Piper PA-23 Apache/Aztec

Later examples of this venerable design are fine aircraft. Early ones may be cheap to buy, but be careful.

The PA-23 is one of those airplane designs that stayed in production so long that the final versions were almost unrecognizable derivations of the original. In this case, the original was small, all-metal, and underpowered to the point that single-engine operations can be extremely hazardous…just like other twins with small powerplants. The last versions, by contrast, are capable load-haulers with very good short-field performance.

The precursor of the PA-23 was the Twin Stinson, which not only had two engines (125-HP Lycomings) but two vertical tails, as well. The design originated at Consolidated Vultees Stinson Division, which was acquired by Piper Aircraft in 1948. This design formed the basis for the PA-23. Piper installed larger engines, changed to a single vertical fin and covered the airframe in metal, and the Apache was born, hitting the market in 1954. The PA-23 retained the steel-tube fuselage frame of the Twin Stinson, and had a fat, constant chord wing that helped its short-field performance, but not its speed.

The PA-23 was a notable departure for Piper. At the time of its introduction, the company was building only three other models, all tube-and-fabric singles: the Pacer, Tri-Pacer, and Super Cub. The Apache was the companys first twin, first all-metal airplane, and first to bear a Native American-inspired name. It was also something new in the marketplace-a light-light twin, economical to buy and operate. There was nothing else like it.

The original Apache had five seats, Lycoming O-320-A1A engines of 150 HP each, swinging two-bladed props. Maximum gross weight was 3500 pounds (to put this in perspective, its only 100 lbs. more than a V35 Bonanza and less than most of the big six-place singles), with a 1320-pound useful load. Top speed was 157 knots, with a recommended cruise of 148. Average equipped retail price was $36,235.

Three years later Piper put 160-HP versions of the O-320 on the airplane, and equipped it with full-feather props. The primary benefit of the change was a 300-pound boost in gross weight. Other specs remained much the same, though single-engine performance actually suffered quite a bit due to the higher allowable weight. Minor refinements a few years later increased the gear and flap speeds.

In 1960, Piper introduced the Aztec, basically a PA-23 airframe with 250-HP Lycoming O-540-A1B5 engines, a larger tail with stabilator, and a longer fuselage. Max gross weight was 4800 pounds, a far cry from the original Apache. The Aztec was sold side-by-side with the Apache, and hurt the lighter airplanes sales badly. In 1959, 368 Apaches were built. In 1960, only 141 Apaches rolled off the line, compared with 363 Aztecs. In 1961 Apache production had fallen to 28 airplanes.

In a questionable attempt to resurrect sales of the Apache, Piper hung low-compression, 80-octane versions of the O-540 on the Apache in 1962, calling it the Apache 235. It hung on through 1965, with a total production run of 114.

Also in 1962, Piper added a longer nose to the Aztec, housing a baggage compartment. This airplane, the Aztec B, came with six seats, a pop-out emergency exit window, and was available with optional fuel injection and AiResearch turbochargers.

In 1964 with the Aztec C fuel injection became standard, and there was another boost in gross weight, to 5200 pounds. 1966 saw the turbo option become a full-fledged model, with a standard oxygen system. During the run of the Aztec C the engine TBO went from 1200 to 2000 hours, a benefit retrofittable to the older engines with the installation of half-inch exhaust valves.

The D models had minor improvements, including a standard instrument arrangement. The E models, introduced in 1971, had another fuselage stretch and an even bigger nose with a larger baggage compartment and room for radar. The final refinement, the Aztec F, came out in 1976 with a one-piece windshield, square wingtips with optional aux tanks, and a revised stabilator. The stabilator proved troublesome, and was changed again in 1981.

The big changes in the PA-23 all happened in the early sixties; after the Aztec C, the alterations were mostly refinements. During its 26-year history, the PA-23 proved quite popular. All told, 2036 small-engined Apaches were built, of which maybe half remain. As noted, 114 Apache 235s were built, and approximately 5500 Aztecs were built.

Used market
The PA-23 can really be thought of as two different airplanes, the Apache and the Aztec. With such a variety of power, weight and age, a buyer can find a PA-23 to fit almost any budget. Original Apaches in average condition carry price tags around $30000, and its not hard to find one for much less.

