British Hang Gliding and Paragliding Association

CAA Mode S Transponder Consultation - 2008

NB. This document is provided for historical interest only as the consultation closed a long time ago.

As the membership will be aware, the CAA has issued a new set of consultation proposals for Mode S transponder usage, requiring a response by 31 May. These can be viewed at www.caa.co.uk , just search for "Mode S". Individual BHPA club secretaries should also all have received CD's direct from the CAA detailing the proposals.

Most members will recall that the CAA launched a public consultation on the proposed expansion of Mode S transponder usage in June 2006. This resulted in a significant level of concern and opposition to the policy from the sporting and recreational flying community. As a result of the feedback from that consultation, the CAA has decided that a more gradual, phased approach will need to be employed, and further consultation will be needed on some elements of the proposed policy. This present consultation is part of that.

The Government recently approved proposals that make Mode S the required means of compliance for transponder carriage in all the mandatory circumstances with effect from 31 March 2008.

So – to be clear – the present consultation is not about whether or not you think Mode S transponders have a future in the UK: that has already been decided. This consultation is about the phased expansion of Mode S transponder usage.

It should be noted that, unlike the 2006 consultation, this consultation on the second phase of Mode S expansion does not propose that all aircraft should carry Mode S transponders in all UK airspace.

The Detail
The CAA's proposals are broken down into four "options", ALL of which they deem desirable to implement but any final recommendation to Government will depend on information and feedback from stakeholders WHICH INCLUDES THE BHPA MEMBERSHIP.

Each "option" is considered in specific documentation on the CAA website with a cost benefit précis and we suggest you read them for more detail.

Initial examination of the documents may suggest foot launch flyers are exempt from the proposals. This is true but we should pay attention to any knock-on effects and to the fact that inevitably sooner or later a suitable lightweight transponder will exist for hg/pg carriage.

Option 1
Require all aircraft (other than gliders) in controlled airspace to operate SSR Mode S transponders.

Pros to BHPA:

• Increased levels of safety for aircraft within controlled airspace, i.e. those BHPA members that use airliners to get to their flying abroad!

Cons to BHPA:

• Once a Mode S infrastructure exists for the majority, the CAA's long-term plan for wholesale airspace reclassification will then be possible.
• Our existing operations in controlled airspace are based on Letters of Agreement (LOAs): as more traffic becomes "known" it is quite possible that the toleration of our "unknown" activities will evaporate.
• Non Mode S equipped powered traffic will have to find routes around controlled airspace, increasing traffic in the airspace where we can fly.

Option 2
Implement a formal process to support applications for "Transponder Mandatory Zones" (TMZs) outside of controlled airspace.

The CAA already have the power to set up TMZ's – and think it likely that more of these zones will be needed in the future. This proposal is about establishing a clear documented process for dealing with future applications for a new TMZ – as against the current vague, undocumented process.

Pros to BHPA

• This perhaps gives us an opportunity to ensure that there is always a proper consultative process, and that the BHPA has a voice within it.

Cons to BHPA

• There is the worry that, once the CAA has a nice new process for establishing TMZ's, they will set to with gusto. (But they can do this using their existing powers).
• There is no certainty that the "formal process" we are invited to vote for will include any consultation and/or criteria we agree with.
• The BHPA is already overloaded with the number of controlled airspace consultations that are going on.

(Nb. An increase in TMZ's is a decrease in the amount of sky left open to us and all the other non-transponder aircraft, thus reducing our safety)

Option 3
Include Gliders in all SSR transponder carriage regulations.

This proposal would mean that gliders would have to operate a Mode S transponder when in any controlled airspace, when above FL100, and when in any TMZ.

In recognition of the challenges of equipping gliders with transponders, the existing regulatory arrangements whereby ATC units can authorise non-equipped aircraft to operate within controlled airspace, where safety and efficiency requirements would not be compromised, would remain. This would, ideally, be through standing LOAs.

As there is currently no suitable Mode S equipment available for HG/PG/SPHG, all foot launched variants would need authorisation from appropriate ATC units to operate within mandatory transponder carriage airspace after 31 March 2009.

Pros to BHPA

• None known

Cons to BHPA

• If all conventional gliders equipped themselves with Mode S then LOAs negotiated by the BGA for glider access to controlled airspace would no longer be required. This would then leave agreements for non Mode S foot-launch operations possibly unsustainable. That said, there will almost certainly be a number of glider owners whose preference is local soaring and who will chose not to equip their gliders with Mode S. So perhaps there will still be some support from within the gliding ranks to help maintain LOAs.
• Notwithstanding the above, it would seem probable that LOAs for Class D access on cross country flights will disappear.
• We should expect to find that once suitable Mode S equipment exists for hg/pg then, if we want access to controlled airspace outside the LOAs, we will be required to fall into line and equip with Mode S. (As at present such access will always be subject to an ATC clearance and probably the use of air band radios and R/T licenses to contact ATC).

Option 4
Mandate the carriage and operation of Mode S transponders on all powered aircraft conducting international flights.

Pros to BHPA

• None known

Cons to BHPA

• None known

Nb. As Self Propelled Hang Gliders (a.k.a. phg and ppg) are currently classified in the ANO as gliders there is no impact for the BHPA membership at the moment.

What Next?
The official BHPA response will be posted on the BHPA website to allow the membership time to reference it before the May 31 deadline.

There are three methods of responding to the consultation document: online, by email, by post. The online response document only allows answers to specific questions – none of which have any direct relevance to us. So any "off topic" response will have to be by post or email.

• Via the web-based consultation response mechanism – follow links on CAA website
• By e-mail to modesconsultation@caa.co.uk
• By post to: Mr Andy Knill, Head of Surveillance & Spectrum Management, Directorate of Airspace Policy, Civil Aviation Authority, CAA House, 45-59 Kingsway, London, WC2B 6TE

BHPA Airspace Panel March 2008

Last updated: 03 April 2025