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Piper Seneca (German)

As we've reported in previous articles on used aircraft, used piston mushrooms are generally good deals in the current market. The Beech Baron, Travel Air, Piper Aztec, and even the Beech Duke are examples. On the flip side, the market for new piston twins remains relatively flat for a variety of reasons, and there are few models to accommodate. Piper is building two of them, the Seminole and the Seneca. Both have held out for various reasons, though neither is being done in much volume these days.,

It's easy to see why the Piper Seneca held out. Sure, it doesn't do anything exceptionally well - it is not exceptionally fast or a joy to fly, nor will it turn heads on the ramp - but it does a lot well enough.

But one can be affordable to buy and maintain (earlier ones anyway), carry a good load and fly without bad habits., There are many used examples in the market and the Piper Seneca is still popular as a multi-engine trainer, but it's not the kind of plane that anyone who's learned immediately wants to take off in favor of something sexier.

From our point of view, the Piper Seneca is a perfectly reasonable aircraft. That, more than anything, may explain why it holds up in Piper's line, even though the newest Seneca V is far more complex than the original Seneca I. The Seneca V is one of only five twins still in production — the others are the Baron, Piper's own Seminole, the Diamond Twin Star and the Tecnam P2006T.

Piper Seneca model history

All modern manufacturers are known for so-called "parts bin" engineering - stretching the parts and parts of one model into another, which makes perfect sense. But few were as good at it as Piper.

The Cherokee line began with the Cherokee Six, the Saratoga, and the Seneca. Saw off the wings of a Seneca and a Cherokee Six and you couldn't tell the two apart., The Seneca first appeared in 1971 when GA was still a growing industry and there was indeed scope for new twins. At the time, The Aztecs - a good seller for Piper - and the Comanche were long growing teeth and Piper needed something new.

The Seneca started off with counter-rotating Lycoming IO-360C1E6 engines that were 200hp each (think a Piper Arrow, times two) and, when launched, cost about the same as the Twin Comanche C / R model, but had larger engines higher gross weight and a more spacious cabin with a rear door that the so-called Twinkie lacked. In other words, it was outfitted near cabin-class comfort for about $ 63,000.

Both the Seneca and Twin Comanche were built in 1972, but when Tropical Storm Agnes pushed the Susquehanna River into Piper's Lock Haven Works, the Twin Comanche drowned with it and the Seneca was relocated to Piper's new Florida operation.

Piper built 360 Senecas that year, a good start in the twin market where the competition was the Cessna Skymaster, which sold poorly in 1972. In three years, Piper sold 933 Seneca Is, dramatically outperforming the Aztecs and Comanche.,

Part of this was no doubt thanks to Piper's decision to modernize the airframe. It threw off the Comanche's Byzantine plumbing and favored a fuel system with only three positions: on, off, and crossfeed. Since the plane had props rotating in opposite directions, there was no need to worry about critical engines.

The Piper Seneca was based on the hugely successful PA-32 series with a long and wide cabin, six seats, a large aft door on the left and a cockpit door on the right., Since passengers may not like to climb over wings, this design proved to be a favorite among charter operators and for owners with large families. It still does. And despite its boxy shape, Piper added some styling accents to make the plane pretty attractive. Early interiors, aside from that unfortunate velor upholstery, were also a step up from early efforts. The modern Seneca V dropped one of the seats in favor of an optional entertainment / refreshment center, add air conditioning, beautiful cabin lighting, leather, and all the other high-end amenities current buyers have come to expect, and it's obvious that the Seneca Has come a long way - and with an even longer price tag.

The original Seneca I was a good start, but it was also missing. Pitch stability wasn't the best and the controls were on the heavy side — Bonanza and Baron pilots wouldn't like it much. The plane also had a noticeable Dutch role in turbulence that would tax the stomachs of the back seat passengers.

There were also design and production issues that resulted in many advertisements, records show that the original Seneca was subject to nearly 50 advertisements, counting the shotgun advertisements that apply to many other aircraft, a dubious record.