Its likely, however, that a PA-23 bearing a used-car price tag has had quite a tough life, starting out in hard use as a multi trainer or cargo-hauler and eventually retiring into neglect and disuse. The irresistibly low prices on some of these airplanes could be siren songs, and keeping one of the tired, neglected birds airworthy could be a very expensive proposition, indeed.

On the other hand, many Apaches and early Aztecs have been flown regularly and kept in great shape; and, though not exactly steals, they can be purchased for the price of a late-model, four-place single. Prices on newer Aztecs are high enough to induce hypoxia, but theyre still lower than those on other light twins, such as Beech Barons and Cessna 310s. Owners assert that, though their Pipers may not be as pretty, quick or fuel-efficient as some other light twins, they are generally easier to fly, reliable and better at hauling heavy loads and operating out of short fields. Several have advised us that a good experience in owning an Apache or Aztec depends to a considerable degree on having a thorough, pre-purchase inspection and good initial and recurrent training.

The fifth seat in Apaches and early Aztecs is relegated to the back of the cabin, where it takes up a lot of space in the 200-pound capacity baggage compartment (and must make its occupant feel very much in steerage). Beginning with the B-model Aztec, there are three full rows of seats and 150-pound capacity baggage compartments fore and aft.

The PA-23 cabin is spacious and comfortable, with plenty of elbow, head and leg room. As mentioned earlier, the airplanes can haul a respectable load (though they cant, as some owners would suggest, fly with anything you can close the doors on). Still, even well-equipped Apaches and Aztecs can carry full fuel, four or five adults and baggage, despite zero-fuel-weight restrictions imposed by an Airworthiness Directive (83-22-01) that was issued to prevent damage to wing-attach fittings. The Apache 235 and the original Aztec have zero-fuel-weight limits of 4,000 pounds. In naturally aspirated B through F models, any load above 4,400 pounds must be fuel. The limit in turbo models is 4,500 pounds.

All Apache 150s and 160s have one 36-gallon fuel bladder in each wing, and many have an 18-gallon aux tank on each side, too. Apache 235s and Aztecs have two 36-gallon cells in each wing. The F model, as mentioned earlier, also could be fitted with 20-gallon internal tip tanks. The fuel bladders were later the subject of an AD, outlined below.

Also on the Aztec Fs options list was an auxiliary hydraulic pump on the right engine. Earlier models came with only one pump on the left engine to operate landing gear and flaps. (If the left engine goes kaput, theres a hand-pump underneath the control console that requires 30 to 50 strokes to get the gear up or down, a questionable undertaking during a real emergency. Theres also a CO2 bottle to blow the gear down if the emergency pump doesnt work.)

Speaking of redundancy (or the lack thereof), though many Apaches have been upgraded with dual alternators and vacuum pumps, be on the lookout for those that have survived with the standard set-up: one generator and one vacuum pump.

Full bladder
Apache owners should be aware of a problem concerning fuel drains. According to safety consultants Norman L. Horton and Jerry L. Wells, the PA-23 line does not meet certification requirements because a portion of the after inboard corner of each main fuel tank is below the level of the quick drain when the aircraft is parked. And, they maintain, water can collect there in sufficient quantities to cause engine stoppage if the water is dislodged and ingested in flight. They based their claim on investigation of several Apaches in the field. They recommended that quick drains be installed in the after inboard corner of each tank to get rid of most of the water from the fuel tanks before flight.

NTSB identified 14 Apache accidents from 1975 through the late 1980s involving power losses due to water contamination. In addition, the safety board suspected water may have caused 23 other Apache accidents and 17 Aztec mishaps. In March 1989, the FAA issued an Airworthiness Alert about corrosion of fuel filter bowls and retaining rods, and recommended that the bowls be removed and checked for moisture and rust every six months.

