Aeronautical Insanity: switching to secondary tolerances

The Something Awful Forums > Discussion > Automotive Insanity > Aeronautical Insanity: switching to secondary tolerances

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vessbot: Jun 17, 2005; I don't like you because you're dangerous

ranbo das posted:

Genuine question: shouldn't planes be smart enough to be able to bring themselves down in altitude in the case of depressurization? Like obviously we're not at "autopilot land the plane" yet but you would think they could step down in altitude to at least theoretically allow someone to recover.

I know I'm making it sound easier than it is but also doesn't seem impossible or even improbable.

Some of the very newest, do.

# ? Sep 5, 2022 16:25

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# ? May 24, 2024 19:51

MrYenko: Jun 18, 2012; #2 isn't ALWAYS bad...

ranbo das posted:

Genuine question: shouldn't planes be smart enough to be able to bring themselves down in altitude in the case of depressurization?

Gulfstreams have had this for a bunch of years now.

ranbo das posted:

Like obviously we're not at "autopilot land the plane" yet but you would think they could step down in altitude to at least theoretically allow someone to recover.

https://youtu.be/IyYxbiZ1FCQ

This is currently available on new TBMs, at the very least. I think Piper Meridians and some others as well.

# ? Sep 5, 2022 16:31

slidebite: Nov 6, 2005; Good egg

MrYenko posted:

This is currently available on new TBMs, at the very least. I think Piper Meridians and some others as well.

That's pretty nifty. How does it work it with ATC? How does it know what to squawk/change frequencies?

# ? Sep 5, 2022 16:48

babyeatingpsychopath: Oct 28, 2000; Forum Veteran

ranbo das posted:

Genuine question: shouldn't planes be smart enough to be able to bring themselves down in altitude in the case of depressurization? Like obviously we're not at "autopilot land the plane" yet but you would think they could step down in altitude to at least theoretically allow someone to recover.

I know I'm making it sound easier than it is but also doesn't seem impossible or even improbable.

It's not impossible, but it's also not EASY.

The Cessna 551 (incident aircraft) was first flown in 1977 or something. Depending on the age of the aircraft, it may not have systems installed that will talk to each other. That is, the GPS system may only be able to give heading cues to the autopilot (not elevation), unless in a specific mode. There are actual physical banks of relays in the nose that switch inputs to the (analog) autopilot computer when going into ILS mode, for example.

There may not be a terrain avoidance system installed, so a na�ve implementation could have the plane fly down to 10,000 or 12,000 feet or something and stick itself into the side of a mountain. That's going to be a hard sell to get approved by the FAA or other governing body.

There are also completely independent systems in place that pop the masks when cabin altitude climbs above 14,000 feet. If the masks drop, you descend immediately. Why that didn't happen in this case is unclear. It's possible that the depressurization event was so slow that the pilots became hypoxic and passed out before reaching the mask altitude; I hope the investigation can provide some answers (in a few years).

edit:

slidebite posted:

That's pretty nifty. How does it work it with ATC? How does it know what to squawk/change frequencies?

Since the entire avionics stack is integrated, the flight system is talking to the GPS/nav, radios, transponder, autopilot, front displays, infotainment system, etc. There was a Cirrus with the tech being demoed that would squawk 7600 and play a recorded message on guard to the effect of "this airplane is going to autoland; closest airport is <x> and the selected runway is <y>". It could also blank out the displays and a happy paperclip would show up on the passenger's side saying "it seems like your pilot is incapacitated. Would you like to learn how to land an airplane?"

babyeatingpsychopath fucked around with this message at 16:54 on Sep 5, 2022

# ? Sep 5, 2022 16:50

Midjack: Dec 24, 2007

mobby_6kl posted:

How could this be possible? Even if there was a depressurization, wouldn't people pass out in their seats? Or was everyone including the pilots having a party in the cabin when it happened?

https://en.wikipedia.org/wiki/Helios_Airways_Flight_522

If you get hypoxic there's no telling what you'll do as parts of your brain start turning off. The description in the link I posted says that the intercepting fighters saw the first officer slumped in his seat but the captain's seat was empty.

# ? Sep 5, 2022 16:55

BIG HEADLINE: Jun 13, 2006; "Stand back, Ottawan ruffian, or face my lumens!"

Yeah, there's a relatively recent video on YouTube of one of those science guys undergoing high altitude training at the Air Force's test chamber and they measure his blood oxygen level past ~FL250 without oxygen and his self-preservation instinct just goes out the window.

Here it is: https://youtu.be/kUfF2MTnqAw

# ? Sep 5, 2022 17:10

Plastic_Gargoyle: Aug 3, 2007

https://flic.kr/p/2nJHtja

Until someone in Ireland comes up with EI-EIO, I think this wins best reg.

# ? Sep 5, 2022 19:23

Beef Of Ages: Jan 11, 2003; Your dumb is leaking.

Plastic_Gargoyle posted:

https://flic.kr/p/2nJHtja

Until someone in Ireland comes up with EI-EIO, I think this wins best reg.

James May had G-OCOK at one point.

# ? Sep 5, 2022 20:15

MrYenko: Jun 18, 2012; #2 isn't ALWAYS bad...

slidebite posted:

That's pretty nifty. How does it work it with ATC? How does it know what to squawk/change frequencies?

