Believe it or don't, the glass IS far more reliable than the steam stuff. The raw data analysis has been done many times over by air agencies, military, governments, and private enterprise. My background is also in the heavy iron, and specifically some time in the reliability department where we generated reams upon reams of data on every minute piece of an airliner. The Brasilia example is a terrible one, because it was certified with old Collins Proline II "glass" designed in the 70's (now almost 40 years old). I'd venture to say some of the sensors in even the lowest cost EFIS or an Ipad are equal to or superior to what was considered state of the art back then.
Personal anecdotal experiences aside, it's really a moot discussion because as I've said before, like or to not the steam stuff is going the way of the dinosaurs. Even the little peanut standby instrument in the heavy iron are all digital (no "steam" in new airliners) and fighters.
No to be sarcastic and I'm probably gonna raise some hackles with this (no flames intended), but again it's a relative waste of time to even discuss it because it doesn't matter what anyones personal experience behind old stuff in old airliners is (and even that is dubious because an individual exposure to the life & abuse of a system in an airliner flying 10+hrs per day 7 days per week is not a good data point), the world is going glass - period. Glass of old does not equal glass of new.
Regarding costs, the Chinese Steam stuff is cheap but terrible in the reliability department. That leaves you with certified stuff, and set of gyros (plus an HSI) will run you MUCH higher than the cost of a simple EFIS. Here's some quick math:
Gyros: - about $6K for certified ones.
Simple CDI - $1800 (no HSI)
ASI+ALT+VSI: $1K for decent ones.
HSI - No way anyone would even consider an analog HSi at $7-10K so we'll leave that out.
That's almost $9K right there and you still don't have an HSI, Autopilot, OAT, AOA, no compass, no fuel computer, no trim indicators, no flap indicators, no warning systems, no annunciator, no moving map, no weather, no terrain, no traffic, no charts, no plates, no sectionals, no Ammeter, no voltmeter, no tachometer, no egt, no cht, no fuel pressure, no oil pressure, no oil temp, no manifold pressure, no W&B, no checklists, no hobbs meter, no G meter, no flight planning, etc.. All of the above which can be had in everything from a Dynon, AFS, GRT and Garmin for about the same price.
Engine instruments are also far superior digitally than analog and have been for some time. Boeing/Airbus/Douglas/Lockheed quit using analog engine instrumentation sometime in the previous century. Again somewhat dubious to debate because that's where the world is going. Even for simple VFR, you're way farther ahead to just go buy a good EFIS and be done with it.
That being said, if you're really stuck on old stuff - I have a box of old steam guages that are for sale cheap! However, if you put it in the plane it'll be worth a whole lot less money and a whole lot less functional than if you'd spent the exact same amount on glass - that's a fact. I won't get into the Space Shuttle metrics but Paul can probably fill us in on that history/progression!
Cheers,
Stein
