DA40 NG solo landing

[Danny_Huang]

Hi, I am a student pilot flying a DA40 NG. I feel that my solo landings tend to bounce a lot more than with instructor, and I am not sure why.

I have done over for over 100 landings, among which about 20 are solo. With instructor sitting next to me, I can land with very good certainty without issue. But for solo, I tend to bounce a lot more often. And the bounces often caught me by surprise, because the touchdown felt the same as usual, but somehow the airplane floated again. (I aim at 70kt crossing the number.)

I think a possible reason is weight. But my instructor is not big (150lb), about 65% of a full tank gas. Can it make that much difference? Or it is just psychology? Thanks if anyone can help.

[Steve]

Final approach speed definitely varies by weight. On my DA40 at max gross weight (2535) I aim for 71 KIAS, at 2407 - 67 KIAS, 2205 - 63 KIAS. So a good rule of thumb is 1 Knot slower for every 50 pounds lighter. In your case, that would equate to 3 K slower final approach speed without your instructor.

The airplane is very slippery and will float a long way if you are even a couple of Knots fast.

[smoss]

and yes, 3 knots does make a huge difference in float time! When I trained, most instructors all just used a generic number '70', and did not adjust for weight.

[DaveS1900]

You probably know this already, but a bounce is a descent with too much downward momentum where the tail is forced down when the main landing gear hits the runway. This causes the nose to pitch up which increases the angle of attack of the wing. If you are still at a fast enough airspeed for the airplane to fly, the airplane will "take-off" into the air. So airspeed control and controlling the downward descent at touchdown is important.

If you have a long runway, practice holding the airplane off as long as possible, with the main wheels just inches above the runway. Your airspeed will slowly bleed off. You will float but you should have a soft landing with no bounce. Once you perfect the landing without a bounce, then go back and work on how to reduce the floating.

Also, the nose wheel should never touch first.

-Dave S.
Woodstock Ohio

[twesselman]

Also, this may seem slightly counterintuitive to the forces that you’re fighting… but I found that Diamond likes to have a little bit of power left in when you’re landing. Doing so helps soften your decent rate when you’re in your flare.

I’m sure your instructor has told you it’s all about the finesse. I also agree with the guys here and make sure you’re going slower. And as counterintuitive as it sounds, as you’re going slower, try leaving a little bit of power in as you go through that soft flare.

[Boatguy]

It is very sensitive to speed, a little fast and you will float. Use the Vref in the DA40NG AFM for your plane (DA40 is entirely different) for your landing weight. Be sure you've considered fuel, passengers, baggage, etc. Cross the numbers right on your Vref, not above and certainly not below.

Foreflight Performance Plus version will do the Vref calculation for you. If you're doing laps around the pattern then your LDG weight is probably not much different than your TO weight and you can look it up in the AFM. You should also use the Vr for your weight from the AFM.

On final, pitch (the stick) for Vref and use power (the throttle) for descent rate (300 - 500fpm). Cut the power, smoothly, just before the flare. If you're a little fast, hold the nose up just a little and let the plane bleed off speed until it lands. If you try to force the plane onto the runway, you will bounce or porpoise, both bad. When over the runway, never push the stick forward. As you've probably already learned, the stick takes a very light touch.

The speeds and power settings I used are in the attached. Interpolate the speeds between the weight columns.

Fly safe!

[Danny_Huang]

Thanks everyone for your replies. Good to know that it is not just me who feels that Diamond landing is quite sensitive to weight. I will try 67 knot next time!

[Boatguy]

Thanks everyone for your replies. Good to know that it is not just me who feels that Diamond landing is quite sensitive to weight. I will try 67 knot next time!

The 67kts that Steve suggested was for his DA40, not a DA40NG and is way too slow for a 40NG. You do not want to get slow while flying the pattern!

Look in the AFM, or the PDF I posted. Your Vref in a DA40NG is somewhere between 72-76 with LDG flaps.