Aerostars carry the dual distinction of being the fastest production piston twins and of having one of the worst safety records in their class. The consensus among Aerostar pilots is that, indeed, its necessary to stay we’ll ahead of the airplane, and that proper training is the answer.
The airplanes are not inherently dangerous. But they are not forgiving, either. Theyre difficult to get to know, and they require a great deal of routine and preventive maintenance. As one owner put it, An Aerostar is not a conveyance for anyone with tight financial constraints.
History
Ted Smith, designer of the Twin Commander, Jet Commander and Douglas A-20 bomber, formed his own company in 1963 in Van Nuys, Calif., to design a family of Aerostars ranging from a single-engine trainer to a jet. All would be built around the same fuselage, wings and tail.
The first off the line was the Model 600 in 1968, with normally aspirated Lycoming IO-540 engines and a max takeoff weight of 5500 pounds. Its ironic that investors in development of the speedy Aerostar sold out to a company called American Cement the same year. In 1969, the 601 appeared with a pair of Rajay turbochargers and manually controlled, electrically actuated waste gates on each engine and a max takeoff weight of 5700 pounds. With turbos, the engines could maintain 290 horsepower from sea level to 16,000 feet. Late that year, American Cement put the company up for sale.
Butler Aviation, the big FBO, happened to be on a buying spree. It acquired Aerostar and Mooney and moved both projects to Kerrville, Texas. (Mooney had been in Wichita.) Then the new owner got into a nasty squabble with the old, claiming it was sold a defective product. Butler alleged the Aerostar had a corrosion problem; FAA checked but found none. Meanwhile, Aerostar jigs and fixtures lay idle for two years.
To the rescue
Several companies, including Bellanca and Vought, tried unsuccessfully to awaken the Aerostar from limbo. Ted Smith and a few investors had better luck, and set up shop again in California, this time in Santa Maria. They began building the 600A and 601A in 1973. Though very similar to the originals, the A models had heavier crankcases and crankshafts, and engine TBO was boosted from 1400 hours to 2000 for the 600A and 1800 hours for the 601A.
The first pressurized Aerostar, the 601P, appeared in 1974. Max differential pressure was 4.25 psi, enough to maintain a cabin altitude of 11,000 feet while slicing along at 25,000 feet. The tenth 601P rolled out of Ted Smiths shop with a longer wing (stretched from 34.2 to 36.7 feet) and higher max takeoff weight, 6000 pounds. These changes were incorporated in the unpressurized turbo model in 1977. The engines on the new B-model 601 were fitted with an automatic waste gate control.
Ted Smith died in 1978 after open-heart surgery. He was 70 years old. Plans for nine-seat Aerostars with 450 HP piston engines and turbine mills passed with him. The company was acquired that year by Piper Aircraft, which later moved it to Vero Beach, Fla.
Piper improved the waste gate system in the 601B and 601P, increasing critical altitude from 16,000 to 21,500 feet, and certified known-icing equipment for the airplanes. In 1981, the 602P was introduced with engines and turbo systems certified and installed as a package by Lycoming. (Previously, turbos and waste gates were tacked on at the Ted Smith and Piper shops.)
End of the line
The last model, the 700P, was introduced in 1984 and had intercooled, 350-hp engines, cowl flaps and outward-rotating propellers. With only 25 built that year, the 700P is the rarest model. The most prolific model was the 601P, with 454 built by both Ted Smith and Piper.
The 600A stayed in production the longest, 10 years, but only 206 were built. Pipers figures show 59 600s, 68 601s, 48 601As, 41 601Bs and 110 602Ps produced before the line was shut down.
The outlook for future support of the Aerostar line was given a big boost in May 1991 when Piper sold the Type Certificate and STCs for the Aerostar line to an organization called Aerostar Aircraft Corp., (509) 455-8872, headed by Stephen Speer and James Christy, both principals of Machen, Inc., a Spokane, Wash. company that specializes in Aerostar support and mods. The new owners said their first priority would be to keep new Aerostar replacement parts flowing.
The company appears to be doing well, and has come up with an upgrade called the Super 700 Aerostar, which takes 601P and 602P Aerostars and fits them with 350 HP Lycoming TIO-540-U2A engines turning three-blade Hartzell props. The resulting airplane gets a gross weight boost, up to 6356 pounds ramp weight. Claimed 75% cruise is 261 knots, and initial climb rate is 1875 FPM. At economy cruise (55%), the fuel burn in 32 GPH, and claimed speed in 225 knots. Owners report that the mod is worthwhile.
