The Duncan Download Blog: Business Aviation Advice & Observations

Who's Looking at Your Legs!

Posted by Diane Heiserman on Thu, Jul 27, 2017 @ 11:45 AM

Aircraft landing gear overhaul is often viewed as a behind-the-scenes inspection and scheduled alongside, but taking a backseat to, a major airframe inspection. However, it can have a huge impact on the entire project's schedule if the landing gear restoration runs into major squawks. Because an aircraft can't go anywhere without its legs.

XOJET is a leader in private jet travel that is personal, flexible, and on-demand. Headquartered in Brisbane, California, the company operates a fleet that includes Bombardier Challenger 300 and Cessna Citation X aircraft. Although XOJET has only been in business since 2006, this modern alternative to fractional ownership is definitely in demand.

According to Carlos Partida, Senior Maintenance Planner at XOJET, the company’s fleet flies 40% more flight hours per aircraft per year than their closest Part 135 competitor. "Our fleet is smaller by comparison to our competitors," says Carlos. "Making sure the aircraft are available as much as possible is one of my top priorities." Needless to say, that makes downtime very important. And if you ask Carlos, no one manages downtime better than Duncan Aviation.

Work Completed Quickly

Since 2014, Carlos has been sending all of XOJET’s Citation X oleo sets to Duncan Aviation for inspection. They are nearly always returned to service and headed back to XOJET within a week. Prior to using Duncan Aviation, Carlos was used to waiting months. "It takes Duncan Aviation a week, including shipping, to do something that previously took two months for completion."

Of course, Citation X oleos are not the only gear Duncan Aviation services for XOJET. Our Accessory shop regularly has a complete set of the fleet’s Challenger 300 gear in the shop for 96-month inspections.

Switching to Duncan Aviation was not only a time saver, Carlos says. It has had a positive impact on XOJET’s bottom line. "When our aircraft are not flying, they are not producing revenue." 

Work Completed Well

Carlos also expresses his appreciation for the level of customer service he has received from everyone at Duncan Aviation. "They always deliver the highest in quality work at the best possible downtime savings, served up with a level of customer service that is first rate. Everyone on the Duncan Aviation team is so willing to accommodate all of my requirements. I can’t speak highly enough about the customer service," he says.


Chris Fields

Chris Fields is a Duncan Aviation Master Technician working on the landing gear team since 2008. He knows a thing or two about landing gear and he knows a lot about the Challenger 300 and Citation X gear that come off of XOJET aircraft.

When XOJET sends their gear sets to Duncan Aviation, Chris often takes the lead, especially when it comes to the Citation X main gear oleo doc inspections.

"XOJET takes great care of their gear. They schedule inspections on time and everything is well-documented," says Chris. "We see several sets of oleos every year and typically will have them completed and returned within four days."

This story was recently published in the Spring 2017 Duncan Debrief magazine. Follow the link below to find more stories like this or subscribe to receive your own copy. 

READ NOW Spring 2017 Duncan Debrief Magazine

Tags: Cessna, Parts & Accessories, Landing Gear, Challenger

Aircraft Landing Gear Repair & Overhaul Is Not a Commodity Service

Posted by Diane Heiserman on Wed, Dec 07, 2016 @ 08:00 AM

An aircraft can't go anywhere without its legs. Landing gear are an integral part of the whole operation, yet their overhaul and inspections are more often viewed as something that is taken care of behind-the-scenes; scheduled alongside, but taking a backseat to, a major airframe inspection. Yet, it can have a huge impact on the entire project's schedule if the restoration runs into major squawks.

So who’s taking care of your aircraft’s legs?

landing-gear_blog.jpgAlthough landing gear overhaul and repair services are not available from everyone from coast-to-coast, it has a bit of a reputation of being a commodity in the business aviation industry. There are almost too many choices on where to send your gear when it comes time for inspection.

It is fair to think with FAA regulations, Chapter 5 requirements, and access to the same maintenance manuals, that all facilities are equal. You would be wrong.

In reality, landing gear overhauls are not created equal, and there are often many differences among the maintenance facilities and the quality of work performed, and out-the-door price.

So how do you decide? Let’s begin with what’s most important to you.

Video: View the entire process of a 192-month inspection of a Challenger 604 landing gear here.


Landing-gear-shop-full.jpgAsk nearly every aviation service sales person what the top deciding factor is for their customers when choosing an MRO for service and they will tell you Downtime.

