Changes to AD/RAD/47
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Changes to AD/RAD/47
There are proposed changes to AD/RAD/47 that will have significant impact on the cost of getting this maintenance carried out. This is the two yearly transponder check that is required for your aircraft to fly in controlled airspace. For details look at this link:
Civil Aviation Safety Authority - NPRM 1001OS
Below I've posted the opinion (in blue) of one of the local Snr Avionics guru's on the subject. The new test equipment that will be required to carry this out to the new requirements is said to be about $20K. Maybe if enough of us jump up and down about it ... ???
This effects in particular most GA transponders (any with cavity transmitters) and relates to the rise and fall time of the pulse chain.
The new SSR stations and TCAS equipped aircraft actually monitor the rise and fall of the pulses and if the on board transponder is faulty it may cause “false” or multiple aircraft replies, and hence in TCAS aircraft may in fact cause advisories. TA or RA.
How it effects maintenance – standard test equipment we use cannot measure the rise and fall of the pulses, the IFR6000 can read it but does not show results it on any screens. (possibly mod software to be released). Maintenance orgs will probably need to invest in an oscilloscope to read and measure the pulse rise and fall.
But the ATC600A, Michal units etc will become obsolete making it hard for most maintenance organisations to “keep up with the times” and remain legal.
You can elect to have every transponder unit sent to a repair organisation to have the pulse measurements carried out, however as per most transponder installations the antenna and coax network “pulls” the frequency and pulses off slightly, (again not an accurate check, because the aircraft results are different to the bench)
How it effects customers - possibly means updating their transponder costing between US$1500-2500, hard to swallow when they may have recently installed an overhauled KT76A for example. But you still have to have the maintenance organisation as mentioned above be able to test the unit when installed.
Civil Aviation Safety Authority - NPRM 1001OS
Below I've posted the opinion (in blue) of one of the local Snr Avionics guru's on the subject. The new test equipment that will be required to carry this out to the new requirements is said to be about $20K. Maybe if enough of us jump up and down about it ... ???
This effects in particular most GA transponders (any with cavity transmitters) and relates to the rise and fall time of the pulse chain.
The new SSR stations and TCAS equipped aircraft actually monitor the rise and fall of the pulses and if the on board transponder is faulty it may cause “false” or multiple aircraft replies, and hence in TCAS aircraft may in fact cause advisories. TA or RA.
How it effects maintenance – standard test equipment we use cannot measure the rise and fall of the pulses, the IFR6000 can read it but does not show results it on any screens. (possibly mod software to be released). Maintenance orgs will probably need to invest in an oscilloscope to read and measure the pulse rise and fall.
But the ATC600A, Michal units etc will become obsolete making it hard for most maintenance organisations to “keep up with the times” and remain legal.
You can elect to have every transponder unit sent to a repair organisation to have the pulse measurements carried out, however as per most transponder installations the antenna and coax network “pulls” the frequency and pulses off slightly, (again not an accurate check, because the aircraft results are different to the bench)
How it effects customers - possibly means updating their transponder costing between US$1500-2500, hard to swallow when they may have recently installed an overhauled KT76A for example. But you still have to have the maintenance organisation as mentioned above be able to test the unit when installed.
Last edited by kingtoad; 21st Apr 2010 at 23:12.
