Cannot replace a Mode C transponder

[QDMQDMQDM]

The old Mode C transponder in my Super Cub has died and I have been told that no new installations of Mode C transponders can be performed on VH-registered aircraft. This is a VFR aircraft that goes into controlled airspace once in a blue moon. Is this right? It seems outrageous to me.

[no_one]

Unfortunately yes....

https://www.legislation.gov.au/Details/F2015C00342

paragraph 9E.2.

options are rip it out and stay out of class C/E airspace and below 10,000 feet or upgrade to Mode $.....:(

[Obidiah]

In a world of increasing madness and mindless bureaucracy some individuals likely hold the last remnants of common sense.

Should you be one of those individuals you will be pleased to note that its frequency of use is entirely at the owners discretion.

KT76A's for example, are abundant in the second hand market, I believe Bunnings will sell you a small allen key that fits in the small hole in the facia of the unit.

It is said that by turning this allen key it will release the tension on the locking pawl and rotate it flush with the unit.

Apparently when this happens the unit can be slid out of it's tray.

This is where the brilliance of common sense shines brightest.....it follows that if you reverse this process the unit will go back in the tray.

Many may not be aware but in some way there was a manufacturing mistake that led to all KT76A's being the same size.

Just sayin'

PS. Common sense also says...don't buy a Bunnings allen key, buy a good one, however if you do buy a Bunnings one and it fails your own common sense will be richer for the experience.

Note. From this point until the passing of the night of the 9th of August in the third quarter I shall relinquish my title of Obidiah and here after be named Justin Saine

[Progressive]

This is true if you want to operate in in Class A, B, C or E airspace; or above 10 000 feet above mean sea level in Class G airspace.

See here for a the brief version and the linked Reg for the full version:
Mode S transponders, ADS-B and VFR aircraft | Airservices (http://www.airservicesaustralia.com/projects/ads-b/mode-s-transponders-ads-b-and-vfr-aircraft/)

However note that under this CAO this only applies to aircraft "modified by having its transponder installation replaced on or after 6 February 2014", thus you can fit any new parts you want to an existing installation:

Also Para 9E.3 exempts an aircraft which does not have "sufficient engine-driven electrical power generation capacity to power a Mode S transponder" which may apply to a cub depending on configuration.

[QDMQDMQDM]

Thanks, everyone. I shall do my utmost not to play CASA's coercive game. I can't see when I would ever go into Class A, B, C or E airspace anyway and this is Australia so I can't see the point of flying a Cub above 10,000 feet either.

Bastards.

[Obidiah]

I shall do my utmost not to play CASA's coercive game..... Bastards.

Welcome to the club brother :ok:

[Kiwiconehead]

Nothing stopping you replacing your U/S KT76A for example with another KT76A.

It is only a complete new installation that must be Mode S.

modified by having its transponder installation replaced on or after 6 February 2014

Replacing a faulty transponder is not a modification, installing a new type of transponder is.

Call your local shop and see what they have secondhand.

[triadic]

QDMQDMQDM..... Check your private messages pls

[peterc005]

Got a quote last week to replace my old Narco AT150 Mode C with a BendixKing KT-74 Mode S for $6,000 all up installed. I think the unit alone is about $3,400. Could probably knock a thousand bucks off this by shopping around.

[Hasherucf]

Plenty of KT76A's on the market at the moment . Even if the shop replaces the board entire the units serial number remains the same ;). I am guessing yours has the cavity gone U/S which can be expensive.

[QDMQDMQDM]

Thank God for pprune is all I can say. I'll let you all know the outcome.

[QDMQDMQDM]

So I'm sending it off to be repaired in the US for $100 fixed rate.

Meanwhile, my maintenance provider has told me that the avionics shop they use refuses to install any transponder which isn't Mode S.

I asked CASA a week ago what constitutes a 'new installation', but no answer.

[Band a Lot]

It is a Avionics LRU and has a self test function.


If AD/RAD/47 Amdt 4 is not due any engine or airframe LAME can change it and certify for it.

The ETT test (I bet they don't do at your shop anyway) is done on the bench during your repair. This test will only be due next time your RAD 47 is due and it will not be a "new unit" then.


Typical avionics shop by the sounds.

[cogwheel]

Meanwhile, my maintenance provider has told me that the avionics shop they use refuses to install any transponder which isn't Mode S.

Maybe they should go and read the reg again....

[Progressive]

From: https://www.casa.gov.au/standard-page/performance-based-navigation-gnss-and-ads-b-equipment-mandates

"From 6 February 2014, any aircraft registered in Australia before 6 February 2014 that is modified by the installation of new or replacement ATC Transponder systems must have a Mode S Transponder capable of ADS-B 1090 MHz Extended Squitter transmission installed"

So unless the aircraft is Modified by the installation (IE: New transponder model fitted under STC or Part 21 EO) then there is no need to install mode S.

