When I was a newly minted driver (16 years old) I was driving home alone in the winter. I was in our subdivision, no traffic and I was going maybe 20 mph but the local roads had not been plowed so were covered in compacted snow from other cars.
I hit an icy patch and the car started sliding towards the side of the road (ditch and trees) and my steering inputs weren’t working.
Every fiber of my being wanted to stomp on the brakes but I knew (from training and only a little experience) that locking up the wheels (before anti-lock was common…I didn’t have it) was the sure way to careening off the side of the road. I waited and eventually the wheels got some grip and the car turned away and all was fine.
But I will never forget me literally fighting my instinctive reaction with my foot hovering over the brakes and wanting so bad to stomp on them and trying to override that instinct. It was a close run thing.
I can’t imagine getting into a scary situation while flying as a student pilot and having to have that mental battle.
A big component of any sort of training is to overcome our instincts, and specifically to do the right thing when there isn’t the time to think through the right course of action. Good on your for keeping your cool!
A number of automotive features are designed to translate instinct into the right action. ABS itself, for one. It’s unambiguously worse than just modulating the brake force correctly, but since you can’t depend on people doing that, it ends up being safer. And ironically, many cars now have an opposite feature–to boost the brake force beyond what the user input. People don’t always brake as hard as they should, but if you can detect sudden braking (maybe combined with radar), it ends up being a good idea to brake harder than the pedal input.
Based just on that video w no other info I’m going to suggest the crew probably had no immediate idea anything was amiss. If the tower controller was looking right at them when whatever failed failed, they might have had time to radio a warning before the gear was selected up.
But you’re on the right track. For sure, any time you know anything is amiss with the gear, Rule One is “don’t retract anything”.
I’d bet the one brake was dragging throughout taxi & takeoff and finally achieved its design max heat input after they broke ground. From the pic alongside the vid it appears the wheel & tire departed, which suggests most of the brake assembly was still on the axle. Since they then flew to the USA, obviously they retracted the gear at some point before too much unplanned fuel was burned.
Circumstantially I tentatively conclude they raised gear as normal & pressed on unaware of what happened until later.
Brake temperature indicators are available options on most (all?) Boeing airplanes, but for that to be useful management needs to have chosen that option and you have to think to actually look at them.
The non-Boeing MD-80 had brake temp indicators and there was an ops limit for a max brake temp to start takeoff roll. So it was a formal part of the “are we really ready to go right now” checks to look at the needles vs. the redline.
Conversely, the 757/767 did not have a formal ops limit for brake temp. Which is how they get away with making the instrument optional. Some, not all, of our 757s and 767s had them, but the display was hidden on a back page / screen and were never looked at unless something else directed you to them. Like maybe a loud Boom! just after liftoff.
Indicators or not, I’ve never flown a Boeing jet that had brake overtemp warnings built into the automatic warning system. The 747-400 may well have that though; I just don’t know.
Wheel wells have an area overtemp sensor that would pretty quickly detect then sound the fire alarm for a tire or brake fire once the gear is retracted & the doors closed to contain the heat. But I doubt a single stupid-hot brake would trigger that warning.
If a wheel well fire alarm sounds, the general response is to lower the gear to blow out the fire, cool the very hot gear parts, and prevent overheating any of the other delicate crap in the gear well. Then after a few minutes, go land someplace. Not proceed across an ocean. So it’s a good bet they did not receive a wheel well fire warning.
Very interesting. Thanks. I’m amazed this wasn’t reported when it was recorded. Maybe the person recording it didn’t realize the wheel came off until later. Can you imagine a mechanic being the first to discover it and telling the Captain he needs to offload a wheel from the fly-away inventory because…
On your pre-departure walk around how many wheels did you see?
Every now and then a wheel falls off. As we saw, it ended up having a LOT of kinetic energy and speed when it got back to ground level. Sometimes they end up well beyond the airfield boundary having bounced / rolled merrily along the runway or nearby grass until it penetrates the perimeter fence and enters city traffic still going north of 100mph. While weighing at least a couple hundred pounds.
I hate it when that happens.
The industry has lots of experience w missing main wheel landings. Obviously a bigger deal on an A320 or B-737 where one main wheel is 1/4 = 25% of the total main wheels, versus a 747 where it’s 1/16 = 6.25% of the total main wheels. As long as you’re not also dealing with a short runway or a crappy slam-it-on landing it’s not a big deal.
Agree that dragging brakes ought not depart the wheel
But perhaps a bearing failure might. Or the retention nut wasn’t properly secured and started to work off, allowing the wheel to chatter back & forth on the axle until the axle failed from unexpected loads or bashing damage or the bearing(s) got wrecked and it pounded itself off the axle.
Planes are assembled so that nuts and bolts can’t back out They use wire nuts which are wired in place or are pinned with a cotter pin. Tires are filled with nitrogen which take heat better than air. but brakes tend to be a weak point. When you’re slowing down hundreds of thousands of lbs of weight they get HOT. I’m surprised that they don’t incorporate a water injection system on brakes to keep them from overheating. I’ve seen smoke coming off the brakes of a recently parked 747 and screamed at people to get away from them.
If an entire wheel assemble came off a plane that’s a part that has completely failed and sheered off.
No. They’re just part of whatever uniform the employer decides to design. There is a convention that the captain has four bars, the first officer three bars and lower ranked pilots two bars etc, but each company can do what they like.
But the number of accidents from wheels falling off are negligible compared to the number of wheels falling off. Which are in turn a negligible fraction of all flights. Damn near zero times damn near zero is a very very small and, at least to me, a very reassuring number.
Wheels falling off cars, trucks, or airplanes have a certain slapstick madcap humor to them. Dangerous to everyone around who’s not inside the vehicle the wheel came from, but funny nevertheless.