Different design
In many ways, Aerostars are very different from other light twins. The wings, mounted midway along the oval fuselage, are the same NACA-64 series used on the Learjet and have only two degrees of dihedral. All external skins are butt-joined and flush-riveted. The highly swept stabilizers came out of the same jig and are interchangeable. Primary flight controls are connected with push-pull tubes, torque tubes and bellcranks.
Landing gear, main gear doors, flaps and the nose wheel steering system are electro-hydraulic. Fuel-selector valves and elevator and rudder trim systems are electric. The fuel system has gained a nasty reputation, thanks to a rash of accidents related to mismanagement.
In theory, the engines draw fuel from the two 62-gallon wing tanks and from the 41.5-gallon fuselage tank at the same time and at a rate that leaves 12 gallons in the fuselage tank when the wings have been emptied. But this only works in straight-and-level flight. The long, thin wing tanks easily become unbalanced (only two degrees of wing dihedral, remember) and crossfeed must be used to bring them back in synch.
A popular procedure was to use double crossfeed in cruise to drain the wings, then tap the fuselage tank. Unfortunately, this shortcut led to real trouble when the single fuel pick-ups in the wings became unported and when electrical power was lost, leaving no way to reposition the valves. AD 79-1-5 sought to solve the problem by placarding crossfeed procedures and installing a low-fuel warning light and individual tank quantity indicators (previously, there was one gauge and a toggle switch).
The 601 models have relatively high-compression turbonorm-alized engines, producing 290 HP at 29.5 inches manifold pressure. The 601P is especially prone to detonation if leaned to peak EGT at altitude. The drill is to lean to published fuel flows. (Look for installation of a cooling kit via Piper Service Bulletin 720; a six-probe EGT also is a good thing to have in a 601P.) The 602Ps engines have a lower compression ratio, alleviating the detonation problem, and are boosted to maintain 290 HP at 37 inches MP.
Alternators on most Aerostars are rated at 70 amps but can actually put out only about 55 amps due to heat. Wed stay away from any airplane with an electric air-conditioning system. Its heavy, has four motors that draw a lot of juice, and cannot be used at night or in IMC. A much better bet is an engine-driven-compressor system.
Performance
Aerostars are just what the doctor ordered for those with the need for speed. The naturally aspirated 600s are low-altitude hot rods, capable of turning in 210 knots, true, on 34 GPH at 70 percent power and 7,500 feet. The 601 models can hit 233 knots on 36 GPH at 70 percent power and 20,000 feet. Book figures for the 602P show 229 knots on 37 GPH at 75 percent and 20,000 feet. The higher-powered 700P trues out at a whopping 260 knots on an equally impressive 51 GPH at 81 percent power and 25,000 feet; throttled back to 65 percent power, a 700P can do 230 knots on 36 GPH.
Quite a few Aerostars have been made to go even faster with Machen conversions. At 75 percent power and 25,000 feet, a Machen Superstar 650 cruises at 240 knots on 42 GPH; a Superstar 680, which has intercoolers, does 250 knots on 40 GPH. Machen conversions also improve single-engine performance, which is average (meaning, not so hot) for the unmodified airplanes.
Maximum published single-engine rates of climb are 360 FPM for the 600, 240 FPM for the 601s and 602P, and 320 FPM for the 700P. Accelerate/stop distances (using 20 degrees of flap for takeoff) are about 3,100 feet for the 600 and unpressurized 601s, 3,400 feet for the 601P and 602P, and 4,000 feet for the 700P.
Handling
Controls are crisp and responsive, and owners say their airplanes go where theyre pointed. However, controllers often expect jet-like descents from the speedy airplanes. Flaps on most Aerostars can be lowered 20 degrees at 174 knots indicated, which helps slow the airplanes down to their 156-knot gear speed. In landing configuration, drag builds very quickly and pilots have to stay on the friendly side of the power curve lest the airplanes drop out from under them. Most owners delay full flaps until they have the runway made.
