The C-12 Huron is a military version of an executive passenger and transport aircraft based on the Beech Model 200 Super King Air. It is primarily used by the US Air Force, US Navy, US Army and US Marine Corps for several functions, including range clearance, embassy support, medical evacuation, VIP transport, passenger and light cargo transport. The C-12 took its maiden flight on 27 October 1972 and entered service with the US Army in 1974.
The hulks of seven DC-3 fuselages are parked alongside Basler Turbo Conversions’ 75,000-square-foot facility in Oshkosh, Wisconsin. Three more DC-3s sit inside, disemboweled, bracketed by yellow scaffolding in a main hangar that looks like a surgical theater. With them, a shiny white and blue BT-67, a “Basler-ized” DC-3, awaits its new owner. Fly-away price: about $4 million.
Since 1990 Basler has given new life to dozens of DC-3s. (In the 33 years prior to that, Basler Flight Service had reworked more than a hundred DC-3s, modifying interiors, restoring airframes, and overhauling engines.) Basler installs Pratt & Whitney Canada PT6A-67R turboprop engines and Hartzell five-blade metal propellers in place of the piston engines and props that powered the original aircraft. The company increases the DC-3’s volume 35 percent by inserting a 40-inch plug in the fuselage forward of the wing and moving the cabin bulkhead forward five feet. A BT-67 boasts 45 more mph of cruise speed and almost 4,000 more pounds of useful load than the original DC-3.
The aircraft’s notoriously temperamental 14-cylinder piston radial engines have always been seen as its weakest feature, so hanging turbines on DC-3s is not a new idea. The British tried it at the end of the 1940s using Armstrong-Siddeley Mamba and Rolls-Royce Dart turboprop engines. The engines helped, but the unpressurized aircraft couldn’t be flown at an altitude that would use the engines to their best advantage, and the project was quickly dropped. The idea was resurrected in the 1960s: In California, a few “Super Turbo Threes” were made and sold, but that project also fizzled. A Taiwanese venture failed as well.
One of the most interesting turbo conversions was done by aviation legend Jack Conroy in the 1960s. His modified DC-3 initially featured three Dart engines, two on the wings and one stuffed in the nose. He sold the airplane to the Specialized Aircraft Corporation, which replaced the engines with Pratt & Whitney models. DC-3 experts then trace the Tri-Turbo to Santa Barbara Polair, Inc., which leased it to the U.S. Navy as a ski-equipped arctic research aircraft. Some have suggested it flew missions for the CIA. The late Warren Basler bought the aircraft in 1992 from a salvage yard in Tucson. It was so distinctive that Basler insisted it be preserved as an important part of the DC-3’s history, and today it sits in Oshkosh, stripped and weathered, awaiting rebirth.
The latest in the PA-46 line of aircraft that includes the -310P Malibu, -350P Malibu Mirage and -500TP Malibu Meridian, the M600 continues Piper’s success with high performance singles.
During a demonstration tour of the M600 in Australia, Australian Flying was fortunate enough to have the opportunity to fly the demonstration aircraft when it visited Archerfield.
The demonstration flight included a flight to the Darling Downs and back at 10,000 feet while truing out at a respectable 240KTAS. This flight ably exhibited the M600’s ability to be used as an executive transport aircraft or family high performance touring aircraft seating six adults in comfort.
Looking it over
This particular aircraft had been fitted with the optional five-bladed composite propeller, which provided smooth performance with a marginal increase in thrust and therefore performance over the standard four-bladed Hartzell propeller. That extra blade also means a slightly smaller diameter and therefore increased ground clearance.
This was the first striking feature I noticed as I walked up to the aircraft outside Archerfield’s Jet Base hangar. With the PA-46’s long nose accommodating the 600 horsepower flat rated PT6A-42A, the aircraft looks similar to the older models until you look much closer.
The M600 has a totally new designed wing from previous PA-46 models that results in reduced drag while being able to carry a total of 996 litres of Jet A-1 in two internal wing tanks.
Each wing leading edge is equipped with pneumatic boots for de-icing and along with a small LED light on the fuselage side below each cockpit window to enable the pilot to observe if any ice is present at night. The vertical tail and horizontal tailplane are also similarly equipped with leading edge boots.
