Autopilot Engagement On Takeoff
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Autopilot Engagement On Takeoff
Can someone shed some light on why the limitation for autopilot engagement is 400' and why my company will only engage the a/p at 1500' agl,
and conversely the limitation of 158' minimum use height on approach for landing.
regards
and conversely the limitation of 158' minimum use height on approach for landing.
regards
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Safety!
If you engage the AP and it goes haywire it's better to be away from the ground.
On approach soft over and hard over tests are used to demonstrate height loss and this then sets the min use height.
158' is a bit high! what ac type?
If you engage the AP and it goes haywire it's better to be away from the ground.
On approach soft over and hard over tests are used to demonstrate height loss and this then sets the min use height.
158' is a bit high! what ac type?
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As for atr 42 min engagement is 100 ft AGL and disengagement is 160 ft for cat 1 and 80 ft for cat 2.However I don't engage the autopilot below 400 ft in climb out .
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Autopilot engagement is specified by the manufacturer, and has to do with the specified height loss specifications.
The L1011, for example, the autopilot can be engaged on the ground (CWS only), and moved to COMMAND, once airbourne.
NO height limitations.
However, having said this, those aircrft on the British/Omani register, cannot engage on the ground....for reasons known only to themselves.
Backward thinking, I would suspect.
The L1011, for example, the autopilot can be engaged on the ground (CWS only), and moved to COMMAND, once airbourne.
NO height limitations.
However, having said this, those aircrft on the British/Omani register, cannot engage on the ground....for reasons known only to themselves.
Backward thinking, I would suspect.
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I agree with the 400' being a safety height with regard to a possible unexpected outcome of engagement.
But, the 400' is set by the manufacturer as the minimum height, not the actual height. Any company can vary this (upwards) if they desire.
I understand the 737NG to have a minimum approach height of 50' on single autopilot.
Just my little bit...FD...
But, the 400' is set by the manufacturer as the minimum height, not the actual height. Any company can vary this (upwards) if they desire.
I understand the 737NG to have a minimum approach height of 50' on single autopilot.
Just my little bit...FD...
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Interesting replies.
Im talking specifically about 737-800. in limitations 400' is min height for autopilot engagement. company minimum is 1500' after N1 is annunciated.
and again 158' is minimunm use height on approach single channel(limitations)
Anyone else have anything more concrete?
Im talking specifically about 737-800. in limitations 400' is min height for autopilot engagement. company minimum is 1500' after N1 is annunciated.
and again 158' is minimunm use height on approach single channel(limitations)
Anyone else have anything more concrete?
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I know there are aircraft limits but i find that very low (just after rotation) altitudes the flight directors on my aircraft are still very lively an as far as i understand it (i'm still very new to airline flying) the a/p will run to the f/d's very quickly and could lead to some very interesting pitch levels ( i had it once in early line training when the a/c went to 24 degrees pitch and wanted to go higher after i put the a/p if i didn't intervene. poor rotation and poor following of flight ditrectors on my part granted but scary none the less)
I personally like hand flying untill we're flaps up and properly in trim. The aircraft gives it to me pretty much in trim when i take out the a/p i feel it's the least i could do to return the favour.
I personally like hand flying untill we're flaps up and properly in trim. The aircraft gives it to me pretty much in trim when i take out the a/p i feel it's the least i could do to return the favour.
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Hallo Joe.
Do you really need the autopilot on an ILS below 158´…?
The company you work for do not think so, and are therefore not willing to pay for that privilege…
But next time you are in the airplane, take a look in the book next to your left knee at the limitations pages, and you will se that the early A/C which have now been sold, as well as the ones that are in the process, have different limitations i.e. 50´ on an ILS, they also have different autoland limitations….
YOU GET WHAT YOU PAY FOR.
If you work for an Irish airline, you should know already by now, that it is all about the money...
Do you really need the autopilot on an ILS below 158´…?
The company you work for do not think so, and are therefore not willing to pay for that privilege…
But next time you are in the airplane, take a look in the book next to your left knee at the limitations pages, and you will se that the early A/C which have now been sold, as well as the ones that are in the process, have different limitations i.e. 50´ on an ILS, they also have different autoland limitations….
YOU GET WHAT YOU PAY FOR.
If you work for an Irish airline, you should know already by now, that it is all about the money...
On the 744, L NAV os available from 50', VNAV from 400'. Perhaps it's the same as the NG and this was the thinking. But it is type specific. On FBW Airbusses, the flight control laws change from ground mode to flight mode gradually over five seconds. So the APs cannot be engaged unti 50' or 5 seconds, whichever is later.
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In 73CL, our limitation is 1000 after takeoff and 50 ft during approach single channel.
After takeoff I normally engage CWS after 1000 ft for pax comfort. CMD only after not much movement of FD.
For approach, as long as aircraft following lateral and vertical path nicely, I let it do the job down to limitation.
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After takeoff I normally engage CWS after 1000 ft for pax comfort. CMD only after not much movement of FD.
For approach, as long as aircraft following lateral and vertical path nicely, I let it do the job down to limitation.
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Quote "For approach, as long as aircraft following lateral and vertical path nicely, I let it do the job down to limitation" unquote.
Then you might as well make an autoland. What's the fun in taking the aircraft manual only for the last 200 feet.
Then you might as well make an autoland. What's the fun in taking the aircraft manual only for the last 200 feet.
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ive experimented with this in the sim (738), basically anything lower than 100ft is regarded as alittle unsafe even in perfect conditions, and for some reason i have the tendancy to look outside for a few moments rather than scanning, wired. also engaging the AP at this level results in more fluctuation of the pitch angle on climbout.
