Turkish airliner crashes at Schiphol
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No, it's "chuks."
Small "c" there.
Well, I have been in aviation for a while now and thought I knew most of the speed designations but this "Vz" threw me. Seriously, while we do have X, Y and Z axes, and those I know about, Vx and Vy have nothing to do with the X or Y axes so that this Vz business seems highly non-standard. ROC and ROD, rate of climb, rate of descent, that is understood by all so that I really think it's preferable.
Of course it is true that if one cannot dazzle with brilliance then to baffle with BS is a good alternative.
Well, I have been in aviation for a while now and thought I knew most of the speed designations but this "Vz" threw me. Seriously, while we do have X, Y and Z axes, and those I know about, Vx and Vy have nothing to do with the X or Y axes so that this Vz business seems highly non-standard. ROC and ROD, rate of climb, rate of descent, that is understood by all so that I really think it's preferable.
Of course it is true that if one cannot dazzle with brilliance then to baffle with BS is a good alternative.
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Of course it is true that if one cannot dazzle with brilliance then to baffle with BS is a good alternative
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Most of us would recognise VS - vertical speed, or ROD - rate of descent , but you are the first one I have heard using Vz in 32 years in the industry.
So, bullsh1t it may not be, but you are trying to invent (or at least introduce) a new acronym that it seems we are all unfamiliar with, why ?
Again , it all smacks a little of "the new kid in town" trying just that little TOO hard to impress.
Anyone can sit and digest reports and pontificate about this that & the other, but really, what REAL experience do you have ?
You said in an earlier post that you had suffered an emergency in which you were greatly helped by intervention from the ground.
With the greatest of respect unless you are a poor little PPL student lost in IMC and sheperded home by ATC , I doubt, if the situation could be influenced from the ground, that it could be categorised as an "emergency".
Losing both engines on short final in a twin engine wide bodied transport category jet aircraft. This you know off pat, EXACTLY what to do Eh ?
I am sorry guy, but you truly come across as a smart-ass armchair pilot, you can analyse everything, but did you actually, in your aviation career, do jacksh1t ? somehow I doubt it.
So, bullsh1t it may not be, but you are trying to invent (or at least introduce) a new acronym that it seems we are all unfamiliar with, why ?
Again , it all smacks a little of "the new kid in town" trying just that little TOO hard to impress.
Anyone can sit and digest reports and pontificate about this that & the other, but really, what REAL experience do you have ?
You said in an earlier post that you had suffered an emergency in which you were greatly helped by intervention from the ground.
With the greatest of respect unless you are a poor little PPL student lost in IMC and sheperded home by ATC , I doubt, if the situation could be influenced from the ground, that it could be categorised as an "emergency".
Losing both engines on short final in a twin engine wide bodied transport category jet aircraft. This you know off pat, EXACTLY what to do Eh ?
I am sorry guy, but you truly come across as a smart-ass armchair pilot, you can analyse everything, but did you actually, in your aviation career, do jacksh1t ? somehow I doubt it.
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With the greatest of respect unless you are a poor little PPL student lost in IMC and sheperded home by ATC , I doubt, if the situation could be influenced from the ground, that it could be categorised as an "emergency".
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It is your prerogative...
I have this wonderful little book, the "Airman's Information Manual," with a list of all the standard abbreviations. It was published by an ICAO-affiliated organisation you may well have heard of, the Federal Aviation Administration of the United States of America. Therein Vz does not appear at all while Vx and Vy are not considered to designate flight along the X and Y axes respectively, hence my scepticism towards this fresh input.
I must admit to occasionally having been proved somewhat less than all-knowing (what my detractors choose to call "ignorant") about all points of flying. This has led me to creep along rather cautiously when drawing conclusions about such things as here an accident or whether some fresh input is valid or not, perhaps even what the Brits call "duff gen," hence my question to you.
This is an old copy of the AIM I am working from so that I will look to see if Vz appears in the latest edition when, if so, you may expect a prompt aplogy by PM. Until then!
I must admit to occasionally having been proved somewhat less than all-knowing (what my detractors choose to call "ignorant") about all points of flying. This has led me to creep along rather cautiously when drawing conclusions about such things as here an accident or whether some fresh input is valid or not, perhaps even what the Brits call "duff gen," hence my question to you.