Entry into the Piper M600’s cabin is via a single two-section door located at the rear left side of the cabin. The bottom section when lowered, houses the stairs for boarding while the locking mechanism is in the top sill. Integral within this lower door are the air ducts to aft cabin.
Once inside, the rear of the M600’s cabin has four seats in pairs facing each other just aft of the main spar that protrudes slightly on the floor.
All rear cabin seats have access to emergency oxygen masks, which are housed in a drawer under each seat. They are the airliner style nose and mouth mask. The two front seats have EROS quick-donning masks located in their boxes behind each seat facing inwards towards the access-way into the cockpit.
Moving forward into the cockpit is not without some difficulty. For the larger pilots amongst us, the cabin ceiling is quite low and after bending over and then lifting one foot over the main spar, you are able to slide forward into the cockpit seats. Once seated the flight deck is very comfortable with all controls falling easily to view and hand without effort without any extended reaching. Similarly, the view over the long nose is not limiting for all operations.
Above the windscreen is located the main switch panel with mainly electrical, avionic master and other systems switches nearest to the command pilot on the left side. This may pose problems for those pilots using multi-focal glasses looking upwards.
The five screens of the Garmin G3000 GNSS/SBAS Avionic System dominate the main area of the panel. The visible components of the Garmin G3000 system comprise three main display screens and two GTC 570 Touchscreen Controllers. The three main screens display most of the information required for IFR flight with the two outboard screens primarily displaying the Primary Flight Display (PFD) information using vertical tape displays of airspeed, altitude and VSI with a full 360 compass rose at the bottom.
The centre Multi Function Display (MFD) screen shows the engine indications vertically on the left with the moving map on the major area of the display. Alongside these primary engine indications are the ancillary indictors for cabin pressure, electrical loads, pitch trim, flap and landing gear.
The MFD also displays the Electronic Flight Bag using the appropriate Jeppesen charts. Below the centre MFD screen, are the twin touch-screen controllers. Each screen allows the pilot to enter the required frequencies on either of the twin VHF radios, transponder codes, navigation waypoints as part of a flight plan, control the charts selected on the MFD, allows the selection of various aircraft systems displays, accesses satellite weather information as well as planning aircraft performance. They truly are the control heart of the aircraft.
Outboard to the left of the pilot’s PFD is the Aspen Avionics standby instruments. This consists of a single flat panel colour display of attitude and heading with tape airspeed and altitude indications.
Situated below these display controllers are the engine controls consisting of the power lever, condition lever and the manual pitch trim wheel. To my liking, the power lever is mounted a little too low and sits just slightly lower than the height of the front seat bases. This posed a slight problem later during the flight.
Located either side of the centre touch-screen controllers are the landing gear switch to the left and the three-position (up, t/o and lnd) flap switch to the right. Outboard on the left, are the various engine bleed air controls and the air-conditioning. The various Auto-flight mode controls are located above the centre MFD. These control the heading bug, navigation course (CRS) selector, flight director On/Off, altitude selector, yaw damper and vertical speed selector (V/S).
Flying the beast
Our flight was planned to depart YBAF on an IFR flight plan at 10,000 feet for a short flight up to Warwick on the southern Darling Downs and back to Archerfield.
After checking that all the electrical and bleed controls were selected appropriate for an engine start, annunciator lights checked, the battery voltage was checked sufficient for an internal power start. After checking that the fuel pumps were selected on MAN, L and R fuel pump messages showed on, the ignition switch selected to man and the prop area was clear, a start cycle was commenced.
Selecting the start mode to auto, lifting the cover and pushing start there was an immediate whirring sound and the Ng % began to increase quite quickly. As it passed 13%, fuel is introduced to the engine by advancing the Condition Lever to run. The main limitation that we were looking for on the start, was a maximum of 1000°C, which is limited for just five seconds. The only other limit that needs to be observed is that the starter has disengaged above 56% Ng.
While waiting for the obligatory warm up and checking of engine parameters, the avionics were selected on and the relevant weight and fuel data were entered or confirmed from fuel onboard and the flight plan route entered into the G3000, we were virtually now ready for taxy.
Of course the most important item for flight in this type of aircraft around SE QLD, making sure the air conditioning was selected on. Immediately cooling air was felt coming from the air outlets making for a comfortable flying environment.
Taxying the M600 required little extra power with our light weight, and the M600 quickly accelerated to a comfortable taxying speed. With the reversing propeller, taxy speed was easily controlled not by riding the wheel brakes, but by pulling the power lever back to the Beta position: zero pitch.
