AIAA-2011-7027

Bob Sardo, Weapons Engineer, Ret, Tom Reilly, Program Manager, Ret., Dyna Benchergui, Bombardier

System Integration and Flight Test of the F-14 Tomcat Weapons System

Bob Sardo, Tom Reilly, Dyna Benchergui

Abstract

The development of the F-14 Tomcat and the AN/AWG-9 Phoenix Weapons Control System began with

the selection of the General Dynamics Corporation to design and build the F-111A (USAF) and the F-111B (USN),

as part of the dual service requirement. The key element of the AWG-9 system was the AIM-54 Phoenix Missile.

Development of the AIM-54 Phoenix began in 1960, following the cancellation of the F6D Missileer and its

associated AAM-N-10 Eagle missile system. A long-range missile, the AIM-54 was intended to be used against

slow, non-maneuvering enemy targets such as bombers and strike aircraft that were intent on attacking US carrier

battle groups.

Initially named the AAM-N-11, the AIM-54 missile was designed by a team at Hughes Aircraft and was

paired with the new AN/AWG-9 radar and fire control system. As development continued, the US Navy planned to

incorporate the new weapons system into the proposed F-111B. Lacking experience with carrier-based fighters,

General Dynamics teamed with Grumman Aircraft Corporation for assembly and test of the F-111B aircraft. In

addition, Grumman would also build the F-111A's aft fuselage and the landing gear. However, Grumman felt the

Navy F-111B would be too heavy for carrier airborne operations. Therefore, Grumman went to work on developing

a series of models of the F-14 Tomcat in parallel with their effort on the F-111B and built a series of actual size

mock-ups, made of plywood. While still involved in the development of the EF-111B, Grumman made an

unsolicited proposal to the Navy for the F-14 Tomcat. Interestingly, one of the models proposed was of a single tail

design, designated Proposal No. 303B.

Figure 1: Proposed Mockup

Flight tests ultimately proved the F-111B was too heavy for carrier operations, and under the leadership of Admiral

Tom Connolly and Admiral Tom Moorer the F-111B was cancelled and eventually replaced by the Grumman F-14

Tomcat. Grumman was awarded the F-14 contract in January, 1969 and the first flight took place in December, 1970,

with Grumman Test Pilots Bob Smyth at the controls and Bill Miller in the rear seat.

System Integration and Flight Test of the F-14 Tomcat Weapons System

System integration tests were conducted in the laboratory by simulating all components of a weapons

system plus its operational environment. In this way, all-around compatibility of total system components is tested,

designs for new concepts or change proposals are studied, and problems and ways to avoid them are evaluated, all

without a single aircraft leaving the ground. With missiles becoming more and more complex, a flight test may

waste a half-million-dollar operation, in addition to being encumbered by other problems of weather, time and

human fallibility attendant on all flight operations.

The SITS laboratory can also provide flight test pilots with valuable experience in the use of the new

weapons system in a simulated environment. Seated in the SITS cockpit, the pilot and the MCO/RIO fly a simulated

mission, realistic in all respects except for the feeling of aircraft and body motion. Looking at radar scopes, they see

simulated targets in flight and can simulate launches of missiles and measure their success.

AIAA Centennial of Naval Aviation Forum "100 Years of Achievement and Progress"21 - 22 September 2011, Virginia Beach, VA

AIAA 2011-7027

Copyright 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.


The SITS laboratory cockpit is a counterpart of that in operational aircraft, thus the avionics that fit into it

can be relied to fit into the other. This is an important factor where space problems are often acute; the greatest

breakthrough in avionics technology is of no advantage if its hardware will not fit into the aircraft.

This highly complex laboratory for the evaluation of the F-14/Phoenix is the first such facility at the Naval

Missile Center at Pt. Mugu, to include all the avionics of a weapons system, such as radar, infrared, and guidance

systems, on-board computers, data links, cockpit displays, and the AIM-54C Phoenix missile itself.

System integration tests of the F-14 Weapons System began operation in the Laboratory at the Pacific

Missile Test Center, Pt. Mugu, CA, starting in late 1969. Major avionics and weapons systems were installed in a

wooden mock-up of the F-14, called the SITS (System Integration Test Station). These systems consisted of the

Hughes Aircraft Corporations AN/AWG-9-Phoenix Missiles System, the AN-AWG-15 Armament System, the Litton LN-15 (CAINS) Inertial Navigations Systems, the Teledyne Computer Signal Data Converter, which

contained the many interface circuits of the aircraft and its avionics. Also included were the various cockpit

displays, such as the Pilots Vertical Digital Integrated Display, the Heads Up Display (HUD) and the Horizontal Situation Display (HSD). All these systems were functional and incorporated into the various SITS Test Procedures.

