F-14 Tomcat Upgrades
The F-14 Tomcat continues to be the Navy's premier long-range fighter. The Tomcat's "Roadmap for the Future" - a plan to incorporate significant performance improvements - made the Tomcat a superb complement to the Navy's current F/A-18 Hornet aircraft. The F-14 will enable the Navy to maintain the desired force structure of strike-fighter aircraft on each carrier deck until it is replaced by the F/A-18E/F Super Hornet.
Due to time compliance requirements (fatigue and correction of deficiencies), keeping the Tomcat just one year beyond its scheduled retirement would cost over $1 billion, and extending the aircraft to 2015 would cost $2.5 billion. The F/A-18E/F cost per flight hour is half that of the F-14.
The F-14 outfitted with the Tactical Airborne Reconnaissance Pod System (TARPS) will continue to provide a manned tactical reconnaissance capability. The F-14's "Roadmap" includes the incorporation of a digital imaging and data link capability in 24 TARPS pods to provide battle group, joint force, and allied commanders with near real-time imagery for the detection and identification of tactical targets, and immediate threat and bomb damage assessment. The F-14's critical role in maintaining air superiority and its ability to launch precision-guided munitions has ensured that the aircraft will remain a vital player in the Navy's inventory until its retirement.
The original design airframe life for the F-14 was 6,000 hours, but was later extended to 7,200 hours. The Navy intends to retire the F-14A force by 2003-4, F-14B by 2007, and the F-14D by 2008. In addition to its outstanding fighter capabilities, the Tomcat is being configured as a potent, adverse weather, medium-range strike aircraft that is being fielded through cost-effective upgrades to F-14A/Bs. With the ability to launch Joint Direct Attack Munitions (JDAM), coupled with an INS/GPS integration and off-the-shelf electronic countermeasure improvements, the Tomcat will provide a multi-mission strike/escort capability which will be part of the inventory until at least 2010.
While the F-14 continues to meet current operational commitments, the Navy has been working to improve those aircraft systems which are the highest readiness degraders; which include the radar transmitter, inertial navigation system, and radar antenna.
The Navy made the decision not to upgrade the engines because they would be too expensive to put in an aircraft which would be removed from service a few years after being re-engined. Through extensive in-service engineering analysis, the Navy installed a low cost, but very effective means of alerting aircrew of impending catastrophic TF30 engine failure. This cockpit warning light alerts the aircrew to a sudden rise in engine breather pressure [an indication of impending engine failure] in time to reduce engine power and safely land the aircraft. This new system greatly increases aircrew awareness and further contribute to safe F-14A operations.
Initially an automatic rudder interconnect (ARI) was implemented to automatically phased out movement of the tails for roll control and phased in deflections of the rudders at high angles of attack. The pilots who flew the F-14 with the ARI system were enthusiastic, and the system allowed the pilot to maneuver the aircraft without regard to angle of attack or switching from differential tails to rudders. The production contract for the early F-14 aircraft called for the implementation of an ARI system. Unfortunately, the early F-14 aircraft also included another late developing preproduction concept -- deployable wing leading-edge maneuver slats for improved maneuver-ability. Early Grumman flight tests revealed that the F-14 modified with both the ARI system and the maneuver slats displayed unsatisfactory air combat maneuvering characteristics because the ARI rudder inputs aggravated lightly damped rolling oscillations (wing rock) induced by the slats during maneuvers. Because of this incompatibility, the Navy deactivated the ARI systems on all fleet F-14 aircraft.
The F-14 proved to be a relatively forgiving aircraft to fly, and pilots adapted to manually switching from using differential tails for roll control at low angles of attack to using rudders at high angles of attack. However, the F-14 fleet began to experience spin losses at the rate of about one aircraft per year. In 1978, a joint NASA, Navy, and Grumman program was initiated to develop a new automatic rudder interconnect (ARI) system to increase the spin resistance of the F-14. Wing rock was suppressed, inadvertent spins were eliminated, and the handling qualities throughout the air combat envelope were improved.
Several years passed before funding constraints per-mitted the Navy to develop the ARI within plans to equip the F-14 fleet with a new advanced digital flight control system (DFCS). Following further refinements during Navy flight evaluations at Patuxent River Naval Air Station in Maryland, the Navy implemented the DFCS with the ARI. The first F-14 deployments with the ARI occurred during the 1999 Kosovo operations, and glowing reports from the F-14 squadrons indicated that the new system was a success.
The Navy decided to incorporate the GEC Marconi Digital Flight Control System (DFCS) into all F-14 aircraft to significantly improve flight safety. The system is designed to protect aviators against unrecoverable flat spins and carrier landing mishaps. DFCS also incorporates a lateral stick-to-rudder interconnect designed to improve less than desirable flying qualities in the powered approach configuration. Pilots agree that with the DFCS the Tomcat is more maneuverable and has crisp response to pilot control inputs. The new system should improve performance and safety during carrier landings. This modification affects 211 active duty and 16 reserve F-14 aircraft. The Foreign Comparative Test (FCT) demonstrated that DFCS drastically decreases the chance of entering out-of-control flight and improves the F-14's ability to recover, if a spin is entered. Departure from controlled flight has been a primary causal factor in 35 F-14 mishaps. Also significant is its ability to improve carrier approach line-up control addressing a problem often cited as a contributing factor in carrier landing mishaps. The incorporation of DFCS increases safety, both during "edge-of-the-envelope" maneuvering flight and carrier landings.
