https://thepointsguy.com/news/hard-airplane-landings/

Sometimes a landing is as smooth as silk. On the Airbus A380, almost every time
I barely notice that the plane has made contact with terra firma — instead it’s
the noise made by the reverse thrusters that lets you know. Other times, the
landing is quite a bit more bumpy with a solid jolt on touchdown that you feel
in your body. Very, very rarely, the landing is so hard that the plane is
damaged, sometimes even beyond repair, like this United Airlines 757 earlier
this year.

But did you know that some of the landings you might have thought were
especially hard are intentionally firm?

I spoke to Captain Doug Morris, a longtime Air Canada pilot with 25,000 hours of
flight time under his belt, and Captain Chris Brady, a commercial airline pilot
who created the Boeing 737 Technical Site and Facebook group, for their take on
landings with a bit more of a jolt.

Snug or Firm…But Not Hard

“First of all, pilots prefer the term snug or firm,” Morris explained. “The term
‘hard’ is bit harsh”. And as it turns out, technically incorrect. Indeed, Brady
explained that a so-called “hard landing” is both colloquially used by
passengers, but also has a technical meaning used by the aircraft manufacturers.

The normal sink rate of an aircraft on landing is two to three feet per second;
when a pilot lands at seven to eight feet per second, it will feel harder than
normal. Pilots have been known to report it as a hard landing, Brady explained,
even though the landing was within the prescribed limits.

The technical definition of a hard landing is a peak recorded vertical
acceleration that exceeds 2.1G, or a force more than twice your own body weight.
Boeing defines a “hard landing” to be any landing that may have resulted in an
exceeding of limit load on the airframe or landing gear, with a sink rate of 10
feet per second with zero roll at touchdown. That would be a big drop, much more
than seven to eight feet per second.

A hard landing is never ok, said Brady. “A firm landing may be ok,” he added.

So, why will pilots land firmly?

First of all, their training manuals for aircraft such as the Boeing 737
specifically state: “Do not allow the airplane to float: fly the airplane onto
the runway. Do not extend the flare by increasing pitch attitude in an attempt
to achieve a perfectly smooth touchdown.” (In layperson’s terms: Don’t pull the
nose up for too long just prior to touchdown. “Flaring” means pulling the nose
up.)

There are few good reasons to fly the airplane onto the runway. One is very
simple: a runway is a coveted space. You don’t want to hog it when there are
dozens of other airplanes that need to get on it quick.

“I fly in to the 10 busiest airports in the world. Many of those are
high-intensity runway operations. You want to get on the runway, and get off to
the nearest taxiway. It’s not the time for finesse and a smooth landing,” said
Air Canada’s Morris.

“[LaGuardia] is a good example. It’s basically like landing on a short-field
runway every time,” he said, noting that he flew frequently to LGA as a captain
on the A320. “We’re going to flare but with no float. We aim to pick a spot on
the runway and put it there.”

“On landing, it’s important to be in the correct place at the correct speed,”
Brady said. “You don’t want to be 10 or 20 knots too fast, and not set up to
land at the right spot on the runway.”

“Everything else is dressing,” Brady laughed.

Slippery when wet

The other reason to land firm is if the weather is poor with a slippery runway
due to “contamination” such as water, slush or snow. Morris explained that on
departure, the primary concern is any kind of mechanical issue, itself quite
rare. “On landing, it’s all related to weather,” he said. This kind of weather
includes cross-winds, wind shear, microbursts, rain, and slippery runways
because of rain or snow. In these instances, the pilots want to put down the
plane firmly.

A firm landing allows for the ground spoilers to deploy more quickly, the wheels
to spin up and the brakes to be applied. All of this helps with the braking
action of the aircraft. Even though the runways are long — at Toronto’s Pearson
Airport where Morris flies, the longest is two miles — there is always the
potential for an overrun when conditions are poor.

Intentional firm landings aside, Brady said that some runways make it very hard
to get a smooth landing, particularly those with an upslope. He cited Naples,
Italy, which “undulates,” and noted that Manchester Airport’s runway 24R has a
large bump right in the middle. “My colleagues and I have tried to flatten it
out with our planes,” Brady joked.

“Some of them are like ski slopes with plenty of oscillations,” he said, noting
that the maps that pilots use will sometimes indicate the runway profile to help
pilots understand where the runway goes up or down. Other runways, he said, are
unusually wide. Madrid’s airport runways, for example, are 198 feet wide,
compared to 165 feet at London Heathrow.

In any case and no matter the landing, pilots like Morris and Brady will greet
passengers as they disembark. Whether a greased landing or a firm one, their
objective is always safety first. And a firm landing is sometimes necessary.





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