TBO Extension

Legacy Aircraft & The JT15D Engine

Read all about legacy aircraft like the Beechjet 400A its JT15d aircraft engines and a growing solution on how to extend their life at half of the cost of an overhaul.

“In the business jet world, JT15D engines are the most prolific. According to statistics from Jetnet, there are 4,102 in service, powering a total of 2,051 aircraft.” This compelling statement, quoted in “Legacy Aircraft Parts” by Aviation Weekly’s Business & Commercial Aviation, underscores a critical issue in aviation: the challenge of maintaining legacy jet engines amidst supply issues and material shortages, particularly when they are due for an overhaul. 

The dilemma deepens when considering the replacement of aging engines. Phil Stearns of Stevens Aero Space & Defense Systems articulates a key concern: “a couple of issues to consider are the unknown and possibly risky condition of mid-time engines and the immediate timing needed to buy them once they are found. These are hot commodities. With no zero-time JT15Ds available, the mid-time sets are usually sold immediately once on the market. A set may be available today and the next set may not become available for months—it’s very unpredictable.” This unpredictability poses a significant challenge for operators, who must decide whether to overhaul engines or potentially retire jets that may not justify the cost. 

Beechjet 400a For Sale - RK-120 - Aft Right

So, why do operators remain loyal to models like the Beechjet 400A? Their appeal is found in comfort, efficiency, and cost-effectiveness. 

Offering a private flying experience without the hefty costs of larger jets like Gulfstreams, legacy aircraft present an attractive choice for both private aviation newcomers and seasoned flyers seeking a practical yet convenient option. 

In response to the engine issue, Atlantic Jet Partners discovered its solution in TBO Extension, a critical yet overlooked aspect in the aforementioned article. 

For operators with JT15D engines nearing hot section inspections or overhauls, TBO Extension offers two viable options: 

  • Option 1: Run your engines to Hot Section or Overhaul (1800/3600 Hours Beechjet or 1750/3500 Hours Citation), then install the monitoring equipment and the STC. This grants a 500-hour extension before the hot section is due. 
  • Option 2: Near your upcoming overhaul, install the STC monitoring equipment and accomplish the HSIs. This extends your overhaul interval by an additional 2000 hours +300, without needing to overhaul the engines. 


The benefits of this Supplemental Type Certificate (STC) are threefold: 

  • Safety: Paramount in importance. Operators like Flight Options, NetJets, and Travel Management have successfully run these engines beyond the factory-recommended TBO intervals, up to 6,000 hours, without compromising performance or safety, thanks to routine HSIs. This method is FAA-certified and aligns with insurance policies. 
  • Value: TBO Extension stands out as the most cost-effective solution when comparing the costs of overhauls to replacing the jet. It can potentially double the value of your aircraft post-midlife, a benefit that extends to future owners. 
  • Convenience: The installation of TBO Extension is straightforward, requiring just 2-3 weeks. This minimizes downtime, particularly if timed with other inspections or repairs. 

Unfortunately, the original article overlooked this crucial information for operators of aircraft with JT15D engines. Our mission is to assist operators in maintaining these aircraft, recognizing their significant remaining value and efficiency – a winning combination in the business jet world. 

As operators ourselves, we have faced similar challenges and have successfully installed TBO Extension in over 10 of our aircraft. Our experience with legacy aircraft fuels our commitment to providing practical solutions for our peers who appreciate these timeless machines as much as we do. 


About TBO Extension: 

TBO Extension is a tailored solution designed to extend the operational life of legacy aircraft powered by JT15D engines, including Beechjet 400A, Hawker 400XP, Citation 550, Citation V, and Citation Ultra aircraft. It offers a unique blend of safety, value, and convenience, ensuring that aircraft can continue flying longer without the need for costly overhauls. Developed in the shadow of a study on the TPE 331 turboprop market in the early 2000s, TBO Extension is FAA, EASA, and Transport Canada Certified, upholding the highest standards of compliance. This innovative approach not only enhances the value of your aircraft but also supports sustainable aviation practices. For more information, visit www.TBOExtension.com. 

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