This is an old copy of the AIM I am working from so that I will look to see if Vz appears in the latest edition when, if so, you may expect a prompt aplogy by PM. Until then!
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So sorry chuks, I've been using a wrong acronym which nobody understood (and dared to ask about for many weeks...)
This of course blatantly demonstrates how amateurish and irrelevant were all of my previous posts, which is precisely why you took some of your precious time to address it.
May I suggest to introduce Vz as the best gliding speed for morons?
This of course blatantly demonstrates how amateurish and irrelevant were all of my previous posts, which is precisely why you took some of your precious time to address it.
May I suggest to introduce Vz as the best gliding speed for morons?
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In response to this and your kind PM, might I say that it doesn't render your contributions worthless. Although you have been particularly unreceptive in understanding the general opinion of the two accidents we are discussing on this thread, and have focused on the minutae rather than the big picture, using a (perhaps technically correct but ) totally unrecognised acronym just makes you seem like the classroom swot who is trying to sound oh so knowledgable to conceal his actual depth of understanding.
You are capable of sounding very convincing, but do you actually have any real understanding of the situation both crew found themselves in, and crucially, have you finally grasped the 1 very very vital difference in what happened ? Some of your recent posts lead me to believe that you have finally acknowledged the difference, 1 crew were trying to extricate themselves from deep sh1t not of their own making, the other dropped themselves in the merde with little excuse.
If you truly understood this, you could perhaps be taken more seriously.
I don't doubt you are well intentioned, and I regret having to take such a robust stand against some of your comments, but you really should listen to what we (often very patiently ) are trying to convey to you, rather than repeatedly pushing your pet theory. Crashing a pretty much perfectly serviceable aircraft is NOT the same as rendering an inevitable crash survivable for all on board, if you want to retain any credibility, please try to understand this very vital difference.
You are capable of sounding very convincing, but do you actually have any real understanding of the situation both crew found themselves in, and crucially, have you finally grasped the 1 very very vital difference in what happened ? Some of your recent posts lead me to believe that you have finally acknowledged the difference, 1 crew were trying to extricate themselves from deep sh1t not of their own making, the other dropped themselves in the merde with little excuse.
If you truly understood this, you could perhaps be taken more seriously.
I don't doubt you are well intentioned, and I regret having to take such a robust stand against some of your comments, but you really should listen to what we (often very patiently ) are trying to convey to you, rather than repeatedly pushing your pet theory. Crashing a pretty much perfectly serviceable aircraft is NOT the same as rendering an inevitable crash survivable for all on board, if you want to retain any credibility, please try to understand this very vital difference.
Originally Posted by chuks
1. Do you hold any sort of pilot's licence/license and if so what is your level of experience? For instance, have you flown large aircraft into Schiphol?
Originally Posted by S.F.L.Y.
Since last year I've already submitted 2 applications to AA (old and new form) and never got any news from them (like many other companies in the region). As I was not expecting anything under such circumstances I intended to go for a self sponsored 737 TR with CAE. Despite 2 face to face meetings and few calls and Emails since October I'm still waitingf for a way to initiate this $25k training...
Originally Posted by S.F.L.Y.
I'm looking for info regarding recruitment & requirements for the B4 sightseeing ops in DXB.
I've been mostly flying military fixed wings (2500H) and I only have 500 H on single turbine attack helicopters but I would love to do this job (despite some of your valuable comments, I have my own reasons).
I've been mostly flying military fixed wings (2500H) and I only have 500 H on single turbine attack helicopters but I would love to do this job (despite some of your valuable comments, I have my own reasons).
Originally Posted by S.F.L.Y.
Just for my personal information, where does the requirement of a full ATPL comes for being capt. on a B1900, even in multi crew? I've been flying multi crew 406s (also FAR23) in Europe without needing it and as far as I know CARs and JARs are quite similar.
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S.F.L.Y
It has long been my belief that each accident is an isolated occurrence, more to be gained from it by avoiding commonalities than pointing them out. Exceptions? Electra, Comet, C-5.
My suggestion if you like is to compare Burkill to Sully.
Both twins, both nearly complete loss of Power at very low altitude, unsuccessful return of power, and forced landing off runway.
I'd read that, I would.
bear
It has long been my belief that each accident is an isolated occurrence, more to be gained from it by avoiding commonalities than pointing them out. Exceptions? Electra, Comet, C-5.
