PPRuNe Forums - View Single Post - Using GPS ground speed to resolve Unreliable Airspeed
Old 4th Jun 2019, 08:58
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Goldenrivett
 
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Originally Posted by yanrair
Dear Pineteam
Thats what I have been saying all along, with the addition of taking GS into account too. At the time of failure maintain status quo and if it was working a moment ago, it still will. And will continue to do so for a time. ...
GS extends your 1-2 minutes almost infinitely . Even if you don't know the wind ( which you will) In your scenario settle at 250 its GS with pitch and power accordingly. Unless you have a headwind or tailwind in excess of 50 kts you are perfectly safe. Your IAS must be in the range 200-300 which are both safe. Neither too fast nor too slow. And if the wind is stronger than that you will surely know about it and take it into account.

Y
Hi yanrair,

You need to include TAS effect with altitude.
In Pineteam's example of climbing away at 250 kts, climb thrust and 10 degrees of pitch works simply perfectly well. If you try to rely on Ground Speed and ignore wind component (when <50 kts) and TAS - then you will be in error by an additional 40 kts by 10,000 feet on the climb. (Your IAS must be in the range 160-260 kts - which is probably not safe).

KISS is the better solution.
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