Thinking of buying a Jetprop…

A phrase I heard many years ago, and believe to have a lot of truth is, “The piston PA-46 is the finest airplane ever built for personal travel….firewall backwards”.  While I love the piston Malibu/Mirage, there’s no doubt that most of the mechanical problems occur “firewall forward” on this airplane.  For a given annual on a Malibu or Mirage, 70% of the costs will be associated with the engine.  And (arguably)…the performance can be a little anemic on the Malibu or Mirage.  Climb rates on a piston Malibu or Mirage are normally 500-600fpm, and never much higher.  Faster cruise speeds can only be found at the higher altitudes after a long gas-guzzling climb.  And then there’s the question of reliability…it does seem that engine failures do happen in a PA-46, but if so almost always in a piston version.

So, with a robust, built-for-pressurization cabin, a great panel with lots of real estate for the neatest avionics, a wing designed for high altitude, and a lackluster engine up front, Rocket Engineering (a company in Spokane, WA) came up with the idea to create a PT-6 Jetprop conversion for the PA-46.  Brilliant.  That’s the best word for these guys.  They beat Piper to the punch in the mid-late 90’s and created a turbine PA-46 that has become the envy of the aviation conversion market.  They hit an absolute home run with the Jetprop Conversion.  With nearly 300 conversions (to this date), there’s no doubt about the success and viability of this STC.  Piper has tried to play catch-up with the Meridian since the late 90’s and arguably have been successful in doing so since there are more Meridians flying today (the newer Meridians are not bad airplanes!).  But, the Jetprop has a loyal tribe of followers and are still selling conversions at a good rate.  It is a really good conversion.  The question is, “How good”? My answer? “Very”!

The earliest Jetprop’s had a PT6-21 engine, soon a -34 conversion was offered, and now most are -35 conversions.  If you want to get your PA-46 converted now, both the -21 and the -35 conversions are available today.  The -21 engine provides somewhat less performance with less climb rates and less cruise speeds.  The -34 and -35 engines have virtually the same power/cruise/climb performance numbers, and they will climb better than a -21 (especially at higher altitudes) cruise faster.

The conversion requires a new “firewall forward” with a new engine of choice, prop, and sundry other items.  On the fuselage the tail is beefed up slightly to handle the additional torque and an 11-gallon “Header Tank” (standard option) is mounted in the forward fuselage.  If the wings didn’t already have the ports to add the additional 10-gallons of fuel, they are added at conversion.  Conversion is a good time to consider upgrading avionics, interior, or paint.

And when you bolt on an extra couple hundred extra horses on the front end…well, the performance is amazingly different.  I remember my examiner asking during my PPL Practical Test (25 years ago?), “What determines the rate of climb of an airplane?” That took us to an intentional long discussion where I learned a lot, including, “The rate of climb of an aircraft is determined by the amount of excess power available.”  The Jetprop is the perfect example of this truth.  It’ll flat-out out-perform any piston PA-46 in existence, bar none.  It is a true game-changer because of excess available horsepower.

Start-up: Start-up is easy and straight-forward for a turbine, which is completely different than a piston engine, but not hard to learn for the uninitiated. Hot starts are the enemy, and every well-trained turbine pilot is always on the lookout for that potential, mitigating risk factors on every attempt.  Once started, the taxi is normal.

Takeoff and Climb:  On the takeoff roll the performance is WAY different than a piston.  Acceleration is brisk, but very manageable.  After rotation the airplane is cleaned up and then the real performance is realized.  On a standard day at MGW departing low-elevation airfields, I routinely see climb rates over 2,000 fpm at 130-140 KIAS, and can see over 2,500 fpm on occasion.  If lighter or colder, the performance only goes up.  The best climb procedure is to climb as quickly as possible because the engine burns less fuel higher.  So, most Jetprop pilots climb quickly adjusting the pitch attitude to ensure 140KIAS at the lower altitudes and 130 KIAS at the upper altitudes.  When passing the mid-teens, climb rate will slow to 1,600+ fpm for the -34/-35 (1,200+fpm for the -21), and as the mid-teens are passed, climb rate will be 1,000+ fpm for the -34/-35 (700+fpm for the -21).  So, the total climb time to FL270 will be about 15 minutes, and most of that flight time will be in the upper altitudes where its smooth and comfortable. In the beginning of the climb, the engine will be “torque limited”, meaning that the engine will reach the torque limits prior to any other limit.  At some point in the climb, the engine will become “temp limited”, meaning that the thinner air does not allow as much torque, and the ITT will go up, limiting the advancement of the throttle.  It is possible for an engine to be “Ng limited”, but I have yet to see that in a Jetprop.