Next the Horton crusade came to a successful climax and was checkmated almost immediately. The FAA issued AD 90-23-18 calling for installation of wedges in the tanks to effectively lower the drain sumps by raising the surrounding bladders. And pre-1975 Aztecs were to get larger fuel bowls. But AOPA opposed the new AD as too expensive and labor intensive, and it was suspended. AOPA instead asked FAA to incorporate Piper SB 827A into an AD. This would allow owners to follow Pipers suggested tank sumping method as outlined in the bulletin.

When they got tired of that, they could install a new fuel drain kit, allowing normal sumping on each preflight. Those who cant install the new drain kit because of space considerations, could opt for new STCed bladders with a drain in the aft inboard corner of the tank. FAA ultimately adopted the suggestion as AD 92-13-4.

Performance, handling
The fat, high-lift airfoil has a lot to do with the PA-23s docility and good low-speed performance, but it costs more than a few knots in speed. Owners of 150- and 160-HP Apaches report 135 to 145 knots on 16 GPH at 75 percent power. The big-engined Apache is faster but is a glutton for avgas. Figure on about 165 knots on 29 GPH at high cruise for the Apache 235. Early Aztecs buzz along at 178 to 182 knots while burning about 26 to 28 GPH at 75 percent. The E and F models are a few knots slower on the same fuel. Up high, around 24,000 feet, a Turbo Aztec can sizzle along at 190 to 200 knots with fuel gushing at 30 to 35 GPH.

As mentioned earlier, the airplanes are exemplary short-fielders. The Apache models need less than 1,100 feet to get in or out over a 50-foot obstacle; early Aztecs require less than 1,250 feet. Newer, heavier Aztecs use up a bit more real estate, but not much more: Figure on nearly 2,000 feet to leave and less than 1,600 feet to arrive over a 50-foot obstacle in an E or F model.

Single-engine performance is on par with other light twins; that is, its pathetic. Published single-engine rates of climb vary from 180 FPM for the Apache 160 to 240 FPM for the Apache 150 and naturally aspirated Aztecs. The Apache 235 and Turbo Aztecs climb at about 220 FPM on one mill. However, some Apache owners have told us theyd consider themselves lucky to hold altitude at gross weight with only one fan turning; and we saw barely 100 FPM while getting single-engine practice in a lightly loaded Apache 160 on a warm day (but, then, we saw little better during a workout in a Seneca III under a hot Florida sun).

In our opinion, the edge of the single-engine performance envelope on light-light twins (i.e. those with normally aspirated engines of less than 200 HP) is really too close to being unsafe for comfort. There simply isnt enough horsepower available to produce anything but a barely flyable airplane. A positive rate of climb depends on perfect technique, and on top of these demands the pilot is presented with the specter of engine-out handling difficulties such as the tendency to roll over towards the dead engine. In this respect, the Apache is no worse than more modern designs. For example, Pipers own PA-44 Seminole, a late-70s design, has 180-HP engines and a useful load of about 1400 pounds. The original Apache, with 150-HP engines and a useful load of 1320 pounds, has a higher single-engine ceiling (5300 vs. 3800 feet), higher service ceiling (17000 vs. 15000 feet), and better single-engine rate of climb (240 FPM vs. 212).

Proper recurrent training is the best protection against these shortcomings. It also helps to fly as much below gross weight as possible, and to install vortex generators if theyre available (we havent seen any for the PA-23s, unfortunately, but its probably only a matter of time before theyre introduced).

In the air, with everything working properly, the twins feel just like big Cherokees. However, the ailerons are somewhat heavier than the rudder and stabilator (elevator in early Apaches). One idiosyncrasy that will present itself to the transitioning pilot is the tendency of pre-1976 models to pitch up strenuously when flaps are lowered. In 1966, Piper published a service letter (No. 474) suggesting the deployment of small amounts of flap, rather than stabilator trim, to counter nose-heaviness in the pattern. One owner told us the procedure works quite well. The manual pitch trim control, by the way, is a large crank on the ceiling with a smaller crank (a knob in later models) inside it for yaw trim; both are very sensitive. Another idiosyncrasy is location of the gear lever on the right and the flap lever on the left of the center pedestal. (As we shall see later, pilots do get these mixed up, and the latch thats supposed to prevent inadvertent gear retraction doesnt always work.)