My suggestion if you like is to compare Burkill to Sully.
Both twins, both nearly complete loss of Power at very low altitude, unsuccessful return of power, and forced landing off runway.
I'd read that, I would.
bear
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How does SFLY keep getting allowed to post any more. Maybe the entertainment? He is totally out of step with the rest of us and doesn't make much sense. Notice, nobody agrees with him on anything?
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[edit] Regulatory V-speeds
These V-speeds are defined by regulations.
V-speed designatorDescriptionV1Critical engine failure recognition speed. (See V1 definitions below)[7][8][9]V2Takeoff safety speed. The speed at which the aircraft may safely become airborne with one engine inoperative.[7][8][9]V2minMinimum takeoff safety speed.[7][8][9]V3Flap retraction speed.[8][9]V4Steady initial climb speed. The all engines operating take-off climb speed used to the point where acceleration to flap retraction speed is initiated. Should be attained by a gross height of 400 feet.[10]VADesign maneuvering speed, also known as the "Speed for maximum control deflection." This is the speed above which it is unwise to make full application of any single flight control (or "pull to the stops") as it may generate a force greater than the aircraft's structural limitations.[7][8][11][9] The heavier an aircraft is loaded the faster this speed.VBDesign speed for maximum gust intensity.[7][8][9]VCDesign cruising speed, also known as the optimum cruise speed, is the most efficient speed in terms of distance, speed and fuel usage.[7][8][11][9]VDDesign diving speed.[7][8][9]VDFDemonstrated flight diving speed.[7][8][9]VEFThe speed at which the Critical engine is assumed to fail during takeoff.[7]VFDesigned flap speed.[7][8][9]VFCMaximum speed for stability characteristics.[7][9]VFEMaximum flap extended speed.[7][8][9]VFTOFinal takeoff speed.[7]VHMaximum speed in level flight at maximum continuous power.[7][8][9]VLEMaximum landing gear extended speed. This is the maximum speed at which it is safe to fly a retractable gear aircraft with the landing gear extended.[7][8][9][12]VLOMaximum landing gear operating speed. This is the maximum speed at which it is safe to extend or retract the landing gear on a retractable gear aircraft.[7][8][9][12]VLOFLift-off speed.[7][9]VMCMinimum control speed with Critical engine inoperative.[7][8][9]VmcaMinimum control speed in the take-off configuration – the minimum calibrated airspeed at which the aircraft is directionally controllable in flight with a sudden Critical engine failure and takeoff power on the operative engine(s).[9]VmcgMinimum control speed on the ground - the minimum airspeed at which the aircraft is directionally controllable during acceleration along the runway with one engine inoperative, takeoff power on the operative engine(s), and with nose wheel steering assumed inoperative.[9][13]VMOMaximum operating limit speed.[7][8][9]VMUMinimum unstick speed.[7][8][9]VNENever exceed speed.[7][8][9][14]VNOMaximum structural cruising speed or maximum speed for normal operations.[7][8][9]VRRotation speed. The speed at which the aircraft's nosewheel leaves the ground.[7][8][9]VRefLanding reference speed or threshold crossing speed.[7][8][9]VSStall speed or minimum steady flight speed for which the aircraft is still controllable.[7][8][9]VS0Stall speed or minimum flight speed in landing configuration.[7][8][9]VS1Stall speed or minimum steady flight speed for which the aircraft is still controllable in a specific configuration.[7][8]VSRReference stall speed.[7]VSR0Reference stall speed in landing configuration.[7]VSR1Reference stall speed in a specific configuration.[7]VSWSpeed at which the stall warning will occur.[7]VTOSSCategory A rotorcraft takeoff safety speed.[7][14]VXSpeed that will allow for best angle of climb.[7][8]VYSpeed that will allow for the best rate of climb.[7][8]
[edit] Other V-speeds
Some of these V-speeds are specific to particular types of aircraft and are not defined by regulations.
