777-300Er unstable on autoland

[guy 24]

On autoland the 777-300 balances from left to right.With no wind it is a light ,almost imperceptible movement , but with wind(even light) it is relatively pronounced.I have not seen this on the 777-200.Guy

[Guest NormanB]

Guy,What date is on your 300 air file?

[guy 24]

I use the Justflight CD version with patch.The date of PSSB773ER-GE.air is 8/04/2006 21:59.Guy

[Guest NormanB]

Only JustFlight can tell you if the file date is correct. It sounds around the right date though.

[guy 24]

I asked the question on the justflight forum.Didn't get any answer.As I applied their patch I suppose I have the right airfile.The 777-300 has also a tendency to turn into the wind on rollout!Guy

[Guest NormanB]

Not always the case, and its why I asked for the date. If you have not done so, I would redownload their patch since there was an issue with the 300 air file patch although this was replaced quite quickly.

[guy 24]

Downloaded it on the 15th of May.So it must be the good one.Guy

[guy 24]

have made some research on the Justflight forum.Found a thread "patch 1.1 NOT UPDATING THE b777-300 AIR FILE ".In that thread yourself intervene and say that you sent a new airfile, that was the 9th of april!Guy

[Guest NormanB]

>In that thread yourself intervene and say that you sent a new>airfile, that was the 9th of april!That may be so, but what JF did after that I don't know. I do however have no doubt they rolled it out.You will need to ask over at their forum since they are the folks who sold you the product. Thanks,

[guy 24]

Martin from the Just-flight forum has answered: I have the right 777-300 airfile, the same he has.He asked also if I load first the default-aircraft, which I always do.To be sure I nevertheless reinstalled the aircraft and the patch.But the problem is still there, there are even 2 problems:1) when auto-landing with sidewind(8 or 16kts) the 777-300 has bank-oscillations which increase when I approach the runway.2) on autoland after touchdown (still with sidewind) that is during autoroll, the 777-300 and also the 777-200 turn or slide to the side the wind is coming from. It is difficult to stay on the runway in those conditions. I have made some research on this forum and seen that this has also been signaled (after the patch) by others (see for exemple the thread:"Aircraft still unsteady when landing").Fortunately handflying the approach and landing is easy.Guy

[opherben 0]

I did not have the time to check the manual, but isn't autoland limited to a 10Kt crosswind component?

[FOD 23]

Guy,1. The PSS 777 does not have auto roll out so you need to disconnect the AP on touchdown in order to control the xwind.2. I believe that there is a rw xwind limit for auto-land - I know you can get "30 kt fog" but normally I am sure this sytem is only used with very little wind. As far as the PSS 777 is concerned, I have the patched LR and this will auto land with a 16 kt xwind component - it tracks the LOC very smoothly to touchdown but you have to be quick in disconnecting the Ap and gaining manual control of rudders and aileron.How is your LR with a 16 kt xwind?John R

[guy 24]

The side-wind limit for the 777 must be something like 20kts, I think. But the oscillation problem on the -300 exists already with 8 kts .My 777-200LR also turns into the wind (8 kts sidewind) on autoroll.The pss 777 does nor have autoroll? But it is indicated on the PFD!Or is not functionning ?Perhaps Norman say something about this.I got also another interesting message from Martin on the justflight forum:"As promised I did test the ER with an autoland and I can confirm that I am experiencing the same issue.On approach with a 12 kts crosswind the ER was unstable at 3.5 miles out rocking noticeably on approach. It's almost as if the aircraft is experiencing a much stronger crosswind than it actually is.As for the rollout I found it necessary to disconnect the AP sooner than normal to prevent running off the runway."Happy (auto)landings to all.Guy

[guy 24]

Did some research on crosswind limitation.Found this interesting article by a real 777 pilot on the site "Flying safely on the 777 "(http://www.geocities.com/khlim777_my/asFAQ29.htm#whyd):"There are 4 crosswind landing techniques on a Boeing 777, namely, 1. Side slipping (zero crab)2. Crabbing - for slippery runway3. De-crabbing - removal of crab during the flare4. Combination of crab and sideslip.In order to use any of such techniques, there are crosswind guidelines. For instance, when applying the crabbing method, the limitations vary according to the existing runway conditions: If it were dry - 45 knots; wet - 40 knots; standing water or slush - 20 knots; snow, not melting - 35 knots and ice, not melting - 17 knots.If the pilot decides to use the side slip technique, (zero crab) the crosswind guideline is restricted to 40 knots. When executing the side slip, over controlling the roll must be avoided because any excessive bank could cause the engine or outboard wing flap to contact the runway.When applying the de-crab technique, the touchdown is made with cross control with both the gears touching down simultaneously. The upwind aileron is used to keep the wings level.On a slippery runway, when using the crab technique, the crab angle must be maintained until touchdown. In this way, the pilot workload is reduced when proper rudder and upwind aileron is maintained.Some pilots prefer to use a combination of the crab and side slip technique. As upwind gears touch down, a slight increase in downwind rudder is applied to straighten the nose. Simultaneously, the aileron is applied to maintain the wings to keep them level.Phew!! A pilot needs to work quite hard if the wind approaches the limit! The difference between a Boeing 777 and a light plane like a Cessna 182 or Piper is the strength of the crosswind. I believe the airplane manual for the light airplanes would recommend the appropriate techniques."On another site of the Chicago O'Hare airport they say that crosswind limitaion for all heavies is 20 kts.On the site "Landing/Autopilot Question for the Heavy Drivers" (http://glocktalk.com/sitemap/topic/210409-1.html) they say : "The headwind/tailwind/crosswind limits required to autoland vary by aircraft but generally 25-30 kt HW/XW limits and 10 kt tailwind limits are pretty normal for heavy metal jets. In lower viz Cat 2/3 approaches, a 10 kt crosswind generally applies"Guy

[guy 24]

Norman,Does the 777 have autoroll, yes or no?Guy