crosswind autoland 737
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Sorry crvm....have to contradict you on the model I am familiar with.
The 737-800 autopilot will disconnect at 158 feet rad alt with single autopilot engaged (certified 'minimum use height' by boeing) and will also disconnect with both autopilots engaged but failure to recieve flare arm annunciation at approximatly 350 ft rad alt. this would occur only if the was an FCC problem...not a normal scenario obviously.
As long as you don not get flare armed the aircraft cannot autoland.
Ref boeing ops manual ch4 page set 20
The 737-800 autopilot will disconnect at 158 feet rad alt with single autopilot engaged (certified 'minimum use height' by boeing) and will also disconnect with both autopilots engaged but failure to recieve flare arm annunciation at approximatly 350 ft rad alt. this would occur only if the was an FCC problem...not a normal scenario obviously.
As long as you don not get flare armed the aircraft cannot autoland.
Ref boeing ops manual ch4 page set 20
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BH : you are right,the plane won't do an autoland on one autopilot,but on classics,I think it won't disconect by itself,it will just slamm on the rwy,having no flare capability.The AT will retard though,at 27 feet,so a very hard touchdown.
Regarding your pertinent answer about the crab position,one question:why not trying to use rudder peddal during flare,to remove the crab angle? Never tried that,just a question.
And also,the book says that you can toucdown in a crab position,then removing crab,on a wet rwy.I did this once,on a dry rwy,
,due to very strong crosswind with gusts,not the nicest soft landing,but a good one.We did taxi after that 
Brgds Alex
Regarding your pertinent answer about the crab position,one question:why not trying to use rudder peddal during flare,to remove the crab angle? Never tried that,just a question.
And also,the book says that you can toucdown in a crab position,then removing crab,on a wet rwy.I did this once,on a dry rwy,
,due to very strong crosswind with gusts,not the nicest soft landing,but a good one.We did taxi after that Brgds Alex
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An extract from our procedures:
AUTOLAND
The Autopilot flies the aircraft onto the runway with a rate of
descent of approx. 150 ft per minute and without removing any
drift. This is a safe manoeuvre up to the autoland crosswind
limitation. The Autopilot must be disengaged at or shortly after
touchdown. If the autopilot is left engaged it will lower the nose
gently but if there is any crosswind there is a tendency for the
upwind wing to lift.
Rudder must not be applied prior to touchdown as the autopilot will apply aileron to counteract this input and the aircraft may drift off centreline. In addition, manual rudder inputs may lead to roll
oscillations and increased touchdown dispersions. Any drift that
was present on touchdown should be removed gently by rudder
after both main wheels are on the ground. Reverse thrust and
brakes/autobrakes should be used as in the manual landing case
AUTOLAND
The Autopilot flies the aircraft onto the runway with a rate of
descent of approx. 150 ft per minute and without removing any
drift. This is a safe manoeuvre up to the autoland crosswind
limitation. The Autopilot must be disengaged at or shortly after
touchdown. If the autopilot is left engaged it will lower the nose
gently but if there is any crosswind there is a tendency for the
upwind wing to lift.
Rudder must not be applied prior to touchdown as the autopilot will apply aileron to counteract this input and the aircraft may drift off centreline. In addition, manual rudder inputs may lead to roll
oscillations and increased touchdown dispersions. Any drift that
was present on touchdown should be removed gently by rudder
after both main wheels are on the ground. Reverse thrust and
brakes/autobrakes should be used as in the manual landing case
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Bomber Harris,
Ah you think so? If that is the case (sure at some points this is true but we are only talking about S CH autolands) but what about the *confidence check* in single channel? Certainly your 800 preforms this even with a single A/P! And you can try this one ;-) . So why would it perform this if it's impossible not to autoland in single channel? (I am not saying anyone should EVER do it but only that it can)
Like I said, Boeing does not want to give any false impressions here so that is why FLARE is not on the FMA but it will autoland. Sure you do not want try this on the real bird but one can ask Boeing (already did ;-)).........
Crvm
Ah you think so? If that is the case (sure at some points this is true but we are only talking about S CH autolands) but what about the *confidence check* in single channel? Certainly your 800 preforms this even with a single A/P! And you can try this one ;-) . So why would it perform this if it's impossible not to autoland in single channel? (I am not saying anyone should EVER do it but only that it can)
Like I said, Boeing does not want to give any false impressions here so that is why FLARE is not on the FMA but it will autoland. Sure you do not want try this on the real bird but one can ask Boeing (already did ;-)).........
Crvm
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crvm:
sorry mate ,but you got it wrong about this so called 'confidence check'
This check,done at 1500' has nothing to do with single or dual channel autoland.
'The ILS deviation monitoring alerts the crew of excessive LOC or GS deviations.This alerting function is operative during SC or DC A/P ILS approach. The alerting system is armed when the a/c descends bellow 1500' RA with LOC and G/S captured.This self-test generates a two-second LOC and G/S deviation alerting display on each EADI.'
So ,as I said it has nothing to do with autoland or manual land.
It is just an ILS 'confidence check' if you want.
Regarding DCh app,shortly after capturing LOC and G/S ,and below 1500' RA ,the second A/P couples with the flight controls,and FLARE armed is annunciated.
You'll probably ask why 1500'? My guess , at 1500' RA you must be on ILS, this is generally near the OM ,very close to RWY for a unstable app.The ils deviation will autotest,also the a/p's systems will do an autocheck at aprox 1500'.But you can select both pilots till 800'RA.
You said you asked Boeing about autoland on SCh ? he,he...
And what did Mr Boeing say? FLARE not armed,then no flare and touchdown capability available,no bias trim also. (as he says on the OM) ,and the plane wiil land on the rwy?!))
That is correct.It will smash on it with 700' ROD.Nice landing.
kids ,we are proffesionals ,don't try this at home,you'll wreck your FSims.
what false impression?
Brgds Alex
sorry mate ,but you got it wrong about this so called 'confidence check'
This check,done at 1500' has nothing to do with single or dual channel autoland.
'The ILS deviation monitoring alerts the crew of excessive LOC or GS deviations.This alerting function is operative during SC or DC A/P ILS approach. The alerting system is armed when the a/c descends bellow 1500' RA with LOC and G/S captured.This self-test generates a two-second LOC and G/S deviation alerting display on each EADI.'
So ,as I said it has nothing to do with autoland or manual land.
It is just an ILS 'confidence check' if you want.
Regarding DCh app,shortly after capturing LOC and G/S ,and below 1500' RA ,the second A/P couples with the flight controls,and FLARE armed is annunciated.
You'll probably ask why 1500'? My guess , at 1500' RA you must be on ILS, this is generally near the OM ,very close to RWY for a unstable app.The ils deviation will autotest,also the a/p's systems will do an autocheck at aprox 1500'.But you can select both pilots till 800'RA.
You said you asked Boeing about autoland on SCh ? he,he...
And what did Mr Boeing say? FLARE not armed,then no flare and touchdown capability available,no bias trim also. (as he says on the OM) ,and the plane wiil land on the rwy?!
))That is correct.It will smash on it with 700' ROD.Nice landing.
Like I said, Boeing does not want to give any false impressions here so that is why FLARE is not on the FMA but it will autoland. Sure you do not want try this on the real bird but one can ask Boeing (already did ;-)).........
kids ,we are proffesionals ,don't try this at home,you'll wreck your FSims.what false impression?
Brgds Alex