No one looks forward to having their aircraft down for inspection. Time is money and your aircraft needs to be available at all times. That is why your time requirement is one of our requirements.

At Duncan Aviation, we continually examine our processes to find more efficient avenues to deliver landing gear faster. However, we will never sacrifice quality or safety for the sake of time.

In 2015, our landing gear shop met quoted turn times a near perfect 98% of the time on scheduled, complete landing gear sets. In 2016, we are on track to improve that number even further thanks to a more efficient process and interactive calendar.


When it comes to overhauling, inspecting, and repairing landing gear assemblies and subassemblies, we’ve been doing it since 1978. The shop started out modestly as a bench at the back of our main hangar but has since grown to a 6,000-square-foot facility equipped with an overhead crane, dedicated paint booth, and cure room.

Are we the largest landing gear shop in the industry? Possibly not, but to the nearly 500 operators who rely upon us each year, we are big enough.

With capabilities on more than 50 different make/model aircraft and 3,143 unique landing gear parts, we’re confident we’re big enough for you, too.

Video: Embraer Landing Gear Before and After


By the very definition, a warranty is a promise of continued support and service even after the project is over. We believe so highly in our own work, that our warranties cover everything. Parts, labor, and not just our work, but the work of others...covered.

I know what you’re thinking! How can Duncan Aviation possibly offer a warranty on work they didn’t perform?

It’s simple. Through our experience, we’ve been able to identify high-failure parts and will take the extra time during overhaul to make sure those parts are able to last.

We think we’ve done a pretty good job at it because our warranty claim rate in 2015 was less than 1%, 0.6% to be exact.


Although price is likely not the most important factor in your buying decision, it still is an important one. That is why we offer three different pricing structures to fit your budget requirements.

Firm Fixed. Before your gear gets to Duncan Aviation, you will know what you are paying. Firm Fixed guarantees one price with no bill-back, regardless of the condition of the gear. We have heard from several operators who chose a lower-cost provider that with additional billing based on the gear’s condition, their final invoice was higher than our Firm Fixed quote.

NTE (Not To Exceed). With NTE, we will provide you with the maximum quote. Your final bill will not exceed that quote. It could even be less. There will be no additional billing that will drive the invoice over the NTE maximum price.

There could be some exceptions to the above pricing structures of which you will need to be aware. These include additional customer requests, optional Service Bulletins, missing or abused parts, and replacement of life-limited parts and engineering fees, if required.

Standard Pricing. Standard Pricing includes all labor required to perform the normal inspection or overhaul, and required parts. Any discrepancies found during the inspection that may require additional parts and labor, will be quoted over and above.

Each pricing structure has its advantages. We will work with you to identify which makes sense for you.

We realize that you have a lot of choices when it comes to servicing your landing gear. We know you want more than the minimum required.

  • You expect your downtime requirements to be respected
  • You require quality and experience
  • You demand a guarantee of a job well done
  • You want flexible pricing options to meet your budget,

Seems like an easy decision really. Duncan Aviation.

Tags: Parts & Accessories, Landing Gear

Embraer Landing Gear Overhauls Land at Duncan Aviation

Posted by Diane Heiserman on Wed, Sep 30, 2015 @ 11:22 AM

Duncan Aviation has acquired the capabilities to completely overhaul and repair landing gear for both commercial and business Embraer aircraft at our Lincoln, Nebraska, facility. With the necessary technical data, maintenance manuals and aircraft landing gear parts, Duncan Aviation's Accessories Services has received and successfully overhauled its first set of ERJ-145 landing gear.


"We have been completing landing gear inspections and overhauls on the most popular business aviation make/model landing gear for 30 years," said Tony Curtis, accessories team leader. "There were no surprises with the Embraer landing gear."

He explained that landing gear all perform the same basic function and have similar features and load capacities appropriate for the aircraft. The only difference was learning the uniqueness of the Embraer gear.

In 2013, the aircraft accessories shop in Lincoln, Nebraska, went through major renovations that more than doubled the shop area, gaining approximately 6,300 square feet of service area, doubling its work benches and adding new tooling and in-house capabilities, including an overhead crane and a new paint booth with curing room.


Tony's team is trained, experienced and equipped with the proper tooling and access to Embraer parts and repair processes. 

