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Comment by SamBam | Hacker News Reader

> Luckily, after descending 500ft in about 18 seconds, audible warnings in the cockpit alerted the crew that things were going awry and they very quickly remedied the situation.

Why did it require audible warnings? How could any pilot not notice that they were coming down that sharply?

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500 feet in 18 seconds isn't that fast (around 20mph), especially if the decline was eased into. It would be visible on the altimeter, but "seat of the pants" wouldn't tell you much.

500 feet in 18 seconds is approx 20mph.

You're right, fixing.

Despite the fix suggested, what you'd actually feel is acceleration, rather than velocity. 500ft descent over 18 seconds would be about -1.2ft/s acceleration.

Which, shortly after takeoff (i.e. shortly after ascending) could very well feel like a continuation of a leveling off maneuver.

Not to mention, in limited visibility you simply can't trust your sensation of G forces. In the absence of visual stimulation, your mind can hallucinate the feeling of movement that doesn't match your actual movement. You can simulate this by standing with your feet together and closing your eyes.

Do commercial jets have things like displays of graphs over time for the altimeter? Or is it all looking at instantaneous values?

Kinda. There's an ascent/descent rate display separate from the altimeter. It's not a graph, just an indicator.

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