One of the clubs at Lelystad has just had an audit by the CAA and has been issued a notice of non-compliance because their aircraft have been fitted with GNS430s and retained the original 25kHz radios as a second box.
Is this a question of the Dutch applying legislation as strictly as possible or is it purely a local thing?
In my opinion its a european rule (euro control)
http://www.daec.de/fileadmin/user_upload/files/2012/fachbereiche/luftfahrttechnik/201012—-Info-Eurocontrol.pdf
page 6 quote : All radios operating in the ICAO EUR region should have the 8.33 kHz channel spacing capability
this because the transmitter frequention spectrum (bandwith) of the “old” 25khz is mutch wider than the new 8.33khz radios , using the old radio’s could cause interference (jamming) on the adjacent-channel
removing,disabling this 25khz com radio will make this aircraft comply to the 8.33 rules but not for IFR (then you need 2ea 8.33khz radios)
Just placard one of them inop.
Jetprop wrote:
this because the transmitter frequention spectrum (bandwith) of the “old” 25khz is much wider than the new 8.33khz radios , using the old radio’s could cause interference (jamming) on the adjacent-channel
NOOOOOOO! Right in theory, completely wrong and irrelevant in practice. It just goes to show that the regulators have no clue if that is the reason.
Example.
119.000 – this is a 25 kHz band, frequency 119.00
119.005 – this is an 8.33 band, actual frequency is 119.000
119.010 – this is an 8.33 band, actual frequency is 119.00833
119.015 – this is an 8.33 band, actual frequency is 119.01666
119.025 – this is the next 25kHz band, frequency is 119.025
If a 119.000 is published, you can use a 25kHz radio.
Once the authorities want to free up some 8.33 bands in the vicinitty, they CHANGE THE PUBLISHED FREQUENCY TO 119.005
You can no longer use a 25kHz radio at that point, and there is NO RISK OF INADVERTENT SELECTION because you cannot set it to 119.005
So as long as you set the radio to the published frequency, there will be no interference. Over time, the published 25kHz frequencies will reduce to the point that only 121.5 remains.
Peter_Mundy wrote:
Is this a question of the Dutch applying legislation as strictly as possible
Yes, it seems ILENT is more strict then some other member states, where one radio is sufficient, and other memberstates. In the end 121.500 MHz will always stay a 25 kHz frequency, so you could always use the radio for that frequency when all other frequencies are converted. Cobalt wrote:
NOOOOOOO! Right in theory, completely wrong and irrelevant in practice. It just goes to show that the regulators have no clue if that is the reason.
Correct. The only issue that could arrise, is when you delibirately tune to 119.00 instead of 119.005. The proper way, IMHO, would be, ok, can not tune that frequency with this box, have to use the other box, which does allow to tune in 119.005
When they argue that the the change of mistuning arrises, this is false argument, as on a GNS in 8,33 kHz mode, you still could tune 119.000 instead of 119.005, or 118.005 instead of 119.005 for that matter.
