B737 Autoland capability in 1 ch only
Per Ardua ad Astraeus
Joined: Mar 2000
Posts: 18,575
Likes: 4
From: UK
May I point out that is is not unusual to 'hand-land' down to 550m RVR in the UK - we've been doing it for decades - without a 'HUD' (just a 'HU'
) - and no-one has been particularly impressed.........................
) - and no-one has been particularly impressed.........................
Joined: Jul 2000
Posts: 942
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From: Thailand
ASFKAP, indeed the Airbus is certified for Cat 111a approaches on one engine. In fact, the Airbus perefoms everything that a B737 will do one two engines, when the Airbus is on one, except maybe climb at the same rate!
A misconception is that the reason for the back trim is to assure a soft touchdown; it is not, it is to ensure that the aircraft is trimmed for the Go/Around, should it be required.
Also, the Airbus has Auto rudder trim, which the B737 does not have, hence an autoland is allowed on a single engine. On the B737 the pilot would have to constantly adjust the rudder when attempting an autoland. In the last event, the Autolpilot on the Airbus is 'Fail Active' whereas the B737 is fail passive, hence the one is certified for single engine landings on the autolpiot and the other is not.
Just to be contentious, as the point has been raised; Why did the DC-10 crew try to land the aircraft at an airport? Under the heading of; 'Attitude at Impact' I once wrote, in a very minor journal, a short piece querying the attitude of pilots when faced with an emergency for which they are patently not prepared. I am not being critical of those pilots who tried so herocially to land the aircraft, I am simply questioning their motives, their reason behind those decisions.
Sioux city is surrounded by flat, open farm land. The aircraft was controllable, up to a point, in that they could command pitch and lateral changes. Why did they not simply apply these techniques to get the aircraft straight and level, reduce the power and fly gently into the ground? I know our instincts and training are to rreturn to the nearest suitable runway, but why? This argument could also have been applied to the Concorde crash. Why not shut down the remaining engines and crash straight ahead instead of with full power applied to one side of the aircraft, rolling it on its back and, well, crashing?
Happy Landings.
A misconception is that the reason for the back trim is to assure a soft touchdown; it is not, it is to ensure that the aircraft is trimmed for the Go/Around, should it be required.
Also, the Airbus has Auto rudder trim, which the B737 does not have, hence an autoland is allowed on a single engine. On the B737 the pilot would have to constantly adjust the rudder when attempting an autoland. In the last event, the Autolpilot on the Airbus is 'Fail Active' whereas the B737 is fail passive, hence the one is certified for single engine landings on the autolpiot and the other is not.
Just to be contentious, as the point has been raised; Why did the DC-10 crew try to land the aircraft at an airport? Under the heading of; 'Attitude at Impact' I once wrote, in a very minor journal, a short piece querying the attitude of pilots when faced with an emergency for which they are patently not prepared. I am not being critical of those pilots who tried so herocially to land the aircraft, I am simply questioning their motives, their reason behind those decisions.
Sioux city is surrounded by flat, open farm land. The aircraft was controllable, up to a point, in that they could command pitch and lateral changes. Why did they not simply apply these techniques to get the aircraft straight and level, reduce the power and fly gently into the ground? I know our instincts and training are to rreturn to the nearest suitable runway, but why? This argument could also have been applied to the Concorde crash. Why not shut down the remaining engines and crash straight ahead instead of with full power applied to one side of the aircraft, rolling it on its back and, well, crashing?
Happy Landings.
Joined: Jun 2005
Posts: 50
Likes: 0
From: Mobile, AL
It will land with one engaged as well as it will with two - in certification speak it is called "fail-operational." The fact that it is not certified is a different kettle of fish entirely...a certified autoland system cannot have a failure mode (i.e. a failure of a single autopilot channel) that would jeopardise a safe landing.
However...just because it can, doesn't mean that you should; hence the certification...
However...just because it can, doesn't mean that you should; hence the certification...
Joined: May 2004
Posts: 230
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From: Godzone
Just to be contentious, as the point has been raised; Why did the DC-10 crew try to land the aircraft at an airport? Under the heading of; 'Attitude at Impact' I once wrote, in a very minor journal, a short piece querying the attitude of pilots when faced with an emergency for which they are patently not prepared. I am not being critical of those pilots who tried so herocially to land the aircraft, I am simply questioning their motives, their reason behind those decisions.
