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F-35 pilot held 50-minute airborne conference call with engineers before crash

cnn.com

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Re: F-35 pilot held 50-minute airborne conference call with engineers before crash

#381

Post by LorenPechtel »

the__alchemist wrote: post #138
crote wrote: post #97

Earlier quoted context omitted.

It makes you wonder if it would be possible for ejection seats to have a safer bailout mode. Sure, the "compress your spine" mode is definitely appropriate during a wartime situation where someone has shot your wings off, but is it really required when a mechanical failure leaves you unable to land yet in a more-or-less stable flight at a reasonably low speed? Perhaps a 6g ejection might be more appropriate in those…

I wonder about that. Maybe the added complexity is a con? I.e. the default would still be full force, but a controlled ejection mode could be gentler, but still capable of clearing the aircraft reliably in straight/level flight.

Straight and level isn't the issue, airspeed is.

Re: F-35 pilot held 50-minute airborne conference call with engineers before crash

#382

Post by LorenPechtel »

gchadwick wrote: post #232
SteveNuts wrote: post #196

Earlier quoted context omitted.

For airliners, it's critical for the aircraft to know when it's on the ground because it kicks on autobrakes, and unlocks the thrust reversers for landing. I'm very curious what the reasons would be for a military aircraft

If either of those accidentally triggered in the air would anything catostrophic happen? Auto breaks I guess have no effect in the air as they break the wheels? Thrust reverse unlock sounds like it allows thrust reversers but the pilot would still have to manually activate them? Someone else was talking about a WoW (weight on wheels) sensor that locks the landing gear down with no manual override but again doesn't so…

There have been problems with thrust reversers deploying in flight, I do not recall the details of why.

Re: F-35 pilot held 50-minute airborne conference call with engineers before crash

#383

Post by wiml »

mrguyorama wrote: post #378
Bjartr wrote: post #372

Earlier quoted context omitted.

That's actually a really cool way to deal with that problem!

It is. Right up until you go to hit your brakes hard and it all boils out and removes your ability to apply brake pressure in an emergency and you had no idea how much water was in your line because there's no easy way to check, like a low spot with a sight glass. Or if you leave a barrel of hydraulic fluid outside until it is partially water and it's not easy to notice when you are handling it.

I think my mental model of hydraulic brakes is too simple. Where is there a low pressure region in a brake line? When I stomp on the brakes, isn't the working part of the hydraulic system going to be at higher pressure?

Re: F-35 pilot held 50-minute airborne conference call with engineers before crash

#384

Post by avs733 »

jasonlotito wrote: post #333
avs733 wrote: post #305

Earlier quoted context omitted.

To clarify because everyone is confused here. The report is a little vague and information is buried in a couple places. Using PDF page numbers > "The MP responded “14.5” ... and then opined a “conference hotel” was appropriate for this situation (Tab N-12)." (pg. 13) > "The MP, utilizing the on-duty supervisor of flying (SOF) in the air traffic control (ATC) tower, initiated a conference call with Lockheed Martin (L…

> If you want to harp on CNN for accuracy, I'm sure there are plenty of opportunities but this feels pedantic. It is like saying 'the astronauts weren't talking to mission control, they were talking to the capcom. Only the capcom talked to mission control'. Um, actually, they were talking to a mic. And the mic converted the noise... /s But yeah, excellent comment here.

I’m sorry but it’s not noise its an electrical signal

(This argument also failed to convince my mom my teenage band didn’t suck)

Re: F-35 pilot held 50-minute airborne conference call with engineers before crash

#385

Post by etler »

diggan wrote: post #267
dfox wrote: post #223

The article is somewhat sensationalistic. If you read the actual report you will find out that: The pilot was not part of the conference call! What froze was not hydraulic fluid for actuators (in some hydraulic line), but hydraulic fluid in the shock absorbers. The last paragraph of the article and seems to be missing a few words and reads as the investigators blaming the people directly involved, which is essentiall…

> The article is somewhat sensationalistic somewhat sensationalistic?! The article clearly tries to give the impression the pilot was on the call: > A US Air Force F-35 pilot spent 50 minutes on an airborne conference call with Lockheed Martin engineers trying to solve a problem with his fighter jet before he ejected Knowing the quality of media these days, it wouldn't surprise me if it CNN just got it really wrong,…

I think there's just some nuance to the scenario. The pilot wasn't directly on the call, but was participating in the call with the flight supervisor relaying the information.

I'd compare it to being in the room with someone on a conference phone call and they're relaying the conversation to you and them both ways. I would still say you were participating in the call even though you weren't directly on the call.

Also, he did initiate the call so "F-35 pilot held" is imprecise, but not totally wrong. Either way, the pilot was in an active tech support session with the plane engineers, making this one of the most intense tech support calls in history.

