Specifications for the Piper PA-34 Seneca III

Some pilots have complained of the with the manual system. Also, elimina- need to use both hands on the flap tion of the flap lever has freed up quite lever to select the last notch. a bit of cabin floor space for charts. On the new system, the combination However, the flap position indicator selector jindicator is located on the and the -in-transit light are difficult to right side of the control quandrant and see from the pilot's position. Some has detents for three flap positions-&. neck-craning could be avoided if the indicators were moved to the upper part of the pilot's panel. Also, the addi- tion of a detent for 10 degrees of exten- sion (the first notch in the manual sys- tem) would be useful for both takeoffs and approaches. An excellent course is offered by Piper at Vero Beach, Florida. The course is taught by Robert (Bob) Scott, manager of training for the company, and staff instructors Steve Bergevin and Linda Sma]kowski. Two days are spent in the classroom, exploring sys- tems, performance and normal and emergency operating procedures. A comprehensive two-hour flight with one of the instructors is available at the pilot's request. The course imparts a great deal of useful information, some of which can- not be found in a Seneca operating manual. Because of this, the course is valuable to Seneca pilots, inexperi- enced alld experienced. Bob Scott has developed a number of operating procedures that work very well in the airplane. Extending the flaps 10 degrees for takeoff allows rota- tion at a slower airspeed (70 to 75 knots, rather than the 79 knots recom- mended for a zero-flap takeoff) and precludes the airplane's tendency to sink a bit after lift-off. The turbocharger on each engine has a fixed wastegate, adjusted to provide 40 inches of manifold pressure at full throttle at 12,000 feet. At sea level, the manifold pressure limit is reached at about half to three-quarters throttle travel. The pilot, therefore, must take care not to overboost the engines. There is a relief valve that is supposed to prevent manifold pressure from ex- ceeding 42 inches, but the valves can, and do, stick closed. Scott recommends bringing the throttles forward to get 25 inches, initially, to allow the turbo- chargers to spool up and stabilize. Then, release the brakes and bring the throttles to 35 inches. The turbocharg- ers will continue to spool, bringing manifold pressure up to between 38 and 39 inches. The pilot then can de- vote his full attention to the takeoff, AOPA PilOT • 51 continued saving fine-tuning of the power for a less busy time, such as after the land- ing gear are retracted and initial climb attitude has been established. The Seneca gets off the ground quickly, but not as quickly as the ac- companying specifications table sug- gests. (AOPA Pilot uses manufacturers' specifications in its tables.) The takeoff distances (a ground roll of 920 feet and 1,210 feet to clear a 50-foot obstacle) and the accelerate/stop distance (2,400 feet) apply to maximum-performance takeoffs, involving 25 degrees of flaps and initial climb at 66 knots. Under standard conditions and using the procedures recommended by Piper for a normal takeoff (no flaps and a rotation/abort speed of 79 knots), ground roll is about 1,500 feet, distance to clear a 50-foot obstacle is about 1,800 feet and about 3,800 feet of pavement are required to bring the air- plane to a stop after it has accelerated to 79 knots. According to Piper, single-engine rate of climb is 240 fpm under stan- dard conditions, which include takeoff at gross weight from a sea-level airport at 15°C (59°F). The calculation also implies near-perfect pilot technique. However, during a single-engine go- around at Vero Beach Airport (eleva- tion, 25 feet) on a 35°C (97°F) day, in a Seneca III substantially below maxi- mum takeoff weight and flown by a somewhat rusty pilot (the author), rate of climb was about 175 fpm. For cruise climb, the Seneca manual recommends 75 percent power (about 34 inches and 2,500 rpm), 102 knots and cowl flaps in trail. Scott recom- mends using more power (36 inches and 2,600 rpm), 120 to 125 knots and closing the cowl flaps. This results in a flatter deck angle, which provides bet- ter visibility for the pilot and enough air and fuel to cool the engines. Engine temperatures, of course, should be monitored closely and cowl flaps opened if necessary. I have used Scott's procedure for climb-outs from a number of airports-including Blythe, California, on a 39°C day-in brand- new, as well as much-used Seneca Ills and have yet to find it necessary to open the cowl flaps during climb. The vigilance required for the procedure is rewarded by a slightly better rate of climb and a higher ground speed. Leaning the fuel-air mixture for cruise requires time and patience. Any change in manifold pressure results in changes in fuel flow and exhaust gas temperature, measured at the turbo- charger turbine inlet. The procedure for the Seneca 11\ is a bit different from its predecessors. At 75 percent power, the mixture is leaned to 14.5 gallons per hour or 1,525°F, whichever comes first. Piper recommends 25°F rich of peak at lower power settings. Most Seneca pilots operate their air- planes between 8,000 and 12,000 feet. At 10,000 feet and 75 percent power, true airspeed is 179 knots, and