To his credit, Piper didn't sit still. It corrected the Seneca's handling and noise / vibration deficiencies. The ailerons were changed to a modified Frize design and made larger. The engine mounts were changed and soundproofing was added. Piper also changed some of the weights to give pilots the ability to carry more weight or more fuel. The gross weight was increased from 4000 to 4200 pounds, of course the increase came with a price.

The single-engine performance at the higher gross weight was marginal at best. Single engine climb rate decreased from 230 FPM to 190 FPM and single engine ceiling decreased from 5200 feet to 3650 feet. Piper also introduced a new constraint: a zero fuel weight of 4,000 pounds, meaning any weight over 4,000 pounds had to be in the fuel, no payload.,


Piper Seneca II

With a strong, if not a hot seller on his hands, Piper continues to improve the Seneca with the PA-34-200T Seneca II. Other changes have been made to the controls to improve handling. The aileron / rudder interconnect was removed and with it went some severity control.

The rudder received an anti-servo tab and the stabilizer was changed with the addition of a bob weight., The ailerons were increased in span and balanced for easier exertion. This time the changes worked and no major changes were made after that.

But the big change in performance for the Seneca II came in the power plants, with the four-banger Lycs making way for six-cylinder turbo Continental TSIO-360 electric motors with solid waste.

Rated at the same 200 horsepower at sea level, they produced 215 horsepower at 12,000 feet., Flying high and fast is nice, of course, but twin drivers are more concerned about the performance of high altitude engines. Here the Seneca II was a completely different animal.

The single-engine climb rate improved to 235 FPM and the single-engine ceiling more than tripled to 13,400 feet. Initial recommended TBO was the same 1400 hours. In 1977 this was increased to 1,800 hours and the owners report that this is realistic with careful operation and maintenance. Still, most owners realize that maintaining the Seneca I's original Lycoming IO-360 powerplants could be an easier and cheaper proposition.,

The plane also gained gross weight, increasing 370 pounds to 4570 pounds. The zero fuel weight stayed at 4,000 pounds, however, so the benefit was a mixed blessing. And another limiting weight was introduced: a maximum landing weight of 4,342 pounds. Once again, pilots were given more flexibility and more ways to get into trouble if the loading limits were not met.,

With the improved controls and motors, the Piper Seneca II also got optional extended range fuel tanks that increased usable fuel from 93 to 123 gallons. The noise and vibration campaign continued with a three-wing support option that weighed 46 pounds more.

The popular club seating option was introduced as well as a Janitrol heater and an optional fan to move heated or ambient air through the cabin., In later years, some system changes and options were added, e.g. B. a primer system to make it easier to start the engine, more powerful brakes, changes to the instrument panel and air conditioning. In 1980 a built-in oxygen system was offered.

Piper Seneca III and beyond

In the late 1970s, when sales were still strong, Piper began overhauling its entire model line, introducing the conical wings, and having an affair with T-tails in arrows and lances.,

The 1981 Seneca III was supposed to have the same T-tail and tapered wing as the Lance, but Piper found that flight characteristics weren't as good as the company had hoped. The configuration was left unchanged. However, there were still significant changes to the Seneca III. Another variant of the Continentals was used with 220 hp each. These engines had a higher speed limit (2800 versus 2575 rpm). This, combined with fuel injection, resulted in a maximum output of 220 hp, albeit limited to just five minutes.,

rated continuous power was still the 200 hp. The single engine rate of increase improved slightly to 240 FPM and the all-engine rate of increase increased from 1340 to 1400 FPM. However, most of the other metrics, such as Runway Required, fell slightly due to a further increase in allowable weights, the inevitable Bugaboo of any manufacturer.

The new weight limits were made possible by a reinforced structure. This time the fuel and landing weights were also increased., The maximum take-off weight was now 4750 pounds, the curb weight was 4470 pounds, and the maximum landing weight was 4513 pounds. The pneumatic system (for air-driven instruments and optional de-ice system performance) was converted from a pressure to a vacuum system in 1981. According to Piper, this improved the mean time between pump failures from an average of 400 hours to more than 700 hours. Owners say the pressure pumps on the field last about as long as vacuum pumps.

