The Duncan Download Blog: Business Aviation Advice & Observations

Honeywell Releases AS907 SAFETY Service Bulletin

Posted by Duncan Download Blog on Tue, Jul 19, 2016 @ 09:00 AM

AS907_HTF7000_-01.jpgHoneywell has released SB (Service Bulletin) AS 907-76-9021 Rev 0 dated May 13, 2016, regarding the possibility of water entering the ECUs (Electronic Control Unit) after the aircraft is parked in the rain for an extended length of time. This may lead to unscheduled maintenance and expense, aircraft dispatch delays, Loss of Thrust Control (LOTC) events and the possibility for inflight shut downs.



This SB is relevant to the following aircraft:

  • Bombardier Challenger 300 (HTF 7000)
  • Bombardier Challenger 350 (HTF 7350)
  • Gulfstream G280 (HTF 7250)
  • Embraer Legacy 450 (HTF 7500)
  • Embraer Legacy 500 (HTF 7500)

Honeywell has categorized this as a CAT 1 SAFETY SB meaning it may require urgent action and may be associated with an FAA AD (Airworthiness Directive). With that being said, this SB, under the Compliance Section E, has recommended compliance be within 400 engine operating hours or 18 months from the date the SB was issued. 

The compliance is to access the ECUs and apply sealant to specifically identified areas on the ECUs.  The job is estimated at 5.5 hours per side.

This can be easily accomplished by Duncan Aviation’s Engine Rapid Response teams or during a regular scheduled airframe maintenance event.

Welcoming the Honeywell HTF7000 Minor Maintenance Authorization

Read More About It

Tags: Engine Maintenance

Duncan Aviation & The Art of Minimizing Downtime

Posted by Diane Heiserman on Thu, May 26, 2016 @ 10:24 AM

Simplifying A Puzzle of Complexity

Puzzle.jpgEver put together a 1,000 piece puzzle? How about one with no straight-edges or picture on the box? What if you only had a couple of hours to finish and the pieces kept changing shape? Sounds a little daunting, if not impossible doesn’t it. Yet this is a daily scenario at Duncan Aviation.

Getting Downtime…Down

Operations Planning Coordinators, Brian Barto, Doug Schmitt, and Jason Kinnan have the difficult job of identifying and pulling together all the loose pieces of every aircraft maintenance event at our Battle Creek, MI, Lincoln, NE, and Provo, UT, facilities to determine an appropriate downtime. On any given day, they may have 35-40 schedules to plan.

They are only able to do this with the help of a very skilled team members who are aware of every shop’s maintenance capabilities and the capacity of work that can be expected. They communicate directly with Project Managers, Team Leaders, and Tech Reps.

They know the work required, the manpower necessary, and the time needed to satisfy the customer’s need for the shortest downtime, while maintaining the quality of work they expect from us.

Read more Duncan Aviation Airframe Maintenance

Hitting the Ground Running

Because of the hard work these teams do prior to every customer’s arrival, all the factory-trained technicians assigned are knowledgeable and well-prepared to begin work immediately upon touchdown with all necessary tools and parts assembled. This is a result of hours of team members being in constant communication with each other, making sure that all work is done in the most efficient time, with no overlaps and minimal interruptions.

“We are very aware that downtime is of high importance to customers. That makes it a high priority to us, as well,” says Shawn Busby, Project Manager. “Because we are a full-service maintenance facility, we have the advantage of doing all that is required under one roof in the shortest amount of time. It also requires a higher level of communication and teamwork so we are able to reduce downtime, increase efficiency and save our customers money.”

Read more Duncan Aviation Avionics Install


“Our engine capabilities are so inclusive that other FBO operations use Duncan Aviation engine team members to support them,” said Mike Bernholtz, Turbine Engine Service Sales Rep. “It is difficult for them to match our expertise, capabilities and downtime with our factory authorizations for Honeywell TFE731, HTF7000 and APUs; Pratt & Whitney 300 series, 500 series, 600 series, JT15, and PT6; Williams International and General Electric CF34.”