V-speed designatorDescriptionVBEBest endurance speed – the speed that gives the greatest airborne time for fuel consumed. This may be used when there is reason to remain aloft for an extended period, such as waiting for a forecast improvement in weather on the ground.[11]VBGBest power-off glide speed – the speed that provides maximum lift-to-drag ratio and thus the greatest gliding distance available.[11]VBRBest range speed – the speed that gives the greatest range for fuel consumed - identical to Vmd.[15]VFSFinal segment of a departure with one powerplant failed.[16]VimdMinimum drag[17]VimpMinimum power[17]VLLOMaximum landing light operating speed – for aircraft with retractable landing lights.[9]VmbeMaximum brake energy speed[18][17]VmdMinimum drag- identical to VBR.[15][18]VmclMinimum control speed in the air in an approach or landing configuration with one engine inoperative.[9]VminMinimum speed for instrument flight (IFR) for helicopters[14]VmpMinimum power[18]VpAquaplaning speed[19]VPDMaximum speed at which whole-aircraft parachute deployment has been demonstrated[20]VraRough air speed (turbulence penetration speed).[9]VSLstall speed in a specific configuration[9][18]Vs1gstall speed at maximum lift coefficient[18]VsseSafe single engine speed[21]VtThreshold speed[18]VtocsTake-off climbout speed (helicopters)[14]VtosMinimum speed for a positive rate of climb with one engine inoperative[18]VtmaxMax threshold speed[22][18]VwoMaximum window or canopy open operating speed[23]VXSEBest angle of climb speed with a single operating engine in a light, twin-engine aircraft – the speed that provides the most altitude gain per unit of horizontal distance following an engine failure.[21]VYSEBest rate of climb speed with a single operating engine in a light, twin-engine aircraft – the speed that provides the most altitude gain per unit of time following an engine failure.[12][21]VZRCZero rate of climb speed in a twin-engine aircraft[18]
Can't find any VZ speeds for the morons our friend is referring to. Maybe he just had a brain fart again.
These V-speeds are defined by regulations.
V-speed designatorDescriptionV1Critical engine failure recognition speed. (See V1 definitions below)[7][8][9]V2Takeoff safety speed. The speed at which the aircraft may safely become airborne with one engine inoperative.[7][8][9]V2minMinimum takeoff safety speed.[7][8][9]V3Flap retraction speed.[8][9]V4Steady initial climb speed. The all engines operating take-off climb speed used to the point where acceleration to flap retraction speed is initiated. Should be attained by a gross height of 400 feet.[10]VADesign maneuvering speed, also known as the "Speed for maximum control deflection." This is the speed above which it is unwise to make full application of any single flight control (or "pull to the stops") as it may generate a force greater than the aircraft's structural limitations.[7][8][11][9] The heavier an aircraft is loaded the faster this speed.VBDesign speed for maximum gust intensity.[7][8][9]VCDesign cruising speed, also known as the optimum cruise speed, is the most efficient speed in terms of distance, speed and fuel usage.[7][8][11][9]VDDesign diving speed.[7][8][9]VDFDemonstrated flight diving speed.[7][8][9]VEFThe speed at which the Critical engine is assumed to fail during takeoff.[7]VFDesigned flap speed.[7][8][9]VFCMaximum speed for stability characteristics.[7][9]VFEMaximum flap extended speed.[7][8][9]VFTOFinal takeoff speed.[7]VHMaximum speed in level flight at maximum continuous power.[7][8][9]VLEMaximum landing gear extended speed. This is the maximum speed at which it is safe to fly a retractable gear aircraft with the landing gear extended.[7][8][9][12]VLOMaximum landing gear operating speed. This is the maximum speed at which it is safe to extend or retract the landing gear on a retractable gear aircraft.[7][8][9][12]VLOFLift-off speed.[7][9]VMCMinimum control speed with Critical engine inoperative.[7][8][9]VmcaMinimum control speed in the take-off configuration – the minimum calibrated airspeed at which the aircraft is directionally controllable in flight with a sudden Critical engine failure and takeoff power on the operative engine(s).[9]VmcgMinimum control speed on the ground - the minimum airspeed at which the aircraft is directionally controllable during acceleration along the runway with one engine inoperative, takeoff power on the operative engine(s), and with nose wheel steering assumed inoperative.[9][13]VMOMaximum operating limit speed.[7][8][9]VMUMinimum unstick speed.[7][8][9]VNENever exceed speed.[7][8][9][14]VNOMaximum structural cruising speed or maximum speed for normal operations.[7][8][9]VRRotation speed. The speed at which the aircraft's nosewheel leaves the ground.[7][8][9]VRefLanding reference speed or threshold crossing speed.[7][8][9]VSStall speed or minimum steady flight speed for which the aircraft is still controllable.[7][8][9]VS0Stall speed or minimum flight speed in landing configuration.[7][8][9]VS1Stall speed or minimum steady flight speed for which the aircraft is still controllable in a specific configuration.[7][8]VSRReference stall speed.[7]VSR0Reference stall speed in landing configuration.[7]VSR1Reference stall speed in a specific configuration.[7]VSWSpeed at which the stall warning will occur.[7]VTOSSCategory A rotorcraft takeoff safety speed.[7][14]VXSpeed that will allow for best angle of climb.[7][8]VYSpeed that will allow for the best rate of climb.[7][8]
[edit] Other V-speeds
Some of these V-speeds are specific to particular types of aircraft and are not defined by regulations.