total fuel flow is 29 gph. Endurance, with reserves, is 2.7 hours with standard ___ 1iI~_ 54. FEBRUARY 1985 \ The biggest change is the electric flap system. Gone is the floor- mounted manual flap handle. AOPA PilOT • 55 COllti1JUed Piper PA-34-220T Seneca III Base price $194,900 Price as tested $272,962 AOPA Pilot Operations/ Equipment Categories·: Cross-country $204,000 to $225,000 IFR $285,000 to $320,000 All-weather $326,000 to $369,000 Specifications Continental (L)TSIO-360-KB 220 hp @ 2,800 rpm (5-min limit) 200 hp @ 2,600 rpm (max cont) Recommended TBO 1,800 hr Propellers Hartzell two-blade, 76 in dia constant-speed, full-feathering 28 ft 7.4 in 9 ft 10.5 in 38 ft 10.9 in 208.7 sq ft 22.8 Ib/sq ft 10.8Ib/hp 6-7 10 ft 5 in 4 ft I in 3 ft 6 in 2,852 Ib 3,2191b 4,773 Ib 1,9211b 1,5541b 1,3631b 8161b 4,750 Ib 4,513 Ib 4,470 Ib 588 lb (558 Ib usable) 98 gal (93 gal usable) Fuel capacity, w /opt tanks 768 Ib (738 Ib usable) 128 gal (123 gal usable) 8 qt 66 KIAS 130 KIAS 108 KIAS 166 KIAS 205 KIAS 67 KIAS 64 KIAS 191 ktf3.1 hr 175 kt/3.2 hr (144 pph/24 gph) @ 55% power, best economy 22,000 ft 10,000 ft 193 kt/2.6 hr 179 kt/2.7 hr (174 pph/29 gph) @ 65% power, best economy 18,000 ft 10,000 ft All specificatiolls are based all mallufacturers calculatiolls. All performallce figures are based all stalldard day, stalldard atmosphere, at sea level alld gross weight, WI less otherwise Iloted. ·Operatiolls/Equipment Categories are defilled ill JUlie 1984 Pilot, p. 108. The prices reflect the costs for equipmellt recommended to operate ill the listed categories. 180 kt/3.6 hr 159 kt/3.9 hr (114 pph/19 gph) Max operating altitude 25,000 ft Single-engine service ceiling 12,300 ft Landing distance over 50-ft obst 2,160 ft Landing distance, ground roll 1,400 ft Limiting and Recommended Airspeeds Vmc (Min control w/one engine inoperative) Vsse (Min intentional w lone-engine inoperative) 85 KIAS Vx (Best angle of climb) 76 KIAS Vy (Best rate of climb) 92 KIAS Vxse (Best single-engine angle of climb) 78 KIAS Vyse (Best single-engine rate of climb) 92 KIAS Va (Design maneuvering) 140 KIAS Vfe (Max flap extended) 115 KIAS Vie (Max gear extended) 130 KIAS Vlo (Max gear operating) Extend Retract Vno (Max structural cruising) Vne (Never exceed) VsI (Stall clean) Vso (Stall in landing configuration) Single-engine ROC, sea level 240 fpm Max level speed, sea level 196 kt Cruise speed/Endurance w / 45-min rsv, std fuel (fuel consumption, ea engine) @ 75% power, best economy 17,000 ft 10,000 ft 920 ft 1,210 ft 2,400 ft 1,400 fpm 100 Ib, 15.3 cu ft 100 Ib, 17.3 cu ft Performance Takeoff distance, ground roll Takeoff distance over 50-ft obst Accelerate/stop distance Rate of climb, sea level Oil capacity, ea engine Baggage capacity forward aft Length Height Wingspan Wing area Wing loading Power loading Seats Cabin length Cabin width Cabin height Std empty weight Empty weight, as tested Max ramp weight Std useful load Useful load, as tested Std payload w /full fuel Payload w /full fuel, as tested Max takeoff weight Max landing weight Zero fuel weight Fuel capacity, std Powerplants fuel tanks and 3.6 hours with optional tanks. The latter are two IS-gallon bladders, a $2,285 option this year. At 65 percent power, the airplane cruises at about 175 knots while burning 24 gph. The endurance figures are 3.2 hours and 4.6 hours, respectively. Descents in any turbocharged aircraft not equipped with speed brakes must be planned carefully to avoid shock- cooling the engines. Often, the only way to keep a Seneca's engines warm while complying with an air traffic control-mandated quick descent is to lower the gear and maintain 130 knots. (Speed brakes are available from Turboplus, Tacoma Narrows Airport, 1520 26th Avenue N.W., Gig Harbor, Washington 98335.) The base price of a 1985 Seneca 111 is $194,000. Options for the airplane in the accompanying photographs, N4380K, include: auxiliary fuel tanks ($2,285); heavy duty brakes and tires ($270); wing tip recognition lights ($495); a 64-cubic-foot oxygen system ($2,990 and 40 pounds); air condition- ing ($ 7,375 and 53 pounds); and a $37,425 avionics package, including King radios and flight control system. The airplane also has McCauley three- blade propellers, a $4,955 option that adds 44 pounds. According to Piper, the standard two-blade Hartzells are lighter and more efficient but are more expensive to maintain. The options brought the price for N4380K up to nearly $273,000. The options-list for the Seneca III is extensive. The airplane is certified for flight into icing conditions when prop- erly equipped. Current price for the de- icing package is about $20,000. A new Seneca, equipped for basic cross-country flying, costs a little more than $200,000. For the businessman- pilot or flight department manager who wants a light piston twin with all- weather capability, the price comes close to $370,000. (One item that should be added to the options list is higher-capacity alternators. In a well- equipped airplane, the power demand can far exceed what can be supplied by the 65-amp alternators.) A light twin must straddle the fence between business and personal flying on one side and commercial operations on the other-it must be a jack-of-all- trades. The key to the Seneca's success is its flexibility. The formula is right for a variety of operations. D 56· FEBRUARY 1985