Read more Duncan Aviation Turbine Engine Services

You Get What You Pay For

We understand that budgets are tight and you want the best value, but don’t mistake the lowest price tag as your best option. When it comes to considering an MRO for aircraft paint or interior refurbishment work, you really do get what you pay for. “We have seen customers go with the lowest offer in order to save money. But end up having to pay more for services their chosen facilities are incapable of providing,” says Suzanne Hawes, Completions Sales Rep.

Read more Duncan Aviation Interior Completions

“In the case of hidden damage and corrosion, if the low-cost service provider does not have engineering and structural capabilities, the customer ends up having to hire a separate engineering consultant to assess the damage. And potentially even a third facility to do the structural repairs..  

At Duncan Aviation we have the experience, that if the damage is beyond tolerance, we work directly with the OEMs to create a repair disposition and have a structures team able to complete the repairs in-house.

Read more Duncan Aviation Aircraft Paint Services

We Have Anticipated Your Needs

There is no simple solution to keeping an aircraft airworthy. The regularly scheduled maintenance events and those that are not expected all add to the cost of doing business by air. As an aircraft operator as well as a service provider, Duncan Aviation understands the daily complexities and has already anticipated your needs before you have.

We make it our business to take the complicated puzzle of aircraft operation and ownership and make it as simple as possible for you.

The best and most economic choice for maintenance events, all the time, every time, is Duncan Aviation. The years of experience and the long list of capabilities at all of our facilities has proven that when we promise to do a job, we are promising to deliver on time, at a fair price, and with the highest quality of work.

This isn’t a random guess disguised as a promise; it is the expert opinion of team members who make it their job to know.

Tags: Engine Maintenance, Airframe Maintenance, Interior Refurbishment, Aircraft Paint

OH...FOD!  Checked Your Drawers Lately?

Posted by Diane Heiserman on Thu, Apr 14, 2016 @ 10:20 AM

FOD-small.jpgThat screwdriver that mysteriously went missing from the toolbox, a scrap of wire or a pack of Lifesavers might not look threatening. But as any A&P Tech will tell you, anything that’s somewhere it doesn’t belong sets the stage for a potentially dangerous situation. Such objects are known as FOD, and Duncan Aviation’s technicians are finding more of them more frequently.

It is common knowledge that any foreign object in, on or around an aircraft can have tragic results. Yet some of our airframe techs have discovered many of these objects during inspections across all makes and models of aircraft. Everything from small bits of trash to misplaced pieces of on-board equipment have been found trapped under floorboards and lying on top of wire bundles.

The definitions of FOD can be as varied as the objects that can cause it: Foreign Object Damage, Foreign Object Debris, etc. One thing all aviation experts agree on is that if FOD is in your aircraft or if it affects the external areas of your aircraft it can lead to an extremely serious situation. FOD comes in many forms–typically debris from other aircraft. It can be nothing more than a small rivet or any other type of object on the ramp or runway.

Tire punctures are common with runway FOD. Hopefully this type of debris is caught during pre-flight inspections and the result is only an inexpensive tire replacement and not a blowout during takeoff.

Internal FOD can result from work crews leaving an object trapped behind a panel or floorboard somewhere on the aircraft. It can even be a part of the airplane that was moved and not returned to its proper place.

During inspections, our techs have discovered items ranging from tie-raps, avionic control buttons, pencils and even an auxiliary gear handle that was lying on top of the flight control pulleys under the co-pilot floor. Any FOD trapped under floorboards can be a potential hazard to the safe operation of an aircraft. Sharp objects found lying on wire bundles, hydraulic lines, pitot static lines, etc., are especially dangerous and can have a chafing potential which can again lead to a catastrophic failure.