So unless you are operating at major international airports or under IFR there is no need.

[Lead Balloon]

But ... surprise surprise... the CASA document is ambiguous. That often happens when people try to paraphrase something.

Are you saying the Mode S requirement is triggered (assuming the airpace class/altitude criteria are met) if I either:

1. install a new transponder system in my aircraft, or

2. install a second hand transponder system to replace the system currently fitted to my aircraft,

but not if I replace unserviceable components of an existing transponder system in my aircraft with serviceable components?

Why does the avionics shop referred to above have a different understanding?

[Band a Lot]

Lead

1) "NEW" is key word - Point to your transponder, is it new? I doubt if it is a KT76A, at best newly overhauled. But that is not NEW.

2a) System is Key word - I don't recall reading that in context of this subject (but could be wrong) A replacement KT76A with different S/N is not any more than a component change.

2B) a complete change of system with a different model transponder will require it to be Mode S compliant - Installation being key word.

Yes endless amounts of repairs can be made to current mode C transponders.

Why use the avionics shop for LRU with self test function?

[Sunfish]

in other words, if the only thing that has changed after maintenance is the serial number of the transponder there is no need to upgrade.

[Lead Balloon]

1) "NEW" is key word ...

2a) System is Key word ...The words "or" and "replacement" are key words too:installation of new or replacement ATC Transponder systemsI'm merely observing that perhaps the confusion is caused by CASA's guidance document?

[Phalconphixer]

Been away from the tools for a while but I would suggest that the supposed problem here is one of definitions...
An Aircraft Installation is by definition all of the major components and the interconnecting wiring.
An Aircraft System comprises the major and contributing LRU's
The replacement of any single LRU does not constitute a change of either the system or the installation:
In fact, one could remove all of the components and the interconnecting wiring and provided that the overall configuration remains the same in terms of LRU part numbers, the installation / system remains unchanged.
In other words, by definition, you can remove, repair and / or replace the Transponder, its mounting tray, its antenna(e), the interconnect and the altitude component with like for like items and nothing changes...

Changing a transponder with a like for like replacement should have no more compliance implications than changing its antenna or re-soldering a disconnected wire on the mounting tray

After replacement I would recommend a check of the transponder installation using the appropriate test equipment to ensure compliance...

As for why your Avionics shop wont do it... it's probably all about the money, plus it's highly likely that locally they don't have the ability, the skillset, or the inclination to repair obsolete equipment.

[Lead Balloon]

In fact, one could remove all of the components and the interconnecting wiring and provided that the overall configuration remains the same in terms of LRU part numbers, the installation / system remains unchanged.I see.

So if I remove the antenna and replace it with the same part number/mod status, remove the antenna coax and connectors and replace them with the same part numbers/mod status, remove the mounting rack and electrical wiring and replace them with the same part numbers/mod status, and the remove the TX/RX unit and replace it with the same part number/mod status, I have not installed a "replacement ... system", even though I literally replaced the system.

I only install a "replacement system" if I install a system that has different part numbers?

[Phalconphixer]

That would be my interpretation and over the life of the aircraft that could happen...
We had a visiting Falcon 20 with a dual all in one GPS / FMS UNS-1 Nav system... just two major components, the main Display / Computer unit and an active GPS antenna... Owner reported that 15minutes into every flight, the Captains display blanked and remained off until rebooted giving a further 15 minutes of use... Owners had replaced the FMS unit three times; all the wiring checked out OK and the FMS units checked out serviceable on the bench. The problem was diagnosed eventually to the GPS Antenna driving the Captains box... its an active antenna and needs a 15V supply which it derives from the Nav unit; in this instance the antenna had developed an internal short circuit which was loading the 15v rail that also powered the display until its self protection system kicked in ... The repair involved replacing the Antenna...
By the logic described in the original question, in replacing the FMS unit, the owners had changed the installation, by removing and bench checking the same unit we had done so too; similarly in replacing the antenna we had changed the installation.
In reality because like was replaced with like nothing had changed insofar as the installation was concerned... The items carried the same part numbers as the original fit, the serial numbers had changed but that irrelevant.

[Lead Balloon]

Just so I have it clear in the context of a discussion about the requirement to fit Mode S....

Bob owns a Cessna 172R fitted with a Brand X transponder system without Mode S. Bob can replace his transponder system with the same Brand X part no. system without Mode S and that is legal and safe.

Jeff also owns a Cessna 172R, but it is fitted with Brand P transponder system without Mode S. Jeff can replace his transponder system with the same Brand P part no. system without Mode S and that is legal and safe.

But if Jeff's transponder system goes kaput and Bob happens to be parting out his aircraft, it's not legal or safe to install Bob's Brand X system in Jeff's aircraft to replace the Brand P system?

