3 ms·

I'm learning today that black boxes don't have any sort of built-in emergency battery power, apparently. For a device that is meant to be a data gatherer up unt

by fooqux 2y ago

I'm learning today that black boxes don't have any sort of built-in emergency battery power, apparently. For a device that is meant to be a data gatherer up until the "last gasp" of the airplane, that seems like a pretty obvious design flaw to me. Does anyone know why?

Filligree 2y ago
It’s a mystery, and according to a cousin post, black boxes from planes manufactured recently do have backup power.
tgsovlerkhgsel 2y ago
Money. Adding a battery adds cost and weight (and complexity, but we know how to engineer and maintain things properly). The cost/weight would have been a lot more prohibitive decades ago when the rules were made, and regulators are slow to adapt.
- dredmorbius 2y ago
  And for every additional kilogram or pound of weight, a typical 2000mi / 3200 km flight will consume an equivalent mass of fuel. Conventional (fuel-powered) aircraft, and to an even greater extent battery-powered aircraft, are absolute marvels of light-weighting engineering, driven by both materials and designs. As FDR/CVR are used only once, and that in a vanishingly small fraction of aircraft, the cost considerations of carrying additional mass are high. It's not just the aircraft that crash, but all aircraft across the entire global commercial fleet. That's on the order of 32,000 aircraft presently, each with multiple flight cycles per day on average.[1] That's on the order of 50--100 tonnes of fuel consumption per day if the total added weight is limited to 1 kg. Black boxes must also survive crash conditions. A battery itself might be a fire risk, and would require additional material to protect both itself and the data storage of a black box in the event of an accident. That said ... one would think that current lightweight battery packs might make short-term battery operation reasonably viable. -------------------------------- Notes: 1. "Information supplied by aviation data specialists ch-aviation shows that at as of July 7, there were 31,734 civil aircraft in the global fleet being used by more than 750 different airlines. " <https://www.key.aero/article/how-many-commercial-aircraft-are-there-world https://www.key.aero/article/how-many-commercial-aircraft-ar...> Story appears to be from 2020 per Internet Archive: <https://web.archive.org/web/20200929012536/https://www.key.aero/article/how-many-commercial-aircraft-are-there-world https://web.archive.org/web/20200929012536/https://www.key.a...>.
  - fooqux 2y ago
    Thanks for that explanation. I didn't realize the fuel costs were quite so bad, and extrapolating it to all aircraft per day makes sense as well.
    - dredmorbius 2y ago
      Yes, that's a key point many advocates fail to consider (or express), and those concerns carry their own risks and costs, including of lives, though often indirect. As an example, what is the contribution of air travel to climate change and wildfire, such as those presently underway in Los Angeles and environs, now costing > 12,000 homes and 24+ deaths? Aviation overall is about 6% of global petroleum consumption as I recall, and safety systems would then be a pro-rated fraction of that. Another lesson of my IT career has been that a frequent cause of outages and risks is safety equipment itself. Failover routers that fail, failover power supplies that wipe out power, load balancers which lock up, firewalls that wall legitimate traffic, logging systems that fill disks, alerting and monitoring systems that overwhelm pagers and staff, etc., etc. Every technological mitigation has both benefits and costs, often manifesting in different timescales and conditions. We tend most often to adopt measures which promise quick and manifest results, or whose negative consequences are temporally distant and vague, but this also means that we underutilise those which offer distant and vague benefits (exercise, healthy eating, as the classics), or whose costs are manifest and immediate (again, exercise, various medical interventions such as exams and vaccinations, many safety measures and mitigations). Commercial jet aviation is remarkably safe, but that's come through an intense focus on safety at all levels, from aircraft to operators to air traffic to ground response and most critically to thorough evaluation of incidents. One consequence is that many notable recent events have come from one or more of those factors themselves: pilots intentionally crashing aircraft (GermanWings 4U9525, 2015; probably Malaysian Airlines 370; EgyptAir 990, 1999), by passengers (most notably the 9/11 attacks in the US, 2001), or by safety or compensatory equipment (most notoriously the Boeing 737 MAX MCAS system, and the crashes of Lion Air 610 and Ethiopian Air 302). As with many other technical and economic phenomena, arguments of marginal utility strongly trend to developments reaching a pain threshold where harms increase to balance benefits, making naive analysis difficult. (A realm in which this is probably evident to many HN readers is the tendency for software and online services to enshittify, in Cory Doctorow's marvelous coinage, to the point that they (attempt to) perch delicately on the threshold of fatal annoyance. A chief problem with such tactics are that the threshold itself is a remarkably unstable point, and induces its own further interactions and harms.)