V-speed designatorDescriptionVBEBest endurance speed – the speed that gives the greatest airborne time for fuel consumed. This may be used when there is reason to remain aloft for an extended period, such as waiting for a forecast improvement in weather on the ground.[11]VBGBest power-off glide speed – the speed that provides maximum lift-to-drag ratio and thus the greatest gliding distance available.[11]VBRBest range speed – the speed that gives the greatest range for fuel consumed - identical to Vmd.[15]VFSFinal segment of a departure with one powerplant failed.[16]VimdMinimum drag[17]VimpMinimum power[17]VLLOMaximum landing light operating speed – for aircraft with retractable landing lights.[9]VmbeMaximum brake energy speed[18][17]VmdMinimum drag- identical to VBR.[15][18]VmclMinimum control speed in the air in an approach or landing configuration with one engine inoperative.[9]VminMinimum speed for instrument flight (IFR) for helicopters[14]VmpMinimum power[18]VpAquaplaning speed[19]VPDMaximum speed at which whole-aircraft parachute deployment has been demonstrated[20]VraRough air speed (turbulence penetration speed).[9]VSLstall speed in a specific configuration[9][18]Vs1gstall speed at maximum lift coefficient[18]VsseSafe single engine speed[21]VtThreshold speed[18]VtocsTake-off climbout speed (helicopters)[14]VtosMinimum speed for a positive rate of climb with one engine inoperative[18]VtmaxMax threshold speed[22][18]VwoMaximum window or canopy open operating speed[23]VXSEBest angle of climb speed with a single operating engine in a light, twin-engine aircraft – the speed that provides the most altitude gain per unit of horizontal distance following an engine failure.[21]VYSEBest rate of climb speed with a single operating engine in a light, twin-engine aircraft – the speed that provides the most altitude gain per unit of time following an engine failure.[12][21]VZRCZero rate of climb speed in a twin-engine aircraft[18]
Can't find any VZ speeds for the morons our friend is referring to. Maybe he just had a brain fart again.
p51guy (#2607) you might have done better to consult the actual certification documents rather than use Wiki. The information there may only be an interpretation and not always correct:- ‘care to "get it right" ’ – item 1 from the first link in http://www.pprune.org/rumours-news/3...ml#post5480904.
Refs:-
Definitions: www.easa.eu.int/.../CS-Definitions_CONSOLIDATED_Def%20Amdt.%201%20(14.12.07).pdf
Certification specifications (CS-25): Agency Measures | Certification specifications
Refs:-
Definitions: www.easa.eu.int/.../CS-Definitions_CONSOLIDATED_Def%20Amdt.%201%20(14.12.07).pdf
Certification specifications (CS-25): Agency Measures | Certification specifications
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The reason for the crash as it looks now is they let the speed deteriorate to stick shaker and added go around power without trimming the aircraft proportional to the power increase. They let it go to max go around power without retrimming during the transition. A manually flown approach or go around would have allowed the pilot to feel the effect of the underslung engines pitching the nose up. That would have been what he needed to not let it go to go around power until he was trimmed properly. Automation works most of the time but not all of the time. I doubt it is tested to stickshaker and go around power because of the speed of the trim with the autothrottle going to max. A pilot can compensate for the out of trim position.
so what was the reason for the crash?
“Accidents arise from the unforeseen and often unforeseeable concatenation (linking) of diverse events, each one necessary, but singularly insufficient”. - James Reason
Look for the contributions which are part of everyday operations – those we take for granted, but might not fully appreciate the risks; e.g. ATM patterns, training crewing, use of automation, instrument scan, systems knowledge, etc, etc.