(Incidentally, the late Pug Piper years ago demonstrated to one of the editors his technique to avoid the pitch-up. He would lower flaps as he let the nose of the aircraft drop in the descending turn onto base leg.)The ability of the bulbous airplanes to bleed off speed fairly rapidly comes in handy when its time to get into landing configuration. Maximum speeds for lowering gear and flaps in Apaches built before 1960 are a ridiculously low 109 and 87 knots, respectively. Limiting speeds in later models are a more manageable 130 and 109 knots. Also, in 1965, Piper came out with a modification kit for Aztecs and Apache 235s allowing quarter-flap deployment at 139 knots and half flaps at 122 knots.

Pre-1971 Aztecs tend to thwart the pilots best attempts at trimming and roam a bit in altitude. A stronger stabilator down spring in the E model improves longitudinal stability, but control pressure in the flare suffers as a result. The stabilator and stabilator-balance system were changed with the introduction of the F model, but Piper later switched again from external to internal balance weights after an AD (79-26-1) targeted cracks and attachment problems. (Another change in the F model was incorporation of a flap-stabilator interconnect to reduce the pitch-up tendency.)

Though owners complain in unison about the high cost of parts, their reports of parts availability are mixed. Some say certain parts are becoming very difficult to find, while others told us everything is readily available from Piper, Av-Pac, PA-23 specialty shops and salvage yards. Owners also tend to be very picky about who maintains their airplanes (indeed, many owners do much of their own work under the supervision of IAs). You can spend a fortune having a mechanic learn your systems, one owner said.

Several ADs require repetitive inspections and work, and some are quite expensive. In addition to the ones already mentioned, there are: AD 63-12-2, on elevator butt ribs and doubler plates; 63-26-3, elevator and rudder castings; 72-21-1, control pedestal support bracket; 74-10-1, flap hinges; 77-12-6, Hartzell Y-shank prop blades; 78-2-3, stabilator tip tubes and weights (on Aztec F); 78-8-3, rudder hinge brackets (Apache 150 and 160); 79-26-1, stabilators (most F models); 80-18-10, fuel selector valves and cables; 80-26-4, cabin entrance step support frame structure; 81-4-5, flap controls and hinges; 85-14-10, Hartzell blade clamps; and 88-21-7, fuel lines, caps and filler compartment covers. In many cases, the repetitive inspections are no longer necessary after affected parts are replaced or modified.

Sierra Industries offers STOL kits for the PA-23, Met-Co-Aire offers tip tanks that increase fuel capacity by 48 gallons as well as new wing tips and turbochargers can be had from Rajay.

Owners Group
Considering the number of Aztecs built, it is curious that there is no organization devoted to their owners. The Flying Apache Assn. caters to Apache owners only, with bimonthly newsletters, periodic get-togethers and tips on maintenance and parts suppliers. They can be reached at (708) 627-8027.

Owner Comments
I have owned a PA-23-180-T fouryears (thats an Apache with larger engines and turbochargers added). The standard mission profile is 400 mile trips with pilot, baggage and full fuel (106 gallons) across rugged terrain for the weekend, flying at night.

The Apache was picked for being the cheapest way to get two engines. Mountains in the dark make me nervous on one engine. The problem with PA-23-160s not staying off the ground on one engine was planned to be solved by staying 400 pounds light of gross at night.

The logs were lost a few years before I became owned by the aircraft (an unhappy mechanic is rumored) and the history was reconstructed using 337s. The 337s make interesting reading. The airplane has had three different noses by two makers, two turbo setups, two sets of nacelles, a square rudder and dorsal fin installed at separate times, two sets of wing tips, etc.Cruise is 165 MPH TAS at 12,500 feet using 18 inches MP and 2400 RPM. Single engine climb with instructor and 100 gallons of gas on board is 500 FPM at 5000 feet. 25 square (left engine at 12 inches) gives about 200 FPM at 95 MPH blue line. VMC is very benign, you just run out of rudder and the nose starts to creep off course at 70 MPH indicated and full throttle (with the left engine set at 12 inches). The stall is around 60 MPH indicated.

-T. Munson
via e-mail

I am the owner of a 1978 deiced Turbo Aztec F. I have owned the airplane for seven years. I fly it for business and pleasure.

