The Beech Bonanza has always been considered the very top of the line in single-engine aircraft, and the top of the Bonanza line for almost 20 years have been the A36TC and B36TC turbocharged long-fuselage straight-tail models, which remain in production to this day. (The normally aspirated 36 is really in a different class and thats why its covered in the previous chapter.)
The 36 turbos offer a sizeable cabin, good high-altitude cruise numbers and the security of the straight-tail design. They have held their value extremely well. But the A model had serious range shortcomings, and both aircraft tend to run hot and fall short of rated engine TBO times.
Genealogy
The history of the turbo Bonanza is a truncated one. Back in 1966, Beech brought out a turbocharged version of the standard butterfly Bonanza called the V35TC. Those were the early days of turbocharging, and apparently neither Continental nor Bonanza pilots were up to the task; the V35TC had terrible turbo reliability problems. The V35TC lasted five years, and only 132 were built.
But as turbocharging grew more popular, Beech reintroduced the idea of the turbo Bonanza in 1979. The company wisely chose to turbo the more stable straight-tailed A36 model Bonanza, and the result, powered by a 300-HP Continental TSIO-520-UB, was the A36TC. It had a sophisticated variable absolute pressure controller that automatically maintained manifold pressure during altitude and temperature changes.
The A36TC was a modest success, selling a total of 272 aircraft in three years, but pilots, with some justification, beefed about the limited fuel capacity of 74 gallons. So in 1982, Beech finally made the airplane what it should have been all along: the B36TC, with a longer wing for better high-altitude performance, and 40 gallons more fuel capacity. The two big changes improved the book range by nearly 50%.
Significant improvements
The B36TC had many other improvements, as well. Gross weight went up by 200 pounds to 3,850. In addition to getting the four-foot tip extension, the wing also got a whole new carry-through structure. In effect, Beech put a Baron 58 wing on the B36TC. A new propeller and hub improved ground clearance. The B36TC had anti-siphon fuel caps, flush fuel drains, a new boost pump system that eliminated some complex fiddling required during takeoff in the A36TC, and larger fuel lines for better resistance to vapor lock. The B36TC also had a couple of weird-looking vortex generators on the wing leading edge out near the tips. The extended wing tips apparently played havoc with the airplanes spin recovery, and after trying all sorts of other things (like limiting rudder travel and increasing down elevator travel) Beech finally came up with the vortex generators, which allowed the B36TC to meet the minimum FAA spin-recovery requirements. Nobodys quite sure how they work, but they seem to do the job.
Resale market
The A36TC and B36TC are real blue-chippers on the resale market. They were (and are) fearsomely expensive to buy new, and theyre fearsomely expensive to buy used. In 1979, a new A36TC cost $137,000 and is worth $193,000 today (were using Bluebook retail figures, which sometimes do not reflect actual selling prices.)
By comparison, the same numbers for a 1979 T210 are $99,000 new and $150,000 used for a 151 percent resale value. The Mooney 231s numbers are $85,000 new, $98,000 used and 115 percent.
Later-model 36TCs took a huge jump in new sticker price, so percentage value retained is not as good as for the earlier model. But the fact remains that, for any given model year, you’ll have to pay about double the price of a Mooney 231, which has similar performance through the middle altitudes, though significantly less space. Obviously, people put a lot of stock in the Bonanza TCs comfort, quality and extra high-altitude capabilities-not to mention the perception of quality and status.
Performance
The 36TCs are good performers in terms of cruise speed. The 36TC can generally keep up with the likes of the Mooney 231 and Cessna T210N, but newer planes like the Mooney 252, Turbo 210R and Piper Malibu are faster. Owners report typical cruise speeds in the 180-knot range at middle altitudes.
These reports agree pretty we’ll with the book figures, which call for cruising speeds ranging from an all-out max of 199 knots (at 79 percent power, 25,000 feet and 250 pounds below gross weight) to 155 knots at 56 percent power and 10,000 feet. The book number for 75 percent/20,000 feet is 190 knots; at 69 percent/15,000 feet, the figure is 174 knots.
There’s very little speed difference between the A and the B models. At very high altitudes, where the Bs bigger wing comes into play, the B has an edge of a couple of knots.
Owners report fuel flows of 17-18 GPH at cruise power. That assumes a middling power setting and a mixture rich enough to keep the valves from cooking.