Then consider the unique event(s) which enabled these weaknesses to combine; and the ‘unsafe act’ (or inaction) which triggered the route to the accident – issues of human performance, didn’t see ‘it’, didn’t think of 'it' at the time, etc, and the likely reasons for these.
There’s no ‘cause’, only contributions; perhaps a significant one is the industry’s complacency in accepting operations which are too close to the edge of safety – they have become the norm, whereas each requires continuous risk assessment for the expected task and situation.
“Accidents arise from the unforeseen and often unforeseeable concatenation (linking) of diverse events, each one necessary, but singularly insufficient”. - James Reason
Look for the contributions which are part of everyday operations – those we take for granted, but might not fully appreciate the risks; e.g. ATM patterns, training crewing, use of automation, instrument scan, systems knowledge, etc, etc.
Then consider the unique event(s) which enabled these weaknesses to combine; and the ‘unsafe act’ (or inaction) which triggered the route to the accident – issues of human performance, didn’t see ‘it’, didn’t think of 'it' at the time, etc, and the likely reasons for these.
There’s no ‘cause’, only contributions; perhaps a significant one is the industry’s complacency in accepting operations which are too close to the edge of safety – they have become the norm, whereas each requires continuous risk assessment for the expected task and situation.
Originally Posted by safety pee
whereas each requires continuous risk assessment for the expected task and situation.
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Originally Posted by p51guy today
The reason for the crash as it looks now is they let the speed deteriorate to stick shaker and added go around power without trimming the aircraft proportional to the power increase.
Originally Posted by p51guy yesterday
One was going to crash no matter what and the other needed manual thrust to go around when the RA malfunction retarded the throttles at a fairly high altitude.
Btw (this means "by the way" and it is not an EASA approved certification speed), I suggest you read slower, that way you wouldn't have missed that Vz isn't an indicated "V" speed but an acronym for vertical speed (speed on the Z axis). It's commonly used by scientists, designers, military pilots and some amateurs).
I sincerely do apologize for all the generated confusion by this very serious matter as it prevail over any other sensible comments I could have posted.
Bearfoil, in regard to your comment on accident comparisons, let me one more time explain that I'm not trying to compare accidents by physics but by human behavior. In these particular cases the situational awareness and acceptance by crews are very interesting. Sully was climbing when he lost his engines... and didn't wait for the stick shaker to react. His capacity to understand, accept and change is mindset for a new strategy in a very short moment was remarkable and noticed by most of us. The (ab)use of automated systems often contributes to extend the disbelief period, delaying proper identification and correction of determined issues. Why waiting for the AT to correct a low speed? Why staring at the AP wasting energy on a wrong path during a VMC approach?
Last edited by S.F.L.Y; 1st Feb 2010 at 04:07.
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Why a new acronym?
I think you might want to drop this Vz term and revert to ROC (Rate of Climb) and ROD (Rate of Descent), S.F.L.Y. That way all of us can be clear about whatever it is you want to tell us. When you stated in a previous post that there was a "high Vz" then it was unclear, to me at least, not just what was meant by Vz but also whether you were referring to ROC or ROD , since the Z axis does have a vertical extent in both directions, positive and negative.
It is not that we are too stupid to understand your prose, just that what you have written is both non-standard and ambiguous and I am happy to share that insight with you as, for one thing, an FAA-licensed Ground Instructor. You, on the other hand, are perfectly free to reject this insight of mine should you so choose, this being just one of the really neat things about PPRuNe.
These axes, X, Y and Z, are more commonly used theoretically to define roll, pitch and yaw respectively around an aircraft in flight's CG (Centre of Gravity) than, as you are using one of them in isolation, some sort of flight path. (Of course an aircraft in flight, free to move in space as it is, rarely moves purely around one axis; it is simply easier to teach the principles of flight by considering them in isolation.) It's fortunately rare to experience motion along the Z axis alone so that Vz as a flight path is generally not a valid description. Instead we usually combine forward speed and vertical speed to arrive at a flight path vector, not the same thing as what you choose to call Vz at all. You may be using an ROD of 2500 fpm but with a TAS of 400 knots for a very different flight path than what an ROD of only 1500 fpm but 80 knots yields, when what matters to us as pilots is the flight path vector (and perhaps the pitch attitude if we want to avoid those thumping noises the trolleys make as they smack into the cockpit door) and not the ROD alone.