Other changes to the Seneca III included a new and more modern instrument panel, one-piece windshield and switch for electric flaps., We've always been fans of manual flaps: they're easy, positive, and hard to break. The change to electric flaps was necessary due to a change to larger flaps, which resulted in high actuation forces.

Amazingly, the Seneca never went out of production even during Piper's troubled times in the late 1980s and early 1990s. example), but it stayed on the price lists. And it's still there today.,

As part of the conversion from Piper to New Piper, the Seneca was redesigned once again, with the Seneca IV and later the Seneca V being redesigned. Relatively few design changes were made, most notably new cowlings resulting in higher speeds. In addition, the interiors have been significantly improved in the last few models, while Garmin's integrated G1000 avionics completely fills the instrument panel.

The Seneca's wide cab naturally allows for a wide instrument panel. This means that the aircraft is equipped with the three-screen version of the Garmin G1000 Glass Avionics Suite, this includes dual primary flight displays (PFDs) for the pilot and co-pilot as well as a large multifunction display (MFD) in the middle. The Seneca V also features Garmin's built-in GFC700 flight control system and electronic engine instrumentation.

Along with these improvements come much higher prices: when the Seneca IV was introduced in 1994, it sold for about $ 425,000. A new Seneca V easy flirts with $ 1 million-plus and takes a run at the G58 Baron.,

Piper Seneca performance

All Senecas have pretty good short field performance, and sea level fields of around 3000 feet are not an issue as long as both motors are spinning. However, as mentioned above, later versions are better once they are in the air. Of all light twins, the Seneca is among the most benign in the runway environment.

It's not a fast airplane, however., The normally aspirating early models cruise in the 160- to 170-knot range at 65 percent and 10,000 feet. The limit speeds are low: 129 to 130 knots for the transmission extension; 138, 121 and 107 knots for 10, 25 and 40 degree flaps.

One owner we spoke to strongly recommends adding speed brakes. The turbo models are of course a bit faster, especially when they are taken high. Owners report cruising speeds in the 180 knots or faster range in the high and low ranges with typical fuel flows of 24 to 28 GPH.,

The later Senecas are decent haulers. Charging the Seneca is about as easy as it gets. The hull is low to the ground so that the rear passengers can easily climb on board and the rear seats are easy to remove. The two overhead bins have weight limits of 100 pounds each. The generous CG range allows flexibility in the choice of seats and the later models were equipped with a clever visual CG computer of the Slide-Rule type, which makes loading child's play.,

Owner tells us that early Senecas have useful loads in the 1200--1300 pound range, while the Seneca II averages closer to 1500 pounds, with its higher gross weight of 4570 pounds. The latest iteration, the Seneca V, has declined due to the higher curb weight with payloads in the 1,300 to 1,400 pound range. This is the case with many new aircraft, the result of weight gain and comfort. It's a compromise.,

Piper Seneca cabin and comfort

With its four-foot-wide cabin, ample seating for all but the tallest of six, and large windows, the Piper Seneca has long been built for comfort compared to most other piston-powered aircraft in its class. Although the club seats often create a tangle of legs in the rear cabin, it's still appreciated by passengers, according to the owners who contacted us., Given its payload, the Seneca is a good five-person aircraft with some luggage or a four-person airplane with a lot of luggage that is stowed either in the nose compartment or behind the rear seats in the cabin.

Flight visibility from the cabin is sufficient, but not exceptional. The large windows are nice but at the front, the large motor nacelles extend in front of the wing leading edge and block the horizontal and downward view.,

This, coupled with the wide chord wing, makes it difficult to see the traffic under the aircraft. Heating and ventilation are typical plumbing with overhead and floor openings that will provide sufficient air under most circumstances. Seats are also typical Piper, that is, reasonably comfortable, but with a tendency to sag and wear with use. Most owners recommend overhauling them.,

Piper Seneca changes

Piper Senecas, starting with II, came up with fixed wastegate turbochargers. These are relatively simple and inexpensive to manufacture, but at the expense of efficiency and longevity and a tendency to oversteer due to sensitive throttle response. Owners say a must-have mod is to mount the engines with Merlyn top deck automatic air controls., We have heard good reviews of these mods and other owners tell us intercoolers can help too. (Contact or 509-838-7500.)

