The Duncan Download Blog: Business Aviation Advice & Observations

Airframe Corrosion Does Not Discriminate

Posted by Duncan Download Blog on Tue, Apr 18, 2017 @ 10:39 AM

Corrosion doesn’t care what make/model aircraft you have or how many flight hours it sees. All it cares about is getting its start and hoping you are not paying attention.

Types of Corrosion

Over the past 60 years, Duncan Aviation has seen and repaired corrosion damage on nearly every make/model business aircraft that has ever flown. Here are some common types of corrosion.

Filiform Corrosion: Occurs under painted surfaces when the protective coating has been compromised. The corrosion extends out from the original corrosion pit causing degradation of the protective coating.

Filiform Corrosion_a.jpgFiliform Corrosion_b.jpg

Galvanic Corrosion: An electrochemical action of two dissimilar metals in the presence of an electrolyte and an electron conductive path, causing corrosion. It can occur when dissimilar metals are in contact.

 Galvanic Corrosion_b.jpgGalvanic Corrosion_a.jpg

Surface Corrosion: Chemical or electrochemical attack on surface of metal. It is a general roughening, etching, or pitting of the surface of a metal.

Surface Corrosion_a.jpgSurface Corrosion_b.png

These photos are evidence of severe neglect. At Duncan Aviation, we have seen issues like this on business aircraft left outside quite often and subjected to the salt air (ocean air) without regular preventive maintenance and inspections for corrosion. 

Paint only needs to crack once to allow oxygen and moisture to get underneath and deteriorate the surface protection. Typically, this occurs anywhere there is a seam on the fuselage, wing, empennage or flight control surface. Corrosion remains hidden by the painted surface, or has been touched up with paint over the surface, trapping the growing corrosion underneath.

These examples of airframe corrosion could occur anywhere on the aircraft that the metal is not protected.  If the anodizing, alodine, or other surface protection is missing in that area, then surface corrosion, galvanic, (dissimilar metal) corrosion, or other forms of corrosion can occur.

It is very important to maintain the surface protection, and to perform regular inspections of all areas to detect corrosion before it grows.

This article is from the April issue of the Duncan Intelligence, a free, technical newsletter for business aircraft owners and operators. Written in-house by Duncan Aviation's aviation experts. It is a free, monthly e-mail subscription for aviation enthusiasts around the world.

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Tags: airframe corrosion

How to Avoid Challenger 600 Epoxy Ramp Removal Damage

Posted by Diane Heiserman on Fri, Aug 03, 2012 @ 03:02 PM

Submitted by Scott Shefke, Airframe Tech Rep

Challenger 600 Door Epoxy Ramp Removal

Duncan Aviation Maintenance Tech using the Aero 40 Series dry ice blasting machine.

Bombardier has released Service Bulletin (SB) for all Challenger 600 model aircraft. SB ATA 55-11 titled "SPECIAL CHECK/MODIFICATION – PASSENGER DOOR –EPOXY RAMP REMOVAL AND CORROSION PREVENTION."

According to the SB ATA 55-11:

There have been several reports of corrosion in the lower structural elements of the passenger door. It was determined that the epoxy ramp installed to prevent water accumulation could deteriorate with time and retain moisture. The purpose of this Service Bulletin is to remove the epoxy ramp to prevent further corrosion, add additional draining holes and modify the door structure to allow access to facilitate scheduled inspections.

Avoiding Collateral Damage

To help support our customers in performing this SB, all three of Duncan Aviation’s maintenance facilities (Lincoln, Nebr.; Battle Creek, Mich. and Provo, Utah) have obtained a cold jet Aero 40 Series dry ice blasting machine. This dry ice blasting machine is integral in removing the epoxy ramp in an efficient manner while ensuring no collateral damage to existing door structure occurs.

Technicians at all locations have been properly trained by Cold Jet, the blasting machine’s OEM. Duncan Aviation has successfully completed this SB in-the-field and have several more in-the-field events scheduled through the remainder of 2012.

For more information about the Aero 40 Series dry ice blasting machine and to schedule the completion of this SB, please contact Duncan Aviation’s Airframe Service Sales.