by fooqux 2y ago

Filligree 2y ago

It’s a mystery, and according to a cousin post, black boxes from planes manufactured recently do have backup power.

tgsovlerkhgsel 2y ago

Money. Adding a battery adds cost and weight (and complexity, but we know how to engineer and maintain things properly). The cost/weight would have been a lot more prohibitive decades ago when the rules were made, and regulators are slow to adapt.

dredmorbius 2y ago
And for every additional kilogram or pound of weight, a typical 2000mi / 3200 km flight will consume an equivalent mass of fuel. Conventional (fuel-powered) aircraft, and to an even greater extent battery-powered aircraft, are absolute marvels of light-weighting engineering, driven by both materials and designs. As FDR/CVR are used only once, and that in a vanishingly small fraction of aircraft, the cost considerations of carrying additional mass are high. It's not just the aircraft that crash, but all aircraft across the entire global commercial fleet. That's on the order of 32,000 aircraft presently, each with multiple flight cycles per day on average.[1] That's on the order of 50--100 tonnes of fuel consumption per day if the total added weight is limited to 1 kg. Black boxes must also survive crash conditions. A battery itself might be a fire risk, and would require additional material to protect both itself and the data storage of a black box in the event of an accident. That said ... one would think that current lightweight battery packs might make short-term battery operation reasonably viable. -------------------------------- Notes: 1. "Information supplied by aviation data specialists ch-aviation shows that at as of July 7, there were 31,734 civil aircraft in the global fleet being used by more than 750 different airlines. " <https://www.key.aero/article/how-many-commercial-aircraft-are-there-world https://www.key.aero/article/how-many-commercial-aircraft-ar...> Story appears to be from 2020 per Internet Archive: <https://web.archive.org/web/20200929012536/https://www.key.aero/article/how-many-commercial-aircraft-are-there-world https://web.archive.org/web/20200929012536/https://www.key.a...>.
- fooqux 2y ago
  Thanks for that explanation. I didn't realize the fuel costs were quite so bad, and extrapolating it to all aircraft per day makes sense as well.
  - dredmorbius 2y ago
    Yes, that's a key point many advocates fail to consider (or express), and those concerns carry their own risks and costs, including of lives, though often indirect. As an example, what is the contribution of air travel to climate change and wildfire, such as those presently underway in Los Angeles and environs, now costing > 12,000 homes and 24+ deaths? Aviation overall is about 6% of global petroleum consumption as I recall, and safety systems would then be a pro-rated fraction of that. Another lesson of my IT career has been that a frequent cause of outages and risks is safety equipment itself. Failover routers that fail, failover power supplies that wipe out power, load balancers which lock up, firewalls that wall legitimate traffic, logging systems that fill disks, alerting and monitoring systems that overwhelm pagers and staff, etc., etc. Every technological mitigation has both benefits and costs, often manifesting in different timescales and conditions. We tend most often to adopt measures which promise quick and manifest results, or whose negative consequences are temporally distant and vague, but this also means that we underutilise those which offer distant and vague benefits (exercise, healthy eating, as the classics), or whose costs are manifest and immediate (again, exercise, various medical interventions such as exams and vaccinations, many safety measures and mitigations). Commercial jet aviation is remarkably safe, but that's come through an intense focus on safety at all levels, from aircraft to operators to air traffic to ground response and most critically to thorough evaluation of incidents. One consequence is that many notable recent events have come from one or more of those factors themselves: pilots intentionally crashing aircraft (GermanWings 4U9525, 2015; probably Malaysian Airlines 370; EgyptAir 990, 1999), by passengers (most notably the 9/11 attacks in the US, 2001), or by safety or compensatory equipment (most notoriously the Boeing 737 MAX MCAS system, and the crashes of Lion Air 610 and Ethiopian Air 302). As with many other technical and economic phenomena, arguments of marginal utility strongly trend to developments reaching a pain threshold where harms increase to balance benefits, making naive analysis difficult. (A realm in which this is probably evident to many HN readers is the tendency for software and online services to enshittify, in Cory Doctorow's marvelous coinage, to the point that they (attempt to) perch delicately on the threshold of fatal annoyance. A chief problem with such tactics are that the threshold itself is a remarkably unstable point, and induces its own further interactions and harms.)