This is achieved by pulling the power lever slightly up and aft of the idle detent. Only momentary selections were required to control the speed before returning the power lever back to idle as we taxied out to Archerfield’s Runway 10.
Having a turbine power unit doesn’t negate the requirement for a propeller check. After entering the run-up bay and parking the brakes, the power lever was advanced to 1900 RPM for a propeller governor check followed by a reverse and Beta lock-out test.
After all the other normal pre-take-off actions, we were now to ready to move to the holding point, obtain our airways clearance and aviate.
With the flaps set to the T/O position, the power lever was advanced to around 1500 psi TRQ and the M600 accelerated rapidly towards an initial rotate speed of 85 KIAS. I found maintaining the centerline relatively easy with the powerful rudder design of the aircraft and direct nose-wheel steering at lower speeds.
The back pressure required at lift-off was a little higher than I expected, but provided positive response.
Initial obstacle clearance climb out speed of 95 KIAS is quickly achieved and after the gear and flaps had been retracted and the circuit area cleared, I accelerated the aircraft to a cruise climb speed of 145 KIAS at 1500 fpm. Best rate of climb is achieved at 122 KIAS.
During the climb, we only needed to monitor the engine’s limits in Torque, ITT and Ng. The pressurization was being looked after for us automatically as we climbed towards our cruising level of 10,000 feet.
United Technologies Corporation’s (UTX – Free Report) business subsidiary, Pratt & Whitney Canada, recently secured an approval from Transport Canada to augment cycle limits on its premium PT6A-140, -140A and -140AG engines. This approval to increase cycle limits will aid it in extending the life of Low Cycle Fatigue (LCF) parts like compressor, power turbine disks and impeller.
Whether it involves recording and inputting data manually or using the latest automated Digital Engine Services, Engine Condition Trend Monitoring delivers net gains for all PT6A customers.
A WORTHWHILE PAYOFF
Rob Winchcomb, PT6A Customer Manager, is the first to admit that doing Engine Condition Trend Monitoring (ECTM) by hand is a hassle.
It requires writing down key engine and aircraft data at a set time during each flight once the plane is at a stable cruising speed, inputting the recorded figures into a computer after landing and sending them to the analysis company for comparison with the results of previous flights.
For busy operators who already have plenty on their plate during a flight, the extra work might seem like an unnecessary nuisance. That’s why Rob’s customers always ask him the same question: “What’s in it for me?”
He’s been telling them the same thing for 25 years: “ECTM reduces the cost of ownership, increases the engine’s availability and gives you more peace of mind.”
Rob walks the talk. Thirty years ago, before joining P&WC, he was on the other side of the fence as a customer, began his aviation career with the Royal Flying Doctor Service and working for other regional airlines in Australia. Back then, he was already a strong proponent for recording and using engine condition data, despite having to do it all the hard way—computing the trend values by hand on a Texas Instruments calculator and plotting his own handmade ECTM graphs.
A LITTLE EFFORT, A LOT GAINED
“PT6A engines are very reliable from one inspection to the next, but in my mind the question is, why not take the next step? With ECTM, you can optimize performance and maintenance planning,” says Rob. “It doesn’t cost you much considering the gains it will bring.”
By analyzing parameters such as power, speed and fuel flow on a flight-to-flight basis, ECTM can identify subtle changes in an engine’s performance. Based on the analysis results, P&WC’s engine health monitoring partner CAMP Systems will let the operator and maintenance team know if any actions are required.
Is a sudden 10-degree increase in temperature simply the result of replacing a fuel nozzle set? Is an increased power load due to excess air leaking from the cabin rather than an issue with the engine itself? Do you need to take a look at the compressor? ECTM will tell you.
This kind of detailed insight into engine performance means that issues can be detected and resolved before they turn into costly repairs and affect operation. It also makes it easier for PT6A customers to move to on-condition hot section inspections.
It all adds up to better maintenance planning, lower expenses and increased engine availability.
There’s also a financial benefit when selling a used aircraft. If you’ve been consistently performing ECTM, you’ll have a record to show potential buyers that the engine is well maintained. That will give them more confidence, which in turn enhances your aircraft’s resale value.