In other words, I want to know the energy state of my aircraft, not just its IAS and ROD. If both are high or if just the IAS is high then I have an aircraft with lots of energy stored. If both are low but steady then I have an aircraft without much stored energy but perhaps not much need for energy. If I have an aircraft with a low and diminishing IAS or a low IAS and a high ROD then I need to be thinking ahead to putting some energy into it using either gravity (assuming altitude to spare) or else engine thrust or perhaps both together because sooner or later I am going to need to alter its flight path. We will need to read this accident report to discover the reason for this accident crew having overlooked this very obvious first principle many have already cited here, what we teach a beginner as simple awareness of airspeed as a top priority.
It is not that we are too stupid to understand your prose, just that what you have written is both non-standard and ambiguous and I am happy to share that insight with you as, for one thing, an FAA-licensed Ground Instructor. You, on the other hand, are perfectly free to reject this insight of mine should you so choose, this being just one of the really neat things about PPRuNe.
These axes, X, Y and Z, are more commonly used theoretically to define roll, pitch and yaw respectively around an aircraft in flight's CG (Centre of Gravity) than, as you are using one of them in isolation, some sort of flight path. (Of course an aircraft in flight, free to move in space as it is, rarely moves purely around one axis; it is simply easier to teach the principles of flight by considering them in isolation.) It's fortunately rare to experience motion along the Z axis alone so that Vz as a flight path is generally not a valid description. Instead we usually combine forward speed and vertical speed to arrive at a flight path vector, not the same thing as what you choose to call Vz at all. You may be using an ROD of 2500 fpm but with a TAS of 400 knots for a very different flight path than what an ROD of only 1500 fpm but 80 knots yields, when what matters to us as pilots is the flight path vector (and perhaps the pitch attitude if we want to avoid those thumping noises the trolleys make as they smack into the cockpit door) and not the ROD alone.
In other words, I want to know the energy state of my aircraft, not just its IAS and ROD. If both are high or if just the IAS is high then I have an aircraft with lots of energy stored. If both are low but steady then I have an aircraft without much stored energy but perhaps not much need for energy. If I have an aircraft with a low and diminishing IAS or a low IAS and a high ROD then I need to be thinking ahead to putting some energy into it using either gravity (assuming altitude to spare) or else engine thrust or perhaps both together because sooner or later I am going to need to alter its flight path. We will need to read this accident report to discover the reason for this accident crew having overlooked this very obvious first principle many have already cited here, what we teach a beginner as simple awareness of airspeed as a top priority.
Last edited by chuks; 1st Feb 2010 at 06:55.
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I wonder if I may attempt some gentle knicker-untwisting so that, like MD83FO, we can attempt to return this thread to the THY crash at AMS rather than a discussion on scientific abbreviations?
Surely the evident massed 'intelligence' here of aviators on this board were able to deduce what the poster meant by 'Vz'? I took me less than .1 of a second to make a subconscious (and correct) assumption that SFLY meant vertical speed and had in fact allocated a scientific factor - velocity in the Z axis - to an aeronautical item. I would assume that most of us knew the term was meant to represent downwards in the context it was used? The fact that he/she used the incorrect aeronautical terminology (velocity in aspects of stability and control are commonly U, V and W in each of the axes, and here would have been -W) is not actually of world-shattering importance, is it?
I for one am more interested in knowing what happened in this accident than in wondering whether I should be setting a Vz of (-)750fpm or a (-)Vs.
Surely the evident massed 'intelligence' here of aviators on this board were able to deduce what the poster meant by 'Vz'? I took me less than .1 of a second to make a subconscious (and correct) assumption that SFLY meant vertical speed and had in fact allocated a scientific factor - velocity in the Z axis - to an aeronautical item. I would assume that most of us knew the term was meant to represent downwards in the context it was used? The fact that he/she used the incorrect aeronautical terminology (velocity in aspects of stability and control are commonly U, V and W in each of the axes, and here would have been -W) is not actually of world-shattering importance, is it?
I for one am more interested in knowing what happened in this accident than in wondering whether I should be setting a Vz of (-)750fpm or a (-)Vs.