Duncan Aviation Embraer Landing Gear Capabilities include the following:

  • Embraer 135 (Legacy 600/650) business aircraft
  • Embraer 145 series commercial airline

For more information, contact Duncan Aviation accessories service sales for quotes and scheduling information.

Take a moment and watch this before and after ERJ-145 overhaul video

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Tags: Parts & Accessories, Landing Gear

Challenger! Learjet! King Air! Oh My! Gear Sets Are Landing at Duncan Aviation

Posted by Diane Heiserman on Thu, Feb 05, 2015 @ 12:16 PM

Landing-gear-shop-fullA near-record number of landing gear sets and components are in-house at Duncan Aviation’s accessories shop in Lincoln, NE.

According to Tony Curtis, landing gear team leader, seven full sets of landing gear and a “whole slew” of individual components, such as struts and oleos, have filled the shop and kept the schedule very busy. All shifts are working tirelessly overhauling or inspecting gear sets and components from Challenger 300, Challenger 604, Challenger 601, Learjet and King Air aircraft.

Although three sets have been completed and already shipped back to operators, Jon Hein, accessories service sales rep, says the workload doesn’t appear to be letting up anytime soon. “Over the next several weeks, many more sets and component parts are scheduled to arrive.”

Because an aircraft can’t go anywhere without its legs, Duncan Aviation has invested heavily in the landing gear customer more than doubling its Accessories shop area, gaining approximately 6,300 square feet of service area, doubling its work benches and adding new tooling and in-house capabilities, including an overhead crane and a new paint booth with curing room.

In 2014, they acquired the capabilities to completely overhaul and repair landing gear for both commercial and business Embraer aircraft. With the necessary technical data, maintenance manuals and aircraft landing gear parts, Duncan Aviation’s Accessories Services has received and successfully overhauled two sets of Embraer gear to comply with the 144-month landing gear restoration.

Take a moment and watch this before and after ERJ-145 overhaul video.



Tags: Parts & Accessories, Learjet, Landing Gear, Challenger

Multi-Shop, Multi-Site Embraer 144-Month Success Story

Posted by Diane Heiserman on Tue, Jan 06, 2015 @ 08:00 AM


Submitted By Jeff Schipper, Project Manager PVU

Duncan Aviation’s Provo, Utah, facility both gave and received an early Christmas present this year in the guise of an Embraer Legacy 144-month (L24) inspection. During this inspection, we restored the landing gear and installed an Aircell ATG5000 cabin Wi-Fi system, among many other smaller items.

Space constraints presented the Provo crew with unique challenges, but with the requested outdate in mind, our teams worked together and creatively resolved those challenges. We aggressively dealt with the turntimes on the landing gear in order to meet our customer's limited downtime. The landing gear team at our Lincoln, Nebraska, facility finished the overhaul and shipped the landing gear back to Provo within a day of the requested return date.

Another challenge resulted from a missing aircraft Electrical Load Analysis (ELA) document. The ELA is comparable to the aircraft Weight and Balance Manual—only it’s for the aircraft electrical system. Our avionics install team worked with our Embraer contacts and procured a manual for this serial number in time for our team to perform the final calculations and produce the appropriate paperwork on our end for delivery.

To limit yet maximize downtime for this popular charter aircraft, our interior team worked with the customer on which repairs we could accomplish after the interior was removed for the inspection. The team ended up finishing several high-profile pieces of woodwork and had everything looking like new by the time installation day rolled around.

As often happens, a couple of gremlins dogged the final day—a landing light burned out and a flow pack gave up just before delivery. Troubleshooting and procuring parts ended up pushing delivery back a day, but the aircraft arrived at its home on Tuesday, December 23.

Once home in Scottsdale, the delivery gremlins reappeared; this time, an APU issue sent our Scottsdale Rapid Response team into action and they resolved the issue by early the following morning. 

One of the things that really shined through to our customer with this project was the way Duncan Aviation as a team banded together to support them no matter what facility they were in. This aircraft was worked on in our Provo facility, the landing gear was completed at our Lincoln location and when the aircraft needed after-delivery support in Scottsdale, our Rapid Response team there was quick to respond. This inspection was a true multi-shop, multi-site success story.

Since becoming a Legacy Authorized Service Center, we’ve completed several types of inspections, including L1, L2, L4, and this most recent L24.

