FPV and FPV Cage
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FPV and FPV Cage
Hi,
Can anybody tell me the difference bbetween Flight path Vector and Flight Path Caged vector.
It will be helpful if there are some images or documents about it.
Can anybody tell me the difference bbetween Flight path Vector and Flight Path Caged vector.
It will be helpful if there are some images or documents about it.
The Flight Path Vector (FPV) is a bit hard to say in the cockpit, so it is referred to as "The Bird", and looks thus:
When The HDG V/S – TRK FPA pushbutton on the Flight Control Unit (FCU - i.e. the autopilot control panel) is pushed, the flight director, normally either cross bars or V-bars (depending on customer option), is replaced by the Flight Path Director (FPD), a symbol which looks like a set of extended wings.
The pilot's task is then to fly the FPV onto the FPD bars, so that they look like one symbol:
Calling the FPV "caged" isn't a term I have heard is this respect, but may be a colloquial term in some companies.
When The HDG V/S – TRK FPA pushbutton on the Flight Control Unit (FCU - i.e. the autopilot control panel) is pushed, the flight director, normally either cross bars or V-bars (depending on customer option), is replaced by the Flight Path Director (FPD), a symbol which looks like a set of extended wings.
The pilot's task is then to fly the FPV onto the FPD bars, so that they look like one symbol:
Calling the FPV "caged" isn't a term I have heard is this respect, but may be a colloquial term in some companies.
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Also known as 'the budgie' so perhaps the 'caged' is a light-hearted expression to do with birds? A bit like 'strangle the parrot' and 'shoot the rabbit'.
Perhaps when the FPD overlays the FPV?
Perhaps when the FPD overlays the FPV?
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Hello Checkboard,
Do you mind me asking where does your last screenshot come from?
That FMA looks completely awkward to me (i.e. the boxed HDG when FPV and D are ON and few other things...!)...
Do you mind me asking where does your last screenshot come from?
That FMA looks completely awkward to me (i.e. the boxed HDG when FPV and D are ON and few other things...!)...
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That description must be airbus 
On the 737 the FPV does not replace the FD and both can be used indepently of each other. And the FPV is of course switched on and off on the EFIS control panel. Anyway, no caged FPV on the PFD available, only on a HUD.
PFD Indications change a bit with activated FPV though, a track indication appears on the horizon line and selected course will be displayed as a small mark on the horizon line.
On the 737 the FPV does not replace the FD and both can be used indepently of each other. And the FPV is of course switched on and off on the EFIS control panel. Anyway, no caged FPV on the PFD available, only on a HUD.
PFD Indications change a bit with activated FPV though, a track indication appears on the horizon line and selected course will be displayed as a small mark on the horizon line.
shortfuel - I just grabbed it from google images, I didn't even look at the site. Yes, it looks like a shopped image, the horizon should be at an angle, not the FPD etc etc.
Denti - yes, an airbus explanation.
Denti - yes, an airbus explanation.
The F18 (as in the twin tailed fighter) FPV can be caged by a pilot selection, in which case the drift element is removed, in order for the pilot to better determine angle of attack. In this case, when the drift exceeds a certain limit, a "ghost" FPV is also displayed.
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OK465, very nice explanation. And yes, i thought about that case as well and honestly do not know how our FPVs react in such a situation. It was always an advise for us to use the FPV during unreliable airspeed/altitude flight as it is IRS generated and makes for a very easy way to see if you fly level or not, same for descending or climbing actually.
The "Cage" of the "Bird"
aviator 521,
Checkboard's fine graphics show the FPV FD as provided on Airbus PFDs from the A320 (certificated 1988) and onwards.
The first EFIS PFD on Airbuses were on the A310 (certificated 1983) and A300-600. This includes a FPV symbol ("Bird") in the same form, but the FD is completely different from the A320 (and inferior). It consists of 4 dashes, arranged something like this:
(Sorry for the cheap graphics)
This was usually referred to as "the Cage", the idea being to fly "the Bird" into it. Perhaps this is what you are looking for. If you are unable to access an A310 Tech Manual, I might be able to dig-out mine. But OK465's idea may be the answer.
Chris
Checkboard's fine graphics show the FPV FD as provided on Airbus PFDs from the A320 (certificated 1988) and onwards.
The first EFIS PFD on Airbuses were on the A310 (certificated 1983) and A300-600. This includes a FPV symbol ("Bird") in the same form, but the FD is completely different from the A320 (and inferior). It consists of 4 dashes, arranged something like this:
|
_......._
_......._
|
(Sorry for the cheap graphics)
This was usually referred to as "the Cage", the idea being to fly "the Bird" into it. Perhaps this is what you are looking for. If you are unable to access an A310 Tech Manual, I might be able to dig-out mine. But OK465's idea may be the answer.
Chris
Last edited by Chris Scott; 30th May 2011 at 13:29. Reason: "Graphic" perfected...
The A300-600 does indeed have the cage .It looks like a hollow + sign.The FPA is set by the efis control panel and the course is set either by the selected VOR or ILS course.Unlike the FBW aircraft it cannot be directly controlled by the autopilot..
