Airbus... Why "Autothrust" and not "Autothrottles"
Joined: Dec 2007
Posts: 175
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From: Cyprus
I seem to remember that Rolls-Royce insisted that when the throttle valve on a Merlin engine was wide open this was zero throttle, and quite right too. Idle was at about 85 degrees because the engine couldn't start with the throttle fully closed. But when the throttle levers were pushed fully forward for take-off the boost controllers partially closed the throttles to prevent over-boosting. The degree of closure depended on the density altitude (QFE, OAT) so who could say where the throttles were? And so the power lever was born, later to become the more trendy thrust lever. HTH 
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Last edited by Lancman; 10th June 2012 at 05:55.
Joined: May 2009
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From: HKG
LimaFoxTango
Errrr, think it says minimum. Which is in fact better English than minimums in the context it is said.
The same reason why the Airbus GPWS announces "Minima" and not "Minimums" like every other aircraft. Trust the French to teach the world how to speak English.
Last edited by SloppyJoe; 11th June 2012 at 21:39.
Joined: Nov 1999
Aviation Qualifications: ATPL
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From: UK
A 'throttle' is a circular plate situated usually downstream of a carburretor in the airstream of the inlet manifold. It is attached to a bar across its center which is hinged so that when turned it can present it's edge to the airflow with minimum impedance, or turn through 90 degrees and completely block the airflow. By this means the mass airflow allowed to pass into the engine, and therefore it's power output can be varied.
Since throttles are only used with carburretors, they are only strictly relevant when talking about engines which use carburretors. (e.g. piston engines).
Gas turbine engines do not have carburretors, but adjust the amount of fuel pumped into the combustion chambers to vary the thrust that the engine will produce, (or power, if it is a turbo prop.).
Therefore, a more correct term for the "engine output control levers" - when applied to gas turbines - is 'thrust levers', since that is the parameter which is varied by adjustment of their position.
Having said all that, they are often called throttles/throttle levers, because everyone knows what that means - a hangover from the piston engined aircraft a lot of us started on - it's a bit like calling your vacuum cleaner a 'Hoover' I suppose.
It's a bit of a pedantic point, but I hope this helps.
U
Since throttles are only used with carburretors, they are only strictly relevant when talking about engines which use carburretors. (e.g. piston engines).
Gas turbine engines do not have carburretors, but adjust the amount of fuel pumped into the combustion chambers to vary the thrust that the engine will produce, (or power, if it is a turbo prop.).
Therefore, a more correct term for the "engine output control levers" - when applied to gas turbines - is 'thrust levers', since that is the parameter which is varied by adjustment of their position.
Having said all that, they are often called throttles/throttle levers, because everyone knows what that means - a hangover from the piston engined aircraft a lot of us started on - it's a bit like calling your vacuum cleaner a 'Hoover' I suppose.
It's a bit of a pedantic point, but I hope this helps.
U
Last edited by Uplinker; 20th June 2012 at 02:08.
Joined: Jun 2012
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From: VTVJM
Interesting to know the reason behind it... I didn't know this for the longest time... Always thought the French were just trying to be different.
On a side note, did you guys know the traffic signal is called the robot in south Africa?
On a side note, did you guys know the traffic signal is called the robot in south Africa?
Joined: Apr 2006
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From: Front right seat
I agree that there is no room for the word 'throttle' in a jet operation. Airbus does however get in wrong with 'speedbrake'. No Airbus has speedbrakes, only flight spoilers. An F28 and a BAE146 have speed brakes.
Irrelevant I know
Irrelevant I know
Joined: Jan 2012
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From: Not far from the edge of the Milky Way Galaxy in the Orion Arm.
Autothrust
The thrust levers on the A320 do not move in unison with thrust changes made by the autothrust system. the thrust levers are put into a detent for that part of the flight, at the required time. thereinafter, the thrust is controlled by the autothrust system with no movement of the thrust levers.
