Ridiculously hard landing on LAND 3 (-771fpm)

[BlueStar 323]

On ‎4‎/‎28‎/‎2018 at 2:47 PM, downscc said:

PANC ILS15 is a CAT I approach

Dan,

I was sure glad to see the RNAV33 approach.  Before then we were doing the ILS07 Circling which was always tough especially at night when the weather was down to minimums.  Get you trusty MD-11 out sometime and try it, gotta hand fly. ROFL

[Driverab330 74]

On 4/28/2018 at 8:19 AM, Andrew Hafey said:

Coming in runway 15 at Anchorage (yes I know sim calls it 14)...777F with 228k, so running heavy.  Intercepted localizer, was on approach mode, flaps 30, manual speed holding at vref+5.  Yes, I had LAND 3, G/S and Flare engaged..but for whatever freaking reason, I hit hard (-771 fpm)!!!  I was watching for the runway (saw it right at minimums) and didn't notice a flare, but I know for a fact it was armed.   I actually came on to the runway heading at a YOHNN +4nm waypoint at 3500 feet...so I know this isn't an issue relating to too short of an approach.  I don't even use it all that much except when needed (very low vis)...according to my logbook, only had 6 autolands on it, all between -65fpm and -400.  I know many people here love to bash on landing rates and I haven't complained about it except that my VA registers anything over -500 as a hard landing with a very expensive repair bill.

Question is, could this be a scenery issue?  I run Orbx with openLC NA, Vector and Southern Alaska sceneries.  Vector has had autoconfigured ran...and there are no visual anomalies to indicate a scenery issue, but I'm at a complete loss as to why it just caused a $2.4M repair bill because of an autoland?  If not scenery, what else could be the issue?  This is the first 777F flight I've ran since upgrading from P3D v4.1 to v4.2...but I have done several 737 NGX flights since then with 1 or 2 autolands and never and issue.

Any suggestions???

The limit of Hard Landing inspection I recall in the MAT is about 800fpm ( it is actually G dependent the Eng will find out). By looking at the figure 771fpm is not too bad, it hurts the spine but the Boeing landing gear are strong enough to take that as long as you are below MLW. When they do the flight tests ( I was shown a video by a Boeing 747-8 test pilot a while ago), they fly at Max Landing weight and literally don't flare to establish the baseline landing distance figures. But I would put it into the tech log and file an air safety report anyway in real life. 

The PANC 15 approach has always causes some problem to our 747 freighter ops in real life, because it has a steeper than usual Glide path angle of 3.2 instead of 3. So you will get a sink rate close to 900-1000fpm on final when you are heavy and couple with some tailwind which is quite typical in ANC. 

The Autopilot Autoland G/S angle limit is 3.25deg, so 3.2 is very close to its limit. Therefore it is one of the reason that auto land on this runway is not approved by our airline in real life. 

Your thinking was correct, in heavy rain on the 777 / A330, the wipers are there to move water around on the windscreens and thats it, you will be able see the runway, but it will be too much to try to attempt manual landing because you will lose the depth perception on how high you are from the ground. I had to go around once into Taipei at 100ft flying into a shower of rain over the threshold and i could only see the lights, and we came back and do an autoland. But if you are doing an autoland even at CAT1, as long as you can identify the runway you are good to go, and you don't need a depth perception to do a manual landing. 

You are also right in pointing out that even the ILS is CAT 1 only doesn't mean you cannot do an auto land, this is a common misunderstanding. The airplane does not know whether the ILS is CAT 1 /2 /3A /3B/3C, the airplane can only detect there is a ILS signal and its internal AP systems are functioning. 

Every airline is different, but my airline would normally have the check and training captains to run a sim test on the specific runway and ILS first, once they are satisfies they would issue a company NOTAM to request any check and trainer to conduct a auto land in VMC condition. After about 5 successful attempts, the auto land is approved on that runway even if its just a CAT 1 runway. 

One example for us is Sydney RWY07 is CAT 1 only but auto land approved. the other one is RJFF ILS runway 16

One thing I keep in mind when I need to conduct a CAT1 ILS autoland is the ILS signal integrity will not be protected and ATC will apply normal traffic separation. So you have to be mindful that someone may taxi inside the ILS protection zone and bend the G/S and LOC beam, so you need to keep an eye on the AP mode. It had happened before when guys continued the approach in IMC despite losing the G/S signal and only realised that when they descend below the cloud at 1200ft and 8nm from the runway, fortunately they were flying over water. 

In summary, since you do not have all the information and necessary support like real world pilots, my suggestion for you is if you see a G/S angle anything higher than 3deg and the ILS is CAT1 only, be careful when you try to conduct an auto land, because the AP may not be quick enough to arrest the sink rate in FLARE mode. Also make sure that the LOC final approach track is the same as runway track, prime example which they aren't the same are RWY 22R in JFK and ILS rwy 23 in RJTT, both ILS are about 2-3deg off from runway track. 

 

 

Edited April 30, 2018 by Driverab330

[Andrew Hafey 1]

Great response Driver!  Thank you!