Personally i have found enganging over 400ft allows for a stable climb out, like people has said above.
G-STAW
Personally i have found enganging over 400ft allows for a stable climb out, like people has said above.
G-STAW
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Sleeper,
Most airports I am operating into only CAT 1. Autoland not in my license as well.
aircraft following lateral and vertical path nicely is a keyword, many factors might affect and we must be prepared to disengage autopilot anytime.
For fun, I prefer to do it in sim. With paying passengers onboard I fly not for fun although I still enjoy every minute of it.
If probability for a go-around is remote, I use single channel. So stabilizer still in-trim below 400 RA.
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Most airports I am operating into only CAT 1. Autoland not in my license as well.
aircraft following lateral and vertical path nicely is a keyword, many factors might affect and we must be prepared to disengage autopilot anytime.
For fun, I prefer to do it in sim. With paying passengers onboard I fly not for fun although I still enjoy every minute of it.
If probability for a go-around is remote, I use single channel. So stabilizer still in-trim below 400 RA.
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Colleagues.
I'm very interested in this scenario. I've asked the question a few times, but had less response than this thread. Please may I contribute. As an aside, I've asked for any links to Boeing SOP's on how they conduct B378 departures. No success as yet.
Yes I've heard about the 1000'agl and the N1% engagement criterea on departure. Why, if there is no limitation problem do some operators use Flaps up? It wasn't even a limitation on the B732, though Britannia did it; and therefore so did many others. However, when BY received the B767 they engaged at 400' and watched what it did and then devised their training syllabus.
Moving on, why do some N1% operators still use Flaps up after a G/A? That is a more stressful manoeuvre, less practised, less height to level off etc. etc. and yet it is done in a high work load manner. Many mistakes seen in sim on the supposed simple manoeuvre. Very odd.
I've tried it in the sim on a V1 cut. A/P in at 400' and just fly the rudders. As PF it gives lots of capacity to follow PNF's analysis and watch the shop. It was a doddle. Same in an emergency turn and same in a 2 engine or SE G/A.
So why do most EU operators I've heard from on Prune not allow it?
I'm very interested in this scenario. I've asked the question a few times, but had less response than this thread. Please may I contribute. As an aside, I've asked for any links to Boeing SOP's on how they conduct B378 departures. No success as yet.
Yes I've heard about the 1000'agl and the N1% engagement criterea on departure. Why, if there is no limitation problem do some operators use Flaps up? It wasn't even a limitation on the B732, though Britannia did it; and therefore so did many others. However, when BY received the B767 they engaged at 400' and watched what it did and then devised their training syllabus.
Moving on, why do some N1% operators still use Flaps up after a G/A? That is a more stressful manoeuvre, less practised, less height to level off etc. etc. and yet it is done in a high work load manner. Many mistakes seen in sim on the supposed simple manoeuvre. Very odd.
I've tried it in the sim on a V1 cut. A/P in at 400' and just fly the rudders. As PF it gives lots of capacity to follow PNF's analysis and watch the shop. It was a doddle. Same in an emergency turn and same in a 2 engine or SE G/A.
So why do most EU operators I've heard from on Prune not allow it?
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Then you might as well make an autoland. What's the fun in taking the aircraft manual
Going into heathrow, its sometimes the case to get a late landing clearance (I.e less than 200 feet and regularly below 400 feet) and its far easier to go around with the auotomatics connected to free up capacity to watch what the aircraft is doing! I feel if a clearance is given at say 200 feet it is far safer to disconnect and land it than autoland- a) you have not briefed it. b) your mate in the other seat may not notice the aircrafts "NO FLARE" at 30 radio etc,? 
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RAT,
My operator permits the full use of the Autoflight systems within the aircraft limitations in the simulator. Except where manual flight is required for the purposes of Licence Proficiency Checks where a Manually flown SE ILS and GA is required. Where this occurs it is NOT intended to infer that this is the preferred mode of flight.
Subject of Autoflight engagement/disengagement;
The disengagement height is often quite high due to some aircraft starting to apply nose up trim below certain heights for the flare maneuovre and then the autopilot 'holds' against the trim for the rest of the approach. This is usual on a Fail Passive or Fail Operational Autoland capable aircraft. e.g. 757 Fail Operational when using only 2 Autopilots for a coupled ILS begins to apply nose up trim below 330FT for the flare. Should the autopilot be disconnected after this height the pilot will find it out of pitch trim by about 20-30lbs force. Should an automatic Go around be performed this increment of pitch trim is removed.
My operator permits the full use of the Autoflight systems within the aircraft limitations in the simulator. Except where manual flight is required for the purposes of Licence Proficiency Checks where a Manually flown SE ILS and GA is required. Where this occurs it is NOT intended to infer that this is the preferred mode of flight.
Subject of Autoflight engagement/disengagement;
The disengagement height is often quite high due to some aircraft starting to apply nose up trim below certain heights for the flare maneuovre and then the autopilot 'holds' against the trim for the rest of the approach. This is usual on a Fail Passive or Fail Operational Autoland capable aircraft. e.g. 757 Fail Operational when using only 2 Autopilots for a coupled ILS begins to apply nose up trim below 330FT for the flare. Should the autopilot be disconnected after this height the pilot will find it out of pitch trim by about 20-30lbs force. Should an automatic Go around be performed this increment of pitch trim is removed.
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Well if you work for FR, then what i have said is true about autopilot limits for landing...
you can find it yourself in the books, and see that the A/C that are being sold off, have different limitations...
sorry but that is the way it is...
you can find it yourself in the books, and see that the A/C that are being sold off, have different limitations...
sorry but that is the way it is...