Because of the low speed limits, Speedbrakes are a good investment, especially in high-traffic areas. Precise Flight makes a set for $ 4995. Contact: 800-547-2558. For Seneca I owners who want turbocharging, the old Rajay is found on used models, but no longer installed.

Owners of Piper Seneca II and III can upgrade their turbos with Turbo-plus intercoolers in kit form. Contact or 888-514-4514., While the Seneca’s takeoff and landing numbers are okay, owners who want better performance can invest in the Sierra Industries R / STOL kit. Call for pricing and expect a long lead time. Contact: 888-835-9377 or for more information.

Hartzell Propeller had an aggressive program of installing three-bladed propellers on the Seneca II and III. The STCs can replace either two-bladed Hartzell or three-bladed McCauley propellers.The three blades provide a better start and initial climb and also remove the RPM / MP limitation for the twin bladed propellers., Contact Hartzell at or 937-778-4200. Although the props are still available, the offerings may not be. Inquire at Hartzell.

The Piper Owner Society supports the purchase and ownership of Seneca and is a good general resource for all types of Piper. Contact 800-313-0582 or Another group is the Piper-Flieger Verein

Piper Seneca owner comments

I own a 1983 Seneca III which I bought used in 1985 and have been flying it for 30 years. I added two aftermarket devices that have proven to be very valuable, one is TurboPlus intercooler and the other is precise airspeed brakes.

The intercoolers were completely maintenance free, but last year I noticed an increasing discrepancy in throttle positions from about 8,000 feet and became quite pronounced in the mid-1990s. A critical altitude test using the workshop manual showed a significant loss in manifold pressure on the left engine. For a while I suspected the turbocharger so I had it decoked but didn't find any improvement., Then I thought the intercooler might be leaking internally and bleeding compressed air. However, no leaks were found. Finally, I took my expert A&P for a test flight. He carefully monitored all of the engine parameters and found that the high RPM fuel flows were way out of setting. He readjusted the fuel pressure on both engines and everything is fine now. Noteworthy to other owners, the intercoolers weren't the culprit, also need to correct engine performance graphs for the temperature drop that the intercoolers provide.

The big advantage of intercoolers is increased engine power at lower fuel flows while keeping the CHTs within operating limits.

In fact, the engines run so cool that I've learned to keep an oil winter plate on each engine year round and add a second plate for the winter. Otherwise, during routine use, the oil temperatures will not be high enough to boil off condensation in the crankcase.,

The Speedbrakes were initially a hybrid electric / hydraulic system that caused rigging issues and leaks. However, Precise Flight switched them to fully electric years ago and they have been problem-free ever since. Their big advantage is to allow faster descents (as ATC so often demands) without shock cooling the engines. The only item of maintenance is making sure the drains are not clogged or raised above the bottom of the box. Otherwise, some water will settle in the crates and freeze in flight — preventing the brakes from extending.,


The intercooler and speedbrakes together were wonderful for the life of the engine. In the first life of both engines, I never touched the top of either engine. It was the crankshaft bearings that needed to be overhauled. Well into the second service life of both engines - almost 15 years, but only about 1000 hours - I only replaced one cylinder on one engine due to the low compression. I recommend these two mods for the Seneca., Aside from GPS and satellite weather system upgrades, I'd call them the two best things I've done for my Seneca in 30 years.

Phil Steeves, N8467X
by email

I pulled out of a Piper Cherokee Six-300. I was looking for something with similar efficiency and carrying capacity and the Seneca, properly equipped, fitted this bill for my family of five and our dog.

I think we've all heard and read the conversations about the added security (or lack of it) of twin engine operation. Of course, all pilots, especially the twins, want to keep the currency, while the Seneca is a step up from a fixed-gear single, it was an easier transition than I expected.

