B/CA Analysis: Cessna Citation S/II

are: high-speed cruise of 374 knots on 1,081 pph at FL 350, and long-range cruise of 327 knots on 690 pph at FL 430. About 80 percent of the S/II’s speed advantage is attributed to aerodynam- ics; the remaining 20 percent results from the higher N1 limits of the -4B powerplant, according to Cessna engineers. More Than More Speed The higher speeds of the Citation are impressive by themselves. For example, the S/II provides a specific range at normal cruise of 0.364 nm per pound, which is about five percent better than the Citation II’s corresponding value of 0.346 nm per pound. But the S/II achieves its speed and spe- cific-range advantage while lifting a higher gross weight than its predecessor. Thus its improve- ment in maximum productivity is greater than the increase in either speed or specific range. The Citation S/II is certificated for a ramp weight of 14,900 pounds, 1,400 pounds more than the II, and it has a max takeoff weight of 14,700 pounds. Thus, the S/II achieves its greater speed while carrying more, thereby emphasizing the benefits of Cessna’s aerodynamic and powerplant changes. Furthermore, the S/II can achieve an initial cruise altitude of FL 410 after a takeoff at max gross. Mainly because the S/II’s flaps extend inboard until they nearly reach the fuselage rather than ending about a foot outboard as in the Citation II, the new aircraft has a stalling speed that is one knot slower than its predecessor’s, despite the S/II’s higher gross weight. Part of the weight advantage of the S/II is consumed in the new aircraft’s heavier B/CA- equipped basic operating weight — 8,756 pounds, compared with the II’s BOW of 8,035 — but the new Citation has a useful load that exceeds the II’s by a respectable 679 pounds. An operator may choose to use that greater useful load for carrying passengers, or he can take advantage of the S/II’s 5,777-pound-capacity fuel tanks, which hold 805 pounds more than its predecessor. FROM THE DECEMBER 1984 BUSINESS & COMMERCIAL AVIATION. COPYRIGHT © 1984, THE McGRAW-HILL COMPANIES, INC. ALL RIGHTS RESERVED. Classic Citation The S/II incorporates all the qualities that made the Citation II a popular aircraft. It offers room for seven to eight passengers and has a fully enclosed lavatory, and its flight deck has space for a full complement of avionics. Interior appointments for the S/II that B/CA flew were attractive and well-built. The S/II also enjoys typical Citation quietness. Cruising with normal power at FL 370, we observed an average noise reading of 80 dBA in the cabin and 84.5 dBA in the cockpit. The relative position of the Citation S/II with respect to a hypothetical aircraft that possesses the average characteristics of all business jets within the S/II’s class is illustrated by the B/CA Comparison Profile. Clearly, the new Citation presents a competitive picture that is enhanced by the aircraft’s speed and useful load, which were areas where the Citation II fell farther below the average than does the Citation S/II. The S/II possesses the good airport performance and fuel specifics that are Citation trade- marks, and its healthy fuel capacity gives the aircraft a highly competitive tanks-full range. B/CA’s evaluation of the Citation S/II’s performance occurred during a trip from Atlanta’s Fulton County Airport to Cessna’s delivery center in Toledo, Ohio. For our flight, which carried a useful load of 4,511 pounds, we had a takeoff weight of 13,200 pounds, which equated to 85, 92 and 97 knots V1, VR andV2 respectively. Balanced field length was conservatively calculated to be 3,350 feet. Once we were released from the confines of Atlanta Departure Control and the congestion of the Atlanta area, we climbed to FL 310 and observed a true airspeed of 399 knots on 1,235 pph, which is two knots and about 85 pph better than what Cessna states is possible in temperatures averaging about ISA+3. We then climbed to FL 370 and observed a TAS of 388 knots with a fuel flow of 1,020 pph, which equates to a specific range 0.018 nm per pound better than book but about six knots and 68 pph under handbook figures. Possibly our power setting was slightly low. On average, however, the S/II lived up to its advertised billing in terms of speed and specific range for our weight, temperature and altitude. As we approached the Toledo area and descended, we applied the spoilers to observe their effectiveness and vibration. While spoiler deployment causes a slight rumble, the disturbance is minimal and should not be a distraction to passengers. With the spoilers deployed, the aircraft can descend at a rate that easily exceeds the limits of the vertical speed indicator, and actuation of the devices causes almost no effect on handling qualities. Below FL 180 we canceled our airways clearance and did some air work, including stalls. The S/II responded in typical Citation fashion: The aircraft has to be one of the gentlest jets flying. Its handling qualities are very well-behaved. The pitch dynamics are nicely damped, and lateral/directional characteristics are equally pleasant. During stalls, the aircraft gave ample warn- ing of its condition, and the stall break was not severe, although we did observe a tendency to roll slightly to the left as the nose pitched down at the stall. The S/II’s speed stability on the approach was very good, with the aircraft responding nicely to power changes and easily trimmed for a stabilized flight path. The fact that Cessna increased the strength of the elevator down spring and added slightly to the bob weight (to account for a small change in pitch stability due to the wing redesign) in the pitch system was apparent as we com- menced the flare. More force was needed to effect the roundout, but otherwise the aircraft behaved pleasantly-like a Citation. The Citation S/II is an example of how technology can subtly improve a good product and make it more attractive. No doubt exists that the S/II is a more capable aircraft than its predeces- sor, and that’s good news for both the operator and the manufacturer. B/CA FROM THE DECEMBER 1984 BUSINESS & COMMERCIAL AVIATION. COPYRIGHT © 1984, THE McGRAW-HILL COMPANIES, INC. ALL RIGHTS RESERVED.