The Duncan Download Blog: Business Aviation Advice & Observations

Contributed by Steve Rothanzl, International Compliance Officer

It’s easy to assume that shipping aircraft parts is as simple as packing them up and sending them off to a service provider. The problem is, units that are sent without necessary documentation can experience long shipping delays and incur hundreds of dollars of extra shipping fees.

I’ve been working in and with Duncan Aviation’s shipping department for 13 years, and I’ve seen more than one case where a unit was received without any documentation whatsoever. No department had any record of who it was from, or what services were needed. Several days were lost while we researched which customer sent in the unit (the return address on the air waybill was from a freight forwarder) so we could contact them to understand what service was being requested on the unit. In overseas shipping cases, units missing the proper documentation, broker information or shipping account numbers were delayed for weeks at U.S. customs.

We work diligently to help customers experience as little downtime as possible when these mishaps occur by providing loaner and exchange units. However, following these five simple steps can help avoid these delays and fees altogether.

1.  Call Ahead

If a service provider knows a unit is being shipped, they can verify critical information like the part number, what services are needed, where it needs to be returned, and if the part is AOG or requires a faster turn time. Sometimes service providers have more than one shop location, and verifying the shipping address can prevent shipping and handling delays.

2.  Include Necessary Documentation

Always include your account number and provide any necessary PO or waybill numbers. It’s also not a bad idea to duplicate any verbal instructions you provided such as turn time requirements.

A Commercial Invoice which states the part number, quantity, description, value of the unit, and the services requested are essential, especially for international shipments. The Commercial Invoice must be in English per U.S. regulations concerning customs clearance. If the item is controlled under the International Traffic in Arms Regulations (ITAR), it must be shipped to the U.S. on a license or under an exemption, this must be stated properly on the Commercial Invoice in order to avoid possible delays and fines. If you are unsure about these regulations, contact your service provider.

3.  Ask About Preferred Shipping Partners

Some service providers partner with specific carriers to handle their shipments. These preferred shipping partners can help waive handling fees, offer substantial discounts, and ensure that packages reach their destinations on schedule. It’s always worth asking if your service provider has a preferred shipping partner and what advantages it offers.

4.  Include Carrier Account Numbers

Service providers often have account numbers with major shipping carriers. It’s always wise to include this information in your shipping documentation in order to take advantage of the above mentioned benefits as well as to ensure quick and accurate billing.

5.  Shipping Internationally? Ask For Broker Info

International shipments are processed by customs before they are delivered. Knowing who your service provider’s customs broker is, and documenting that information on both the Commercial Invoice and the air waybill can save you weeks of delay and frustration.

Duncan Aviation is a full service aircraft parts supplier. Our shipping information and preferred shipping partner is available online at www.DuncanAviation.aero/parts.

Contributed by Curt Campbell, Avionics Tech Rep with permission from Carter Hart of Airframe Service

Isolation diode shorts in the stab actuator can disengage the autopilot.

Last week I received a call from Carter Hart of Airframe Service, who was working with an autopilot problem. The autopilot would engage properly, but would immediately disengage as soon as the pitch servo tried to drive the elevator.

The autopilot computer had been sent to the factory but was returned with no fault found. Through several telephone conversations, Carter and I concentrated on the autopilot pitch trim operation and troubleshot the aircraft wiring, and measured voltages and verified logic conditions in the aircraft. This process led to the discovery of a shorted diode internal to the horizontal stabilizer actuator.

Checking with our accessory technicians, it was determined that we could repair the actuator the same day it was received. The stabilizer actuator was pulled by Carter on Thursday and arrived at Duncan Aviation on Friday. The unit was inspected, repaired and returned to service that same day then shipped back to Carter for delivery on Saturday. Carter reports the aircraft is now flying fine.

Duncan Aviation autopilot technicians have seen the isolation diodes in the stab actuator fail before, and we are trained to assist in diagnosing this problem without having to pull the stab from the aircraft. We can provide one-day repairs on all Learjet stab actuators if we are given prior notice of the unit coming in.

Contact Curt Campbell or an Accessory Technical Representative for troubleshooting assistance.

Written by Chris Gress, Component Solutions Manager

There is a grocery store where I live that isn't very big. In fact it is rather small. It isn't a "super mega" store that offers everything under the sun in all sizes, flavors and brands, but there is one thing it does offer that NONE of the major chains do- great Customer Service. They may not know my name, but I'm greeted with a smile, a welcome and the feeling that my presence in their store is important. If I have a question, they listen and offer many suggestions. I always leave with what I need. This little store isn't the cheapest. It isn't the closest. It isn't the biggest. But I'll drive further for a place that I trust, makes me feel important and acts like they want my business. Larger chains are perfectly capable of providing this same level of service. But more often than not, they choose not to.

In my opinion Duncan Aviation's Component Solutions Avionics/Instruments Customer Account Reps, Accessories Customer Account Reps and Tech Reps provide the greatest customer service to the aviation parts repair and overhaul customer. I am proud of the personal level of service each provide to our customers who call looking for assistance. They listen, ask questions and offer suggestions and troubleshooting advice. They share their expertise making sure that every customer is equipped with the right information to make the best decisions. They are some of the highest skilled aviation professionals in business aviation.

Of course, that is just my opinion. I want it to be your opinion too. If you are less than completely satisfied with your experience with any Duncan Aviation Components Solutions Avionics/Instruments Customer Account Reps, Accessories Customer Account Reps and Tech Reps, I want to know about it.

Thank you for your business.

Written by Larry Troyer, Avionics Tech Rep

The FZ-500 Flight Director computer that is installed in many business aircraft and King Airs provides the mode annunciator drive out to the mode selector annunciators. If some of the mode annunciators do not test or light up the problem may be the FZ-500 computer. However, it could also be the lamp in the mode selector switch.

Great care should always be taken when replacing the lamps in the mode selector. Due to the construction of the switch sockets, it is possible to short the bulb supply voltage to the control terminal that comes from the FZ-500. This can spike and take out a very expensive part in the FZ-500 computer.

Written by Dan Magnus, Avionics Tech Rep

Honeywell's GNS-XLS is a Flight Management System that provides control for an aircraft's navigation sensors, computer-based flight planning, fuel management and frequency management, among many other necessary capabilities. When this unit begins to malfunction, it is critical to get it back on line quickly.

I recently fielded a phone call from a DOM asking for troubleshooting advice when the screen on the GNS-XLS went white. Here are the steps I used to determine the cause and provide the solution.

The best way to determine if a unit is faulty is to install another and see if the squawk disappears. I sent out a loaner to arrive the next day. After the unit was installed, the screen remained white, telling me it wasn't the unit causing the squawk.

Next, I had him unhook the antenna. This immediately brought the screen back to its normal state. We replaced the antenna and the system is back on-line.

Squawk solved.  

If you need help troubleshooting or repairing your avionics, contact Avionics Tech Support.

Written by Larry Troyer, Avionics Tech Rep

I had a Challenger 600 customer call this morning with this squawk:

It was quickly determined something in the aircraft took out both computers, but what?

I recalled a similar situation with this computer where the aircraft had a short to ground on the FD VALID logic output pin that was taking it out and causing the same symptoms. After instructing the technician to check this wire in the aircraft, he found it was indeed shorted to ground. If left unfixed, this would again take out the flight director computer.

This is the second instance where I have seen this scenario occur.

This pertains to only aircraft with Honeywell SPZ-500 ( ) systems installed, which does cover a good share of corporate, twin turboprops and corporate jets of the 1980s and 1990s.