Real-World_FOD_033_FIN.jpgDuncan Aviation's technicians found this red Auxiliary Gear Handle (which belongs to the aircraft) sitting on top of the flight control pulleys.
Consider this fictional nightmare scenario: After a maintenance event, an auxiliary gear handle is left under the pilot’s floor lying on top of the flight control pulleys. The crew has done a thorough preflight, but does not have X-ray vision and has no idea what’s below them. They start down the runway for the flight home and just as the PNF (pilot not flying) calls V1 (the decision speed to abort the takeoff or fly) one engine quits, so the PF (pilot flying) immediately adds rudder for directional control. The auxiliary gear handle slips from its resting place due to the abnormal side loads and wedges into the rudder cables. The rudder is designed to travel a set number of degrees to give a pilot the required directional control at the speed above V1. Since the handle is now restricting the designed amount of deflection, the pilot’s only option is to reduce power on the good engine to match what rudder is available and PRAY that is enough.

Depending on the type of FOD, a loss of any system aboard an airplane is possible. This can lead to a life-threatening scenario during takeoff, flight and landing. Normally these types of FOD issues don’t arise because of the professional training and maintenance ethics of A&Ps. Vigilance to the task at hand can eliminate many forms of FOD.

When it comes to FOD, carelessness should never be tolerated and strict procedures must be followed. Duncan Aviation is extremely serious about FOD and has an inspection system in place that is strictly adhered to in order to ensure that all foreign objects, regardless of area of origination, are secured prior to panel/floor close up. At Duncan Aviation a task on or around an aircraft is not completed until FOD is eliminated. Make sure to review the FOD procedures at any maintenance facility you might choose and make sure they take FOD as seriously as they should.

Engine FOD Potentially Catastrophic


Engine FOD can be the most dangerous of all FOD. Any material that rips through any engine can cause a catastrophic failure. Engine FOD is both internal and external. Internal FOD can be mitigated through the use of strict procedures. (Check to see the procedures your service provider uses.) External FOD requires proper planning and observation to eliminate.

Internal FOD may include any tool, part or anything a technician may use while servicing an engine. Rivets are common FOD elements for engines. Years ago, a chief pilot decided to test his flight crew’s FOD procedures by placing his hat inside an engine intake. Before he could warn them of his plan, they tested the engine. Several thousand dollars of damage resulted.

External FOD is much more dangerous if the aircraft is in flight. External FOD may include airborne debris such as a sand storm or volcanic ash from an eruption or even hail or ice ingestion. Be aware of FAA NOTAMs in the area of your flight plan. Also be careful when taxiing behind large aircraft as their jet blast and general size can kick up quite a bit of debris.

The damage to the TFE731 engine above was caused by a bird strike. We found damage to the fan blades, nose cowl leading edge, fan stator, and compressor impeller... just to name a few. Depending on the strike, one bird can cause more than half-a-million dollars in damages.

Tags: Engine Maintenance, Airframe Maintenance

Duncan Aviation : Aircraft Turbine Engine Services From the Beginning

Posted by Diane Heiserman on Fri, Jan 15, 2016 @ 01:45 PM

IMG_1979.gifIn The Beginning...

In 1973, Leo Sawatzki stepped off the Navy ship U.S.S. Constellation and signed on with Duncan Aviation in Lincoln, Nebraska, as a jet engine mechanic. He was prepared to service GE CJ610 and Pratt & Whitney PT6 engines. However, it wasn’t long after he arrived that Airesearch introduced a new engine, the TFE731. This engine showed lots of promise. Leo and six other Duncan Aviation turbine engine mechanics, with only a four-section wooden box filled with plugs, caps and hardware, were eager to discover and learn all they could.

Early on, as with many first-generation technologies, this new engine had some growing pains. Our engine technicians were called upon many times to provide Aircraft on Ground (AOG) services. Just by the sheer volume of hands-on, field-repair work, they discovered first-hand how the engines operated and what was needed to fix them.

Seeing an unmet need, it didn’t take long before we invested in the necessary tooling and equipment to dispatch a team to any location whenever the calls came in. And the calls did come. On a weekly basis, mechanics were sent as far away as Iceland, Argentina or Canada... or to the hangar just down the road. Their quick responses made them the go-to guys for TFE731 on-the-road engine services.

