The Most Modified Business Aircraft in History

The Most Modified Business Aircraft in History

We routinely ask King Air operators what options they would add to their aircraft and why, and the following is what we’ve learned.

When buying your King Air, you probably figured out pretty quickly that it is one of the most modified and optioned airplanes in history. No other business type aircraft has more available options. From engines to avionics to airframe, the list seems endless. Add to that the fact that each of these options increases the value, or even worse in some cases decreases the value and confusion reigns.

My goal in this article isn’t to explain what the different options and modifications do for your airplane, but instead what they do for YOU and for your aircraft’s VALUE. I find that when you buy a King Air with or add the modifications to your aircraft, and those options both have a functional aspect to your mission AND increase the value of the aircraft, you have achieved a win-win.

RAISBECK Engineering

I sometimes wonder how different the vulnerable King Air would be without the efforts of men like James Raisbeck, the founder of Raisbeck Engineering. The fact that most of his modifications have been incorporated into the current production aircraft are a testimony to just how important they are.

In the King Air world Raisbeck options are highly desirable and always increase the aircraft’s value. Here’s a brief overview of their most popular King Air modifications.

Aft Body Strakes

Aft Body Strakes are designed to improve flight characteristics and they do, but they also look really cool! They are worth the investment, and a must-have on any King Air.

Market Value Add: $20k – $25k

Installation New – Less than $30k; call Raisbeck Dealer for a quote (requires paint).

Tip – Don’t get new exterior paint without adding Strakes.

Raisbeck’s Aft Body Strakes reduce drag and increase climb and cruise performance among other things. They also provide a high percentage of your cost back to the resale value of your King Air.

Wing Lockers

Raisbeck Wing Lockers aren’t cheap and are on the lower end of value retention for Raisbeck’s products, but they score on the charts of functionality. On the King Air 90 they are critical because you need the storage; in the King Air 300 / 350 they are great because you typically have plenty of useful load.

Market Value Add: $40k – $60k

Installation New – Less than $90k; call a Raisbeck Dealer for a quote (requires paint).

Tip – If you are shopping for a King Air and know you want lockers, try to find one with them already installed.

Ram Air Recovery / Leading Edge

These are two options that make the list because they are very important when combined with other mods, but don’t stand alone as well. Both increase the performance of the aircraft but add little in the way of functionality regarding daily use.

Market Value Add: depends.

Raisbeck and Hartzell worked together to develop the first Swept-Wing Turbine Propeller for business aviation. The swept-wing technology increases thrust while reducing noise and vibration, as well as inherently improving all phases of flight.

Swept Blade or Composite Props 

Huge increase in performance, decrease in noise and they look awesome.

Market Value Add: depends on time remaining, but a very high per­centage of installation cost.

Installation New – Depends on prop and model of aircraft; call a Raisbeck Dealer for a quote.

Tip – Don’t overhaul your props, replace them with new props and then sell the old props to offset some of the cost.

CenTex Aerospace

CenTex is making big changes to King Airs! If you find that the King Air you have or are considering can’t do the mission required, CenTex Aerospace can fix that.

The CenTex mods add critical usability to the King Air line and while the value retention depends of who is buying the aircraft, if you NEED the CenTex mods they are priceless.

The CenTex King Air 200 HST Package combines the Halo 275 and ST120 Saddle Tank conversions at a package price, but both items can be purchased separately in the size/capability to meet your needs.

Saddle Tanks

If range is what you are looking for, the saddle tanks are what you need. The ST72 / ST120 option will give you 72/120 gallons of extra fuel respectfully – that’s an hour of additional flight time! Plus, you still have plenty of storage in the wing locker behind the tank.

If you need max fuel, get the ST190 and max out the lockers with 95 gallons per side.

HALO mods

If useful load is what you need, the HALO mods are a great choice.

The HALO 250 mod raises the MTOW of the King Air 200 / 250 to 13,420 pounds, while landing weight remains 12,500 pounds.

The HALO 275 increases the MTOW to 14,000 pounds (High Flotation Gear required).

The HALO 350 mod brings the MTOW of the King Air 350 to 15,950 pounds.

Tip – Some HALO mods require a special type rating.


When it comes to upgraded avionics in King Airs, the gold standard is the Garmin G1000 panel that increases useful load, modernizes the avionics and autopilot, increases weather capabilities, lowers operating cost and flight discrepancies and increases the value of the aircraft far beyond the 50 percent normally seen with avionics installations.

A King Air 300/350 with a G1000NXi installed has an added resale value over 80 percent of the cost of doing the install.