Now available on a growing number of PT6A platforms, the FAST solution captures, analyzes and wirelessly transmits a wide range of engine and aircraft data after each flight, providing detailed, customized alerts and trend monitoring information directly to the operator within minutes of engine shutdown.
“I wish I’d had this technology 30 years ago,” remarks Rob. “It’s light years ahead of what we were doing back then—and it keeps evolving.”
Besides making operators’ lives simpler through automation, the FAST solution also has the capacity for enhanced functionality going forward. For instance, the company is looking at introducing FAST’s propeller vibration trend monitoring technology – available for regional turboprop aircraft – as a solution for PT6A-powered aircraft in the future. That’s another reason why Rob believes it is now the most attractive solution for customers.
Ultimately, though, what’s most important is to be doing ECTM, no matter whether it’s with pen and paper or state-of-the-art digital solutions. “When I talk to customers about FAST,” Rob concludes, “what I’m selling them is not the hardware itself, but the full value of automated ECTM to their operations and asset value.”
Rob has also helped PT6A customers master the art of engine rigging by appearing in a detailed instructional video.Read all about ithere.
Cessna was a little late out of the gate getting a turboprop into its lineup. First was the Cessna 441 Conquest in model year 1978, a full 14 years after Beechcraft’s King Air. Next was the Model 425 Corsair in model year 1981. The Corsair is smaller than the 441 and uses 450-shaft-horsepower Pratt & Whitney PT6s versus the 441’s Honeywell (Garrett) TPE 331 engines.
Concurrent with a max takeoff weight increase to 8,600 pounds, Cessna dropped the Corsair moniker and renamed the 425 Conquest I while reassigning the 441 the name Conquest II. Confused yet? The 425 is best described as a 421 Golden Eagle with turbines in place of pistons. Aside from sharing the same basic dimensions, the similarities between the 421 and Conquest I fade quickly. The 425 is substantially beefed up structurally and has more robust systems.
Since it’s based on a piston design, the 425 is easy to fly and an easy step up. In fact, with the easy-to-operate turbines, many would argue that the 425 is less complex than the 421. Cockpit visibility is excellent, as is the instrument panel layout. Cabin seats are comfortable once seated. Cessna’s “wide oval” cabin biases more toward elbow room than headroom, so there will be nothing close to stand-up comfort.
Performance-wise, the Conquest is good for 250 KTAS at typical cruise altitudes in the mid teens to low 20s. As is usual with turbines, the fuel burn drops off the higher you fly. Also typical of turbines, the winds will dictate choice of cruise altitude vs. fuel burn. Owners often figure 500 pounds of Jet-A the first hour and 400 pounds/hour after that. Blackhawk Modifications Inc. offers 425 owners PT6A-135 engines in place of the original -112s. The Blackhawk holds its max power to much higher altitudes than the original engines, resulting in faster time to climb and a 20-knot increase in true airspeed.
Range with tanks full is about 1,200 nm, which leaves about 700 pounds of payload. With six adults on board, range is about 700 nm. The 425 is confident at all weights on 4,000-foot runways at sea level. At lighter weights, 3,000-foot runways are doable.
Vref values a 1981 Conquest I at $625,000 while a 1986 model fetches an average of $875,000. Once an owner swallows the reality of six-figure engine overhauls, higher fuel burn, and other substantial cost increases of owning a turbine, he or she will be impressed with the Conquest’s performance and reliability.
Pete Bedell is a pilot for a major airline and co-owner of a Cessna 172 and Beechcraft Baron D55.
SPEC SHEET Cessna 425 Conquest I
Powerplants | (2) 450-shp Pratt & Whitney PT6 Length | 35 ft 10 in Height | 12 ft 7 in Wingspan | 44 ft 1 in Seats | 2+6 Max takeoff weight | 8,600 lb Takeoff distance over 50-ft obstacle | 2,800 ft Max cruise speed | 264 kt Landing distance over 50-ft obstacle | 2,482 ft Range | 1,200 nm
Peter A. Bedell
Pete Bedell is a pilot for a major airline and co-owner of a Cessna 172M and Beechcraft Baron D55.
Blackhawk Modifications has sold 800 of its XP engine upgrades with the delivery of a Phoenix-edition King Air C90-1 with its XP135A engine upgrade. The company also announced that flight testing of its latest program, the XP67A engine upgrade for 12,500-pound and 14,000-pound-gross-weight models of the King Air 300, is underway and that it is continuing a $50,000 pre-certification discount on orders for that program, first announced this summer.