This Duncan Aviation team was the original AOG engine road crew before such crews became popular. This practice of being ready to travel at a moment’s notice is the genesis of Duncan Aviation’s Engine Rapid Response Teams (RRT). Today, our RRTs are strategically located all across the United States, able to reach an operator’s location in as little as 24 hours.

The Authorizations

We had become a reliable resource for TFE731 operators flying all over the world, proving that even a small shop from the middle of America had a worldwide impact. In 1981, we hit two milestones and received major level authorization to work on the Airesearch TPE331 and TFE731engines. These authorizations allowed all who previously relied upon us to come to their rescue during times of need to entrust their engines to us for high-level, expert Major Periodic Inspection (MPI) service.

In those early years, the Duncan Aviation engine team disassembled the engines and sent them out for repair, relying on the abilities and time schedule of others. The culture at Duncan Aviation has always been to deliver only the best, on time and at budget. Unfortunately, not every company has the same level of customer commitment. "We knew we could provide these same services better, faster and cheaper," says Leo. With that, the decision was made to invest in the research, tooling and training to bring those capabilities in-house.

Engine Services Today

Engine-Line_002.gifToday, Airesearch is now Honeywell and Duncan Aviation Engine Services has grown to include 73 licensed factory-trained turbine engine technicians working two shifts to provide line maintenance, MPIs, AOG road services and technical expertise, in support of Honeywell, Pratt & Whitney, Rolls Royce and Williams International aircraft turbine engines.

The "four-room" wooden box is now a modern 20,000-square-foot facility with 12 separate engine bays.  In 2014, we added a 4,050-square-foot engine line maintenance shop to support in-house aircraft maintenance events. This makes Duncan Aviation truly a one-stop shop for all turbine engine maintenance events.

Obtaining the maximum performance out of your engines is an art mastered by the Duncan Aviation turbine engine professionals. Generations of experience combined with investment in all Original Equipment Manufacturer (OEM)-authorized repair methods bring the most reliable and proven techniques to ensure performance and reliability of your engines.

Leo, now the Engine Acquisitions and Sales Manager, has seen first-hand the changes the TFE731 has gone through over the last 38 years. One thing has remained constant—Duncan Aviation has remained Duncan Aviation. The company has never changed its name, its ownership or its commitment to delivering only the best.

Years To Come

In 2015, we reached another milestone with the designation as a Honeywell AS907 (HTF 7000) Series Minor Maintenance facility.

Duncan Aviation is the only U.S.-run, family-owned company with this length of historical and technical experience on the TFE731. We are still Duncan Aviation. We have been there since the beginning. And we’ll be here for generations to come.

Tags: Engine Maintenance

New Leadership in Duncan Aviation's Engine Rapid Response Network

Posted by Diane Heiserman on Thu, Feb 26, 2015 @ 11:49 AM

RRT-Travel_KitDuncan Aviation’s Engine Rapid Response network has grown and is more widely dispersed than ever. With 30 technicians strategically located across the United States, the demand for AOG and scheduled support at customer locations continues to increase. And they are answering the call, making the trip and getting each customer back in the air and back on schedule.

With this continued growth, we are proud to announce the appointment of new leaders within our Engine Rapid Response (RRT) network.

Download The Engine Rapid Response Fact Sheet Now

Joe Stubbs—Atlanta, Georgia

Joe Stubbs has been with Duncan Aviation for 10 years, nine of those on the engine line at the company's headquarters in Lincoln, Neb. In 2014, he successfully launched a new Engine Rapid Response office in Long Beach, Calif., then moved on to join the Seattle RRT. Turbine Engine Service Manager James Prater says that when the Atlanta leadership opportunity became available, Stubbs was the clear choice. "Joe's flexibility, versatility and wealth of engine knowledge make him a valuable resource in our RRT network. We are happy that he has accepted this leadership opportunity in Atlanta."

For engine service and support in the Atlanta region, Joe Stubbs can be reached at +1 770.286.4410.