There is also a vaiable thrust position which is manually controlled by the pilot from idle thrust (notwithstanding revers idle and reverse thrust etc) and can be used as a normal thrust lever up to the point of CLB (Climb thrust) which is the default setting for all the autothrust commands. If left in a position short of CLB then the thrust in the engines will not increase beyond the thrust lever position however much the autothrust system wants it to be so. Effectively, the autothrust system controls thrust and not the levers.
We can guage and monitor the thrust required, avaialble or selected (by us or the machine) by monitoring the N1, N2, EGT, and Fuel Flow indications.
further "thrust" settings/detents are FLX/MCT (take your pick) TOGA, Idle (manual) Idle Reverse and full Reverse, not only but also, the whole thrust system is monitored by FADEC too, which provides protections and re-starts and therefore thrust settings will be contained within maximum parameters taking into consideration the sensors of FADEC including temperature and a whole lot more, no doubt.
Thrust management.
I would like to thank, my manager, my agent, my parents, but most of all my pet canary called Boeing.
There is also a vaiable thrust position which is manually controlled by the pilot from idle thrust (notwithstanding revers idle and reverse thrust etc) and can be used as a normal thrust lever up to the point of CLB (Climb thrust) which is the default setting for all the autothrust commands. If left in a position short of CLB then the thrust in the engines will not increase beyond the thrust lever position however much the autothrust system wants it to be so. Effectively, the autothrust system controls thrust and not the levers.
We can guage and monitor the thrust required, avaialble or selected (by us or the machine) by monitoring the N1, N2, EGT, and Fuel Flow indications.
further "thrust" settings/detents are FLX/MCT (take your pick) TOGA, Idle (manual) Idle Reverse and full Reverse, not only but also, the whole thrust system is monitored by FADEC too, which provides protections and re-starts and therefore thrust settings will be contained within maximum parameters taking into consideration the sensors of FADEC including temperature and a whole lot more, no doubt.
Thrust management.
I would like to thank, my manager, my agent, my parents, but most of all my pet canary called Boeing.
Last edited by Natstrackalpha; 22nd June 2012 at 13:36.
Joined: Jun 2010
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From: TinselTown
So does this mean Cirrus drivers have a thrust lever, not a throttle? Seeing as the lever controls both RPM and MP to vary the amount of thrust. Or should we call them power levers. Or who cares what they're called.
Joined: Oct 2006
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From: Ankh Morpork, DW
You guys all wrong! They should be called "Newton's Second and Third Law Reaction Force Second Class Levers!"
I wonder if the guys who came up with the gas engine had critics saying, "You can't call that part a throat and this part a mouth! Those are animal parts."
I wonder if the guys who came up with the gas engine had critics saying, "You can't call that part a throat and this part a mouth! Those are animal parts."
Thread Starter
Joined: May 2005
Posts: 196
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From: usa
I just rode jumpseat on a USAirways A319.
Impressive cockpit - spacious, comfy, great air conditioning, pleasing to the eye.
But I must say - as far as Situational Awareness, it was definitely lacking.
-It was hard to tell who was the PF (I figured it out when the PF rotated, but only by leaning forward to see who was handling the "joy sticks". )
- I could not really tell how much control input the PF was making.
- PF told me that when hand flying, he could turn the stick left, then let it go - the plane would stay at that exact bank attitude and hold altitude. WTF?? Who's really flying the plane, the pilots or George?
- In the descent, I had a lot of trouble correlating the fact that the engines were at Flight Idle while the throttles were stuck at climb power position. WEIRD!!!
"Retard, Retard???" in the flare?? WHO comes up with this BS! Do we really need a computerized voice to remind us to take the power off? What's next, a voice to tell us to use the lav if we have to pee.
Airbus Human Factor engineering = EPIC FAIL, in my opinion... sorry to you Airbus enthusiasts, but I'm a pilot first, not a bloody computer game operator.
When I'm hand flying, I want to turn the yoke/stick, put some nose up trim, and make whatever control inputs necessary to hold altitude.
When the autothrottles are on, I WANT to see them move! Visual and tactical cues are extremely important in the area of Situational awareness.
Finally, I WANT to see my yoke/joy stick move when the other pilot makes an input. Otherwise we risk another AF447 scenario - one pilot is not aware that the other is holding the wrong control input.