The resale value depends on the model, but with a King Air 300 / 350 that has the G100NXi installed, we are seeing an increase in resale values that is north of 80 percent of the cost of doing the install! This is primarily because there are very few glass upgrades available for the 300 / 350, so most aircraft are either stock or have been upgraded to the G1000.

The G600 and G600TXi certainly deserve mention here, but remember they are only options in the 90 and 200 series King Airs. The resale value of the G600 / G600TXi as well as the G1000 in 90s and 200s are more difficult to determine, mainly because there are so many options and configurations.

Tip – Consider downtime as well as total cost – the premier G1000NXi installers like Elliott and Stevens can install a G1000 in less than four weeks. A G600 / 750 panel can easily take two to three times as long and retains the original autopilot.

The Garmin GTN 750 / 650 is standard equipment in every King Air. If you haven’t been told that yet, wait until you sell your airplane and you will. We spoke with the top King Air resellers and they all said the same thing, for a King Air to sell, it has to have at least a 750 / 650 in it and needs to be ADS-B Out compliant.

Blackhawk Modifications

Jim Allmon is another guy who has made a dramatic impact on the Beechcraft King Air and like James Raisbeck’s modifications, Jim’s engine upgrades have been incorporated into current production aircraft.

The investment for Blackhawk engines is significant, but when considered in lieu of engine overhauls that routinely exceed $1 million, the sticker shock fades pretty quickly. Plus, the new five blade props are included as well.

Tip – Aircraft with Pro Line 21 avionics require the Collins Modernization upgrade.

The King Air 350 with Blackhawk -67A engines makes it the fastest King Air in the world. When the STC for placing the -67s on a King Air 300 is approved, it will take the reign of being the fastest.
(Photo credit: Matthew McDaniel)

-135A Conversion

The vulnerable King Air C90 is a great airplane, but it is slow. In today’s world 220-230 knots just doesn’t get you much respect in the turbine world. However, that same airplane with -135A engines is a screamer! We’re no longer talking about value retention, we are talking about a whole different airplane with a different price point completely.

-52 / -61 Conversion 

The King Air 200 / B200 is the most prevalent turboprop ever built! The 200 was designed in the early ‘70s and BB-2 rolled off the line as a 1974 model. Since then, Beechcraft has built over 2,800 King Air 200 series aircraft. That doesn’t include the 300 and 350 that grew out of the 200 series.

In 1981 Beechcraft replaced the -41 engines with -42 engines, a noticeable but not exactly a game-changing improvement. When Blackhawk was granted its STC to install -52 engines on the 200 series airframes it was a game changer! The 300-knot King Air was born.

-67A Conversion 

The King Air 300 with Blackhawk -67A engines is the fastest King Air ever built; in fact it is one of the fastest non-military turboprops available! As of this writing, the -67 powered King Air 300 is still in flight test but it looks like normal cruise speeds will be around 345 knots.

The -67 powered King Air 350 is without a doubt the ultimate King Air 350! I had the opportunity to take a ride in one we modified for a client and I can tell you that I could fill this page with words and you still wouldn’t understand. You simply have to fly/ride in it.

BLR Winglets

Besides looking cool – they are the single biggest cosmetic improvement you can make to a King Air – the BLR winglets aid in climb and increase flight height capabilities.

The cool factor with BLR Winglets is off the charts. Sure, they help with climb and increase flight heights with higher altitudes that are very important, especially for operations at RVSM altitudes, but who cares?

Winglets are the single biggest cosmetic improvement you can make to a King Air. I’d rather have a King Air with BLR Winglets and old paint, than one with new paint and no winglets.

It’s hard to say what the value retention is, but one thing is for sure is that they absolutely modernize the aircraft and will help it sell before a similar aircraft without them. If I were to guess, I’d say that you’ll get at least 50 percent of your money back; add that to the resale and cool factor and winglets are a hot item to have.


King Airs have been built for over 50 years and during that time, over 8,000 have been sold. Most of those aircraft had numerous options available from the factory and add the hundreds of aftermarket options and upgrades available, some mentioned here, but there are also many other upgrades out there, as well as other modifications offered over the years.

I didn’t even mention AvFab and their fabulous interior upgrades. There are also window shades and tinted windows. Do you have any idea how many different autopilots have been installed in King Airs over the years?

Why are King Airs so darn complicated? Because, my friend, they are the most viable and prevalent turboprop aircraft ever built and have changed business aviation. Heck, it may have even created it!

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