As I understand it the Eurocontrol TCAS Review unit recommends that if you are flying a wounded bird, i.e. you have performance issues and do not want to receive an RA which requires an undesired manoeuvre, you should select TA Only. This will alert other a/c TCAS's that they will need to execute the avoiding RA. Seems quite simple and common sense to me. The only Boeing QRH that has this included is the Engine Failure/Loss of Thrust scenario. This is practised every 6 months in the sim and so everyone quotes it as the only occasion it is required. It might be their only experience of so doing. Ww do not always operate in a radar environment, remember.
Think about other scenarios where you do not want an RA requiring undesired manoeuvring. Jammed Flight controls: Stab trim problems requiring manual trim: Loss of HYD's = Manual reversion flight: Emergency Descent: Any flight control problem or thrust problem. There could be a whole host of them that should be at the crew's discretion. It is a tool to be used to help you survive the non-normal. If 2 a/c are conflicting I want to tell the other fella to get out of the way. How do I do that? TA Only. That's what it is for. It tells us that in the notes of the QRH SE case. Why does it not tell us that in other QRH's? Why are we not educated/encouraged to use airmanship and select it when needed to help us survive? Cast off the cloak of trained monkey and ask questions.
I quote the change in Boeing's advice on Stall recovery. Moons ago in basic training I was taught that a stall was an aerodynamic matter. it needed to be solved by aerodynamics. This includes basic physics. It was the same erect or inverted. Break the stall. Even an incipient stall it was the same basics. Boeings FCTM said Power & Reduce Attitude. I used to teach Reduce Attitude and increase Power that split second later. I did not know Boeing had changed the laws of aerodynamics. Reality stepped in and changed the philosophy. In other words questions were asked after an event (THY AMS) to see if improvements could be made, and they were. We are in an evolving environment where Mother Nature, Aerodynamics and Physics are always trying to tells us we shouldn't be there. We should not stop thinking and asking questions about how to improve our chances of the slaves defeating the lions. SOP's are not cast in stone; they should be an evolving living beast.
This is demonstrated by the many different ways airlines redefine the basic instruction manual of an a/c. They all do it differently yet all those different SOP's. They might all work, but they can't all be the best. They are adequate. I'm sure many have experienced every changing SOP's in an airline. Were they always for the better? How often have you changed companies, having flown with what you thought were excellent SOP's, only to learn new tricks and have the Ureka moment. I've done it a few times and in both directions: i.e. from crap to good and visa versa. Tit bits here and tit bits there. The brick walls I found trying to suggest improvements were as Jericho, but I didn't have any trumpets. We all survived, so that was the yard stick.
An open mind is a joy forever, but it brings some headaches from the blinkered.
I leave you to debate it out.