Cruise: 90% of the Jetprop flights will be at FL270 when going eastbound and FL260 when going westbound because the fuel burn is lower and the cruise speed faster up high.  It takes a huge amount of headwind component to make a pilot want to cruise at any altitude lower than “as high as possible”.  Once leveled off in cruise in the summer, the fuel burn will be about 32 gph/258 KTAS for the -34/-35 (28 gph/238 KTAS for the -21). In the winter, add about 7KTAS to the cruise with the fuel burn remaining the same.

Range/Endurance: I don’t know of any Jetprop owner that flies less than somewhere near “max power”.  “Max power” is usually defined by “Max ITT”.  Most pilots operate within 25 degrees of “Max ITT”.  Any lower ITT setting would have a lower fuel burn, but also a slower speed.  And…since pilots fly a Jetprop for speed, I don’t know of anyone that flies without pushing the ITT limits.  Since the PT6 is a derated engine (meaning, it was designed for 1,000+SHP, but derated for FAR less in the Jetprop application), pushing ITT limits is not a big deal on this engine at all.  With this knowledge, the range of the Jetprop can be determined.  The main tanks hold 140 gallons (main-60 each + 10 extra per side) and the Header Tank has 11, so the total is 151 gallons.  It’ll take 20 gallons to get up to altitude, so the pilot will have 131 gallons at his/her disposal for the cruise/descent/landing portion of the flight.  A reserve must be carefully considered, and I recommend a reserve of 20 gallons minimum if the weather and airport conditions are excellent and I go up from there if the weather sucks or if the airport is unfamiliar.  So, a pilot could have 110 gallons for cruise flight if completely full of fuel at takeoff and has great landing conditions.  That’s 3+ hours in cruise, which should equate to a 750+NM range, not counting the terrain covered during takeoff and climb (50+NM?).  So, if full fuel is available, a pilot can normally plan for an 800+NM no wind range, and if winds are favorable, even longer.

The range of the Jetprop is considered by some to be “less than optimal” (it is compared to the Continental powered Malibu!).  But, I rarely want to spend more than 3.5 hours in any airplane without landing.  Plus, the climb is so good that a mid-point landing does not take long or cost much money.  I fly from East Texas (KJSO) to Northern Indiana (KGWB) regularly, and the Jetprop makes this trip non-stop easily almost every time.  Ditto for the trip from KJSO to KCAE, KAPA, or KLCQ.  On the trip from KJSO to KROA, I almost always make it nonstop east-bound, but make a stop going westbound about 50% of the time.  To me, range is just not an issue.  But, every pilot must consider their mission.

Descent and landing: At the time of descent, I usually turn the Ice Door (which saps power, but protects the engine from ingesting icing FOD) to the “ON” position (Thanks Travis for that advice!).  The reason is that I’m going to reduce power any way, so to turning on the Ice Door will not hurt me at all.  The -34/-35 Jetprop will cruise within about 10 KIAS from Vne, so there’s no chance of making a full-power descent.  Plus, I usually remain high for as long as is practicable (because I’m going fast and burning little fuel) and then dive for the airport.  In a no-wind situation, I’m leaving FL260/270 about 90NM from my destination (assuming no ATC demands).  Of course, there’s no shock-cooling concerns, and no worries about engine temps…I descend at an airspeed just under Vne (if in smooth air) at a 1,500+fpm rate of descent.  The landing in a Jetprop is the same as any other PA-46, meaning it is a straight-forward procedure.  The biggest advantage is the ability to go into reverse (Beta).  And…to me this is a HUGE advantage over any piston-powered PA-46!  The PA-46 can have random brake failures (I’ve had 5 and have seen at least 5 others in people I train), and the ability to go into reverse provides a tremendous safety factor, IMHO.