Mike Bruhn—Chicago, Illinois

Mike Bruhn joined the Rapid Response Team in Chicago with experience as an A&P certified technician in flight departments and repair stations on a broad spectrum of corporate jets. In his five years at Chicago, he has built a strong rapport with area operators. "We are excited to allow Mike the opportunity to continue to strengthen those relationships while serving as Team Leader and work toward his vision for growing the team and expanding its presence throughout the area," says Prater.

For engine service and support in the Chicago region, Mike Bruhn can be reached at +1 773.294.5169.

Regis Biarrieta—Fort Lauderdale, Florida

Fort Lauderdale is Duncan Aviation's largest Engine Rapid Response Team. Regis Biarrieta has taken over as the new Team Leader for the Fort Lauderdale office. Baiarrieta has been with Duncan Aviation for four years, having worked in both Atlanta and Fort Lauderdale. His prior A&P experiences include airlines, corporate jets and government contracts where he spent seven years in Spain maintaining the Spanish Air Force Presidential and Royal fleet. Prater believes these experiences along with his Venezuelan roots and multilingual ability make him a great fit for Duncan Aviation's south Florida clientele. "He is a great asset in Fort Lauderdale and will be a tremendous Team Leader."

For engine service and support in the Fort Lauderdale region, Regis Biarrieta can be reached at +1 954.410.0058.

Tags: Engine Maintenance, AOG

Duncan Aviation Knows Business Aircraft Engines

Posted by Kate Dolan on Wed, Nov 12, 2014 @ 06:00 AM

There are 15 technicians at our Lincoln, Nebraska and Battle Creek, Michigan facilities who have worked on turbine engines at Duncan Aviation for more than 20 years. They have touched hundreds of Honeywell, Pratt & Whitney, General Electric, Rolls Royce and Williams’ engines.

They have worked untold hours exchanging engine parts, performing non-destructive testing and MPIs and repairing or overhauling engines. They have the technical know-how, tooling, training and industry contacts to offer nearly comprehensive services for your turbine engines.


All of those years and all of the engines add up to an impressive amount of experience.

  • Jim Smith, 38 years
  • Dan Soderstrom, 28 years
  • Stan Schwarkopf, 36 years
  • Jeff Schwebke, 26 years
  • Greg Palensky, 26 years
  • Chris Peet, 26 years
  • Troy Pedersen, 25 years
  • Lance Boatwright, 25 years
  • Scott Hamilton, 25 years
  • Dennis Gully, 24 years
  • Mark Earnest, 24 years
  • Terry Fransen, 24 years
  • Lanny Renshaw, 24 years
  • Rod Porter, 22 years
  • Scott Pengra, 20 years

Because of this experience, our customers trust us with their engines.

Sharon Klose, engine service and sales manager, has been selling aircraft engines for 25 years. She sums up Duncan Aviation’s capabilities by saying, “I’m working for a company I fully respect, with team members I consider the best in the business, and selling products I know and trust.”  

We support the following engine models:

  • TFE731
  • JT15D
  • CF34
  • P&W 300, 500 & 600
  • PT6

And our service authorizations cover:

  • Honeywell TFE731 Major Service Center
  • Honeywell CFE738 Line Service Center
  • Honeywell HTF7000 (AS907) Flight Line Service Center
  • Rolls-Royce 3007A/C Line Maintenance
  • William FJ44 Line Maintenance
  • General Electric CF34-1/3 Line Maintenance Service Center Authorizations
  • Pratt & Whitney/Canada Line Maintenance Service Center Authorizations
  • Honeywell APU Service Center Certifications

We can troubleshoot, replace line replacement units (LRUs), do performance runs and change engines. With our state-of-the-art equipment, we can also troubleshoot and change auxiliary power units (APUs).

“We are not just another aviation company,” says Joe Tulowitzki, engine sales and service manager. “As a family owned business, we still conduct business based on family core values.”


Sharon Klose, Airframe/Engine Services & Sales

570-523-1676 (Office)

570-815-3992 (Cell)




Joe Tulowitzki, Airframe/Engine Services & Sales

540-349-3142 (Office)

540-272-2656 (Cell)

Tags: Engine Maintenance

At Duncan Aviation, AOG Means “We Will Make This Work.”

