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How to start up a Boeing 737 [video]

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Re: How to start up a Boeing 737 [video]

#41

Post by downandout »

spc476 wrote: post #36
downandout wrote: post #28

Well.....what could possibly go wrong there? There have been several air disasters over the years that resulted from a failure to flip the right switch or check certain settings, either in-flight or pre-flight. A Greek crash where the pilot forgot to flip the auto-pressurization switch, killing most on board before the crash itself, comes to mind. This video leaves little wonder why these things happen. Having spent…

I don't know. At work, I'm responsible for the regression test. I wrote the regression test. And I have a check list with 52 items required to run it (step 50 is actually running the test, the next item is making sure it's running, and the 52nd item is "walk away for the next five hours"). Could it be simpler? Yes, but it would require even more setup (since it involves generating several datasets that are copied to…

The difference is that if you accidentally skip one of these steps, you won't destroy a $50M+ piece of equipment, devastate 100+ families, and/or disable an airport or neighborhood for days while rescuers collect the body parts of all the people you killed. Complexity is the enemy of humans in stressful situations. Where lives and tens or hundreds of millions of dollars are on the line in a zero-fail environment, I would strive for simplicity.

Re: How to start up a Boeing 737 [video]

#42

Post by snom380 »

yetanotherphd wrote: post #37
downandout wrote: post #28

Well.....what could possibly go wrong there? There have been several air disasters over the years that resulted from a failure to flip the right switch or check certain settings, either in-flight or pre-flight. A Greek crash where the pilot forgot to flip the auto-pressurization switch, killing most on board before the crash itself, comes to mind. This video leaves little wonder why these things happen. Having spent…

I was also thinking about this. Even if the controls and procedures remain completely unchanged, it should be possible to issue warnings when things were done wrong. In fact I'd be surprised if this wasn't at least partially implemented already.

Some modern airplanes do have integrated electronic checklists.

Re: How to start up a Boeing 737 [video]

#43

Post by bdonlan »

downandout wrote: post #28

Well.....what could possibly go wrong there? There have been several air disasters over the years that resulted from a failure to flip the right switch or check certain settings, either in-flight or pre-flight. A Greek crash where the pilot forgot to flip the auto-pressurization switch, killing most on board before the crash itself, comes to mind. This video leaves little wonder why these things happen. Having spent…

Some modern airliners have computer-based checklists that will verify that all checklist steps were completed correctly for you. They also have alarms that will go off if the aircraft configuration is egregiously wrong on takeoff (eg, http://www.youtube.com/watch?v=hOqMttyD_Zc). With older or smaller jets, however, some of these safety features might be missing or less sophisticated, so it's more on the pilots to correctly execute the checklist.

Re: How to start up a Boeing 737 [video]

#45

Post by snom380 »

downandout wrote: post #28

Well.....what could possibly go wrong there? There have been several air disasters over the years that resulted from a failure to flip the right switch or check certain settings, either in-flight or pre-flight. A Greek crash where the pilot forgot to flip the auto-pressurization switch, killing most on board before the crash itself, comes to mind. This video leaves little wonder why these things happen. Having spent…

What this video doesn't show is the multiple redundant checks that are done, and the warning systems that sound if something is out of place (like the one that the Helios pilots misunderstood). Newer airplanes do have more human friendly designs and more automation, including electronic checklists. For existing cockpits, they are usually only upgraded when serious design flaws are discovered. But that doesn't happen often.

Re: How to start up a Boeing 737 [video]

#46

Post by ballard »

bdonlan wrote: post #43
downandout wrote: post #28

Well.....what could possibly go wrong there? There have been several air disasters over the years that resulted from a failure to flip the right switch or check certain settings, either in-flight or pre-flight. A Greek crash where the pilot forgot to flip the auto-pressurization switch, killing most on board before the crash itself, comes to mind. This video leaves little wonder why these things happen. Having spent…

Some modern airliners have computer-based checklists that will verify that all checklist steps were completed correctly for you. They also have alarms that will go off if the aircraft configuration is egregiously wrong on takeoff (eg, http://www.youtube.com/watch?v=hOqMttyD_Zc ). With older or smaller jets, however, some of these safety features might be missing or less sophisticated, so it's more on the pilots to co…

Automation sounds great, but it must be followed-up as to how it's used or abused in the real world in order to maintain air safety.