The advantages of the counter-rotating engines make single-engine operation and the (practiced or real) Vmc demonstrations a much more manageable event, even for pilots who do not practice these scenarios as often as they should. For safety reasons, running a well-equipped twin in the regular IMC is a great advantage over a well-equipped single. I believe the additional alternator and engine offer many options.,

While my Seneca has several upgrades (220hp intercooler and three-bladed props), it works exactly where the revised operating specifications call for it. I can typically run the engines at 9.5-10 GPH per side, with 165-knot ground speeds ranging from 10,000 to 12,000 feet. If I push the power up a bit, I can get 175 knots at 25-26 GPH at the same altitudes. I usually plan for 21 GPH total and 165 knots. This allows for a simple five hour stamina with a little more IFR reserves than required.

From the point of view of the tugs, the Seneca is not a slouch. As it is currently configured, I can fill the tanks, all five seats plus luggage and never really have to worry. Most models from the late 1970s to mid 1980s have very respectable payloads - typically in the high 1400s to low 1600s, depending on engines and equipment installed.

The crew and passenger cabin is very spacious, but the club seats are best for smaller passengers as the tangled legs can be a bit uncomfortable for four full-sized adults. Entrance and exit is very easy thanks to the large co-pilot and pilot-side passenger door., The additional luggage door and the nose compartment ensure sufficient stowage for all but the heaviest packers.

Numerous upgrades and STCs are available for all Senecas of the model year. The wide instrument panel is a great platform for a wide variety of avionics upgrades. Plus, since the Seneca is still in production, parts are readily available

Many have said that the Piper Seneca isn't really great at anything in particular. If you want speed in a similarly sized twin, consider the Cessna Turbo 310R. If you want to haul a large load, maybe consider a Piper Aztec, but if you want something in the middle, the Seneca seems well placed among the twins to be.

Andy Jones
by email

My 1973 Seneca I is a capable six-piston twin, though it's not incredibly fast. It averages 145 to 150 knots, but it has a spacious cabin that is comfortable even on long flights. It's also stable in flight and easy to fly-aided by the props rotating in the opposite direction.

The only thing to get used to when transitioning from a single engine airplane is the amount of back pressure needed in the landing flame.

The major disadvantage of the Seneca is the lack of single-engine climbing power, as it loses around 90 percent in a coasting situation. This is because the curb weight CG is close to the forward limit. You can help by having passengers and cargo in the tail of the plane.

The only downside to the cabin is the center seats as they are right behind the pilot's seats and don't offer much legroom until the front seats are moved forward.,

Both holds (nose and cabin) offer ample space and with 100 pound limits, both offer good flexibility in loading luggage.

I recommend filling the rear baggage area first as this helps maintain CG limits and is fairly accessible in flight.

I usually plan for maximum endurance flights of around three hours, which still allows for 1.5 hours of fuel reserve. I plan on 20 to 24 GPH for fuel expenses.

I've found the wide instrument panel to be very upgradeable for both flight instruments and panel avionics., My aircraft has an Aspen PFD / MFD suite with three screens, S-Tec 55X autopilot, Garmin GTN touch screen -Navigators, a satellite weather receiver, an ADS-B system as well as digital engine monitors and fuel computers.

The only downside to all of these upgrades is that you have to rely on adequate electrical power. Each engine has a 60 amp alternator that is more than capable of producing the power for all of the avionics, but a generator failure requires load shedding. Fortunately, the Aspen Displays have backup batteries.,

As with any aircraft, as long as preventive maintenance is followed, annual maintenance costs can be controlled, but like any twin, there are basically two of everything. In my experience, the Lycoming IO-360 motors are excellent, worry-free motors. Quality overhauls can be expensive, but thanks to a 2000 hour TBO and thorough preventive maintenance, these costs can be spread over a long period of time.

Overall, my Seneca I was a great family airplane that I always praise., I would only improve two things: more horsepower from the engines — which helps the single engine power — and more generator power to step up with the increased electrical demands of a panel full of avionics hold.

Jonathan Baldwin
by email