Jeff Schipper is a Project Manager at Duncan Aviation's Provo, Utah, facility serving as the central point of contact for his customers' projects ensuring overall project quality and timely aircraft delivery. His aviation career began in 1987.


The Embraer Legacy takes off from Duncan Aviation's picturesque view in Provo, Utah. 

Tags: Avionics Installation, Airframe Maintenance, Duncan Aviation-Provo, Landing Gear

Duncan Aviation in 2013: A Year of Accessory Service Expansion

Posted by Diane Heiserman on Thu, May 22, 2014 @ 01:27 PM

For Duncan Aviation’s Accessories area, 2013 was a year of growth. The service shop doubled in size and cutting edge technology bolstered available in-house capabilities. This growth and accompanying shop enhancements were all completed with the customer in mind. Marty Lincoln, manager of Duncan Aviation’s accessories area, is serious about doing all he can to support every accessories customer. “By investing today, we are prepared tomorrow to meet all of their needs in our house,” he says.

Here’s a brief glimpse into the 2013 expansion of Duncan Aviation’s Accessories Services featured in the Spring 2014 Duncan Debrief.

Duncan Aviation accessories expansion

The expanded accessory shop service area added approximately 6,300 square feet, doubled bench space and added new tooling and expanded in-house capabilities, including an overhead crane and a new paint booth with curing room.


A new 300 square foot paint booth and a 400 square foot curing room increase work capacity and improve efficiency.


The new Fryer Machine Systems CNC mill has a near 3,000 pound load capacity, a table size of 17x63 inches and a position accuracy of +/-0.0002 of an inch.



The in-house hydraulic Skydrol test bench provides additional capacity and capabilities for large-body aircraft.

Click on the link below to continue reading other feature articles in the Spring 2014 Duncan Debrief magazine. 

 Spring 2014 Duncan Debrief Download & Read Now

Tags: Parts & Accessories, Landing Gear

Duncan Aviation Landing Gear Services by the numbers: infographic

Posted by Diane Heiserman on Tue, Nov 19, 2013 @ 01:50 PM

Today we are taking a break from the typical Duncan Download blog post to do something a little different. Rather than tell you all the facts about how the Duncan Aviation Accessories area has expanded its landing gear services or explain why all landing gear service facilities are not created equal, we are going to let the numbers speak for themselves.

Here's a detailed pictograph of the Duncan Aviation's landing gear services over the last 35 years.

 landing gear infographic

Tags: Parts & Accessories, Landing Gear

King Air 90 / 200 Landing Gear Actuators

Posted by Diane Heiserman on Tue, Sep 24, 2013 @ 02:25 PM

Contributed by Jerry Cable, Accessories Tech Rep

When the landing gear actuators on the King Air 90 and 200 model aircraft arrive at Duncan Aviation for their six year or 8,000 cycle overhaul, the first thing performed is the actuator screw and nut end play inspection on each actuator assembly (two main/one nose). The end-play inspection measures the play between the threads of the screw assembly and nut assembly. A large majority of the time the nut assembly will require replacement due to extended wear.

The actuator screw and nut end play inspection should be performed every 1000 cycles or 30 months, whichever comes first. The allowable tolerance between the actuator screw and nut assembly is .016 of an inch, but the actuator can remain in service up to .018 of an inch but must be re-inspected every 200 cycles. If the inspection finds the tolerance beyond .018 of an inch, the landing gear actuators must be sent in for overhaul. Keep in mind that even if the Actuator passes the end play check at 1000 cycles or 30 months, it may not pass the more stringent end play check required by the overhaul manual. The maximum allowable end play at time of overhaul is only .009" before it must be replaced.

This nut assembly wear is caused because the nut assembly is made of a bronze material that rubs against the steel screw assembly. Symptoms of extended tolerance could be a loud noise when the LG is extended and retracted. If any foreign material were to get in between the threads, this assembly will bind up and the LG will no longer be able to extend or retract.

If you should have any questions about this, don’t hesitate to contact me. To schedule your King Air 90/200 landing gear overhaul, contact your Duncan Aviation accessories customer account rep.

Jerry Cable is an Accessories Tech Rep located at Duncan Aviation’s Lincoln, Nebr., facility. He is a landing gear and accessory components and systems specialist. His aviation career began in 1991.

Tags: Parts & Accessories, Landing Gear

Is there really a difference in landing gear service facilities?