Pilots praise the airplanes climb performance. They consistently report climb rates between 1,000 and 1,500 FPM, and have no trouble getting on up to 20,000 feet. Much higher than that, and the turbo wastegate is fully closed in the bootstrap mode, and manifold pressure begins to fall off. But cruising at the max certified ceiling of 25,000 feet is a reasonable thing to do, say TC pilots, unless the day is hot and the load heavy.
Payload/range
The A model has a gross weight of 3,650 and a typical IFR empty weight of around 2,400 to 2,500 pounds. Typical useful load is around 1,150 pounds. With only 74 gallons (444 pounds) of fuel available, a hefty 700-800 pounds is available for the cabin even with full tanks. Thats the equivalent of four people and some baggage.
The bad news, of course, is you cant fly very far on 74 gallons. Factory specs list ranges from 609 to 730 NM, depending on altitude and power setting, but these are a bit optimistic. Taking into account full-rich climbs to altitude (necessary for engine cooling), richer-than-peak cruising (also a good idea for engine longevity) and IFR reserves, you wouldnt want to fly one more than three hours. Five or six hundred NM is more like it.
If you want to take advantage of the big cabin and put six adults inside, range will be limited indeed. Six 170-pounders each carrying 20 pounds of luggage leaves zero-yep, absolutamente nada-for fuel. (You could hold a nice conference on the ramp, though.) The A36TC is a six-place airplane only if some of the six are kids.
The B model does a bit better. Empty weight is about 60 pounds higher, but gross weight is up by 200 pounds, for a net useful load boost of 140 pounds. If you take the bonus in fuel, the B36TC will carry three adults up to 1,000 NM, or even a bit more if you throttle way back. If you want to settle for the short range of the A36TC and only pour in 74 gallons, the B will carry one more passenger than the A model.
However, even the B36TC looks bad next to a Cessna T210R in terms of payload. The big Cessna will haul 250 pounds more weight, comparably equipped, which translates into an extra passenger and a half, or an extra 40 gallons of fuel-enough to fly 500 miles farther.
Creature comforts
Unlike the T210R, however, its actually possible to fit six people in the cabin. (The back two seats of a 210 are suitable only for midgets.) Virtually every 36TC has the optional club car seating, which puts the four rear-seaters facing each other, Orient Express-style. Owners seem to like the bizjet-style separation of crew and passengers, but tall folks in the back will require some sort of intricate leg-interlock system. Weight limitations almost assure that at least a couple of the club section passengers will be kids. The big right-side cargo door is also a boon to the rear-seaters.
Cabin noise level is fairly low. Its quieter than the S35 and the Skylane I used to own, commented one B36TC owner.
Handling
The stretched 36 model Bonanzas handle much differently than the shorter V-tail 35s and straight-tail 33s. The 36s were stretched several inches forward of the wing, which lengthened the cabin and improved the limited CG envelope of the short-body Bonanzas. The result is a much heavier-feeling airplane. Lateral response is also slower. Its not as much fun to fly as the V-tails, commented one owner. You fly it by the numbers instead of by feel. With two people up front and the rear cabin empty, the 36TCs tend to be nose-heavy on landing and takeoff. While the heavier pitch forces may not feel as sporty, they certainly contribute to better stability and make the 36 a safer airplane to fly IFR.
Engine
All the 36TCs have the same engine: a 300-HP Continental TSIO-520-UB. TBO is 1,600 hours, but reports suggest that not many make it that far. Few 36TCs have been around long enough to go to 1,600 hours (many are flown by private individuals who put 200 hours or less a year on them), but the pattern seems to indicate a top overhaul somewhere in the 800-1,200 hour range. We queried one overhauler about the engine, and he replied, It has no major problems Im aware of, but the last major we did came at about two-thirds the TBO time. It needed a top overhaul, and the guy decided since he was spending that much money anyway, he might as we’ll do the major.
Part of the problem may be hot running due to a lack of cowl flaps-an odd choice by Beech for such a sophisticated temperature-sensitive aircraft.
The engine/boost-pump combination on the A36TC is an odd one that requires some extra fiddling by the pilot on takeoff. The A36TC book calls for a full-rich fuel flow of 32.5 to 34.0 GPH on takeoff. If this is not achieved, the pilot must turn on the fuel pump to Low or Auto (the book doesnt say how you decide which one), and then lean the mixture back to the correct fuel flow. The same complex rigmarole must be continued throughout the climb in warm weather.