As mentioned a few posts up, it squawks emergency (which is glaringly obvious to any radar facility in a couple hundred miles,) and announces on guard what it�s going to do. We then make a giant hole in the sky to let it do it�s thing. I got to hear one of the test run announcements on guard when Piper was certifying theirs; It�s pretty slick.

One video I saw about it from Garmin mentions that from their point of view, the hardest part of the entire project was getting the buy-in from the airframe manufacturers to install actuators for the brakes. All of the other elements of the system were either already in place, or just software. The brakes were the last piece of the puzzle that allowed the system to work.

# ? Sep 5, 2022 20:50

illectro: Mar 29, 2010; ROCKET SCIENCE

Hullo, I'm Scoot Moonbucks.
Please stop being surprised by this.

The cirrus I fly has an autopilot with the aviation equivalent of a screensaver timeout, if you�re above altitudes where oxygen may be needed and you stop doing things on the control panel it�ll alert you, and if you don�t respond it�ll descend to lower altitudes.

# ? Sep 5, 2022 21:47

Nebakenezzer: Sep 13, 2005; The Mote in God's Eye

Thread favorite Learjet had a teeny tiny flaw where in a loss of cabin pressurization getting oxygen to the aircrew was just a smidge too slow to be useful

# ? Sep 5, 2022 22:22

PT6A: Jan 5, 2006; Public school teachers are callous dictators who won't lift a finger to stop children from peeing in my plane

I think I saw in that story a sentence about "pressurization system not working as expected" in which case, uh, don't climb to altitudes where it's necessary or don the mask before you think you need it.

My current pet peeve as an active pilot is any circumstance where we ignore poo poo because it would be inconvenient to alter the flight, snag the plane and have it properly fixed. There's no loving place for that stupid poo poo when we're doing something as relatively unsafe as aviation; we can make it exceptionally safe, but only if we never, ever put up with bullshit.

Normalization of deviance is exceptionally dangerous and we need to address it at all levels. Transport-category operators are, pretty much across the world, on top of that poo poo. GA isn't, and it kills people.

EDIT: From the Guardian article: "The German newspaper Bild said that the plane had reported shortly after takeoff that there was a problem with pressurisation in the cabin."

Maybe this was more than just bad luck!

PT6A fucked around with this message at 23:23 on Sep 5, 2022

# ? Sep 5, 2022 23:19

Arson Daily: Aug 11, 2003

Nebakenezzer posted:

Thread favorite Learjet had a teeny tiny flaw where in a loss of cabin pressurization getting oxygen to the aircrew was just a smidge too slow to be useful

Do tell! The Learjet model I flew had a flaw where the supplemental oxygen bottle valve would indicate off when it was actually on. What a country!

# ? Sep 6, 2022 01:36

ranbo das: Oct 16, 2013

Just wanted to say thanks for all the responses! Hypoxia is not something to mess with.

# ? Sep 6, 2022 04:44

hobbesmaster: Jan 28, 2008

BIG HEADLINE posted:

Yeah, there's a relatively recent video on YouTube of one of those science guys undergoing high altitude training at the Air Force's test chamber and they measure his blood oxygen level past ~FL250 without oxygen and his self-preservation instinct just goes out the window.

Here it is: https://youtu.be/kUfF2MTnqAw

This is a good scary one too
https://www.youtube.com/watch?v=_IqWal_EmBg

The crew sounds drunk and is incoherent. 4 minutes in they�re at 11,000 ft and completely normal again

edit:

quote:

Unable to control altitude
Unable to control airspeed
Unable to control heading
Kalitta six-six. Other than that, everything A-Ok

Is an all timer

hobbesmaster fucked around with this message at 16:06 on Sep 6, 2022

# ? Sep 6, 2022 04:52

slidebite: Nov 6, 2005; Good egg

e: nvm

slidebite fucked around with this message at 05:56 on Sep 6, 2022

# ? Sep 6, 2022 05:53

Invalido: Dec 28, 2005; BICHAELING

Here's a still from a video shot from the ground on the island of Bornholm as the Cessna was being inspected from a pointy jet. Even if the windows weren't iced over it would be pretty hard to see much detail from that distance unless you had a back seat with a guy in it using binoculars or something, I assume? I also assume you wouldn't want to get much closer than that to any plane not flown by somebody you trust completely, but I'm no pilot man.

# ? Sep 6, 2022 06:44

tactlessbastard: Feb 4, 2001; Godspeed, post; Fun Shoe

hobbesmaster posted:

This is a good scary one too
https://www.youtube.com/watch?v=_IqWal_EmBg

The crew sounds drunk and is incoherent. 4 minutes in they’re at 11,000 ft and completely normal again

When I was 16 I was copilot in a Cessna 210 on a trip that went over the continental divide. As we crossed over with me as PIC with 1000' feet below us but '500 above us peaks to either side, I realized I was feeling a little loopy, I said to the pilot, I think I'm getting hypoxic.

The pilot pulled out O2, took over, and I looked back to our passengers who I found were drooling on each other, unconscious.

In the end we landed and everyone was fine lol.

# ? Sep 6, 2022 06:46