Few people, if asked, would include the Cessna Citation in any list of military aircraft. Although a biz jet, 68 Citations have served in the US military, and many continue to serve today. In this post, I’ll discuss one of those variants.
In the early 1980s, the US Navy needed to replace its fleet of aging North American Rockwell T-39D Sabreliners used in the Undergraduate Naval Flight Officer (UNFO) training program. Following a competitive procurement process, the Navy awarded Cessna Aircraft a contract for 15 modified Citation S/II aircraft in 1984. Cessna called the new version the Model 552, and the Navy designated it the T-47A. The T-47 soon became the first in a line of Citations that found military applications.
Compared to the Citation S/II, the T-47A had more powerful engines (P&W JT15D-5 turbofans), a 5.7-foot shorter wingspan (46.5 feet vs. 52.2 on the S/II), a 0.8-foot longer fuselage to accommodate the nose-mounted radar (the same one used on the F-14 Tomcat) and three student radar stations in lieu of the S/II’s executive seating. This combination gave the T-47A an edge over the S/II in acceleration, rate of climb maximum speed (Mach 0.733 vs. Mach 0.721 at 40,000 feet).
The Navy issued a $160 million, five-year UNFO/Training System Upgrade contract (with an optional for three more years) for a turnkey training package. FAA certification for the T-47A was received on November 21, 1984, with deliveries to the Navy beginning in December. This contract helped pull Cessna out of 1983’s slump and $18 million loss.
To provide the required total training program, Cessna teamed with Northrop Worldwide Aircraft Services, Inc. (NWASI) for pilots and maintenance personnel and Singer/Link for the radar training simulators. Cessna delivered 15 T-47A aircraft to Training Air Wing Six at Naval Air Station Pensacola, Florida. Although the Navy assigned the aircraft sequential serial numbers, they retained civilian “N” numbers on the tail with “NAVY” stenciled just below the horizontal stabilizer and the military star-and-bars on each engine pod.
Final deliveries lagged six months behind schedule due to some operational deficiencies, including unexpected radar target acquisition range limitations (quickly corrected by the radar contractor). Other problems necessitated installation of:
- Hydraulically-actuated, graphite-composite Fowler flaps extending farther inboard than standard (improved lift-to-drag ratio in landing configuration);
- Aileron boost system and geared aileron trim tabs (improved roll rates); and
- Impact resistant polycarbonate windscreen able to withstand the impact of a five-pound bird at 455 KIAS (due to the high speed, low altitude operations).
NWASI hired the first T-47A pilots in January 1985, almost all with prior military flight experience (primarily in fighter aircraft). NWASI carefully screened the pilots, who had to be approved by the Navy’s T-47 Training System Manager and whose job was to follow the guidance provided by the UNFO students — closely supervised by UNFO instructors — during departures, arrivals, and airborne intercept training.
The standard UNFO training mission required two T-47A aircraft (taking turns flying as the interceptor and the attacker) with two or three students and one UNFO instructor on each aircraft. An unusual feature was that the UNFO instructor (a non-pilot) was actually the mission commander, and his authority included all facets of the mission, including veto rights over safety-of-flight decisions.
In the training area over the Gulf of Mexico, a ground controlled intercept officer radar vectored the two T-47s to an initial intercept set-up with 500 feet altitude separation. Once the student NFO on the interceptor T-47 confirmed radar contact on the attacker T-47, he assumed control of the intercept and attempted to direct the pilot to a successful stern intercept. On each training sortie, the students alternated NFO responsibility.
The T-47 program also introduced students to low-level navigation procedures over the flat, featureless inland terrain of Florida and southern Alabama, usually at 500 feet AGL and groundspeeds up to 330 KIAS. The students took turns vectoring the pilot to the entry point for the low level route, directing speed and course corrections, and calculating wind drift and fuel consumption.
In 1992, the Navy replaced the T-47A with contractor-operated T-39Ns (refurbished and upgraded T-39Ds). In seven years, the T-47A fleet had logged over 100,000 flight hours, a 95-percent mission completion rate, only a handful of minor incidents, and no major accidents. However, rumors suggested that the T-47 fleet had begun to show structural wear-and-tear and also may not have met Navy desires for high altitude performance.
Cessna eventually mothballed all T-47s in a hangar, where a subsequent fire destroyed all but one.