PPRuNe Forums - View Single Post - AF 447 Thread No. 12
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Old 23rd Jan 2015, 15:16
  #910 (permalink)  
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Join Date: Jun 2009
Location: florida
Age: 81
Posts: 1,610
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It's hard for folks used to conventional flight controls to "appreciate" all the "protections" or "limits" as I prefer. Once you abandon a direct stick/yoke movement or pressure on a hydraulic valve and the corresponding action at the control surface, all kinda neat things are possible to smooth out the ride and then make it easier for a pinball wizard to fly a jet.

The gee command is hard to understand unless you see it during training. As in the Viper, AoA plays a role if the sensors are deemed reliable ( although the Viper AoA was deemed reliable if weight was off the gear - we had different criteria for "reliable" sensors than the 'bus). With a neutral stick and the jet trimmed for any gee, it would maintain the gee until the AoA reached the "limit", then ride the AoA limiter until speed increased/AoA decreased. We did not correct the gee for pitch attitude due to our mission requirements, huh? So we had a simple function that related gee to AoA. At 27 degrees or so AoA, max gee was 1 gee!!! At 15 degrees, max gee was 9. Sucker would even command zero gee to stay at 27 degrees AoA or below. So I would demo a loop to Joe Baggadonuts student by trimming to 3+gee, and let go of the stick. Sucker would smoothly pull up and then reach max AoA as it slowed, unload over the top, then increase gee as we came down the back side and AoA allowed. Due to our awesome vis, you could look back at the horizontal stabilators and see them almost maxed out as we came over the top ( nose down command just about as much as it could, but not quite. If nose wasn't moving and stabilators were maxed out, you were in a deep stall).

I mentioned this before, but our first group of youngsters in the Viper were of the Atari generation ( Xbox and Playstation 20 years away). We were worried that they would forget basic aerodynamics, as the jet was very easy to fly without getting into trouble. However, they had accumulated 250 or so hours in "conventional" jets that had no auto-anything!!! They did just fine, and went on to fly other jets after the Viper.

The key is to have a decent amount of flying in simple airplanes and no auto anything. Some "refresher" training is also highy recommended.

Finally. @engineers, quit trying to protect the plane so much when the primary modes go tango uniform. A straightforward reversion that can be easily understood seems logical, and I think I saw a comment to that effect in the accident report.


BTW, my pearl of wisdom I alluded to earlier was to do thousands of "thought" emergencies. What if? Sitting in the barbershop, waiting for a bus/train/plane. When the actual emergency happened, I had a personal procedure someplace in the back of my brain. I also had a philosophy of "hold what you got", at least if the plane wasn't tumbling end over end.

So what did I do when this happened shortly after lifting the gear handle?

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