Things to consider when buying a Jetprop:

  • Useful Load: Be sure to consider how much load you can carry before buying.  The Jetprop has 6 seats, but you will almost never consider filling every seat. Why? Because if you do you won’t have enough fuel to go very far.  The Jetprop is really a 3-4 seat airplane, unless some of the people onboard are large, and then it is really a 2-3 person airplane.  If you have a late model Mirage conversion, the Useful Load can be very low due to the fancy/heavy interior.  FYI…one of the better “deals” in the JP world are the Malibu’s (not the Mirage) that have been converted (especially with a -34 engine!).  They usually have about 200 lbs of additional useful load, and are just as fast as any late model -35 equipped JP.
  • It’s all about the engine: Always get a pre-buy inspection, but be sure to have the engine on a JP you are considering borescoped and inspected.  An engine with problems can cost you BIG after purchase.
  • Trend Monitoring: A vast % of JP’s have an Engine Monitor installed.  To me, this is one of the coolest and most important instruments available.  It continuously monitors the engine functions and records EVERYTHING.  Every start, every shutdown, ITT, IAS, OT, OP, Ng speed, position, altitude, and a whole host of other parameters are monitored.  And…when limits are exceeded, the monitor will record an “exceedence” .  These “exceedences” are golden to a potential buyer since they will give you the clues as to whether or not the airplane was treated well or not.  An owner can option to pay (about $1,000/year) to have the data recorded by The Trend Monitoring Group.  They will store that data and advise the owner if “things begin to change within the engine” and this info will provide a windfall of information to a potential buyer.  An engine that has been monitored gives all sorts of confidence to a buyer.  And…IMHO…should be more highly valued in the marketplace.

Who should buy a Jetprop? If you’ve determined that you want a PA-46, then the only real question is your budget.  Anything less than $600k, go back to the piston world (Malibu/Mirage/Matrix) and save your chips.  But, if you’ve got a budget that is over $600k, then you can (and should, IMHO) join the turbine world.  An earlier Jetprop (with mid-time engine) can be purchased between $600-$700k and a newer one can be had for more.  The best Jetprop on the planet can be bought for $1.3m.

Arguably, here’s the best reason to buy a Jetprop: I don’t know of anyone who bought a JP and went back to a piston Malibu/Mirage because they didn’t like it.  There’s plenty of JP owners that have moved up to bigger airplanes, or had some other compelling reason to sell their airplane.  But, I don’t know of a single pilot that sold his Jetprop because he did not like it.

I’m going PA-46 Turbine…”: If you’ve made this statement and are ready to commit to action, the only question is whether or not to buy a Jetprop or a Meridian.  Be sure to check out my post “Thinking of Buying a Meridian” (should be out soon!).  There’s some good reasons to buy a Meridian over a Jetprop, but for this post I’m focusing on the Jetprop.  If you’ve decided to go turbine, here’s the reasons to buy a Jetprop over a Meridian:

  • Additional baggage: The JP leaves the front baggage compartment mostly available.  The Header Tank does take up some room in the front baggage, but most of the baggage is still available. The Meridian has no front baggage.
  • Better climb than a Meridian: The JP will out climb the Meridian by at least 500 fpm down low, and to a lesser degree up high.  It will beat the Meridian to FL270 from sea level by at least 4-5 minutes.
  • Lower fuel burn: In cruise, the JP will burn 32 gph and the Meridian (-42A powered) will burn 39 gph to do the same thing.  Some of the early Meridians (with no vortex generators, but a correspondingly lower MGW) will go a little faster, but not much.
  • Cheaper to buy for same equipment: Comparing apples to apples, the JP will be several hundred thousand less to buy.
  • Lower Engine Reserve: The -35 engine TBO is 3600 hours and the -34 TBO is 4000 with an overhaul cost average of $230k+.  The Meridian has a 3,600 hour TBO and will cost $270k+ to overhaul. Obviously, overhaul costs can vary greatly, but there is no doubt the JP, regardless of the engine installation, will have a lower engine reserve than any Meridian.  My personal favorite?  The -34 engine appears to be nearly bulletproof.  The additional 400 hours TBO is very realistic and it rarely has a problem at inspection. Don’t let a number fool you…the -34 is just as good as the -35 in terms of power, speed, and climb.
  • HSI not required: If the engine has been trend monitored, then the Hot Section Inspection (HSI) is “on condition”, meaning there’s no need to have a HSI unless there’s some compelling reason as indicated by Trend Monitoring.