Scott Shefke serves as an Airframe Technical Representative at Duncan Aviation's full-service facility in Lincoln, Nebr., specializing in Challenger, Global and Learjet aircraft. His aviation career began in 1991.

Tags: Airframe Maintenance, Challenger, airframe corrosion

Avoid Escalating Aircraft Maintenance Fees with Firm Fixed Pricing

Posted by Diane Heiserman on Tue, May 08, 2012 @ 06:00 AM

Contributed by Dale Hawkins, airframe service sales rep.

Business Aircraft Maintenance

Business aircraft budgets are tight. Firm Fixed Pricing gives more control over maintenance expenses.

When it comes to business aircraft maintenance costs, most operators are able to effectively budget what they want to spend on interior, paint, and avionics. But when it comes to airframe maintenance, there are many unknowns. Even a well-educated guess can still result in the Director of Maintenance (DOM) having to explain why the aircraft maintenance costs came in higher than expected. Firm Fixed Pricing offers business aviation customers a guaranteed labor price for scheduled inspection packages, giving more control over maintenance expenses.

How does Firm-Fix Pricing work?  

An MRO offering Firm Fixed Pricing agrees to perform scheduled inspections and all discrepancies noted as a result of these inspections at a predetermined fixed price. The price includes the inspection labor (often called flat rate), miscellaneous parts needed for the inspection, labor for discrepancies noted as a result of the inspection (unknowns) and all consumables. Due to continuous price fluctuations, major parts or outside vendor services are not included in Firm Fixed Pricing.

With all the unknowns, how is an MRO able to offer Firm Fixed Pricing?

Knowledge and experience is the only way a qualified MRO is able to offer Firm Fixed Pricing. Through years of performing the same airframe inspections over and over, innovations are discovered, efficiencies are gained and valuable historical data is collected; reducing the risk of a guaranteed labor rate.

Why aren’t more MROs offering Firm Fixed Pricing?

Simply put, the potential risk of losing profit margins is just too high. The majority of the reluctance stems from the unknown possibility of discovering major corrosion damage during an airframe inspection. A discovery of this type is not uncommon and can escalate the cost and extend the downtime of any airframe inspection.

Minor airframe corrosion is covered under the Firm Fixed Pricing program and corrosion that requires Engineering Services from the OEM are offered at an exceptionally discounted rate.

Firm Fixed Pricing for Falcon Airframe

Duncan Aviation has been offering Firm Fixed Pricing on Falcon airframes for six years. Since then many Duncan Aviation customers have taken advantage of the guaranteed labor rate. Here’s what a few have had to say.

Ken Peartree, Hewlett Packard DOM — “No other company was willing to use such a creative approach. It was great for us!"

Joe Sasser, DOM — "I challenged Duncan Aviation to create this program as I believe the industry is moving that direction. We performed two separate C inspections on our Falcon 50 and 900EX. We were very pleased with the team's performance and our accounting department loved knowing where we stood before performing the work."

Chuck Baker, Greenleaf DOM— "I have maintained this aircraft for many years, but never been to this level of an inspection. I really don't know what will be found. I do suspect there will be some S-duct cracking and possibly some tank corrosion. Given that, we believe Duncan's Firm Fixed is the way to go!”

Bottom line for us is simple. Duncan Aviation has a tremendous amount of history and expertise with all Dassault airframes that we are willing to take the risk for our customers.

Our relationships with our customers are very important to us. We continually look for ways to enhance and improve their Duncan Aviation experience and are challenging our other teams to pursue offers of Firm Fixed Pricing for other airframe types. Stay tuned.

Let's Talk Firm Fixed Pricing at EBACE

Dale is attending European Business Aviation Convention and Exhibition (EBACE) in Geneva, Switzerland, May 14 – 16. If you have any questions or want to talk about Firm Fixed Pricing for you next Falcon inspection, schedule an appointment with Dale or stop by Duncan Aviation’s stand #456.

Dale Hawkins is an Airframe Service Sales Rep at Duncan Aviation’sBattle Creek,MI, facility. He specializes in the Falcon and Hawker airframes. His aviation career began in 1981.

Tags: Airframe Maintenance, Falcon, firm fixed pricing, airframe corrosion


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