Re: F-35 pilot held 50-minute airborne conference call with engineers before crash

#386

Post by etler »

dfox wrote: post #223

The article is somewhat sensationalistic. If you read the actual report you will find out that: The pilot was not part of the conference call! What froze was not hydraulic fluid for actuators (in some hydraulic line), but hydraulic fluid in the shock absorbers. The last paragraph of the article and seems to be missing a few words and reads as the investigators blaming the people directly involved, which is essentiall…

The call was being relayed to the pilot by the flight supervisor. While he wasn't "on" the call, I think it's fair to say he was "part" of the call. He's still getting live tech support and trying to trouble shoot the plane while flying it. He had an intermediary but I don't think that totally changes the scenario.

Re: F-35 pilot held 50-minute airborne conference call with engineers before crash

#387

Post by somerandomqaguy »

mrguyorama wrote: post #378
Bjartr wrote: post #372

Earlier quoted context omitted.

That's actually a really cool way to deal with that problem!

It is. Right up until you go to hit your brakes hard and it all boils out and removes your ability to apply brake pressure in an emergency and you had no idea how much water was in your line because there's no easy way to check, like a low spot with a sight glass. Or if you leave a barrel of hydraulic fluid outside until it is partially water and it's not easy to notice when you are handling it.

Can't agree at all about a sight glass. The lowest point in nearly every brake system is the brake calipers themselves. Wheels going to make it difficult anyways on a car. Not to mention the risk of a rock striking and damaging rigid glass. Or the old interface that's sealing the glass to the calipers wearing out and causing a leak.

It's not worth the expense to manufacture and it's not worth the risk. Not when a litre of DOT4 is $20 and that only needs replacing every 3 years at an aggressive schedule for passenger cars.

Larger vehicles you can purchase a brake fluid tester, but most of the really large ones I know use air brakes anyways.

Re: F-35 pilot held 50-minute airborne conference call with engineers before crash

#388

Post by mrguyorama »

aduty wrote: post #32
mbirth wrote: post #12

Earlier quoted context omitted.

I bet, once the gear malfunctioned, Clippy popped up on the screen and suggested to call support.

Hey, all Clippy ever wanted to do was help.

Clippy never sold my data. Clippy never forced me to update when I didn't have time. Clippy never advertised things to me. Clippy never lied to me. Clippy didn't take hundreds of watts of power to provide incorrect answers.

Clippy was an assistant, built to help me solve problems I didn't understand, and built to help computer illiterate people use their computers more effectively and was made out of genuine expressions of making their product better for more people.

Re: F-35 pilot held 50-minute airborne conference call with engineers before crash

#389

Post by somerandomqaguy »

wiml wrote: post #383
mrguyorama wrote: post #378

Earlier quoted context omitted.

It is. Right up until you go to hit your brakes hard and it all boils out and removes your ability to apply brake pressure in an emergency and you had no idea how much water was in your line because there's no easy way to check, like a low spot with a sight glass. Or if you leave a barrel of hydraulic fluid outside until it is partially water and it's not easy to notice when you are handling it.

I think my mental model of hydraulic brakes is too simple. Where is there a low pressure region in a brake line? When I stomp on the brakes, isn't the working part of the hydraulic system going to be at higher pressure?

There isn't a low pressure braking region in the brakes.

But brakes can get really hot. Passenger brakes can easily get over the boiling point of water. Keep braking long enough and adding enough heat, and they'll get over the boiling point of brake fluid under pressure.

Thing is, brake fluid is incompressible. Brake fluid vapor however is very much so a compressible gas. Even more so: the water in the brake fluid has an even lower boiling point then that.

So stomping on the braking quickly isn't going to cause much of a problem. But if your riding the brakes down hill for a long distance with 12 year old brake fluid in hot Florida summer on very heavily loaded car? That... might get you into a spot of trouble.

Re: F-35 pilot held 50-minute airborne conference call with engineers before crash

#390

Post by potato3732842 »

foxyv wrote: post #368
potato3732842 wrote: post #213

Everyone in these comments making quips about software is missing the elephant in the room, where the heck did that water in the hydraulic system come from? Pretty much any hydraulic fluid for outdoor use will suck up a lot of water so as to prevent situations like this so this clearly isn't a teaspoon or even cups of condensation problem.

Hydraulic fluid is very hydroscopic. It will happily suck the moisture out of the air if it is exposed long enough. This is why you don't use half empty bottles of brake fluid. I suspect that the fluid was left in opened containers for too long before being installed in the jet, allowing it to load up on water.

You are massively mixing things up.

Water boils/evaporates off from oil based fluids in normal operation. Hydraulic fluid additives don't suck up water like brake fluid, they just mix with it if present, and they can't mix with all that much. If these first two things weren't true it would have huge implications for the design of all sorts of things. If hydraulic fluid could mix with a lot of water we wouldn't be reading this story.

I assume these jets use skydrol. I'm only casually familiar with it but unaware of it having special water related properties that differ from normal petroleum products.

Glycols are a different story.

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