Transponder - Switch to ALT not just ON
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Transponder - Switch to ALT not just ON
Sorry about this for the regular flyers - but I am posting it so save peoples skin, airframe or hopefully just embarrasment (for you) and/or paperwork (for me).
I am not sure what training is given to newer pilots about operation of Transponders, but this is a problem I am seeing on about a dozen occassions every shift - often close to vertical or lateral CTA boundaries. And it is getting worse for some reason.
Please ensure the Transponder is selected to ALT when you line up - not just ON.
All those aircraft with TCAS get very twitchy if you are near the approach path (and the controllers) and you are not showing ALTITUDE.
(In G airspace in non-radar areas, or even in E airspace it might be your last line of passive defence)
*The only time your transponder should be switched only to ON in flight is if you are instructed to Squawk Alpha only when previously advised that the Altitude reporting is out of toelrance by the Radar Controller (tolerance +/- 200FT Displayed [Qnh Adjusted])
Transponder Basics (from Avweb)
I am not sure what training is given to newer pilots about operation of Transponders, but this is a problem I am seeing on about a dozen occassions every shift - often close to vertical or lateral CTA boundaries. And it is getting worse for some reason.
Please ensure the Transponder is selected to ALT when you line up - not just ON.
All those aircraft with TCAS get very twitchy if you are near the approach path (and the controllers) and you are not showing ALTITUDE.
(In G airspace in non-radar areas, or even in E airspace it might be your last line of passive defence)
*The only time your transponder should be switched only to ON in flight is if you are instructed to Squawk Alpha only when previously advised that the Altitude reporting is out of toelrance by the Radar Controller (tolerance +/- 200FT Displayed [Qnh Adjusted])
Transponder Basics (from Avweb)
Last edited by Shitsu_Tonka; 16th Oct 2006 at 14:09.
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Fun evening at the office, ****su?
And NAS has compounded the fact that when we call "vfr a/c tracking westerly at position X (scouring the charts for an obvious landmark) this is XXX centre, do you read?", we receive silence coz they're on one of 15 other appropriate frequencies.
And NAS has compounded the fact that when we call "vfr a/c tracking westerly at position X (scouring the charts for an obvious landmark) this is XXX centre, do you read?", we receive silence coz they're on one of 15 other appropriate frequencies.
****zu, good post and always good for a timely reminder. I drill my students, and I think most other instructors do the same regarding the use of transponders.
I think the problem is more of dodgy transponders than anything. In recent times I have flown aircraft with transponders whos knobs fall off, stiff to turn, the OFF SBY ON & ALT markings are either faded or worn off. Others, to be set on ALT, the knob index had to be turned 90 deg past the ALT detent. Got it working by trial and error.
Oh the joys of slipping into the seat to find in the instrument panel one of those flash Garmin transponders, you know, the ones with the numeric keys along the bottom of the unit. Was like a kid with a new toy........ and it even has a count up, or count down clock. Neato!!!
I think the problem is more of dodgy transponders than anything. In recent times I have flown aircraft with transponders whos knobs fall off, stiff to turn, the OFF SBY ON & ALT markings are either faded or worn off. Others, to be set on ALT, the knob index had to be turned 90 deg past the ALT detent. Got it working by trial and error.
Oh the joys of slipping into the seat to find in the instrument panel one of those flash Garmin transponders, you know, the ones with the numeric keys along the bottom of the unit. Was like a kid with a new toy........ and it even has a count up, or count down clock. Neato!!!
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I'm halfway(ish) through PPL training and have been properly told how to use the transponder, the difference between ON and ALT - although must confess I also thought it was Alternate for a long while 
The detailed information may have been only due to me being confused about the different modes (especially with the Mode S controversy) so read up on it and asked lots of questions.
It really should be drilled into people though, given its uses and the requirements for it especially with TCAS.
The detailed information may have been only due to me being confused about the different modes (especially with the Mode S controversy) so read up on it and asked lots of questions.
It really should be drilled into people though, given its uses and the requirements for it especially with TCAS.
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Transponders
Roger
Good point and when will that be????
Having a new (ish) one it is easy to tell what mode its in, some old units are not so good. So is there aproblem with leaving it on ALT right from Start up?
J
Good point and when will that be????
Having a new (ish) one it is easy to tell what mode its in, some old units are not so good. So is there aproblem with leaving it on ALT right from Start up?
J
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Poor Training
Good post ****su.
In my experience talking to a number of pilots when I'm accompanying them on flights, they are totally ignorant as to how an ATC radar system works, the function of the transponder in this process or how it affects a target on the ATC display or a transponder's impact on the ATC separation function itself.
One pilot recently told me that although he had read material on radar, he had no idea what "Mode C" really meant (what chance trying to describe what "Mode A" is?). Many private pilots that I have ever spoken to (and some commercial pilots) cannot even properly describe the function of each of the transponder modes and just select the modes based on what they have been told during training. One guy wasn't even aware that there was an ident button on the transponder and also had no idea what its purpose was!