The task of integrating the many systems of the F-14 was simplified by the use of the SITS frame. As each

new system arrived from the Supplier, the new LRU (Lowest Replacement Unit) was inserted into its location and

connected. Should any cable wiring require changes due to the new configuration, this task was made easier due to

the accessibility of the cabling. Test Plans for the new configuration were also easily modified and test and

integration task continued with the least amount of effort.

By far, the most comprehensive integration task was the Hughes AWG-9 system. This was a rather large

system and contained a large number of LRUs. Among these were the NDRO (Non-Destructive Read Out) which contained the memory circuits that stored all of the digital information. The main memory components consisted of

a new memory device called thin film memory. These sub-units consisted literally of thin pieces of glass with wire

wrapped across each plate which was coated with a magnetic surface. At that time, this was the cutting edge of

computer circuitry.

Responsibility for the testing of the AWG-9 rested with Hughes Aircraft Corp. In their lab in Culver City,

CA, commonly called the Roofhouse because of its location, their Engineers tested the software and would submit

their revisions to the SITS lab for verification. Our responsibility was to determine if the software corrected

previously reported problems and to verify system improvements. Grummans responsibility was to insure the software changes also provided the correct inputs to the various subsystems and displays.

Several months following the loss of the first F-14 in December, 1970, the SITS Lab had a visit from the

then-Under Secretary of Defense, David Packard (see Figure 2). This visit was apparently an assessment of the

impact the loss had on the status of the program and it was rumored that he was there to determine whether or not

the program should be continued. What Mr. Packard saw was a fully operational system that resulted in his coming

away being visibly impressed. Incidentally, Mr. Packard was the co-founder of Hewlett-Packard.

Note the slanted board in the front cockpit. This board covered the original design of the Heads Up Display, a thick pane of glass that was nearly parallel with the front cockpit windshield. During Air to Air combat

maneuvers, the various heading, attitude and target symbols would be projected on the glass to aid the pilot in

targeting enemy aircraft. In the SITS, this worked as advertised. However, on the first weapons system night flight, conducted some months later, it was found that when lining up with the runway, the HUD glass interfered with

runway landing lights as three sets if lights appeared on the windshield and the Test Pilot reported he did not know

what set of lights to land to. As a result, the decision was made by Grumman to remove the glass and go to a direct

Windscreen Projection system.


Figure 2: System Integration Test Station

The location of the SITS frame was on the third floor of the PMTC Building, located on the beach at Pt.

Mugu. Mounted on a track assembly, the SITS had the ability to be rolled out through an open door where it had

full exposure to the Pacific Ocean (Figure 3. With all the systems fully operating, a target aircraft would come

inbound towards the SITS from a distance of 150 miles and be tracked by the Tomcats Weapons System.

Figure 3: SITS Live Target Tracking

A major part of the SITS lab was the LIS, (Laboratory Integrated System) which consisted of large, main frame Sigma V computers that were programmed to take data from the SITS during live target tracking exercises

and also from Data Tracking sites, located on St. Nicholas Island off the coast of the mainland. By comparing this

data from the Data tracking and from the AWG-9 on the SITS, the tracking information can then be determined with

great accuracy.

Upon arrival of the first F-14 (No. 4) from Bethpage, LI, NY, the system was removed from the SITS and

taken to the flight line for installation into F-14 No. 4. After several weeks of on-aircraft testing and integrating the

Weapons System, the first systems flight took place. Unfortunately, the results were disastrous. The MCO (Missile

Control Officer, at that time) reported that his main Tactical Information Display (TID) was inoperable, as he could

not detect any display. Fortunately, we had a TV Flight Recorder system that recorded the displays in the rear seat.


One glance at the results showed exactly why he had no display; the TID Symbol Delete button was pushed and the

resultant display showed only barely discernible dots where the actual symbols should have been. Following a series

of successful flight tests, No. 4 was turned over to the Hughes Aircraft Corporation for their Flight Test and

Evaluation of the AWG-9 Phoenix Weapons System. The subsequent arrival of Aircraft Nos 5, 6 and 7 were then prepared for Grumman Flight Tests. In the meantime, the SITS was utilized to conduct System Test and

Verification of various software changes, either from the results of the Hughes flight tests and/or from the Grumman

flight testing. Improvements in any of the avionics systems hardware and/or software were also tested in the SITS

prior to incorporation into the F-14 systems.

Following a series of successful system flight tests, the Naval Preliminary Evaluation (NPE II) trials began

at Pt. Mugu in mid-Summer of 1972. Significantly, F-14 No. 7 was preparing for its third flight of the day,

scheduled for a night flight. This was a first for any Pt. Mugu aircraft, in that no system aircraft had flown three

system hops in one day. However, just prior to the third flight, a Quality Control engineer noted a hydraulic fuel

leak coming from the engine area of the aircraft. He accordingly downed the aircraft and ordered the port engine

lowered. It was discovered that the leak was the result of an unsecured hydraulic line that was chafing across a fuel

line. Both lines showed a severe indentation and it was a good bet that the night flight could have had a disastrous

ending.

