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Why It's Hard To Make A Smooth Landing In An Empty Jet

Boldmethod

If you've ever flown a jet, have you noticed how much harder it is to make a smooth landing when the plane is light vs. heavy? Don't be too hard on yourself...there's some science behind this.

We spoke to engineers and test pilots for one of the world's largest commercial aircraft manufacturers to find out more. Here's what they had to say...

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Flight Controls And Inertia

When the airplane is empty, it's more responsive to elevator and aileron inputs. This can lead to overcontrolling, or misjudging how/when to flare. But why? It all comes down to inertia.

Using a simple force calculator (Acceleration = Force/Mass), you can test the theory yourself.

If you input a force of 1,000 lbs and a mass (weight) of 30,000 lbs, you get an acceleration of 0.03333 m/s^2. If you change the MASS to 40,000 lbs, leaving force at 1,000 lbs, you get a significantly smaller acceleration of 0.025 m/s^2.

Long story short, you get much more acceleration for the same control inputs at a lower weight.

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So what does this mean in terms of your flying skills? If you're accustomed to the plane responding to your control inputs within a typical weight range, flying significantly lighter planes can result in overcontrolling.

The plane will physically feel lighter on the controls. This alone doesn't cause a firm landing, but it's a factor when considering the small adjustments necessary to nail a smooth landing.

Landing Gear Tension

Commercial aircraft landing gear certified by the FAA and EASA are required to withstand a 10ft-per-second impact with the runway without failing. That's the equivalent of a descent rate of 600 FPM on touchdown. Upon wheel touchdown, a normal descent rate is 60-180 FPM. Anything over 240 FPM is generally considered a hard landing, and may result in a maintenance inspection. Most tires and landing gear are rated to 25-50% more than the maximum landing weight of the aircraft.

Long story short, the landing gear struts on your airplane are built to compress under intense weight and impact scenarios. When the airplane is light, the struts or hydraulic compressors won't compress as well. Think of it as a difference between landing on rigid pegs vs. a compressible cushion.

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Low Approach Speeds

Unlike smaller aircraft, weight makes a significant impact on approach speed for large aircraft. Your approach speeds are based on specific weight and flap configurations. On a fully loaded Embraer 145, you'll fly a flaps 22-degrees approach in gusty winds as high as 150 knots on final. The same airplane, now empty, with flaps 45-degrees, flies as slow as 120 knots on final.

Large weight changes impact everything from your flare speed, to sight picture, to trim settings.

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Fly Manually To Refine Your Anticipated Controls

One test pilot we spoke to said the best thing you can do to prepare for landing a light airplane is to fly manually as much as possible through descent and final approach. See what trim setting feels right, and test the ailerons and elevator to see how the plane is "calibrated" to your inputs.

CG location on the airplane will play a big role in the "heaviness" of the nose during your flare as well. Playing with little elevator movements during final approach will give you an indication of how easy or hard it will be to hold the nose off the ground during touchdown.

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Smooth Doesn't Always Equal Safe

In the end, we all love nailing a smooth landing. But that's not the only thing you should be striving for. The perception of your passengers and crew on your "smoothness" shouldn't matter nearly as much as touching down on-target, and stopping with plenty of room to spare. Never trade a smooth landing for safety.

Fly the airplane manually to get a good feel for the control inputs you'll make during your flare, and stick to the published approach speeds. Between inertia, landing gear characteristics, and control differences, you've got a lot of factors working against a smooth landing when you're flying a light jet. And that's completely normal.

Swayne Martin

Swayne is an editor at Boldmethod, certified flight instructor, and an Embraer 145 First Officer for a regional airline. He graduated as an aviation major from the University of North Dakota in 2018, holds a PIC Type Rating for Cessna Citation Jets (CE-525), and is a former pilot for Mokulele Airlines. He's the author of articles, quizzes and lists on Boldmethod every week. You can reach Swayne at swayne@boldmethod.com, and follow his flying adventures on his YouTube Channel.

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