Your Attention Please!
This article is outdated. Heatblur and ED have developed a new missile API in late 2020 so the way the WCS guides the missiles has changed.
I am waiting for them to finalize the new implementation before writing a new study about the updated guidance model and the AIM-54.
What happens when you lose track of a target right after firing a Phoenix in TWS? Is the AIM-54 wasted or something else happens? These are not marginal questions that a RIO should be answered to because depending on how the AIM-54 behaves, the F-14 crew can try to reacquire the target, look for another one, go cold and get manoeuvring space or something different again.
Locked by AWG-9 WCS or AIM-54?
Speaking of lock by the AIM-54 is partially incorrect. Unless the AIM-54 is active, either when it turns on automatically in proximity of the target (at the moment the AIM-54 behaves like an AIM-120) or is launched already Active, is the AWG-9 WCS that guides the AIM-54.
If the AIM-54 is fired from the F-14 in TWS mode, this is what happens:
From the TacView image above you can see the AIM-54 lofting and the moment it goes active (I marked it by a white arrow). In order to improve the range of the AIM-54 the WCS guides it higher, before turning its internal radar on and diving down on the target. The target receives a RWR missile warning only at that very moment, not before.
No WCS. What happens?
As we have seen, the WCS guides the AIM-54 until it goes Active. What happens if the target disappears entirely from the AWG-9? In order to simulate this behaviour, I turned the WCS to STANDBY right after launch. This is the result:
As you can see, no loft if the WCS is not in XMIT mode. The AIM-54 follows a straight path until it goes active, finds a target, and tries to reach it. No loft also means not enough energy to reach the target if the distance between the F-14 and the target is quite high.
The WCS tries to guide the AIM-54 back to the target if we manage to illuminate it again with the AWG-9:
This is very important because a lock lost mid-flight can be reacquired and, if the AIM-54 still has enough energy, can still hit the target.
However, this behaviour has a drawback..
What happens if you lose a lock and later re-acquire a different aircraft? Is that even possible? Let’s find out.
Test 1: Acquiring a different target
I launched at the hostile target, moved the antenna away and the AIM-54 carried on as expected by following it’s original trajectory until it went active. Nothing new here becase the targets are separated by many miles.
Test 2: IFF
I launched at an UNKNOWN target, turned the WCS to STBY then to XMIT again and identified the target as FRIENDLY in the CAP. The WCS didn’t bother though and guided the missile to its original destination.
Test 3: Merge
For the last test I placed 2xE3 and 1xA-50 in a wide formation. I found the A-50, launched at 40nm and at ¾ of the AIM-54 flight path I moved the antenna away. The AIM-54 later went active and pointed to a target that was different from the one I launched to. Result: friendly kill.
This is the reason why you do not fire active radar-guided missiles into a furball! If you have to take the risk of shooting into a merge in order to help someone, use semi-active radar guided missiles such as the AIM-7. There is still a chance to hit a friendly target, either due to the large warhead of the Sparrow or directly (the radar can be confused if two targets are very close), but it is much safer than IR or Fox-3 missiles.
Pulse Search and Pulse Single Target Tracking
Last series of tests. The AIM-54 can in fact be launched in Pulse mode as well, as long as the radar acquires a target STT mode.
I locked an aircraft in a group of notching targets by means of Pulse STT and fired an AIM-54.
I disabled the WCS to lose the contact after firing and the AIM-54 behaved in the same way it did before: it follows a straight trajectory until it turns active and scans for targets.
Pulse Doppler to Pulse and vice versa
The AWG-9 DCS is able to switch guidance from Pulse Doppler to Pulse while the AIM-54 is flying. I am honestly not sure if this is intented or will be changed later and how reliable this procedure is when dealing with manoeuvring targets.
Nevertheless, at the moment it means that the RIO has the option of switching to Pulse mode in order to reacquire a notching target while ensuring that the AIM-54 is still guided.
This is the result of switching guidance from PD to Pulse and from Pulse to PD in two subsequent launches:
Multiple TWS launches to Pulse
As expected, only one missile continues for the target guided by the AWG-9 WCS. The others stop lofting and proceed straight until they run out of energy or acquire a target.
I hope you have found these tests useful.
As usual, feedback and suggestions are always welcome!