FAA-Approved Supplemental Type Certificate Service Life Extension Programs Provide Cost Savings, Continued Airworthiness, & Operational Readiness

Although the Learjet is a proven aviation industry workhorse, early models such as the Learjet 24, 25, 35 and 36 are approaching lifetime limits. An owner or operator concerned with tight operating margins, which are strongly dependent upon maintenance costs required to operate the Learjet, must consider cost-effective approaches. Therefore, the need to keep a Learjet flying beyond the design life limit within an extremely affordable manner is vital. Extending the life of an existing fleet, which still has acceptable operational capability, is quite challenging but when planned properly, can result in cost savings, continued airworthiness, and accelerated operational readiness.

Aerospace defense industry leader Michael Carroll, Director of Maintenance at Vertex Aerospace, says contractors must invest in the development of Service Life Extension Programs (SLEP) to make this possible for Learjet owners and operators. Vertex has developed two SLEP for the Learjet Models 24, 25, 35, 36, and their derivatives which are FAA approved under Supplemental Type Certificates (STCs). Vertex’s Flight International business area in Newport News, Virginia operates an FAA Certified Repair Station that includes avionics, accessories, and sheet metal shops. “These STCs, our FAA repair station, and FAA licensed technicians help extend aircraft lifespan and provide thousands of dollars in aircraft repair savings,” said Carroll.


FAA Approved STC ST00738WI Flight Control SLEP Saves $200,000 On Each Airframe

In addition to increased readiness, STC ST00738WI flight control SLEP offers great value to owners and operators. This STC eliminates mandatory flight control replacement at 20,000 hours. An extensive inspection of Learjet Models 24, 25, 35, and 36 flight controls and 20-series engine mounts is conducted using innovative Non-Destructive Inspection (NDI) techniques. “The lead time for just one aileron is typically six months, but this SLEP allows our team to perform the inspection on the entire set of flight controls in less than three months resulting in less downtime and more flight time,” said Carroll. Complete instructions, including recurring inspection criteria, are provided to each customer in the Maintenance Manual supplement to ensure continued airworthiness for the life of the program. Carroll added that “Vertex’s flight control SLEP extends the life of the flight controls on the Learjet by an additional 10,000 flight hours and is less than one-third the cost of replacement parts ultimately saving over $200,000 per airframe.”


FAA Approved STC ST00814WI Main Landing Gear SLEP Provides 5,000 More Cycles

Similar to the flight control SLEP, the STC ST00814WI main landing gear SLEP offers many benefits to owners and operators. This SLEP extends the life of the main landing gear from 12,000 landings to 17,000 landings providing an increase of 5,000 cycles. Ultimately, this eliminates the need to purchase new gear as well as associated assembly expenses, saving time and money. “Additionally, the landing gear SLEP can be done in the onsite accessory shop. Therefore, it does not require the aircraft to be onsite,” said Carroll.


Proven Solutions Accelerating Operational & Mission Readiness

Vertex’s Flight International business area is one of two companies holding the Learjet 35/36 SLEP STC. The company has successfully completed twenty SLEP modifications, allowing Learjet operators to extend the useful life of their fleet with significant affordability. “For air ambulance customers, this ensures they continue their mission of providing vital service to patients around the world for many years to come,” said Carroll. “For a large fleet Learjet operator like Vertex, SLEP allows us to continue supporting electronic warfare missions while maintaining low operating costs.” More information about Vertex Aerospace’s Flight International business area can be found at vtxaero.com/aerospace-defense-services/flight-international

Michael L. Carroll III Bio

Michael L. Carroll III, Vertex Aerospace Director of Maintenance, has over 20 years of aviation maintenance experience with nearly 19 of those at Vertex directly overseeing the maintenance and inspection of the Learjet 35/36 fleet. Carroll is responsible for the performance of maintenance, preventive maintenance, and alterations of aircraft in accordance with applicable regulations and customer requirements at Vertex’s Flight International business area in Newport News. He has a Bachelor of Science in Aviation Maintenance Management graduating with honors recognition and holds FAA Airframe and Powerplant certificates as well as an FAA Inspection Authorization Certificate. In addition to his Director of Maintenance duties, Carroll also serves as the FAA Accountable Manager for the Repair Station, overseeing the facility to ensure Vertex follows regulatory requirements while providing customers innovative and affordable solutions for critical mission readiness.