The West Coast preliminary report of NPEII stated that the integrated F-14A Avionics and Weapon Control

System displayed outstanding performance characteristics and potential to accomplish the air superiority fighter and

fleet air defense missions. However the report also noted 33 deficiencies to be corrected prior to NPE III and BIS

trials. Of these deficiencies, nine were to be corrected prior to NPE III and 24 prior to BIS trials. The East Coast

report stated the F-14A continued to exhibit outstanding potential for the fighter mission within the expanded flight

envelope available for NPE II. There were, however, 29 deficiencies noted during NPE II. Of these deficiencies, 9

should be corrected prior to NPE III and 20 should be corrected prior to BIS trials.

For the next several years, the F-14A was subjected to flight testing at Pt. Mugu and on board several

aircraft carriers. Notably, the first of several F-14A carrier sea trials took place in March, 1973, aboard the USS

Independence (CVA-62). Our test aircraft, F-14A No. 5, was flown to Norfolk, Va., and towed to Pier 12 to be

hoisted aboard ship. The primary purpose was to develop the software to attain an on-deck alignment of the INS

system, using the ships Ships Inertial Navigation System (SINS) as the basis for the alignments. These tests were limited to hangar deck testing only, as the aircraft was not carrier-qualified.

In the summer of 1973, our Pt. Mugu team traveled to NATC Patuxent River to utilize F-14A No. 15 for a

series of catapult testing, using their C7 catapult. The first series of cat shots with all systems operating were not

successful. The gyro-stabilized IMU of the CAINS navigation system would dump on each and every launch

attempt. This required two or three days of intense evaluation and it was determined that the system could not

tolerate the initial high g force of the catapult. The problem was determined to be due to a defective CAINS circuit

board and was solved by installing modified boards. Subsequent catapult tests proved successful and the F-14 tests

continued.

Carrier selection to accommodate the F-14A in the early days was limited, due to the size of the Jet Blast

Deflectors (JBDs). Each of the CVA class of carriers were required to replace their existing JBDs because of the larger size required for the Tomcat. Among the first was the USS Forrestal.

Later in 1973, Carrier Suitability Trials took place aboard the USS Forrestal (CVA-59) during the period 26

November 2 December. This exercise also included other aircraft, such as the Lockheed S-3A, RA-5V Vigilante, the McDonnell Phantom, and the Chance-Vought Corsair II. While these aircraft were aboard for specific suitability

trials, the primary purpose of our visit was to collect data for the continued development of the Inertial Navigation

System (INS) and to evaluate the Carrier Alignment modes and accuracies. As these aircraft were on loan from

NATC Patuxent River, the CAINS system would undergo actual alignment and catapult testing to aid in the

software development. These catapult tests included a back-up CAINS alignment mode called, Catapult Alignment.

While not as accurate as the on deck alignment, it did serve to provide an accurate attitude and heading to the

various displays. An additional scope of the exercise was also to evaluate the AN/AWG-9 Phoenix Missile System

to perform in the carrier environment. Project pilots from NATC Patuxent River included LCDR Frederick Hauck,

F-14A Project Officer and LCDR Virgil Jackson, F-14A CAINS Project Officer were aboard to conduct these tests.


Overall results of the testing aboard the USS Forrestal were mixed. The Inertial Measurement Unit, the

main gyro-based platform unit of the CAINS system, failed on numerous occasions under varying conditions. The

sum total of failures included: One IMU No-Go while tanking, four IMU No-Gos during on deck alignments and two prior to catapult and two on receipt from Supply. Needless to say, the Navy was unhappy with the IMU.

However, overall the testing of the systems on the hangar deck and the ensuing on deck testing yielded an enormous

amount of data that would be used back at SITS to provide the improvements needed to improve system

performance. The overall navigation test results were that, while the navigation system did not meet expectations,

some good results did emerge. This was borne out by applying lessons learned to additional SITS testing back at Pt.

Mugu.

Other problems occurred with the CAINS IMU system. The first time the gun was fired during testing at

sea, the IMU dumped. This was also found to be a CAINS circuit that required a modification to withstand the g forces experienced by the IMU. Also, the first time in-flight refueling took place, the IMU dumped. This was easily

traced to the electrical wiring from the refueling boom, located on the starboard side, being laid too close to the IMU

power supply, also mounted on the starboard shelf. Re-locating the cabling from the refueling boom away from the

IMU Power Supply forever solved that problem.