About that -21 conversion: Let me say that I love the -21 conversion for the Jetprop.  It is fast, cheaper to operate, has a slightly higher range, and can be bought nearly $100k less than a -34/-35.  Plus, operating costs are lower since the -21 engine is so plentiful, easy to work on, and cheap to overhaul (just about every King Air C90 has two of them installed!). But…and this is a big “but”…it is much less desirable in the marketplace. Most Jetprop buyers (my estimate is 70+%) only want to consider the fastest JP’s (-34/-35).  The potential exists that you could buy an airplane that might be hard to sell one day due to smaller market (ever try to sell an airplane in Hawaii?).  There’ll always be a market for these airplanes, but the numbers are lower. For this reason, I would not buy a -21 unless you really knew Jetprop’s, knew you had a “deal” at purchase, did not mind the lesser performance, and/or thought you were going to keep the airplane a long time and didn’t mind riding out a market.  But, if you can stomach this caution, I personally think the -21 JP’s are the hidden secret of the JP world. If I were buying a personal “magic carpet”, I’d seriously consider a -21.

Ownership costs: I want to be careful to not write exact costs because the total cost of ownership is viewed so differently by so many people.  But, having this been said, a good contrast needs to be made.  So, let’s contrast the Jetprop to any piston PA-46.  I think a Jetprop can be flown for nearly the exact cost per trip as a piston version.  It burns more fuel, but it goes faster.  The big savings are in the maintenance arena.  I recommend a piston PA-46 receive an oil change every 35 hours or less…only because a mechanic needs to look under the cowl that often because something will be wrong or something is about to go wrong.  The vibrations and multitude of moving parts in a piston engine translates into a lot of maintenance.  On a Jetprop, the oil is changed every 800 hours.  And…there may be an entire year where the cowl is not removed.  There are simply fewer parts and fewer vibrations.  The PT6 just does not need much maintenance.  This translates into cheaper operating costs. Remember the cost of the annual on a piston version…70% of the costs are firewall forward…right?  Well, the annual costs on a PT6 is normally minimal.  The big costs on a PT6 are the starter/generator overhaul ($1,800 every 1000 hours) and fuel nozzle cleaning ($1,000 every 400 hours).  Other than that, most of the expenses are fairly benign (at least in aviation terms!).  Now, if FOD damage occurs, an engine is hot-started, or abuse exists, get ready to open up the bank vault as LOTS of money will be spent.  But…all of those conditions are under the control of a competent and well-trained pilot.

Describe the “normal” Jetprop owner? Usually, a certain kind of pilot with a certain mindset gravitates to a particular airframe.  Here’s my shortlist of descriptors for the typical Jetprop owner:

* An eye for efficiency: The acquisition costs to enter the Jetprop world are (arguably) high ($600k – $1.3m), but there is no airplane that is more efficient operationally.  It has the lowest operational costs of any airplane that has 6 seats, bar none.  

An eye for mechanical reliability: The PT6 is the most trusted name in aircraft propulsion and the PA-46 airframe is widely considered to be nearly bulletproof.

* A need for speed: To go faster than 260KTAS will cost you exponentially.  The “next move up” in the single-engine world is a TBM ($2m purchase, triple operational costs) or a PC-12 (2.5m purchase, quadruple the operational costs). All other airplanes to compare will be multi-engine airplanes, and the operational costs will be 4 times as much easily.  If you want to move up from the piston PA-46’s, the Jetprop is a logical “next step”.

* A mechanically-minded pilot: I’m not talking about an A&P Mechanic, I’m talking about a pilot that understands “how things work”.  The systems on a Meridian are simpler and are easier to manage.  The Jetprop is not “hard to manage”, especially for the pilot that understands “how machines work”.  But, it is an STC’d airplane, which means it has been converted and the systems have been adapted for a purpose, not intrinsically designed for the current purpose.  Pilots that are not “mechanically minded” tend to gravitate to the Meridian, and Jetprop owners tend to first “understand the nuts and bolts” of things prior to jumping into purchase.  I’m very mechanically minded, and think the Jetprop is well thought-out and logical.

In case you haven’t figured it out, I really do like the Jetprop!  Keep a lookout for future posts about the Jetprop.  And…if you have any questions, please give me a call.  I love to talk about these fabulous airplanes!

About Joe Casey

ATP, CFI, CFII, MEI, CFI-G Commercial Pilot - SE, ME, Rotorcraft, Glider US Army AH-64 Pilot and UH-60 Instructor Pilot and Instrument Flight Examiner
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