How hard a landing is very hard in a 747?

[Copper. 78]

http://www.boeing.com/commercial/aeromagazine/articles/2014_q4/pdf/AERO_2014q4.pdf

 

Start at Page 15. it tells you all you need to know. Boeing philosophy and policy is to rely on pirep for hard landing reporting. Generally 1.4g to 1.8g vlf is the limit. Anything below 1.4g vlf would mean just the basic check is done. Above 1.4g vlf, generally phase 1a and 1b etc etc.

 

i regularly land in the 300-400 fpm sink rate range. It's hard to land on a needle like runway properly. I'm sure many simmers would land in the 150fpm range if they were to fly the real deal. It's a bit like driving a car in a game, it doesn't compare to driving the real thing.

[BlueStar 323]

As part of the certification process the B747 can be safely landed at 6 feet per second at MGTOW and 10 feet per second at MGLW. 

blaustern

 

[KevinMM 22]

How is this landing fps Measured? As the bottom surface of the wheels touch the tarmac and go to 0 FPM, the seat cushion passenger interface is still at 200 FPM!

The struts contract spreading out the deceleration. It this how much the deceleration  is spread out that you feel. Remember, you never notice the 1800 FPM from altitude.

[Copper. 78]

7 hours ago, KevinMM said:

How is this landing fps Measured? As the bottom surface of the wheels touch the tarmac and go to 0 FPM, the seat cushion passenger interface is still at 200 FPM!

The struts contract spreading out the deceleration. It this how much the deceleration  is spread out that you feel. Remember, you never notice the 1800 FPM from altitude.

Vertical speed (from memory) comes from accelerometers around the aircraft and its data is sent to the computers.

What is a seat cushion passenger interface?

No, you do not generally notice sink or climb rate once this rate is established, you do however feel the changes. If you go from 1800fpm sink rate to 2500fpm sink rate suddenly without compensating for the change in g, you'd feel it. Same for when the aircraft roll's, you feel the changes.

As a further note, students should NEVER put achieving a "greaser" above landing in the touchdown zone with normal attitude.

There are so many YouTube videos, so so many, where this is not done. The students realise that they need to get 150fpm, for whatever reason, and risk tail strike by using abnormally high nose up pitch with a flare that extends beyond the touchdown zone. This would have to be my biggest criticism of all the videos on YouTube.

[Werner747 107]

What I normally do is use the proper approach speed, and at 20 feet go to idle and raise the nose just a degree or two.   That results in excellent landings, however, as I said I think I hit some sheer on those last ones.   I am seriously contemplating getting ASN to avoid getting caught out by those nasty sheer buggers on finals!

Regards

[Copper. 78]

Thanks for the tip. I'll try when I can.

[richcam427 29]

You know what they say. A good landing is one you can walk away from. A great landing is one where you can reuse the airplane afterwards.

[Quink 13]

A more practical way to determine if the landing was a bit firm without becoming overly involved in "sink rates", etc. is to open the cockpit door.  If all the" carry on trash" has fallen out of the overhead bins is laying in the aisle and the stew is standing there with her panties around her ankles inquiring, "who made THAT one?" then, yes, it probably wasn't a greaser! 

[Captain Kevin 586]

3 minutes ago, Quink said:

stew is standing there with her panties around her ankles

That can happen?

[Quink 13]

Quote

stew is standing there with her panties around her ankles

Anything's possible Kevin. Depends on the almighty sink rate!  The overall effect would be very slow and hostile service to the cockpit for the rest of the trip...........

[1290SASRider 26]

If Atlas drops the globe it was too hard!

[Driverab330 74]

On 9/19/2017 at 1:33 PM, Werner747 said:

What I normally do is use the proper approach speed, and at 20 feet go to idle and raise the nose just a degree or two.   That results in excellent landings, however, as I said I think I hit some sheer on those last ones.   I am seriously contemplating getting ASN to avoid getting caught out by those nasty sheer buggers on finals!

Regards

Anything below 3ft / sec will be very good landing on the jumbo. 

 

If you want to guarded against those sinking shear below 50ft, try this:  at 30ft call out begin to raise the nose first, at 20ft call out being to reduce the thrust to idle.

 

sometimes flaring at 20ft on the jumbo at a very high land weight just do not give sufficient time for the airplane to arrest its sink rate hence resulting 300-400fpm sink rate at touch down. 

At max landing and high approach speed, sometimes you may need to initiate your flare at 40ft call out but slow with the pitch up. And keep the thrust on for a bit if you feel a sinking shear. 

FSX or inside a simulator is hard because in real life you can feel the airplane is dropping. 

 

Have fun 

[walfob 10]

Landing once on an extremely wet runway post typhoon at Kai Tak I was given to understand it was a procedure to get the wheels spinning, and not aquaplaning down the runway, which at Kai Tak could result in the plane ending up in Kowloon Bay. This happened on a few occasions.