Posted by Duncan Download Blog on Tue, Jun 18, 2013 @ 02:22 PM

Contributed by Jerry Cable, Accessory Tech Rep.

LandingGear Global blog

Duncan Aviation has landing capabilities that will cut your expenses and downtime not found at other aircraft landing gear shops.

Most definitely. Yes.

Landing gear overhauls, inspections and restorations are sometimes called a commodity service. Any shop that has received an OEM Maintenance Manual and follows FAA standards is free to advertise that it can inspect and overhaul aircraft landing gear. The FAA states "a thorough inspection of the landing gear involves the entire structure of the gear, including attachments, struts, wheels, brakes, actuating mechanisms for retractable gears, gear hydraulic system and valves, gear doors, and all associated parts. The manufacturer’s inspection procedures should be followed where applicable."

But not all landing gear service is equal. There are many additional service and capability requirements related to landing gear maintenance that can cut expenses and downtime that can’t be found at every aircraft landing gear shop.

The landing gear is a behind-the-scenes inspection, most often scheduled alongside, but taking a backseat to, a major airframe inspection. However, it can have a huge impact on the entire project’s schedule if the landing gear restoration runs into major squawks. You will want to use a shop that has invested heavily in the landing gear customer and understands full well the impact a landing gear overhaul or inspection has on an airframe inspection. After all, an aircraft can’t go anywhere without its legs.

Controlling Costs

At Duncan Aviation, we take several extra steps that help reduce costs. For example, on select inspections and restorations, we ask customers to leave the harness and brake pipes on the gear when removing it from the aircraft. By leaving the gear intact, this will save customers approximately 35 labor hours when removing and installing the gear. Duncan Aviation has also established some special pricing programs that help provide assurance to customers through pricing controls. These are just a sampling of the above-and-beyond landing gear available at Duncan Aviation.

Feel free to reach out and contact Duncan Aviation's landing gear experts. We will address the most common questions and concerns that customers ask us daily regarding landing gear work.

  1. How much will it cost?
  2. How long with the inspection take?
  3. What about corrosion removal?

Jerry Cable is an Accessories Tech Rep located at Duncan Aviation’s Lincoln, Nebr., facility. He is a landing gear and accessory components and systems specialist. His aviation career began in 1991.

Tags: Parts & Accessories, Landing Gear

WOW: An Overlooked Cause of Many Nose Wheel Steering Faults

Posted by Diane Heiserman on Tue, Mar 05, 2013 @ 02:24 PM

Contributed by Jerry Cable, Accessory Tech Rep.

Weight On Wheels

Don't overlook the Weight On Wheel or WOW system when troubleshooting systems faults.

When experiencing an intermittent nose wheel steering fault, the first thought is generally, “what is wrong with the steering servo, computer, valve, actuator or strut?” But don’t overlook a very important part of the system—Weight on Wheels (WOW). This system is very easy to test and replace. It has been my experience that WOW is the cause for more than half of these types of faults.

The WOW System

Most aircraft utilize some type of WOW Sensor or Switch that activates when the aircraft is on the ground. They come in many different sizes shapes and technologies and can be in various positions in the aircraft and landing gear. The one thing they all have in common is they complete the circuitry required to do many other things on the aircraft. From thrust reversers to nose wheel steering and many in between, the aircraft relies on these switches to operate correctly. A faulty or incorrectly adjusted switch/sensor may cause vital systems to not function or function intermittently.

The Wow System

There two basic types: mechanical switches and proximity sensors. Mechanical switches are easier to test; however, they fail more often because they rely on mechanical contacts to create the circuit. Proximity sensors do not utilize a direct mechanical contact but instead use circuitry to decipher when the magnetic field is interrupted. The proximity sensors are more reliable, but more difficult to troubleshoot. Most mechanical switches are either open or closed. Yet due to the circuitry of a proximity sensor it can be partially open and partially closed at the same time. So a proximity sensor that is known to be good but set to an incorrect clearance can cause very erratic behavior of other systems.

Systems that are run through the WOW system are exclusively used either in the air or on the ground, not both. Systems that utilize the WOW system include but not limited to, thrust reversers, nose wheel steering, trim and autopilot.

Jerry Cable is an Accessories Tech Rep located at Duncan Aviation’s Lincoln, Nebr., facility. He is a landing gear and accessory components and systems specialist. His aviation career began in 1991.

Tags: Parts & Accessories, Troubleshooting, Landing Gear


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