Notwithstanding, the comments by Ozgrade 3 are also a significant contributor to the problem - particularly the illegibility of transponder mode markings. I've been caught there more than once.
In my experience talking to a number of pilots when I'm accompanying them on flights, they are totally ignorant as to how an ATC radar system works, the function of the transponder in this process or how it affects a target on the ATC display or a transponder's impact on the ATC separation function itself.
One pilot recently told me that although he had read material on radar, he had no idea what "Mode C" really meant (what chance trying to describe what "Mode A" is?). Many private pilots that I have ever spoken to (and some commercial pilots) cannot even properly describe the function of each of the transponder modes and just select the modes based on what they have been told during training. One guy wasn't even aware that there was an ident button on the transponder and also had no idea what its purpose was!
Notwithstanding, the comments by Ozgrade 3 are also a significant contributor to the problem - particularly the illegibility of transponder mode markings. I've been caught there more than once.
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Ozgrade3.
The obvious fix for that problem is for the flying schools and other operators to severely jump on their pilots who deliberately elect not to write up defects such as these in the maintenance release. In truth I suspect that the culture of being scared of the chief pilots reactions if a defect (especially avionics is written up,) is why Ozgrade 3's comment is so appropriate.
Leave it to the next 100 hourly is the usual excuse for not recording the snag - and yet it is the transponder read-out that could literally be the difference between life of death. You have only got to read the preliminary accident report where a Legacy twin jet had a mid-air with a 737 in South America where someone's failure to activate ALT on their transponder caused everyone on the 737 to be killed.
I think the problem is more of dodgy transponders than anything. In recent times I have flown aircraft with transponders whos knobs fall off, stiff to turn, the OFF SBY ON & ALT markings are either faded or worn off. Others, to be set on ALT, the knob index had to be turned 90 deg past the ALT detent. Got it working by trial and error.
Leave it to the next 100 hourly is the usual excuse for not recording the snag - and yet it is the transponder read-out that could literally be the difference between life of death. You have only got to read the preliminary accident report where a Legacy twin jet had a mid-air with a 737 in South America where someone's failure to activate ALT on their transponder caused everyone on the 737 to be killed.
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Maybe there should be a subsidy on offer for the 'new fangled Garmin' type units that even switch AUTOMATICALLY from mode A to C once the aircraft has taken off (activated by pressure change). The transponder becomes something that only has to be thought about for squawks then (and of course that count-up or count-down timer...
)
There is a lot that can be said for investment in new avionics... It is a better feeling than even an IT geek can imagine with having the latest computer upgrade...
)There is a lot that can be said for investment in new avionics... It is a better feeling than even an IT geek can imagine with having the latest computer upgrade...
Naval vessels quite often transmit a mode "A" type signal. For those of you who are TCAS equipped, a sudden "TA" ( TRAFFIC...TRAFFIC ) can quite often get your attention when flying into and out of Sydney.
A regular "TA" departing to the north off 34R appears to come from a gaggle of small naval vessels just to the west of Milsons point. I think they are Mine Sweepers. Anyone in the know care to comment?
When this is pointed out to ATC, often the response is " OH really, thats interesting", or words to that effect.
A regular "TA" departing to the north off 34R appears to come from a gaggle of small naval vessels just to the west of Milsons point. I think they are Mine Sweepers. Anyone in the know care to comment?
When this is pointed out to ATC, often the response is " OH really, thats interesting", or words to that effect.
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Krusty, What would you expect ATC to do about Naval Vessels? I think most navy vessels have Transponders; plus a whole lot more floating things.
The point of this thread is amking sure Mode C otherwise known as ALT is on unless you have been explicitly instructed to turn it off as it's out of tollerance; hopefully then you'll get aircraft as TAs with an altitude and can lessen the reaction to ship transponders etc.
Lets not forget there is a whole range of txpdrs out there without Mode C; and in G below A050 I think are not required.... So you will still get no Transponders and no ALT transponders below you in G or around you in G when you are there.
What's happening with low level ADS-B; surely they are the way forward; oh thta's right 'spoofing'.
The point of this thread is amking sure Mode C otherwise known as ALT is on unless you have been explicitly instructed to turn it off as it's out of tollerance; hopefully then you'll get aircraft as TAs with an altitude and can lessen the reaction to ship transponders etc.
Lets not forget there is a whole range of txpdrs out there without Mode C; and in G below A050 I think are not required.... So you will still get no Transponders and no ALT transponders below you in G or around you in G when you are there.
What's happening with low level ADS-B; surely they are the way forward; oh thta's right 'spoofing'.
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What's happening with low level ADS-B; surely they are the way forward;
[tongue in cheek mode]
Possibly one of the reasons DOTARS has taken over a lot of the political decisions on Airspace? [/tongue in cheek mode]
Last edited by Shitsu_Tonka; 17th Oct 2006 at 05:11.