Posted by Duncan Download Blog on Mon, May 05, 2014 @ 03:44 PM

Jad Donaldson, Avfuel

"It doesn't matter when I call...late at night or over the weekend, Duncan Aviation has a bunch of people who really care…."
Jad Donaldson, Chief Pilot for Avfuel.

Jad Donaldson, chief pilot for Avfuel Corporation, along with Co-Captain Chris Kosin, flew the company’s Citation XLS+ from Ann Arbor, Michigan, to Harbor Springs last July.

As they prepped the Citation for the flight back to Ann Arbor, they saw a yellow Crew Alerting System (CAS) message, stating LH ENGINE CONTROL FAULT (ECF).

After discussing the CAS message, they shut down the entire aircraft, including powering off and pulling the battery. When they restarted the battery switch, 45 seconds in, the ECF message appeared again.

Unwelcome News

Reviewing the Aircraft Checklist delivered unwelcome news: The message required correction before flight. Jad also retrieved maintenance pages, reviewed the fault codes and analyzed the TLA maintenance screen.

“We were AOG,” says Jad, “so I immediately called Jayme Park, the Airframe Alternate-Shift Supervisor at Duncan Aviation in Battle Creek, who has spent the last 17 years helping Duncan Aviation customers resolve their maintenance issues.

Bill Walker, Engine Tech Rep in Battle Creek, was confident that the codes indicated a multiple-level power supply failure on the motherboard in the engine computer.

Park Located Parts

Jaymie Park, Duncan Aviation

Jayme Park, Airframe Alternate-Shift Supervisor at Duncan Aviation in Battle Creek.

Jad called Co-Captain Jeff Squires to prep Avfuel’s second aircraft. Jeff flew from Ann Arbor to Battle Creek to pick up Aaron LaClair, a Duncan Aviation Engine Tech, on to Muskegon to get the new EEC and then to Harbor Springs.Within 15 minutes, Jayme had located the necessary EEC and set about gathering and processing the necessary paperwork to prepare the aircraft for eventual signoff and return to service.

Five and a half hours after Jad received the error code, Aaron was on the ramp, downloading the data from the Citation’s left-hand engine’s DCU.

Jad has a saying: Usually when people make something look easy, it’s not because it is easy but because they work so hard and have the necessary knowledge and experience to do the work right. He says, “Everyone I’ve worked with at Duncan Aviation has exhibited this principle. They work hard, and they have the knowledge and experience to stick with a problem and resolve it.”

That perseverance paid off. Around 2 a.m., Aaron and Jad pulled the functioning right-hand EEC, swapped it into the left-hand engine, and put the new part in the right-hand engine. By 3:45 a.m., when Jad brought the Citation back online, the onboard maintenance diagnostics returned no error codes, the TLD screen showed an N for both engines, and the channel assignments were normal.

The aircraft was no longer AOG, and there was still a little time to get back to the hotel and get some sleep before the day of shuttling passengers began.

A Valuable Relationship

Jad says, "We at Avfuel are fortunate to have access to technicians like Jayme Park. Jayme jumped in and used her leverage, intelligence and experience to get this issue resolved. I'm also fortunate to have the relationship I do with Duncan Aviation—it's like having my very own maintenance team. It doesn't matter when I call, either; whether it's late at night or over the weekend, Duncan Aviation has a bunch of people who really care… people like Jayme who are passionate about what they do and do everything they have to do to take care of their customers."

Duncan Debrief

You read more details about this story in the Spring 2014 Duncan Debrief. 

The Duncan Debrief is a free. You can subscribe to receive a printed copy of the magazine or access the current and past editions online at

Or if you are truly on-the-go, the Duncan Debrief is available on Apple’s Newsstand for the iPad.

