AXP340 Transponder Specifications

I note that the Avidyne Brochure references "elementary" surveillance capability. I contacted "Warren" online yesterday, seeking some understanding, and I was rather put-out at his response. Can you explain what "surveillance" is; how is it distinguished from "interrogation"; and what is the difference between "elementary surveillance" and "enhanced surveillance"? Following these comments, could you compare the Becker remote unit to the AXP340 in terms of capabilities, costs, and ease of use?

Thanx,
John

Surveillance is a generic term used to describe a system or device that is used to monitor the location of aircraft.  All transponders are surveillance devices in that they receive interrogations and send data in response.  The term surveillance (whether elementary or enhanced) does not imply that a transponder is capable of interrogating other aircraft or providing traffic data to the pilot.

The term interrogation is typically used to describe a signal that is transmitted to query the transponder on board an aircraft.  Interrogations are used by the secondary surveillance radar sites and by some airborne traffic alerting devices such as TAS and TCAS.

Some transponders are able to transmit more data than others.  For instance, the older style Mode A/C transponders only send altitude and squawk code, whereas Mode-S transponders include a unique aircraft ID and potentially many other additional data elements. 

Elementary surveillance means that a transponder does not support the Mode-S transponder Enhanced Surveillance (EHS) capabilities.  This is a distinction defined primarily for the European aviation community.  A Mode-S transponder compliant with the enhanced surveillance capabilities will be capable of transmitting a number of additional data elements such as aircraft magnetic heading and vertical rate.  It should be noted that these extra capabilities also necessitate that there is a source for that data on board the aircraft and that the source is connected to the transponder. 

Can foreign made Mode-S transponders handle USA ADS-B?

Yes; Mode-S transponders are designed and certified using an internationally approved design specification and will operate properly world-wide.

Why do some pilots equip dual transponders?

I believe this is simply for redundancy.  A functioning transponder is required equipment for operations in many air spaces; therefore I believe some pilots prefer to have a backup, especially those flying high performance aircraft that will frequent Class A/B/C airspace.  I don't believe there is any RVSM requirement for dual transponders, and I am unaware of any reliability issues that have led pilots to equip two transponders.

How does the AXP340 compare with the Becker BXP6402?

There are no significant differences between the AXP340 and the BXP6402 technical specifications; however the Becker BXP6402 does not currently comply with the ADS-B out TSO (TSO-C166b).  Obviously the AXP340 is panel mounted versus the remote mounted BXP6402.

Not initially.  We have deferred that capability out of the initial release for the IFD540 for time-to-market reasons.

Yes, soon.

Steve is the MLB100 the announcement you were referring to or is there another one comng?  I was hoping for a remote transponder that would interface with the 540 and 440.