[Band a Lot]

modified by having its transponder installation replaced on or after 6 February 2014;

Avionics systems and installations follow the same rules and regulations as engine and airframe.

By removing a TSIO 540 J2B and fitting an exchange factory overhauled TSIO 540 J2B. Has the installation been modified?

No modification has taken place (even if part numbers of cylinders are different) it is still a J2B.




Modification. A modification to an aeronautical product means a
change to the design of that product which is not a repair.

[Lead Balloon]

And the answer to my question is ...

[Phalconphixer]

Like the man says...
f27gqyV7al8

[Band a Lot]

That is correct Lead. That is a modification not a repair.

[Band a Lot]

If the task requires a STC, CASA or CAR 35 person approval to make any changes to the transponder system - you need to fit Mode S.

[Phalconphixer]

@Lead Balloon... But if Jeff's transponder system goes kaput and Bob happens to be parting out his aircraft, it's not legal or safe to install Bob's Brand X system in Jeff's aircraft to replace the Brand P system?
Correct... but in Jeff 's case, I would be more inclined to establish exactly which part of the original system had failed and repair or replace that part... gotta be more economical... but that's just me being a tight Yorkshireman...

[Band a Lot]

The OP could give the repaired unit to his LAME to refit, get the LAME to make a Log Book entry "Transponder P/N xx S/N removed for repair and refitted".

Get LAME to enter on Maintenance Release "AD/RAD/47 A4 due" then get local Avionics shop to carry out a RAD 47 and sign off on MR.



Return to Service Requirements
 For VFR aircraft, the airframe and engine privileges allows for an airframe LAME to certify for the replacement of removable items of radio equipment.
Note: Be aware that a functional test to establish the integrity of the code lines will be required when replacing a Mode C equipped transponder utilising the altitude data from a Gillham source. As special test equipment is required this task will require the certification of an appropriately trained and rated LAME.

[Lead Balloon]

Bob owns a Cessna 172R fitted with a Brand X transponder system without Mode S. Bob can replace his transponder system with the same Brand X part no. system without Mode S and that is legal and safe.

Jeff also owns a Cessna 172R, but it is fitted with Brand P transponder system without Mode S. Jeff can replace his transponder system with the same Brand P part no. system without Mode S and that is legal and safe.

But if Jeff's transponder system goes kaput and Bob happens to be parting out his aircraft, it's not legal or safe to install Bob's Brand X system in Jeff's aircraft to replace the Brand P system?That is correct Lead. That is a modification not a repair.Pure regulatory genius! :D

[Band a Lot]

From memory several blind encoder brands are interchangeable.

A-30 blind encoder.

mod 1,2,3,4 & 5 different wiring mod 6,7,8 &9 same plug.

Same regulatory genius will apply. So a $100 part (or swapping 2 wires over) could ruin your day if they no longer make or repair your breed.

[Sunfish]

OMG, I'm starting to think like CASA - negative affirmations:

Modification. A modification to an aeronautical product means a
change to the design of that product which is not a repair.

So if you improve the efficiency of your existing product via a software upgrade which involves no physical change to the product, what have you done?

[Band a Lot]

Nothing actually other than maintenance.

It is still (if by manufacturer) part of original Type Data Certificate or approval approved by a relevant authority.


eg Improved and different P/N cylinders on the TSIO 540 J2B engine for about 15 times in last 50 years.

[Progressive]

Band a lot has hit the nail on the head. As for as CASA are concerned "the design" for a product is what is included in the TCDS, ATSO standard or TSO standard. If this does not change with the software update or part number change then the "design" has not been modified.

As for the Bobs old transponder cannot be fitted to Joe's plane argument, I think it is reasonable to require upgrade to the latest standard when a new complete system is being installed. The installation of a different system will require engineering approval or an STC as well as Avionics LAME regardless if it is old or new standard. As a result the price difference between fitting a complete mode C and a complete mode S will be minimal.

So repair your mode C until a lack of parts makes a mode S upgrade the cheaper option.

[Lead Balloon]

So it's legal and safe to have two 172Rs, one with a Brand X transponder system and the other with a Brand P transponder system, neither with Mode S.

But it's not legal and safe to swap those transponder systems and end up with two 172Rs, one with a Brand X transponder system and the other with a Brand P transponder system, neither with Mode S.

I guess it shows that one man's "reasonable" can be another man's "mule-stupid". :(

[cogwheel]

Nobody here it seems is reading the ANO.....

[Band a Lot]

Lead not legal.

Safe?


What has that or cost got to do with anything.

[triadic]

This might answer the original question and some of the posts since?

If fitting a new transponder Post 6 February 14 a mode S transponder is required unless the aircraft is restricted to operations Below A100 in Class G and Class D. In such areas a mode C transponder is acceptable.

[Lead Balloon]

Or not.

It's certainly irrelevant to the question I asked.