A telling number is the Aerostars wing loading, which is a stiff 35.4 pounds/sq. ft. Compare this to the typical Mooney wing loading in the 20s or a docile Cessna single in the teens. High wing loading means speed and a good ride in turbulence, but it also means sharp stall behavior, higher operating speeds and a bigger appetite for runways.
Only the 700P has a stall-warning system, but under normal conditions there’s supposed to be enough airframe buffet to advise of an impending stall. Both Piper and Machen have modifications to improve the Aerostars stall behavior at aft CG and alleviate the restrictions imposed by AD 83-14-7. Most owners prefer Machens vortex generators to Pipers water rudder. It should be noted that stall behavior has been the focus of some attention in the past, thanks to earlier tendencies to stall sharply when held into the break, with strong pitch and roll digressions after modest aerodynamic warning. The AD was issued to improve controllability during stalls with flaps extended, calling for aerodynamic kits like those mentioned above.
Comfort and loading
There’s one door, and passengers have to clamber in over the folded pilots seat. One owner quipped that getting into the right front seat is problematic for anyone over 40. Once inside, an Aerostar is reasonably comfortable, though the close-fitted props raise quite a din, especially in models without pressurization. The cabin is more than three inches wider than a 55-series Barons but three inches narrower than a Cessna 310s, and has two inches less headroom. Most owners have taken out one of the middle seats to make more space in the cabin.
However, an Aerostar would be hard-pressed to carry even five adults, their bags and a reasonable load of fuel. Real-world useful loads vary from a meager 1,600 pounds for a lavishly equipped Aerostar to a marginal 1,800 pounds with average equipment. Also, the airplane has a relatively narrow CG range, and its quite easy to bust the limits. Weight-and-balance calculations are a good idea for takeoff and landing profiles, because the CG moves forward as fuel is burned.
Safety record
Our initial study in 1984 of accident statistics from FAA and NTSB data on the Aerostar (covering the years 1978 through 1982) showed the Aerostar had the worst accident rate (both fatal and total) of any twin-engine aircraft still in production in 84. The Aerostars fatal accident rate for the period was 4.4 per 100,000 flight hours. By comparison, the Beech Baron 58s was only 1.4-more than three times better. Similarly, in total accidents, the Aerostar had a rate of 12.9, compared to 4.9 for the Baron.
In raw numbers, the Aerostar had a total of 67 accidents during the five-year period, 23 of them fatal. The Aerostar fleet was about 500 planes during that time. The leading cause of Aerostar fatal accidents during the study period was engine failure after takeoff. Six of them accounted for nearly a quarter of all Aerostar fatals. And the vast majority of Aerostar fatals involved 601Ps. A study of three years worth of accident and activity figures conducted in 1986 by our sister publication Aviation Safety also found Aerostars to have the highest rates of accidents and fatal accidents of eight models of six-place piston twins. (The total rate was 10.27 accidents per 100,000 hours, the fatal rate 3.5, for the years 1981-83.)
Door openings
Inadvertent cabin door openings have also been the focus of special attention on the Aerostars. Since the split clamshell door is right next to the pilot on the left side of the fuselage, with the spinning prop in close proximity, an opening can be critical. In a highly publicized accident, champion race car driver Al Holbert was killed in his Aerostar 601P in September 1988 when it crashed shortly after takeoff. Investigators determined that the top half of the cabin door was open on impact.
An Airworthiness Directive issued by the FAA in 1988 required inspection of doors for proper rigging, installation of warning placards and a cabin entry door ajar warning system complying with Piper service bulletin No. 980, issued in February 1985. Earlier, the NTSB, calling for an AD, noted that since 1980 four accidents and eight incidents had occurred in Aerostars in which the main cabin door opened, and in some cases actually separated in flight.
In February 1991 the FAA New York Aircraft Certification Office issued a special engineering alert on Flight Shop Inc.s pneumatic cabin door struts installed on pressurized Aerostars. The alert noted that installation of the strut may have involved cutting away part of the upper door gusset. That mod could result in failure of the door structure and rapid decompression of the aircraft, the FAA said, noting that the faulty installation could have been made on about 150 pressurized Aerostars. Corrective action included replacing the door gusset and relocating the upper bracket, also replacing the striker plate bolt.
Maintenance
Owners report that the Aerostar is a maintenance-intensive airplane, but say in the same breath that its to be expected in any aircraft of its class and age.