Staying Boeing....
73
Impressive cockpit - spacious, comfy, great air conditioning, pleasing to the eye.
But I must say - as far as Situational Awareness, it was definitely lacking.
-It was hard to tell who was the PF (I figured it out when the PF rotated, but only by leaning forward to see who was handling the "joy sticks". )
- I could not really tell how much control input the PF was making.
- PF told me that when hand flying, he could turn the stick left, then let it go - the plane would stay at that exact bank attitude and hold altitude. WTF?? Who's really flying the plane, the pilots or George?
- In the descent, I had a lot of trouble correlating the fact that the engines were at Flight Idle while the throttles were stuck at climb power position. WEIRD!!!
"Retard, Retard???" in the flare?? WHO comes up with this BS! Do we really need a computerized voice to remind us to take the power off? What's next, a voice to tell us to use the lav if we have to pee.
Airbus Human Factor engineering = EPIC FAIL, in my opinion... sorry to you Airbus enthusiasts, but I'm a pilot first, not a bloody computer game operator.
When I'm hand flying, I want to turn the yoke/stick, put some nose up trim, and make whatever control inputs necessary to hold altitude.
When the autothrottles are on, I WANT to see them move! Visual and tactical cues are extremely important in the area of Situational awareness.
Finally, I WANT to see my yoke/joy stick move when the other pilot makes an input. Otherwise we risk another AF447 scenario - one pilot is not aware that the other is holding the wrong control input.
Staying Boeing....
73
Joined: Jan 2012
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From: Not far from the edge of the Milky Way Galaxy in the Orion Arm.
who`s flying the pilot or George . .?
Well, when the pilot banked the aeroplane your A319 and let go of the lever, then the aircraft was holding the attitude to within 1 G, this has nothing to do with George, we don`t refer to A/P as George anymore as George went off to marry Georgina, a nice young hostie, from Zanaduu Island, it is a shame that we all loved George, but we received a postcard from him, on his honeymoon and apparently Georgina, was not all she, or rather . . he, was cracked up to be. Still there won`t be the patter of tiny feet, rather a jingle of little drinks trollies.. They are still on their island living happily together (seeing as Georgina burnt the only rowing boat available and so he is kind of stuck with it).
The correct terminology of course is volume control. Levers forward, volume increases, levers rearward volume decreases. I love noisy approaches.
Sometimes it all goes quiet on the vestun front and therefore, the volume control is useless, to cater for this anomaly one could carry a ghetto blaster stereo set on which was recorded the distinct sounds of the CFMs.
Also we refer to the sidestick as a sidestick and not a joy stick. there have been many pilots with the name george, who have spent far too much internet time on long haul flights confusing joysticks with sidesticks. The sidestick cpncept was developed by a well developed student pilot with very large personalities whose multi-tasking skills came to the fore (or indeed the side) on those very long haul flights in the A330 and such.
Refreshingly down and technical don`t you think?
The correct terminology of course is volume control. Levers forward, volume increases, levers rearward volume decreases. I love noisy approaches.
Sometimes it all goes quiet on the vestun front and therefore, the volume control is useless, to cater for this anomaly one could carry a ghetto blaster stereo set on which was recorded the distinct sounds of the CFMs.
Also we refer to the sidestick as a sidestick and not a joy stick. there have been many pilots with the name george, who have spent far too much internet time on long haul flights confusing joysticks with sidesticks. The sidestick cpncept was developed by a well developed student pilot with very large personalities whose multi-tasking skills came to the fore (or indeed the side) on those very long haul flights in the A330 and such.
Refreshingly down and technical don`t you think?
Last edited by Natstrackalpha; 28th June 2012 at 10:37.
PPRuNe supporter
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From: Planet Earth
Airbus Human Factor engineering = EPIC FAIL, in my opinion... sorry to you Airbus enthusiasts, but I'm a pilot first, not a bloody computer game operator.
) move until I need them, either for Toga or landing, and let's not even talk about the autoflight systems, the Boeing is is like stepping back into the sixties, I'll be glad to get back to the bus!