when a real 737 is landing

[geoziag]

A simple question

what is the maximum ft/min desc. rate that a, real,737-400 can have when touching the ground without damaging the gear?
I suppose it has to do with the A/C's weight.

George Z.

[abent]

Not sure, but man you can grease that 737 onto the runway every time. I just watch the radio altitude and yank back on the stick a bit at about 20 ft and she settles onto the runway smooth as silk. This plane is a DREAM to land! Try manually landing PMDG's 777 sometime!
I'd still like to know the answer to your question.

[ET]

Damaging of gears (and other aircraft structures) can occur at several ways during landing.It indeed has to do with weight. If you land at a weight above the MLW (54.900 for the -400)than it depends on the sinkrate low to moderate or more than moderate how bad the damage is. You can also make a hard landing. This means if the vertical acceleration on the main landing gear is more than 2.1 G, damage can occur.(This is measured by the flight data recorder accelerometer) High drag/side load landing/off runway excursion can also cause damage to the gears.
During final approach, your sink rate is about 750 ft/min. Cut power to idle at 50 ft and then start to flare. So at touchdown your sinkrate should be less than 750 ft/min.
I have to find out the figures of low and moderate sinkrate to give you the correct answer. Or does anybody else know?

For now happy landings.

Erwin.

[ET]

It took some time, but i have now some figures.
Boeing commercial airplanes are designed for a 600 ft/min sinkrate at or below the MLW. When the aircraft is above the MLW the design sinkrate is 360 ft/min.
When an aircraft lands with 240 ft/min, most flight crews will experience this as a hard landing.
So a sinkrate of 120 ft/min will be moderate.

Erwin.

[deLattre]

Hi,

By certification, an aircraft have to be abble to handle an impact on main wheels of 600ft per minutes at max landing weight.

Now, note this:

If your aircraft is not certified to land at max take off weight, it must be equipped with the Jettison system. I am not a specialist of the 737, but on the Airbuss, for example, you have a weight limitation for the landing, but you do not have the Jettison system. It is because during the certification, Airbus industrie prooved that the bus could land at max take off weight on an emergency landing after take off.

Nevertheless, they have input a weight limitation for landing to save the material.

It is probably the same for the737, but once again I do not fly on this bird.

Cpt Cyrille de Lattre