The new the Digital Flight Control System [DFCS] provides enhanced maneuverability for the F-14. The DFCS control panel replaces the current AFCS panel in the front cockpit, the analog system in use since the aircraft's inception. It contains the modified SAS switches, and also displays maintenance codes for system failures identified during IBIT and in flight. The DFCS system has lived up to its promise of enhanced controllability and performance in the high AOA regimes and in the landing configuration. However, the structural issue raised by the enhanced roll rates achievable with the DFCS is a potential factor affecting the crucial problem of F-14 fatigue life.
During validation of the existing NATOPS rolling G envelope, the primary F-14 test asset sustained extensive structural damage to the starboard engine weekly doors and aft fixed cowl when certain structural limits were exceeded. As it turned out, the problem was not due to DFCS but was related to a NATOP's operational envelope which had not been previously verified. This resulted in the fleet-wide rolling G restrictions from NAVAIR. The impact to the program is going to be felt in an initial envelope for DFCS with reduced rolling g above and beyond the cutbacks for AFCS roll SAS-on, simply because the Navy cannot support any further structural testing until the F-14 test aircraft is repaired. Data is still being analyzed and the restrictions haven't been fully defined yet, but it was anticipated that the initial envelope would still include 6.5 g's symmetric throughout for gross weights of 49.5K or less. For the clean configuration: 4 g's rolling to 570 KCAS, 3 g rolling to 700, and 1 g rolls/no abrupt stick inputs above 700/1.4 For external tanks or Pylon mounted AIM-54s: the "region 3" from NATOPS will begin above 570 KCAS/1.15 TMN at low alt, or 500 KCAS above 25K.
The F-14 DFCS began fleet introduction in July 1999 with the initial fleet release software version OFP 4.1.1 in F-14A squadrons. An aggressive transition schedule has seen the subsequent incorporation of the DFCS into all F-14A, B, and D variants. Every F-14 squadron has commenced or completed DFCS integration and the last AFCS squadron deployment was completed in April 2000 with the VF-102 Diamondbacks. The DFCS has been a tremendous success story. The system greatly increases departure resistance and provides enhanced recovery capability as well as significantly improves landing approach handling qualities. The F-14 operational and maintenance departments have been pleasantly surprised not just by the significant improvements in flying qualities of the DFCS, but also the improvements in the safety, reliability, and maintainability of the DFCS versus the older analog AFCS it was designed to replace.
The final DFCS software version (OFP 4.4) released in August 2000 included improvements to the existing control laws for the automatic carrier landing system (ACLS), roll SAS control laws easing maneuvering flight envelope restrictions, and expansion of system self-test fault reporting capability. Flight test of the new ACLS flight control laws was completed in April 2000 onboard the USS Enterprise (CVN-65) for both the F-14D and F-14A aircraft with very favorable results. The final ACLS configuration includes hardware and software modifications that abandon the old pitch attitude command system in favor of a new vertical velocity or "h-dot" command system with integrated direct lift control (DLC) for smooth glideslope control. The new design even corrects many maintenance limitations of the old system including pitch feel switch failures and force link disconnects.
The F-14 currently uses the ALE-39 Countermeasure Dispenser System. The system has limited flexibility, limited control of the LAU-138 BOL rails, and has been attributed to unexpected expendable magazine losses. An F-14 ALE-47 retrofit program has been developed to replace the existing ALE-39 systems on the F-14B/D aircraft. The replacement will essentially be a box for box swap with removal of unnecessary ALE-39 components. Unlike the ALE-39 system, which had limited communication with the LAU-138 rails, the ALE-47 will be fully integrated with all four BOL launchers enabling expendable deployment programs using the expendables from the buckets and the BOL rails as part of a combined dispensing program.
The F-14 will be modified in the aft cockpit with a new Digital Control Display Unit (DCDU) and an aircraft unique brightness control that is designed to permit NVG compatibility for the LED display. The ALE-47 system will be loaded with an Operational Flight Program (OFP) common to all Navy Aircraft with a platform specific Mission Data File (MDF) for tailored expendables programs. The OFP will support seven dispense programs that can be initiated using the currently existing ALE-39 controls. The ALE-47 system was included in functional and carrier suitability testing at Strike Aircraft Test Squadron during the summer of 2000. Retrofit from the ALE-39 to ALE-47 system will begin after successful ground/flight test and NAVAIR configuration approval.
Naval Air Systems Command's F-14 Program Office announced on March 20 that it had accelerated and deployed a software upgrade program that will allow U.S Navy's F-14 D model Tomcats to carry Joint Direct Attack Munitions (JDAM).
Completed operational tests already in progress indicated that the software upgrade was mature and stable. The test community determined that with an acceleration of remaining critical tests, they could provide a recommendation for an early release of the JDAM capability.
On Jan. 31, 2003, a NAVAIR software support team was assembled to modify the aircraft and install the new software. They reported aboard USS Theodore Roosevelt Feb. 2 and received required hardware two days later to start modifying F-14Ds. In 17 days, the team modified all forward deployed F-14Ds. The team loaded the software, assisted with the hardware modifications on the aircraft, and trained more than 90 aircrew and maintainers on JDAM employment.
A Tomcat can carry four JDAMs, each weighing 2,000 pounds. March 1, 2003 marked the first operational employment of JDAM from an F-14D.
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