During the mid-seventies, the Shah of Iran had decided to purchase an American fighter and had reviewed

a number of them, the USAF F-15 and the F-14A. Having decided on the Grumman F-14A, a purchase order for 80

Tomcats was given in mid-1974 time frame. Grumman Pt. Mugu was tasked to install certain modifications to the

aircraft, such as removal of the tail hook and other minor modifications. Chief among these modifications was to

provide two of the Tomcats with the ability to fly the aircraft from the rear RIO cockpit. This was a near impossible

requirement as it required the use of the left console to house the throttle and wing sweep assemblies, as well as

incorporate the flight control stick and the rudder panels, where the pedestal portion of the Tactical Display

Indicator was located. The large Computer Address Panel of the AWG-9 system was successfully relocated. A

prototype of the arrangement was made, but before this was finalized, the Shah was overthrown and the program

subsequently cancelled. The Grumman contingent based in Isfahan left Iran carrying key spare units under their

arms, such as the CSDC. This system contained key interface circuitry that made it nearly impossible to conduct

system flights. Of the original order of 80 aircraft, 78 were delivered, with one crashing enroute to Iran and the

other at Calverton being readied for delivery. Today, it is rumored that only a small number of Tomcats remain, but

have become the subject of cannibalizing retired Tomcats to this day.

Flight testing continued at Pt. Mugu and now included live target missile firing. One such exercise

included the first firing of the Sparrow missile over the Pacific Ocean one sunny day, aboard F-14A No. 6. The

Sparrow was mounted in the fuselage, with its large, sharp vertical tail inserted inside the fuselage. Upon release,

the missile was programmed to drop, do a 45 degree roll-over command, and then fire. Unfortunately, it did not

follow its orders. Upon release, it immediately ignited, then began bumping up against the fuselage, ripping open

the fuel cells, then cycling up and down out of control. When it turned toward the chase plane, who was filming

these scenes, the latter wisely pulled away. Upon returning to the scene, the Tomcat was seen in a 45 degree dive,

with flames trailing the entire aircraft. The crew successfully ejected and were seen parachuting to the surface of the

ocean. Both crewmen showed up at the weekly Grumman Bowling League that evening, none the worse for wear.


The first Phoenix Missile launch testing was more successful. The AWG-9 provides the ability to track up

to 24 targets in the Track While Scan mode, and then assign a firing order of the six closest to the aircraft. This

mode was tested over the Pacific, with six drones sent aloft by PMTC personnel. The results were very successful,

with five of the Phoenix missiles hitting their assigned targets and only one miss. The latter, however, was

attributed to a faulty drone.

Grumman production of the Tomcat continued and when F-14A No. 15 was completed, a request came to

Pt. Mugu to provide Engineering support for the production team at Calverton, L.I. After a period of three weeks,

No. 15 took to the air for its first full system flight, with successful results.

During the late 1970s, the Navy requested that a reconnaissance version of the Tomcat be developed and the aircraft known as the RF-14A TARPS (Tactical Airborne Reconnaissance Pod). The initial version was

developed by Bethpage Engineering but required assistance from Pt. Mugu, whose responsibility was to develop the

modifications required to Weapons Station No. 5, located on the under fuselage of the Tomcat. As West Coast

Program Manager, it was our responsibility to develop the mods to the airframe at Station No. 5, and install the

TARPS pod. The pod itself was being designed and built at Naval Air Development Center, Johnsville, PA. Flight

tests of the TARPS were scheduled at Grumman Calverton. The early version consisted of a K-99 Reconnaissance

camera which had the ability to provide close-up telephoto shots of ground targets and/or bombing results, a

panoramic camera located in the mid-section which had the capability to photograph nearly a 180 degree range, and

an Infrared Camera that provided night photos of target areas. The TARPS program continued development and

made drastic improvements to the internal cameras over the years. In a short space of time the capability spread

throughout the fleet, until every airwing had one squadron of F-14's equipped for the mission (typically 3 aircraft out

of a squadron of 10/12).

SITS testing proved to be such a success the Navy decided to add a second SITS frame to the Lab at Pt.

Mugu. Rather that construct a plywood version, it was decided to locate an airframe from a crashed Tomcat and

modify it for the Lab use. A trip was planned that included visits to Calverton, Patuxent and Oceana, where these

airframes were located. One was eventually selected and delivered to Pt. Mugu for installation in the Lab. The

purpose of this unit was to test the proposed AWG-9 improvements to the Tomcat while the current configuration

continued its support and test of the existing system.

The highlight of our effort in the SITS Integration Lab was receiving invitations to the Commissioning of the first F-14A Tomcat squadrons, VF-1 and VF-2, at NAS Miramar on Saturday, the fourteenth of October,

nineteen hundred and seventy two, as the Department of the Navy invitation had stated. It was truly a memorable event.

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AIAA-2011-7027