I feel the need to provide a bit of detail missing from Distant Voice's history of the 'CWS on Tornado' saga. It is not a simple question of funding for TCAS being delayed. At the very start of the programme, TCAS implementation was one of the options on the table, but the weaknesses of TCAS within the FJ operating context were considered to be excessive. In a decision which, in hindsight, seems utterly characteristic of its time, UK plc set out to develop a new FJ-optimised CWS. The aspiration was for this to be TCAS-compatible to 'standard' TCAS units; to other platforms equipped with the optimised unit it would be intelligent enough to ignore 'intentional' proximity such as crossover turns, tanker joins, visual combat etc. It would give warnings for 'unintentional' proximity - and, importantly, without requiring the aircrew to make any in-cockpit selections, so it could remain enabled throughout an entire sortie. A worthy ambition indeed, but one that proved to be pie in the sky, as any number of intra-formation near misses and actual collisions could have told the boffin dreamers. After all, what's the difference between a 'tally-visual' 1000ft pass, and a 'blind-no joy' bubble bust, other than a gnat's cock of pressure on the stick and about 0.01 seconds? By the time this concept was abandoned, years and years had passed; the decision to go with TCAS is comparatively recent in glacial DE&S terms. The regression from "work in progress" to "unfunded" broadly coincides with the abandonment of the CWS project; TCAS had to be funded anew because of its rejection within the earlier project.
And, of course, TCAS has its limitations in the FJ context, as identified all those years ago. I am quite concerned by the following statements from those currently operating the system on other platforms:
Constant TCAS alerts from within your formation tend to cause you to become deaf to the system and ignore it at times. "Oh it's just no3 etc...)
Every battle turn brings a TA which will then steal one of your MPDs. It also trips off at large angles of climb and bank triggering further avionics warnings (which will self reset but its still annoying!). It proved useful on several occasions but my worry is the breeding of a blasé attitude to lookout. It is not a panacea in its current form.
because these suggest that whoever handled the Concepts & Doctrine work for that system did a disservice to the users.
Consider GPWS for a minute. A great system, especially when IMC or when conducting dive attacks towards rising ground - but one that in certain (VMC!) FJ contexts, such as valley flying or OLF, can become a hindrance and a downright distraction. It has long been accepted practice, documented in ASOs, that if GPWS produces a high rate of false alarms it should be disabled until terrain or flight conditions allow it to be re-enabled. This is specifically to avoid breeding a culture of ignoring GPWS warnings. Why should similar logic not be applied to the use of TCAS?
Self-evidently, there are situations where having TCAS enabled is entirely inappropriate for the training being conducted - would we expect a formation being 'bounced' to receive TAs against the dastardly bounce dropping in from the high six? No - and given the choice of achieving this by having the bounce squawk standby, or having the formation running with TCAS in standby, the latter option is more palatable to external players (such as ATC and other TCAS-equipped aircraft) who would rather not have a singleton batting around semi-randomly whilst squawking standby.
To follow a line of argument once employed by W.S. Churchill, if we can agree on the example above, we have established a principle - and any further discussion is merely negotiation upon where to draw the line! So, should all members of a formation fly with TCAS enabled, and become inured to the frequent TAs? Should wingmen disable TCAS, relying upon their leader for timely traffic calls (the leader will just have to put up with the TAs)? Or should all members of formations engaged in tactical manoeuvring disable TCAS entirely, accepting that it was never designed to prevent collisions in such environments and that its implementation is intended merely to reduce, not remove, collision risk? All players could continue to squawk to give SA to TCAS-equipped 'strangers'. Even the airline world does not insist on TCAS being used on each and every flight - it can be carried U/S for up to 10 days (although I believe there are moves afoot to reduce this to 3 days... but the point still stands).
The examples quoted above say to me that the "R" in "ALARP" has been cast away in whatever SOPs are being applied on those platforms. Given the high profile of CWS amongst the hierarchy, it is understandable how timid staff officers could recommend blanket use of TCAS during all stages of flight; that doesn't excuse the laziness of thought. Those with responsibility for SOPs and regulations need to have the balls to say why the sub-optimal solution that is TCAS needs to be handled in a certain way in order to extract maximum value from it without hindering training. It is quite reasonable to recognise the limitations of the system as provided, and work around them without compromising the (un-changed) flying task.
Unlike the FJ CWS pipe-dream, TCAS was not designed with aggressive manouevring in Class G airspace in mind, and was certainly not designed to guarantee 100% collision avoidance. To use it with that aspiration in mind is to ignore its fundamental nature.