The B36TC book warns the pilot not to use the boost pump in the Hi position because of excessive fuel flow. Beech, in a masterpiece of understatement, says that this may cause engine combustion to cease on the takeoff roll.
The engine is subject to the notorious cylinder-cracking AD, number 86-13-4, which calls for inspection of the cylinders for cracks every 50 hours. (The -UB engine is not alone; virtually all 520s are subject to it.) The engine is also prone to crankcase cracks, as are virtually all other front-alternator Continental 520 engines. Check carefully for cracks on any 36TC considered for purchase-a bad crack will cost a minimum of $5,000 to replace or repair, mostly because of the teardown costs.
Service Difficulty Reports
FAA records of service problems highlight several areas to watch out for when inspecting an A36TC or B36TC for possible purchase. Heres a list of the main A36TC problems from a decade of SDR files:
Cracked boarding steps. Beech service instruction 972 refers to this problem, but A36TCs arent listed as having it. Check it anyway.
Cracked oil cooler baffles (10 reports).
Cracked crankcases (10 reports).
Cracked cylinders (four reports).
Cracked turbocharger inlet, part number 642668 (15 reports).
The B36TC models, with benefit of 20/20 hindsight, did not reflect these problems. However, two B model trouble spots were the fuel return line, which tended to chafe against the wastegate drain (four reports) and cracked cooling baffles at the air pressure pump inlet above the oil cooler (four cases).
ADs
The 36TC models have only a few of ADs that are unique to the type. One, for older A models, requires modification of the fuel drain hose. Both A and B models are subject to 84-8-4, which requires modification of the oil line check valves. But 36TC owners don’t get off easy; the airplane is subject to many of the shotgun ADs on engines and accessories that cover numerous aircraft types. Examples: Hartzell props, Airborne pumps, ELT batteries, air filters, Bendix mags, and cracked cylinders. The biggest potential problem is the repetitive inspections for cylinder cracks, AD 86-13-4. AD 92-17-1 called for fixing leaks in the fuel metering system.
Other ADs are the same as for the other Bonanzas. Recent ones of particular note include 95-4-3, inspection, repair and reinforcement of the front wing spar carry-though frame; 93-24-3, repetitive inspection of the front rudder spar, 91-17-1, horizontal stabilizer spars; and 89-5-2, inspection and possible replacement of the elevator.
Modifications
A36TC buyers should look for the 30-gallon tip tank STC offered by Beryl DShannon ((800) 328-4629), one of the best-known purveyors of Bonanza mods. Fuel in the tip tanks must be transferred with a pump into the main tanks. Speed will probably suffer a few knots. Installation time is estimated at two or three man-days. DShannon also offers vortex generators.
There are also intercooler mods for the A and B models. Both mods allow power to be produced at lower manifold pressures, thereby reducing stress and heat in the engine. Considering the 36TCs reputation for running hot and failing to make TBO, we think an intercooler is a superb idea.
Another desirable mod to look for on a used 36TC (or to consider adding after you buy it) is a set of speed brakes for descending rapidly from high altitudes without overcooling the engine. Precise Flight offers wing-mounted speed brakes.
Owner comments
I bought a 1981 A36TC with 500 hours on it in 1983. I paid $125,000. It now has about 1,300 hours on it, which works out to about 200 hours a year.
I generally plan on getting about 170 knots block-to-block, usually at about 12,000 feet, although sometimes I have to go higher to get over the mountains out here. Thats at 75 percent power. I lean it about 50 degrees rich of peak TIT, and this results in a fuel burn of about 17 GPH. It has very good climb performance; I typically see 1,400 or 1,500 FPM after takeoff, although thats usually below gross weight. For the cruise altitudes I usually fly at, it takes less than a minute per thousand feet to get there.
I do have to watch the cylinder head temps on climbout. On a warm day, I may have to climb as fast as 130-135 knots to keep the CHT 50 degrees below the red line, which is where I like to see it. Ive had no major problems with the machine. The airframe has been pretty much maintenance-free, and the annual inspection usually runs around $1,200 to $1,300. I have had avionics problems, however. And the engine required a premature top overhaul at 1,200 hours because of low compression and excessive oil consumption. TBO is supposedly 1,600 hours, but I think its pretty standard among A36TC owners to need a top overhaul at half or two-thirds of the TBO.