...here's another thing that we can add to the armada of bad information perpetuated by VAs:

 

Landing touchdown rates need to be hawkeyed, and anything more than 200 FPM is super hard and terrible.

 

 

 

As mentioned, the AUTOLAND is meant to be firm.  Additionally, it's not a CAT III autoland - those are two different concepts.  It's simply an autoland.

The real 777 autoland usually try to grease the landing based on my own experience hence it floats quite a bit sometimes, but it varies from airports to airports. That's why when we calculate the landing distance, we always add 600ft on top on the value based on manual landing.

 

From my experience, 400ft/min is quite firm, the limit required for hard landing is 8ft/sec if I remember correctly, which is 480ft/min. So 400ft/min is not far from it. On the ER, anything less than 4.5ft/sec feels normal. And touching down at 400ft/min (6.6ft/sec) will feel like hitting a wall. On the real 777, we can check the touch down sink rate using MAT computer behind the FO seat, I always do it after each landing.

 

Never try autoland with PMDG, may be you can try to do it at a different airport with different weather condition. Sometimes the add on weather engine introduces abrupt wind shift below 100ft which may lead to hard landings.

Driverab330 - Ask to take a look at your company's QAR & AIMS data. The aircraft should definitely not be trying to grease the landing,  it is definitely not something  I have seen looking at QR's data (they have a huge 777 fleet)

 

Limits are :Above Max landing weight: Max 6ft/sec=360fpm Below Max  landing weight: 10ft/sec=600fpm

 

Btw, am 99% sure the MAT uses a quick and dirty algorithm to determine the landing rate. You have to dig into the QAR/AIMS data to get an accurate readout.

 

Regards  

Driverab330 - Ask to take a look at your company's QAR & AIMS data. The aircraft should definitely not be trying to grease the landing,  it is definitely not something  I have seen looking at QR's data (they have a huge 777 fleet)

 

Limits are :Above Max landing weight: Max 6ft/sec=360fpm Below Max  landing weight: 10ft/sec=600fpm

 

Btw, am 99% sure the MAT uses a quick and dirty algorithm to determine the landing rate. You have to dig into the QAR/AIMS data to get an accurate readout.

 

Regards  

Yip, spot on:

 

A hard landing is defined as a landing with a vertical acceleration of more than 2.6 g at the center of gravity or:

-a vertical speed (v/s) of more than 600 ft/min.

 

This is taken from PPRuNe where you can follow the discussion here:

 

http://www.pprune.org/tech-log/408083-hard-landing-limit.html

 

Makes for interesting reading actually!

 

Kind regards

Driverab330 - Ask to take a look at your company's QAR & AIMS data. The aircraft should definitely not be trying to grease the landing, it is definitely not something I have seen looking at QR's data (they have a huge 777 fleet)

 

Limits are :Above Max landing weight: Max 6ft/sec=360fpm Below Max landing weight: 10ft/sec=600fpm

 

Btw, am 99% sure the MAT uses a quick and dirty algorithm to determine the landing rate. You have to dig into the QAR/AIMS data to get an accurate readout.

 

Regards

Driverab330 - Ask to take a look at your company's QAR & AIMS data. The aircraft should definitely not be trying to grease the landing, it is definitely not something I have seen looking at QR's data (they have a huge 777 fleet)

 

Limits are :Above Max landing weight: Max 6ft/sec=360fpm Below Max landing weight: 10ft/sec=600fpm

 

Btw, am 99% sure the MAT uses a quick and dirty algorithm to determine the landing rate. You have to dig into the QAR/AIMS data to get an accurate readout.

 

Regards

The 8ft/s i talked about was what i see on the MAT sink rate page, not the FAR regulation. I am just wondering what's the average sink rate on based on the QAR data you have seen? Since I don't experience that many autoland a year, the max sink rate I have got is around 3ft/s so my data bank is obviously much less than what's the fleet average which I would like to know if possible. Like i said before anything less than 3.5ft/s on the ER feels right. And of all of them I have done, they feel way better than the 330/340 and certainly sometimes does a better job than me.

 

What gives me the impression or illusion of it to try to grease a landing was it for a number of times, it just keep pitching up in the flare in order for it to achieve a certain sink rate before it finally touch down. And this is something that pilots wouldnt do. because they all try to touch down at the correct point and will lower the nose if the airplane floats for too long.

 

Whilst I understand the definition of a hard landing based on FAR, regardless what the MAT generates, in the Sink Rate page, it writes "8.0ft/s MAX" next to the sink rate the airplane had, along with data collecting from -1.0sec from touch down to +1.0 sec after touch with 0.1sec ( if I remember correctly ) interval. It's data is shown along with angle of bank, pitch, G etc etc. That's what my statement was based on, I don't know what would happen if this 8.0ft/s is busted. I was advised unofficially if I see anything above 8ft/s I better write it down in the log book for the engineers to have look.

 

The worst I have ever experienced was around 7ft/s, and my elbow slammed hard onto the arm rest. That wasn't a pleasant experience.

 

The regulatory limit to my understanding is for the aircraft manufacturer to design airplane that can withstand 10ft/s below MLW. Would boeing require an early inspection is required slightly before those values are reached? It would be great if someone who has got some insight information can share it.

 

Thanks gentlemen for pointing out the important points. Will check the QAR when I have time.

 

PS some extra info from Boeing I found online regarding to this matter

http://www.boeing.com/commercial/aeromagazine/aero_14/conditional_story.html

Hey Driver,

 

I am in the UK on holiday for the next few months. Will Pm you some info when I get back if you are still interested. 

 

Cheers

I've executed six autolands since yesterday at different airports (SCEL, SBGR, SAEZ, KMIA, KLAX, and KDEN), and they've all been smooth and on the money with the 300. There are three tricks:

 

1. Do not land overweight.

2. Keep your landing speed at no less than 155kts.

3. Shes tough to slow down so start your slowdown early during downwind.

 

Hope this helps.

 

Dennis

I just did a flight from KSFO to KSNS.  GS intercept alt was 3500 per FMC route and final approach speed was suggested by FMC as 30/130.  Craft was not overweight and fuel was at 17%.  The craft initial touchdown was smooth but the nose of the aircraft came down hard.  The result, crash.  Speed brakes armed and deployed as they were supposed to.  No winds to contend with.