A primary concern of automating error detection is that it leads to laziness by cognition of least resistance. In the real world, pilots will simply rely on the machine to give them feedback rather than knowing what's fundamentally wrong themselves. This is dangerous because mastery goes away and you end up with experienced, routine button-pushers that slap a 777 into a seawall or trim some trees.

The other concern is zero incident complacency. If there were a "chaos monkey"-like system that could continuously introduce fire drill challenges, while being able to reveal themselves as authentic or not, would keep pilots alert and grade reactions before something larger happens. This is an instance where automation by purposeful fault injection might be able to maintain reaction fitness more consistently over time.

Re: How to start up a Boeing 737 [video]

#48

Post by gvb »

bulte-rs wrote: post #39
gvb wrote: post #35

Earlier quoted context omitted.

I wrote a lot of the "Dual FMS" BootROM and also the cross-FMS data link communications handling (TCP/IP originally over a high baud rate async serial channel). Most of my code is deeply embedded.

Awesome!!! Never knew it actually operates over TCP/IP, I always assumed some custom protocol/ARINC interop between the two units. Can you perhaps elaborate in some way on the dev environment When working on "stuff like that"? :)

New systems (not the 737 FMS) use ARINC-664[1] - UDP/TCP/IP/ethernet with all the good parts disallowed. :-) The original Dual FMS predates ARINC-664.

The original Dual FMS was a Motorola 68040 (the predecessor FMS was the TI TMS9900 architecture implemented in bit-slice processors(!), later an ASIC, because the TI 9900 was a bust. The original code was Fortran, with the Dual FMS it was ported to Ada.

The development environments back in the late 1980s, early 1990s was custom hardware and in circuit emulators (ICEs). The ICE plugged into the processor socket and emulated the processor but with breakpoints and trace. The 68040 was about the end of the line where this worked (the head of the 68040 ICE was pretty large. There were no "eval" boards to develop code on... we wrote code and waited for the hardware guys to get the first article built. When the hardware guys got done with the initial checkout on the first article, we got the system and started making the code work.

Once we got the hardware, software development was a lot like now: start with basic functionality, cross your fingers, burn and learn. With the ICE, "burning" was faster because you substituted ICE RAM for the target flash and the trace of the ICE was a lot more useful than today's JTAG-based debuggers - you could see everything for the last 1K-4K instructions, including the actual states of the pins of the processor.

The development lab had real equipment (e.g. the Control Display Units (CDUs)) and a lot of simulated I/O. The simulated I/O was driven by a flight simulator running on a Dec MicroVAX. The flight simulator simulated the flight characteristics of the 737, responding to the commands given by the FMS. Since I was mostly low-level, I didn't do much with the flight simulators, but I could enter flight plans (typically "company routes" which are pre-canned airports, runways, and waypoints) and go through all the motions of flying. The simulator could speed up time to save time waiting for things to happen. IIRC, 4x real time was about as fast as you could go because the systems would go wonky.

[1] http://en.wikipedia.org/wiki/Avionics_Full-Duplex_Switched_E...

Re: How to start up a Boeing 737 [video]

#49

Post by toomuchtodo »

takluyver wrote: post #23
vpeters25 wrote: post #22

Why aren't all these switches hooked to a computer which could run the whole procedure?

Some of the steps look like they're checking that various warning lights and systems work correctly, which needs a human in the loop. I guess there are other bits which require human decisions - e.g. you can't start the engines without visually checking that no-one is standing near them. Finally, any automation is another possible system that could fail, so it needs more examination and testing.

Well, I mean, you could if they integrated sensors into the engine cowling to detect the presence of a foreign object greater than size X within X meters of the engine.

Baby steps. Another 5-10 years, and flight will be entirely a tech issue. Example: Airbus A380 fly by wire.

Re: How to start up a Boeing 737 [video]

#50

Post by ChuckMcM »

I'm curious about something though, the author "golfcharlie232" has a great youtube channel [1] with lots of cool videos, but this one is copied off youtube into its own little player. So basically its taking ad revenue away from this guy (I presume he keeps the ad revenue).

What is up with that?

[1] http://www.youtube.com/results?search_query=golfcharlie232&o...

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