There are two main factors in the maintenance picture. First, the Aerostar is a compactly built airplane, therefore its systems are tightly packed and difficult to get to. Second is the complexity of the systems themselves. One owner reported literally dozens of individual failures in his first 18 months of ownership.
Since the type certificate is owned by a solvent business, owners do have a place to go for support. It seems that Aerostar Aircraft is holding up its end of the bargain, picking up on the task of issuing service bulletins. Some 11 have been published since the company bought the TC. Most recent of these is replacement of the nose gear lower drag brace link assembly on Aerostars with Weibel nose gear systems.
Owners Group
The Aerostar Owners Assn., 2904 North Patterson Street, Valdosta, Georgia 31602, publishes a quarterly magazine and holds regional meetings that focus on safety and maintenance. The association also is putting together an insurance program for its members. Call (912) 244-7827 for more information.
Owner Comments
I bought a 1982 602P Aerostar with known ice that had been upgraded to a Super 700 in February 1995. I had owned a Seneca III; I liked it a lot, but it was just too slow when I wanted to take a long trip.
The Aerostar is a great owner-flown aircraft, and is a lot of fun to fly – like a BMW 525 with wings. I typically cruise at 220 to 250 knots at 15,000 to 25,000 feet and 65 to 75 percent power. I find the airplane very straightforward to fly. The most complex airplane I flew before was the Seneca. Things seem to happen twice as fast in the Aerostar, but if you keep ahead of it, its very predictable. It is a heavy, fast airplane with high wing loading, so pitch and airspeed control are the things you really have to watch. It is much easier to fly on one engine than the Seneca, and the 350 HP Machen conversion climbs very we’ll on one engine. The pilot sits ahead of the engines, so visibility is fantastic. The passengers sit just ahead of the spar, and with the high wing loading the ride is very smooth.
On the maintenance side, it has a lot of hydraulics and electrical systems and everything is packed very tightly, so there is a lot to keep track of and it is expensive to maintain. Remember that this is a high performance airplane with big engines, and even if you can find a 601P at a cheap price you are flying an airplane with the maintenance expenses of any heavy piston twin. I have replaced most of the O rings (seven different actuators, struts, valves, etc.), both alternator belts, an alternator idler bearing, nose gear door shear pin (one of the spares you should carry), for a total of 35 separate failures in the last year and a half. the airplane had about 825 hours total when I bought it and some of these failures were just due to it being 14 years old. My maintenance cost including one annual has been $147 per hour since I bought it. You need to find good mechanics used to working on complex airplanes. There are six or eight shops in the United States that specialize in Aerostars. It really helps to develop a relationship with several experts so your regular mechanic has a place to call for parts and advice.
Insurance is $9350 per year for $5 million liability and hull. However, I did not find it any more expensive than my Seneca for comparable hull values. I am in one of the expensive categories, being owner-flown and a small business owner with only 1700 hours.
The mods I have are worthwhile. Auxiliary fuel tank, the Super 700 upgrade to 350 HP engines with intercoolers, new props and a gross weight increase, spoilers and an Insight engine monitor.
If youre looking at buying an Aerostar, get the current list of ADs from Aerostar Aircraft and make sure they are permanently fixed. Complying with the frequent inspections can be very expensive.
In summary, if youre willing to put the work into maintaining pilot proficiency and paying the price to maintain an Aerostar, it is really fun to fly!
Bill Lawson
Somerset, Wisconsin
I am the owner of a 1976 601P/700 Aerostar. I have owned the aircraft for approximately one year. Like most aircraft, the Aerostar story is a combination of some good and some bad. First, the bad.
It will come as no surprise that the bad regarding an Aerostar is essentially one item, i.e., unscheduled maintenance. The two most nagging problems in this regard are rivet leaks in the wet wings and pressurization problems. though both of these problems should be no surprise in a 20-year-old aircraft, the nature and extent of the problems was more extensive than I anticipated.
As to the leaking rivets in the wet wing, when I had the aircraft painted numerous rivets were simply removed and replaced. In addition, I installed a vent system provided by Machen, Inc. The combination of replacing any rivet that even looked like it might leak and the vent system has eliminated, at least for now, the leak problem. Parts and labor for the job were almost $4000.