Sioux city is surrounded by flat, open farm land. The aircraft was controllable, up to a point, in that they could command pitch and lateral changes. Why did they not simply apply these techniques to get the aircraft straight and level, reduce the power and fly gently into the ground? I know our instincts and training are to rreturn to the nearest suitable runway, but why? This argument could also have been applied to the Concorde crash. Why not shut down the remaining engines and crash straight ahead instead of with full power applied to one side of the aircraft, rolling it on its back and, well, crashing?
Happy Landings.
Sioux city is surrounded by flat, open farm land. The aircraft was controllable, up to a point, in that they could command pitch and lateral changes. Why did they not simply apply these techniques to get the aircraft straight and level, reduce the power and fly gently into the ground? I know our instincts and training are to rreturn to the nearest suitable runway, but why? This argument could also have been applied to the Concorde crash. Why not shut down the remaining engines and crash straight ahead instead of with full power applied to one side of the aircraft, rolling it on its back and, well, crashing?
Happy Landings.
O
Joined: Jun 2004
Posts: 25
Likes: 1
From: Durham, NC, USA
Joined: Aug 2001
Posts: 755
Likes: 0
From: Europe-the sunshine side
rubik: the 737 can also be 'fail active' depending what option you select on buying the plane.Also it can autoland on single channel ,and also on single engine operation.The thing is ,it was not authorized to do this by the FAA when it first appeared,and due to large number of 737's in operation,it had to remain the same,mainly for commonality.
The NG is a lot smarter,but then again,it had to fit with the classics.Look at the Southwest airplanes for ex:no VNAV,no autothrottle...
The A320 it's a very new airplane compared with the 737 .( compare the 6 million flights done by the 320 familly with the 76 million done by the 737 untill the end of 2005).
About the DC-10 incident I think the main reason for landing on an airfield was the emergency services..critical on saving lifes..
Also,the flat farm land will prove not so flat or obstacle free when looked at from close range,ask any bush pilot,glider or ultralight pilot.
Any tree,ditch,rock,ravine,swamp... can prove fatal for your plane on a 'nice' flat farm land.
Concorde?..hmm..not a plane with which to try a landing outside,on the grass..the engines nacelles,the NOSE...I think it was a big NO.
The NG is a lot smarter,but then again,it had to fit with the classics.Look at the Southwest airplanes for ex:no VNAV,no autothrottle...
The A320 it's a very new airplane compared with the 737 .( compare the 6 million flights done by the 320 familly with the 76 million done by the 737 untill the end of 2005).
About the DC-10 incident I think the main reason for landing on an airfield was the emergency services..critical on saving lifes..
Also,the flat farm land will prove not so flat or obstacle free when looked at from close range,ask any bush pilot,glider or ultralight pilot.
Any tree,ditch,rock,ravine,swamp... can prove fatal for your plane on a 'nice' flat farm land.
Concorde?..hmm..not a plane with which to try a landing outside,on the grass..the engines nacelles,the NOSE...I think it was a big NO.
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Ladies&Gentlemens!
Intresting topic indeed, i dont have much to contribute because many wise things are allrddy said. I´m not an experienced B737 pilot but to summ up the topic "just fly the big fat lady as you´ve been learned to do and everything will go quite slick"
peace
Intresting topic indeed, i dont have much to contribute because many wise things are allrddy said. I´m not an experienced B737 pilot but to summ up the topic "just fly the big fat lady as you´ve been learned to do and everything will go quite slick"
peace
Joined: Mar 2001
Posts: 33
Likes: 0
From: Chicago, Illinois, USA
Oops. Thanks BizJet.
Yeppers, I aviate on the "Gander" side of things.
Sorry for the confusion.
I"ll have to try the 737 autoland in the sim next time I'm at the school house in Dallas. Interesting.... !
Pat
Yeppers, I aviate on the "Gander" side of things.
Sorry for the confusion.
I"ll have to try the 737 autoland in the sim next time I'm at the school house in Dallas. Interesting.... !
Pat
Joined: Jun 2001
Posts: 4,835
Likes: 85
From: Boldly going where no split infinitive has gone before..
a certified autoland system cannot have a failure mode (i.e. a failure of a single autopilot channel) that would jeopardise a safe landing.
