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0 pointsseo-speedwagon3y ago0 comments

A long time ago I was on a FAA certification test flight where we tested maximum braking. I wasn’t in the flight deck, so I don’t know if it was literally true, but it was described as “pilot standing on the brakes” and it sure felt that way. All our equipment was strapped down and when the pilot hit the brakes for our first test my glasses flew off my face. Those brakes are no joke

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techdragon3y ago

Maximum breaking, is powerful stuff… Real red hot metal and tolerances engineering stuff. You have to be able to stop the airplane at it’s maximum take off weight at the maximum takeoff ground speed (got to account for tail winds) within the acceptable safety stopping distance on the runway, and they have to sit there after this without any help for several minutes to represent the time it can take to scramble ground safety and rescue crews to assist... On big jets this involves sacrificing the breaks and often even the tires, as the breaks get glowing red hot and the heat radiating off them will be strong enough to heat up the air in the planes tires to the point that safety systems like fusible plugs/patches designed to melt (but not break from normal pressure) kick in and the tires blow out the plugs and deflate due to the exposure to sheer heat coming off the breaks as they sit there for a few minutes soaking in the heat from the red hot breaks…

Good video of the test conditions for a 747-8 here https://youtube.com/watch?v=qc_v6tXsv6g

ip263y ago

The classic:

https://m.youtube.com/watch?v=qew09gao3S8

In short, the whole brake assembly catches fire- and continues to operate.

techdragon3y ago

Definitely a much better view of the brake assembly and the extreme forces they deal with. I’d forgotten how much the sound reminds me of a sort of bad off key imitation of the “Deep Note” Dolby THX intro sound. As the rotation speed slows it pitches down the frequency scale into more audible tones and sounds slightly louder as the microphone picks it up better and then it fades out towards the end.

I do think it even though it’s a better brake mechanism video it’s not quite as visually impressive as watching a 747-8 just about to nose up suddenly nosing down as it slams on the brakes and they come to a stop in a dissipating cloud of smoking revealing the red hot brakes glowing in the wheels.

HeyLaughingBoy3y ago

s/breaks/brakes

techdragon3y ago

Phone autocorrect ducking sucks at times. ;-)

j / k navigate · click thread line to collapse

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techdragon3y ago

Good video of the test conditions for a 747-8 here https://youtube.com/watch?v=qc_v6tXsv6g

ip263y ago

The classic:

https://m.youtube.com/watch?v=qew09gao3S8

In short, the whole brake assembly catches fire- and continues to operate.

techdragon3y ago

HeyLaughingBoy3y ago

s/breaks/brakes

techdragon3y ago

Phone autocorrect ducking sucks at times. ;-)

j / k navigate · click thread line to collapse