Quote from fmgc:
Doesn't the A300-600 have the bird caged rather than a moustache?
Quite...
Like I said, delete the "moustache" ("........."). (The A310 and A300-600 are identical.)
EDIT
Have now used colour to camouflage the moustache and add realism.
tubby linton,
According to my 1984 A310 tech manual, the proportions are about right?
Regards,
Chris
Doesn't the A300-600 have the bird caged rather than a moustache?
Quite...
Like I said, delete the "moustache" ("........."). (The A310 and A300-600 are identical.) EDIT
Have now used colour to camouflage the moustache and add realism.
tubby linton,
According to my 1984 A310 tech manual, the proportions are about right?
Regards,
Chris
Last edited by Chris Scott; 30th May 2011 at 17:29.
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Use of FPV is to be avoided if the reason for the unreliable speed are the static ports. Many simulators cannot simulate this failure, they only simulate pitot freezings and you may come to the conclusion that the FPV always gives a good indication.
Which makes me think of a question: in the ureliable speed procedure we have to level off and use the tables and then be able to troubleshoot. But how can we be sure that we are maintaining an altitude? If we have GPS available we can check the GPS page, but if not, how can we rule out a static problem?
Which makes me think of a question: in the ureliable speed procedure we have to level off and use the tables and then be able to troubleshoot. But how can we be sure that we are maintaining an altitude? If we have GPS available we can check the GPS page, but if not, how can we rule out a static problem?
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Microburst, is that an airbus fcom advise? Just asking as we were told on the boeing that the FPV is purely IRS driven, no air data input at all and therefore a good tool (however pitch and power is primary) to be used in IAS disagree situations.
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The systems manuals for the 737 state that there's a barometric input to the FPV:
The Flight Path Vector (FPV) symbol represents airplane flight path angle vertically and drift angle laterally. The flight path vector is displayed on the PFD when the EFIS control panel FPV switch is selected on. The FPV shows the Flight Path Angle (FPA) above or below the horizon line and drift angle left or right of the pitch scale's center. The FPA uses inertial and barometric altitude inputs. The vertical FPA is unreliable with unreliable primary altitude displays. (C) Boeing Aircraft Systems Manual.
This is contradicted by the QRH which states:
The flight path vector is based on inertial sources and may be used as a reference in maintaining proper path control. (C) Boeing.
The Flight Path Vector (FPV) symbol represents airplane flight path angle vertically and drift angle laterally. The flight path vector is displayed on the PFD when the EFIS control panel FPV switch is selected on. The FPV shows the Flight Path Angle (FPA) above or below the horizon line and drift angle left or right of the pitch scale's center. The FPA uses inertial and barometric altitude inputs. The vertical FPA is unreliable with unreliable primary altitude displays. (C) Boeing Aircraft Systems Manual.
This is contradicted by the QRH which states:
The flight path vector is based on inertial sources and may be used as a reference in maintaining proper path control. (C) Boeing.
Microburst, is that an airbus fcom advise?
A320 series QRH: Page 2.16
UNRELIABLE SPEED INDICATION/ADR CHECK PROC
...
...
- If remaining altitude indication is unreliable :
- Do not use FPV and/or V/S, which are affected.
Originally Posted by FCOM 1.34.10.1000.4
The system includes :
- three identical ADIRU's (Air Data and Inertial Reference Units).
Each ADIRU is divided in two parts, either of which can work separately in case of failure in the other :
• the ADR part (Air Data Reference) which supplies barometric altitude, airspeed, mach, angle of attack, temperature and overspeed warnings.
• the IR part (Inertial Reference) which supplies attitude, flight path vector, track, heading, accelerations, angular rates, ground speed and aircraft position.
- three identical ADIRU's (Air Data and Inertial Reference Units).
Each ADIRU is divided in two parts, either of which can work separately in case of failure in the other :
• the ADR part (Air Data Reference) which supplies barometric altitude, airspeed, mach, angle of attack, temperature and overspeed warnings.
• the IR part (Inertial Reference) which supplies attitude, flight path vector, track, heading, accelerations, angular rates, ground speed and aircraft position.
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denti, yes it is specific airbus
thankyou checkboard
it seems however that in boeing you have to disregard it too, when static is erroneus.
It seems that they could easily develop a tool for unreliable speed situations based on inertial so that at least we can level off and maintain an altitude so we can troubleshoot the faulty indication/s.
thankyou checkboard
it seems however that in boeing you have to disregard it too, when static is erroneus.
It seems that they could easily develop a tool for unreliable speed situations based on inertial so that at least we can level off and maintain an altitude so we can troubleshoot the faulty indication/s.
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they could easily develop a tool for unreliable speed situations based on inertial so that at least we can level off and maintain an altitude so we can troubleshoot the faulty indication/s.
Disregarding/rejecting the erroneous indicated data are the most difficult and resource consuming parts here. And I am not talking about troubleshooting yet but just about the mental process involved and required by the pilot to decide he now needs to set the a/c in this safe configuration before doing anything else!
IMHO, procedure and training are specifically lacking here (i.e. immediate actions in case of unreliable data (speed and/or altitude) at CRZ level).