Primarily for general aviation discussion, but other aviation topics are also welcome.
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By Boxkite
#1846719
riverrock wrote:
Boxkite wrote:
xtophe wrote:From the VASA youtube video (I haven't checked the original from LiveATC), tower did pass traffic information to the Cirrus crew on the Metroliner and the Cirrus reported traffic insight.

Not quite as I read it. He was told about the Metroliner and a Cessna. It is not clear which aircraft he was referring to when he reported "traffic insight".

The tower calls out the traffic they are following, a cessna, the Cirrus replies traffic in sight.
The tower then calls out additional traffic, a metroliner, northshore [presumably its position] landing on the parallel, the Cirrus replies traffic in sight...............0

In that case the earlier posted link to AOPA is incorrect: https://www.aopa.org/news-and-media/all ... mpaign=RSS
By riverrock
FLYER Club Member  FLYER Club Member
#1846723
Traffic wouldn't have been possible to keep in sight, as it would have been below his wing (others have said).
I suggest it would have been difficult for him to judge traffic speed / likely hood of closing before his turn due to the distance? He would (should) have been concentrating on lining up rather than looking for the traffic at that point.

On how far out on final, it appears he was extending downwind to follow the cessna who had turned final inside of him, although his downwind was fairly wide. I'd have thought he could turn in more tightly? No scale on that virtual radar video.

Out of curiosity I was wondering how many dots on a CDI he would be if he had been on an instrument approach. CDI would be 1 mile full deflection sensitivity for LNAV (as more than 2 nmi away from threshold), so the parallel final for 17L would be only 0.1nm away - so 10% off full deflection, so pretty much in the center of the CDI.
By Ibra
#1846733
riverrock wrote:Out of curiosity I was wondering how many dots on a CDI he would be if he had been on an instrument approach. CDI would be 1 mile full deflection sensitivity for LNAV (as more than 2 nmi away from threshold), so the parallel final for 17L would be only 0.1nm away - so 10% off full deflection, so pretty much in the center of the CDI.


Depends if he has WAAS or not?

It should be 0.3nm on LNAV for non-SBAS box all the time but with SBAS box you have localizer performance and angular guidance of CDI +/-2deg at some point, the geometry data is usually publised in FAS section of approach in AIP (I don't have plate to check course width and if linear scaling is applied, but I gather he will be 1/2 scale deflection on non-WAAS box and pretty much full CDI scale deflection with WAAS box
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By Josh
#1846747
There are all sorts of rules for proper parallel instrument approaches that this airport would not be able or willing to support. Visual separation is the US ATC go to and they are fairly permissive as long as the aircraft are in sight of one another.

I know that isn’t what you’re discussing but in a visual circuit if you are anything but eyes out something is wrong.
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By riverrock
FLYER Club Member  FLYER Club Member
#1846748
I thought LNAV was distance from center line - not angular, with LPV being angular (I'm not instrument rated).

Its academic anyway - they were both on visual approaches, and there isn't an instrument approach for 17R which the Cirrus was on. I was just trying to get a feel for how much he overshot by.
By IMCR
#1846753
I think discussion about IAPs while interesting, is not relevant, because this was clearly strictly a visual approach. I dont think either aircraft would have been doing anything else and they would have intended to position entirely on visual cues. If they were it would have been exceptionally irresposible because ATC were not providing any form of approach service or any seperation.
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By Tall_Guy_In_a_PA28
FLYER Club Member  FLYER Club Member
#1846784
riverrock wrote:Transponders can only switch if they have some sort of speed information, speed switch or weight on wheels reference. For example, the popular Trig TT21 needs ground/air info wired to it to automatically switch. Most small GA doesn't have that.

Garmin transponders (even the basic 328) use an altitude increase to trigger ALT mode if no other input is available. The altitude is programmable - I think the default is 20ft. Not sure why all manufacturers cannot do this as it works very well.

Regarding various previous posts that "my transponder behaves like this..." I would comment that much of the behaviour is programable via settings (considered once at installation and then forgotten) so two identical transponders can behave differently.

Regarding the use of ALT on the ground, "Lights, camera, action" that many of us were taught is now 'old school' and the US mandates ALT on the ground (FAR AIM 4-1-20), specifically
The FAA wrote:Select the transponder mode which allows altitude reporting and enable ADS-B during pushback or taxi-out from parking spot. Select TA or TA/RA (if equipped with TCAS) when taking the active runway.

CAA advise the same but I cannot find a reference in the AIP so I guess it is optional.
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By riverrock
FLYER Club Member  FLYER Club Member
#1846788
I don't know this with regards auto-on, but Garmin have a whole pile of patents around transponders to do obvious things, such as if you have a remote ADS-B device (say a Sky Echo 2) then it would be obvious for it to be able to recognise the Mode-S response from an installed transponder (based on the broadcast ICAO ID) and copy it's output Mode-A/C info into the ADS-B output. However I seem to remember a fight between Garmin and Uavionics about a patent on that ( https://www.avweb.com/avionics/adsb/gar ... t-lawsuit/ )
By riverrock
FLYER Club Member  FLYER Club Member
#1846791
A transponder with mode-s should be set to Ground when on the ground, so it can be correctly interrogated by ground radar and to not interfere with flying traffic - set to Alt when about to go flying. If your aircraft / transponder can do this automatically, then keep it set to Alt.

Pilot aware warned me about traffic that was taxiing on the ground at Prestwick last time I took off. A minor annoyance, but its the reason that people turn traffic info / alerts off in the circuit.
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By skydriller
FLYER Club Member  FLYER Club Member
#1846802
Tall_Guy_In_a_PA28 wrote:Garmin transponders (even the basic 328) use an altitude increase to trigger ALT mode if no other input is available.


Are you sure about this? I sometimes fly an aeroplane with a G328 and I distinctly remember that I was once asked by ATC to confirm Transponder was transmitting mode C/S for altitude. On checking the Transponder I realised I had turned it "ON" but not pressed "ALT" before take-off... on pressing the "ALT" button they confirmed all good... Not made that error since, but I admit I have not read the manual :oops:
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By skydriller
FLYER Club Member  FLYER Club Member
#1846806
Tall_Guy_In_a_PA28 wrote:I am sure about it for 'my' 328, but as I said all these options are configurable so 'your' 328 may behave differently.


Well its not "mine", but the aircraft owner does read this forum and I will ask him about it and your post has at least reminded me that despite thinking "I know how to use that gadget", perhaps I should find a manual to read... :thumleft:

Regards, SD..
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By PeteSpencer
FLYER Club Member  FLYER Club Member
#1846815
Three weeks ago on my second post lockdown flight at 2800 ft I was reminded by ATC that 'alt' was no showing from my Garmin 328. :oops:

It is pretty old and the installer is pretty well known for his thoroughness....................... :roll:

Break-break Just read our 328 pilots' guide (2011) which mentions that 'if 328 is configured for Automated Airborne Determination' normal Alt operation starts when takeoff speed detected.

When on ground screen automatically displays GND which does not respond to interrogation. When delay time is set in config mode, 328 after landing waits for a specified length of time before switching to GND.

Not thorough enough, evidently...................:roll:

Edit: @Dave W beat me to it :wink:
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