The F-14D was the point at which the Tomcat's airframe finally matched its mission. Replacing the troublesome TF30 with the F110-GE-400 removed the throttle-handling restrictions that had constrained F-14A crews in the high-alpha regime, while the AN/APG-71 swapped the AWG-9's analogue processing for digital signal processing borrowed from the F-15E's APG-70. The practical gain was less in raw detection range than in clutter rejection, jamming resistance, mode flexibility and non-cooperative target recognition — the qualities that matter when an interceptor has to sort a raid rather than simply see it.
The variant nevertheless arrived at the worst possible moment. Its capability was sized against a Soviet regimental anti-ship missile threat that disappeared as the type entered squadron service, and Pentagon budget decisions capped the line at 37 new-build aircraft and 18 rebuilds rather than the several hundred once envisaged. The Navy chose to consolidate on the cheaper, more maintainable F/A-18 family, and Grumman's proposed further developments such as Super Tomcat 21 were never funded. Fewer than sixty airframes could not sustain a separate logistics and training pipeline against that argument.
What the F-14D did prove, in its final decade, was the value of a large, two-seat, sensor-rich carrier aircraft in the strike and forward air control roles. With LANTIRN, JDAM and finally the ROVER downlink, the D-model flew as a precision strike and airborne FAC platform over Iraq until 2006 — a mission profile its designers never intended and one the Navy has arguably been rebuilding toward ever since with two-seat and long-range unmanned tanking and sensing programmes.