****su_Tonka
You might like to elaborate on a situation which would only require mode alpha. Yesterday I was doing a scenic in Class C airspace, departed from a GAAP with ATIS QNH set and checked for accuracy. (was within 30') When handed over to Approach and maintaining 1500' I was told to re-cycle as he was receiving no mode C from my transponder. Recycled and back to Alt then was told my alt readout was 1700' and given the QNH. I replied that my QNH was already set and whether I needed to rectify my altitude. I was not given a response as the freq. was very busy.
Woul this be such a situation in which either the transponder signal is in error or something else?
You might like to elaborate on a situation which would only require mode alpha. Yesterday I was doing a scenic in Class C airspace, departed from a GAAP with ATIS QNH set and checked for accuracy. (was within 30') When handed over to Approach and maintaining 1500' I was told to re-cycle as he was receiving no mode C from my transponder. Recycled and back to Alt then was told my alt readout was 1700' and given the QNH. I replied that my QNH was already set and whether I needed to rectify my altitude. I was not given a response as the freq. was very busy.
Woul this be such a situation in which either the transponder signal is in error or something else?
Grandpa Aerotart
Yeah but?
Once I was doing 'a scenic' down the outside of Moreton Is...at an altitude that suggested mode C was innappropriate
and I got a call from Brissy asking me to switch it on..."aircraft tracking coastal Moreton Island Southbound squark mode charlie". Seems I was scaring the Boeing boys inbound from AKL. Everytime I fly a boeing in from AKL I am 5000+ feet crossing Moreton...tell em to fly higher...big girly's blouses
Do I get brownie points for being on the right frequency?
Once I was doing 'a scenic' down the outside of Moreton Is...at an altitude that suggested mode C was innappropriate
and I got a call from Brissy asking me to switch it on..."aircraft tracking coastal Moreton Island Southbound squark mode charlie". Seems I was scaring the Boeing boys inbound from AKL. Everytime I fly a boeing in from AKL I am 5000+ feet crossing Moreton...tell em to fly higher...big girly's blousesDo I get brownie points for being on the right frequency?
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Chadz,
1700 is within our tollerence; so that would be ok. But we might just confirm that you have the QNH right, seen many examples of wrong numbers set.
Often there is a difference with what the transponder transmits and what your altimiter says; sometimes it depends on which altimeter it is using if you have more than one too. Sometimes there is an error somewhere and it's just safer to turn it off, mode C that is, not the transponder.
With TCAS RAs it is very important to have an accurate output as TCAS might say climb to another aircraft to avoid you, but if your Transponder is broadcasting lower than you actually are then descent might be the better choice for the other aircraft, etc.
1700 is within our tollerence; so that would be ok. But we might just confirm that you have the QNH right, seen many examples of wrong numbers set.
Often there is a difference with what the transponder transmits and what your altimiter says; sometimes it depends on which altimeter it is using if you have more than one too. Sometimes there is an error somewhere and it's just safer to turn it off, mode C that is, not the transponder.
With TCAS RAs it is very important to have an accurate output as TCAS might say climb to another aircraft to avoid you, but if your Transponder is broadcasting lower than you actually are then descent might be the better choice for the other aircraft, etc.
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****su_Tonka
.../... maintaining 1500' I was told to re-cycle as he was receiving no mode C from my transponder. Recycled and back to Alt then was told my alt readout was 1700' and given the QNH.....
Would this be such a situation in which either the transponder signal is in error or something else?
.../... maintaining 1500' I was told to re-cycle as he was receiving no mode C from my transponder. Recycled and back to Alt then was told my alt readout was 1700' and given the QNH.....
Would this be such a situation in which either the transponder signal is in error or something else?
As an aside, The Qnh setting given by ATC of course doesn't affect your transponder but your True Altitude (not strictly speaking but close enough for the argument) - the transponder has it's own encoder linked to your static port(s). it will always report Pressure Altitude (i.e. your Altitude above the 1013.2 datum). The ATC radar data processor then adjusts to an Inidcated altitude based on auto/manual local Qnh input (the equivalent of asort of a radar sub-scale).
Qnh only affects where you as the pilot level off the aircraft - the transponder altitude (if calibrated) will always be accurate for PA. Some of the newer transponders will dislpay PA to the pilot - so unless the actual Qnh is in the range of ~ 1011-1015, it will generally show a different level to that you are actually at.
Everytime I fly a boeing in from AKL I am 5000+ feet crossing Moreton...tell em to fly higher...big girly's blouses
Do I get brownie points for being on the right frequency?
Do I get brownie points for being on the right frequency?
Hmmmm... but What is the appropriate frequency out there Chuck? [I normally monitor 125.7 and 126.7 on COM2.(YTGA/YDUN/YBCX etc.]