When I purchased the airplane it was very low time and had been sitting for awhile. It was a real hangar queen for the first several years. Biggest headaches were the panel, the fuel system, and the turbocharging. Finally replaced the panel, rebuilt the fuel systems and waste gate controllers (four of them), and found and fixed a persistent oil pressure problem. I highly recommend finding and using a mechanic who is familiar with the Aztec turbocharging systems (the Navajo system is similar; the Seneca is not).

The airplane is a great multi-task airplane. I would equate it to the family station wagon or minivan-not sleek and sexy, but very practical. It doesnt have any bad habits. It will haul a load and isnt particular about CG. It is a stable IFR platform.

The fat Hershey bar wing makes it a better short field airplane than a Baron or a 310. It gives up speed to those two airplanes at middle altitudes, but not much at oxygen altitudes. I often fly at 15000 to 18000 feet. Published ceiling is 24000 feet. The fat wing also makes it a better airplane in ice, but dont forget about the tail!

It is a gas hog. At 2300 RPM and 31 inches, at 12,000 to 13,000 feet, the plane burns 34 to 36 GPH at a true airspeed of about 180 knots. Long range tanks are a plus.

Look for a model with dual hydraulic pumps and Cleveland brakes. The earlier models didnt have these from the factory.

An inflatable door seal is a good investment. Youll notice a big difference in sound (and heat if you fly at oxygen altitudes).

The Lycoming engines, true to reputation, seem to always have an oil leak somewhere, but they are bulletproof. No case cracking like the Continentals in the Baron and 310.

The gear is tough and holds up to unpaved fields, but the short gear and two-bladed props dont leave a lot of ground clearance, so be careful on taxi.

Gear speed is slow (130 knots) so IFT transitions from higher altitudes can be interesting. Sometimes you have to educate air traffic controllers,

Parts are sometimes hard to locate. Sometimes the only answer is an overhaul of your own equipment with no exchange available, which means down time.

Insurance is about $3000 a year for $95,000 hull and $2 million liability (smooth).

The initial troubleshooting took several years and was extremely frustrating (not to mention pricey), but since everything got sorted out, Ive been very happy with the airplane. It isnt as fast or sexy or light on the controls as the competition, but it is more versatile for those of us who can only afford one plane and use it for long trips, winter IFR in the mountains, and short unpaved strips.

-J. Patrick Aylward
Wenatchee, Wash.

I would like to tell you about my experience with the Piper Aztec. Since 1964, I have owned four of these magnificent machines.

In 1964, I bought my first Aztec and flew it for 4 years. I loved it; its baggage door was a little small in the back and there was something about the instrument plan that gave me an excuse in 1968 to trade for a D model. This aircraft I truly loved-it had 144 gallon fuel capacity and was the fastest of my four Aztecs. I flew this airplane for perhaps 1500 hours and I was talked into trading for a new one approximately 10 years later.

Unfortunately this beast had the Hershey bar horizontal stabilator. This airplane had the undesirable trait of tail vibration the minute you would lower the nose and pick up about 10 knots. This made me get rid of the third airplane fairly quickly. Fortunately, I was able to acquire one of the last Aztecs built, which had the redesigned tail.

This airplane is the one that I own today and it is truly a magnificent plane. All in all I have approximately 5000 hours pilot time in the Aztec, and I use them for my personal and professional transportation.

The Aztec in itself is a very gentle aircraft. It is easy to fly, it carries a magnificent load and has never in anyway let me down these past 32 years. The cost of ownership has been very low. Part of this is due to the fact that I live in a small rural community where our T hangar costs us $35.00 a month and we have a local mechanic who does the annuals. The annuals average somewhere between $1000 and $1500. There has never been a major problem with any of my Aztecs except the first one. That airplane was used as a demonstrator for some 50 hours before I purchased it. In those days they to shut one engine down to demonstrate the single engine flying capabilities and when I got the airplane I noticed an unusual amount of oil consumption in the right engine. Piper helped me redo that engine because by that time all the rings had been cracked by the rapid cooling brought about by the shutdown procedures.

