I’m more concerned about the failure mode than the failure rates. Mechanical and hydraulic brakes can experience gradual failure, giving the driver a chance to pull over get the car repaired.
EVs usually have a single motor and a single inverter , both of which can fail suddenly. Electronics usually work perfectly fine until they suddenly don’t work at all (blown fuse, bad connection, blown capacitor etc)
How are they gonna build redundancy so that no single component failure means youre freewheeling downhill on the highway
That’s the real difference to me, maintenance. Planes have a strict schedule of inspection and replacement. Moms minivan last saw an oil change before the kids made it to middle school. There’s going to be some failures.
I mean, airplane brakes probably have about a 3% duty cycle (the percentage of time they’re in use), so they’re generally idle. For city driving, car brakes probably have about a 25% duty cycle.
If those numbers are close to accurate, that means planes are using their brakes about 10x less than cars.
BTW, I didn’t pull those plane numbers directly out of my ass, but they’re definitely a rough estimate. I’m figuring about 5 minutes of breaking time per flight, counting landing and during the taxi to and from the runway. And I’m assuming a 2.5 hour flight, figuring that could be close to an average flight time.
That’s going to be very interesting to see failure rates and modes on the road over time.
We at least know it could potentially have really low failure rates since airplanes have the same type of systems today, and that’s highly regulated
I’m more concerned about the failure mode than the failure rates. Mechanical and hydraulic brakes can experience gradual failure, giving the driver a chance to pull over get the car repaired.
EVs usually have a single motor and a single inverter , both of which can fail suddenly. Electronics usually work perfectly fine until they suddenly don’t work at all (blown fuse, bad connection, blown capacitor etc)
How are they gonna build redundancy so that no single component failure means youre freewheeling downhill on the highway
Do people really think Professional Engineers are stupid?
No, but their bosses might be.
Brakes on airplanes are used infrequently (though when they’re used, they’re safety-critical) so the usage pattern is very different than for cars.
And inspected after every use.
That’s the real difference to me, maintenance. Planes have a strict schedule of inspection and replacement. Moms minivan last saw an oil change before the kids made it to middle school. There’s going to be some failures.
Does at least once per flight really count as “infrequent?”
I mean, airplane brakes probably have about a 3% duty cycle (the percentage of time they’re in use), so they’re generally idle. For city driving, car brakes probably have about a 25% duty cycle.
If those numbers are close to accurate, that means planes are using their brakes about 10x less than cars.
BTW, I didn’t pull those plane numbers directly out of my ass, but they’re definitely a rough estimate. I’m figuring about 5 minutes of breaking time per flight, counting landing and during the taxi to and from the runway. And I’m assuming a 2.5 hour flight, figuring that could be close to an average flight time.