Blackhawk expects the XP67A upgrade for the King Air 300 to deliver improved performance, including a maximum cruise speed of 345 to 350 knots, time to climb from sea level to FL350 in less than 17 minutes, and better performance at higher density altitudes. The upgrade includes two new P&WC PT6A-67A engines with a factory new engine warranty of five years/2,500 hours, installation drawings, STC paperwork, approved flight manual supplement, instructions for continued airworthiness, training from FlightSafety International for PT6A line maintenance, and a two-year subscription to P&WC engine maintenance/parts manuals. Qualifying core PT6A-60A engines will be trade-in credited at $70 per hour each for time remaining on the 3,600-hour TBO.
The STC flight test program for the XP67A upgrade for the King Air 300 will include measuring parameters such as single- and multi-engine handling, aircraft performance, engine and accessory cooling, stall speeds and characteristics, landing characteristics, propeller noise and vibration, and high-speed airframe/engine characteristics. Blackhawk expects FAA STC approval for the upgrade next summer.
Blackhawk’s Phoenix program allows owners of legacy King Airs to upgrade from a menu of options, including engines, avionics, and paint and interior. Blackhawk’s 800th XP upgrade, a 1982 King Air C90-1, was delivered to Gregg and Jan Goodall of Breckenridge, Texas, and replaced the stock PT6A-21 engines with the XP135A engine upgrade, generating a 36 percent increase in available horsepower, a 59 percent increase in climb rate, more than 270 knots maximum cruise speed, and a 19,000-foot single-engine service ceiling. The Goodalls also opted for Phoenix signature paint and interior design, the Raisbeck Epic package, and new Garmin glass-panel avionics including two G600TXi displays, WAAS-enabled GTN 650 and 750, GTX 335 transponder for ADS-B Out, and the L3 Lynx transponder for ADS-B In and Out.
This is an excerpt from a very interesting article you should fully read over at FlyingMag. Below are quick highlights.
What is this voodoo? I’d been glancing outside the airplane, a last check for traffic on short final, as Eric Smedberg, chief pilot for Innovative Solutions & Support, swung the Pilatus PC-12 onto the runway and engaged the autothrottle system with a simple press of a button.
I looked down just in time to see the power lever advancing from the idle position to max continuous takeoff thrust, which on this day was a little more than halfway to the forward stops. Seeing the autothrottles in action on a business jet or airliner is no big deal, but in a PC-12 powered by a Pratt & Whitney PT6A lacking full-authority digital engine control, that lever shouldn’t move by itself. It was like a ghost was in our presence — a decidedly friendly ghost, I had to admit.
For nearly the next two hours of flying, including climbs, cruise flight, descents and required navigation performance (RNP) precision instrument approaches, neither Smedberg nor I adjusted the power lever or touched the yokes. Occasional button pressing and knob twisting, plus radio calls and the requisite scans for traffic on this VFR day, were about the only duties necessary for the human pilots on the round-robin demonstration flight across central New Jersey. It wasn’t until we were on final approach for landing back at Morristown Municipal Airport that Smedberg clicked off the autothrottle at 500 feet and took manual control from the unseen computerized apparition that had been working furiously — and flawlessly, I must report — behind the scenes to keep us perfectly on speed, course and altitude throughout our time aloft.
Smedberg says the autothrottle can be adapted to virtually any PT6A-powered airplane by adding the ISU standby display, which operates the thrust computer software that makes the autothrottle function. Testing of ThrustSense aboard a King Air 200 is well underway. IS&S and Blackhawk Modifications have already announced an agreement for Blackhawk to distribute and install IS&S’s NextGen flight deck and integrated turboprop autothrottle system for King Air 200s and 350s — and for good reason. The two models account for more than 3,000 airplanes, according to IS&S, and there are another 2,000 C90 through E90 and F90 King Air models that are candidates for the upgrades as well.
The King Air NextGen flight deck will be similar to the STC’d PC-12 avionics upgrade, but in the twin-PT6A King Air applications, the autothrottle will include engine-out thrust control, which in case of engine failure automatically sets the remaining engine to the correct power level if airspeed drops below minimum controllable airspeed. The idea is that the pilot can maintain control as the autothrottle works to mitigate adverse yaw, allowing the airplane to safely accelerate under full control.