In summary, I highly recommend this beautiful aircraft. I am sorry it is no longer built because it was a true example of a gentle airplane that was able to carry great loads in and out of short fields.

-Dwaine J. Peetz, MD
Neligh, Neb.

I purchased a 71 E model Aztec with 3000 hours, mid-time engines, decent paint and interior, and avionics seven months ago for $63000. I spent another $7000 or so to fix problems found during the pre-purchase inspection. I got my multiengine rating in the airplane having amassed 600 hours previously (350 in a Comanche). My research suggested that this plane was more docile on one engine than, say, the 310, and had better short field capabilities. I needed six seats and figured on 100-150 hours per year. Thus far I have been very pleased with my decision. Typical trip length Is 100-500 miles and includes one destination with 2200 feet of grass.

Performance is what you would expect with that huge wing and pot belly. Cruise at 23/23 is 160 knots. Useful load is a whopping 1968 pounds. With 140 gallons of fuel at 26 GPH, I can carry a lot of people and stuff a long way in surprising comfort. In fact, when I take my family (four kids under age 8) to the beach 400 miles away, it literally takes a Suburban to unload the plane. The baggage areas are large (150 pounds fore and aft).

Comfort is good, with good leg and shoulder room. I considered a 210, but there is no comparison in interior room and comfort. The 310 is similar, but certainly no better. Noise is a problem, but a six place intercom makes this a non-issue. The plane is easy to fly. The only real quirk Is a significant pitch change with flaps which is easily handled.

Costs are hard to pin down exactly, but I have not been terribly surprised thus far. Owning a light twin Is not for the faint of heart. Insurance 13 $3000/yr. for $1 million liability. The first annual was $1800 which was cheaper then I anticipated. This was obviously a reflection of a thorough and somewhat expensive pre-purchase inspection. I have spent a few hundred dollars on the Janitrol heater and exhaust system. In all, I expect to spend around $140/hr and maybe less after the Initial bugs are out based on 125 hours per year. This is not scrimping on anything.

Altogether, I couldnt be happier with my Aztec all things considered. Its relatively cheap to get into and relatively expensive to keep (additional toys like an IFR GPS dont help…but thats another story). Its not too fast, but it will carry a ton in comfort out of short strips.

-John DeLoach
N.Little Rock, Ark.

I have owned and operated various Aztecs for the last 20 years. I have over 3000 hours in a PA-23-250 and have flown all over the country. My first Aztec was a C model and it performed as advertised. I longed for more performance and moved up to a turbo D model. While the turbochargers improved performance, the aircraft became a maintenance quagmire. It seemed I could not fly more than four or five hours without an oil pressure problem or even a downright oil leak. Almost all of these problems were associated with the turbos. None of these ever proved to be remarkable, but I got tired of the unreliability.

Our next (and current) model was a normally aspirated 1977 F. My son and I have now put over 1100 hours on the airframe and overhauled each engine once. For me, the F represented a compromise from my two previous aircraft. It is certified for known ice and carries the updates of the D without the expense of the turbochargers. We fly a lot in winter, so the ice equipment was a must. We also go on long (1000 NM-plus) cross-countries, and opted for the long range tanks.

Operationally, our F flight plans at 160-170 knots at 25-27 GPH, depending on altitude. We generally fly at 70 percent power. We fly about 100 hours per year and expect maintenance, fuel and hangar costs to be $125 per hour, not including insurance or overhaul reserve. The Aztec is not the most fuel-efficient aircraft, but she offers a stable IFR platform with very good winter behavior-carries and sheds ice well, the Tanis heaters allow for easy starting, generally adequate cabin heat, and outstanding load-carrying ability. Its a true six-place with luggage and four hours fuel airplane.

We get both simulator and dual training at least once per year, including Instrument Competency Checks. We agree with those who advocate proficiency as the route to piston twin safety.

-Name withheld

I own a 1963 PA-23-235, which looks more like a short-nosed Aztec than an Apache. I operate out of a 2700-foot runway. At gross weight (4800 pounds) I can hold a sustained climb of 1000 FPM to optimum cruising altitude, 7000 feet. I have found the book performance figures of 191 MPH and 29 GPH at 75 percent power to be accurate.