Regarding the pressurization system, there were a number of problems. First of all, the ducting was old and had to be replaced. Second, a vacuum pump failed and no doubt was causing problems before it went. Finally, certain internal plumbing including a pressure relief valve had to be adjusted and/or cleaned. The cost of the vacuum pump ($1300) was a surprise. However, other parts have not been as bad.
Adjusting the pressurization and plugging all the leaks (holes in the pressure door seal, holes in the bulkhead seal, leaky emergency escape window, etc.) took a lot of time and labor before everything finally worked correctly. I would strongly urge anyone considering an Aerostar to have the pressurization system thoroughly and completely checked during the pre-buy inspection. That would include a flight to altitude to make sure the system is capable of producing full pressurization without any problems.
The engines on my Aerostar were upgraded to 350 HP per the Machen STC in 1988. I have overhauled the props and eliminated the need for a 50-hour inspection by installing the hub modification. However, I have not purchased the Machen tail pipe system to eliminate the repetitive inspection on the pipes. The reason is simple: The new pipes cost $5000, and thats a lot of inspections. Ive not had any problems with mine, and theyve been inspected twice.
The engine overhaul and conversion was performed by Firewall Forward in Colorado. They now have 700 hours and are running strong. I got two surprises, though, during the first year of ownership regarding the engines. The ducting for the turbo induction system was worn out and had to be replaced ($500), and the turbo controller on the left engine failed to work ($900).
Though I hopefully will not be overhauling the engines in the near future, overhauls are very expensive. Just for fun I checked with Firewall Forward and was quoted about $30,000 per engine.
When I bought the airplane I had planned on painting it and overhauling the props. However, my contingency fund for unscheduled maintenance was quickly exhausted. I would recommend that anyone buying even a good condition Aerostar set aside an amount equal to at least 10% of the purchase price in addition to scheduled maintenance costs for surprises.
Due to the limited time Ive owned the airplane, I cannot be precise regarding scheduled maintenance costs. My first and only annual was quite expensive but that was primarily due to personal decisions regarding certain upgrades, i.e. replacement of all hoses with top-grade lifetime hoses, new mags, new tires, etc. The basic annual labor takes 40-45 hours of shop time.
The 50-hour inspections run anywhere from $500 to $1000. Obviously, any discrepancies found and fixed during inspections cut the cost of the annual. I change the oil every three months, regardless of flying time. Changing the oil four times a year instead of twice adds about $500 to the maintenance cost. I have installed a Capehart lifetime oil filter. It seems to work we’ll and its magnets do appear to pick up iron residue in the oil. I have also installed a filter for the waste gate oil supply. This is recommended by Machen.
My insurance costs about $5000 per year, for $200,000 hull coverage and $5 million liability. Though its certainly not cheap, I don’t find it unreasonable in light of the fact that my prior airplane, a Seminole, cost $3000 a year with half the hull value and $3 million liability. I have 2200 hours total, 2100 multi, with military training and an ATP including a Convair type rating. Its a good idea to get an insurance quote before even shopping for an airplane.
Now for the good. The Aerostar has awesome performance. I am an Air Force-trained pilot with tactical airlift experience, and the Aerostars performance exceeds that of many aircraft Ive flown. For acceleration, climb and cruise I do not believe there is an equal. Due to the pushrod and bellcrank control system, the aircraft is positive in its control response. Though I imagine those transitioning from a light single might find the forces heavy, compared to a transport category aircraft the controls are very responsive.
The speed and rate of climb do carry a price: High fuel consumption. However, you get where youre going much faster, so the actual fuel use is not all that much higher. Cruising at 15,000 to 17,000 feet I typically burn 44 to 46 GPH, but the true airspeed is 230 to 240 knots.
The aircrafts reputation as a widow maker is simply not deserved. Like any high performance aircraft, proper training is required. Anyone who has multi-engine experience and goes through an appropriate checkout course will not have any difficulty transitioning into it.
In conclusion, the Aerostar is a delight to fly and I cannot imagine any other aircraft available, including some turboprops, that performs better. As noted above, a prospective purchaser of an Aerostar must accept the possibility of an extensive amount of unscheduled maintenance during the first year of operation. However, once the aircraft has been brought up to squawk-free status, I believe it cannot be beat.
Robert Muhlbach
Manhattan Beach, California
Also With This Article
Click here to view charts for Resale Values, Payload Compared and Prices Compared.
Click here to view the Aerostar 601P features guide.
