systems, and their backups, are "hopelessly intertwined" to an aircraft designer?
- inferiorhuman 9y ago
  > Sure. But do all those correct statements mean that the A380 hydraulic control systems, and their backups, are "hopelessly intertwined" to an aircraft designer? I'd hope so, given that all the redundancy didn't prevent an engine control failure on the A380.
  - eesmith 9y ago
    I don't see your point. Redundancy is meant to make things more survivable in case of failure. It is not meant to prevent failure. Everyone survived. As for Qantas Flight 32, which I believe is the engine control failure you are referring to, my reading of http://www.atsb.gov.au/media/4173625/ao-2010-089_final.pdf http://www.atsb.gov.au/media/4173625/ao-2010-089_final.pdf says that only one hydraulic system, Green, was damaged. The redundancy worked. > Damage to the wiring also resulted in the loss of monitoring capability of the Yellow hydraulic system engine-driven pumps on the No. 4 engine and the crew disconnected both pumps as per the ECAM procedure. The Yellow hydraulic system was powered by the No. 3 engine for the remainder of the flight. The Yellow hydraulic system maintained 5,000 psi for the remainder of the flight and subsequent examination found no fluid loss. The inability to shut down engine #1 was due to "[d]amage to wiring looms located in the left wing and the fuselage belly fairing." Again I ask why "hopelessly intertwined" is a meaningful description for the A380 hydraulic control systems.

eesmith 9y ago

Sure. But do all those correct statements mean that the A380 hydraulic control systems, and their backups, are "hopelessly intertwined" to an aircraft designer?

inferiorhuman 9y ago
> Sure. But do all those correct statements mean that the A380 hydraulic control systems, and their backups, are "hopelessly intertwined" to an aircraft designer? I'd hope so, given that all the redundancy didn't prevent an engine control failure on the A380.
- eesmith 9y ago
  I don't see your point. Redundancy is meant to make things more survivable in case of failure. It is not meant to prevent failure. Everyone survived. As for Qantas Flight 32, which I believe is the engine control failure you are referring to, my reading of http://www.atsb.gov.au/media/4173625/ao-2010-089_final.pdf http://www.atsb.gov.au/media/4173625/ao-2010-089_final.pdf says that only one hydraulic system, Green, was damaged. The redundancy worked. > Damage to the wiring also resulted in the loss of monitoring capability of the Yellow hydraulic system engine-driven pumps on the No. 4 engine and the crew disconnected both pumps as per the ECAM procedure. The Yellow hydraulic system was powered by the No. 3 engine for the remainder of the flight. The Yellow hydraulic system maintained 5,000 psi for the remainder of the flight and subsequent examination found no fluid loss. The inability to shut down engine #1 was due to "[d]amage to wiring looms located in the left wing and the fuselage belly fairing." Again I ask why "hopelessly intertwined" is a meaningful description for the A380 hydraulic control systems.