Useful load of my aircraft is 1921 pounds. With a full 140.3 gallons of fuel, I can carry 1057 pounds of passengers and baggage. This is ample payload; with five seats installed, there is little room for baggage. (Care must be taken not to exceed the 4000-pound zero fuel weight restriction.) Getting in and out of the pilots seat is difficult and cramped, due to the location of the wing spar. But access to the passenger seats is good. The Apache is an excellent trainer, as it is very forgiving. It trims well and makes an excellent instrument platform. However, it is somewhat heavy on the controls, and the abrupt pitch-up when the flaps are deployed is an annoyance. I have found that owner maintenance of two hours is required for each hour flown.

The aircraft was designed for 80/87 octane fuel, which is not readily available in my area. When using 100LL, TCP and proper leaning are a must. I have lead-fouled plugs while taxiing by forgetting to lean the mixture after starting the engines. The service manual procedure for servicing the hydraulic power pack must be followed. It requires placing the aircraft on jacks with gear retracted and flaps extended before adding fluid to the reservoir. If the procedure isnt followed, the added fluid will be vented out. I have had to replace one leaking fuel bladder, which required 10 hours of labor and $600 worth of parts. A knowledgeable shop is a must for this operation, as an inexperienced mechanic can easily spend 40 hours making the switch. I used Maryland Airlines at Easton, Md. to install my fuel cell. Replacement parts for this airplane are in short supply. Av-Pac in Nebraska has been a good source. Piper Air Parts in Lock Haven, Pa. has an excellent inventory and a superb technical staff, but charge premium prices.

Ive been quite satisfied with this airplane. The performance achieved for dollars invested favors this airplane over most singles I considered. The negatives are high fuel consumption and maintenance costs, though the latter can be substantially reduced if the owner gets involved and implements a preventive maintenance program.

-Jack Mundale
Silver Spring, Md.

I have owned a 1957 150-HP Apache for more than 12 years. During that time, I added the Geronimo kits to increase speed and performance. The modifications by Seguin Aviation have lived up to my expectations. I flight-plan for 145 knots and about 16 GPH at 6000 to 8000 feet. The airplane is predictable and has no bad habits. I would highly recommend taking Apaches to Seguins shop for maintenance, regardless of where you are based. My experience with other shops throughout the country has been disappointing. The Apache requires experience that cant be found in the usual FBO. I also have owned a 1969 D-model Aztec.

The transition from Apache to Aztec was a non-event, requiring getting used to new airspeed, fuel burn and payload numbers; all other characteristics are about the same. I had always heard that the Aztec will pitch up when flaps are lowered, but found that when the aircraft is flown according to Piper Service Letter 474, dated April 21, 1966, it is easy to handle. Like Apaches, Aztecs need maintenance facilities that are familiar with the type. I suggest that an operator purchase all the manuals and become knowledgeable about the aircraft.

-Tom Baum
Kaufman, Texas

I have owned two Piper Aztecs, a 1962 and a 1969, and have found the handling and single-engine capabilities to be extremely good. Short-field takeoff and landing capabilities are excellent, even when fully loaded. The Aztec will take off and land with full fuel, even with long-range tanks, and about anything you can cram inside. It is also a very stable instrument airplane. Fuel burn is usually 26 to 28 GPH. Now the bad news. Annuals cost $5600 on one, $9400 on the other. Fuel cells have been a problem, and they cost about $500, exchange, plus labor to replace. Removing the cowling for almost any repair is very time-consuming. All Aztecs I have flown have had a problem with leaky gas caps; I had one come off in flight and lost all the gas in that tank. Always check the gas caps after refueling. The 1962 model has had two cylinders damaged when valve seats were dislodged and the valves stuck open. Parts availability, especially electrical and body parts, is very poor. I strongly recommend replacing generators with alternators. A good Aztec is an excellent airplane, but problems can be very expensive.

-Mike Carey
Harlingen, Texas

Also With This Article
Click here to view charts for Resale Values, Payload Compared and Prices Compared.
Click here to view the Piper Aztec features guide.