# Positive rate of climb

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What does that mean exactly? I will typically raise the gear at about 100' AGL. So why can't you just have a stipulation to raise gear at 100' AGL or even 50' AGL? What is positive rate of climb?
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I would think it means you are in a steady climb and not pretending to be a porpoise. You can always pretend to be a fighter pilot and have the gear handle in the up position before takeoff so the gear raises as you leave the deck....believe me, not a great idea!;)

Still thinking about a new flightsim only computer!

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A positive rate of climb is when you are climbing. A negative rate of climb is when you are descending. I suspect that the reason those terms arose is that the panel gauge is a "rate of climb indicator" although it has more recently also become known as a vertical speed indicator.

So why can't you just have a stipulation to raise gear at 100' AGL or even 50' AGL?

They don't want you descending, or even just level, when you are that low and raising the gear, since gear down is a protection against scraping the aircraft on the ground.

Perhaps it would be more clear to you if they just said to be sure you are actually climbing before raising the gear.

Larry N.

As Skylab would say:

Remember: Aviation is NOT an exact Science!

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What does that mean exactly? I will typically raise the gear at about 100' AGL. So why can't you just have a stipulation to raise gear at 100' AGL or even 50' AGL? What is positive rate of climb?

Hi CRJ.

There is no "exact" measure / number, that I know of, but there are two things that I look for, VSI shows a continuous positive rate, at most airports above 500 FPM climb and crosschecked against the Altimeter. The VSI may initially show a descent right after takeoff due to external contributors, like Ground effect.. and VSI errors / lag, you must go past that point.

About the AGL there are more factors to consider, like obstacles, than just the VSI, Altitude.. if I have a long runway I will keep the gear down until I run out the distance that would allow me to abort the landing and land on the same runway, or end of runway, and only after that I look for the positive rate.

If there are obstacles at the end of the runway, that needs short field take off, and I use Vx, I will get the gear up as soon as I see the VSI above zero / positive rate, and the altimeter shows a climb. In some older VSI the Altimeter may be ahead, faster response, than the VSI.

There are actually 2 stages that the VSI (analog) goes through, initially there is trend, it knows / senses that there is a change and then it decides which direction / rate.

When you fly IFR the primary instrument for level flight is the Altimeter, and after that you can use the VSI to adjust the rate, if needed. Most VFR pilots use the VSI which is OK, but not not sufficiently accurate for precision flying.

There are some instructors that think / say otherwise but that is what I recommend, and use.

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Ah! The VSI. That makes sense then. Thanks!