Tags: Customer Testimony, Engine Maintenance, AOG

Fault Code 237, ECTM Buffer Filled

Posted by Diane Heiserman on Fri, Jul 19, 2013 @ 08:59 AM

Shawn Schmitz, Turbine Engine Tech Rep

DEEC downloading

It is not uncommon for me to receive a phone from an operator flying with a TFE731 engine asking me to review their engine downloads. After several flights the engine computer light begins to flash and the only fault they can see is fault code 237, ECTM Buffer Filled. They want to know why they are getting this. In all cases after reviewing the engine downloads, I found they all have an uncommanded engine shutdown logged. This triggers an event record, which in turn causes the engine computer light to flash.

What causes a fault code 237 on engine start up?

An uncommanded engine shutdown occurs during engine start when the throttle is brought out of cutoff and advanced past the idle position and then back again. This causes the uncommanded engine shutdown to be recorded in the DEEC and causing the computer light to flash. To prevent an unnecessary engine download, cautiously bring the throttle from cutoff to idle without advancing it past idle.

This information can be reference in the SIL F731-90 the N1 DEEC

Shawn Schmitz is a turbine engine tech rep located at Duncan Aviation’s Lincoln, Neb, facility specializing in Honeywell engines. His aviation career began in 2001

Tags: Engine Maintenance, Squawk Solution

Honeywell TFE731: Foul Cabin Smell

Posted by Diane Heiserman on Wed, Dec 26, 2012 @ 10:09 AM

Shane Heier, Engine Tech Rep

Gearbox Pressure Check

A qualified Duncan Aviation TFE731 technician performs gearbox pressure checks, as part of a 5-point incoming engine run.

Have you ever had an early morning smell of napalm in your pristine cabin? If so, the boss and other passengers are probably not impressed by the slimy synthetic smell. The blue tint in the air is probably a little disconcerting as well. Below are three steps to identifying the source and getting rid of the bad smell.

Step One: Identify the Offending Engine(s)

This offensive smell is caused by engine bleed air and the first step is to try and isolate which engine is contributing to the condition. Oftentimes, one engine is not always the answer as both engines may be contributing; but it often helps. Pilots need to take note of when the smell is at its worst: during the first start of the day; during take-off or at the top of descent? That type of information is useful.

Step Two: Gearbox Pressure Checks

Next, a qualified TFE731 technician needs to perform gearbox pressure checks. This will tell the technician where the fault area is located. It is either in the #l or #3 carbon seal area or in the #4 or #5 carbon seal area.

Step Three: Borescope Inspection

After the fault area is identified, a borescope inspection through the LP bleed port will, in many cases, demonstrate evidence of oil on the HP compressor impeller. Now, in order to repair the #4 and #5 carbon seals, the engine will need to undergo a compressor access. The #l and #3 carbon seals are field repairable and, in most cases, you can be back in the air in a couple of days.

After the new carbon seals are installed, it is not uncommon to see a slightly different oil pressure reading than observed previously. This is largely due to the combination of negative scavenge pump pressure in the fan gearbox that wasn’t there before, combined with positive pump pressure. This is something different than you are used to observing, but is not a cause for alarm. The engine oil pressure should still fall within normal tolerance levels; it just won’t be quite the same as before. You can find more detailed information on oil pressure changes, in the Honeywell Service Information Letter F731-83.

For help in troubleshooting and solving your maloderous cabin problems, contact any Duncan Aviation Engine Service Sales Rep or Rapid Response Engine Technicians.

Shane Heier is an Engine Tech Rep located at Duncan Aviation's Lincoln, NE, facility. He has traveled all over the world troubleshooting, educating and providing engine technical support to business aircraft operators. He specializes in Honeywell engines. Shane's aviation career began in 1991.

Tags: Engine Maintenance

200+ Aviation Acronyms in Celebration of Duncan Download's 200th Post

Posted by Diane Heiserman on Fri, Oct 12, 2012 @ 11:15 AM

Aviation Acronyms

There are nearly 3,000 identified aviation acronyms. Do you know them all?

Each industry has their own set of acronyms and abbreviations that often leave outsiders scratching their heads. There are nearly 3,000 identified aviation acronyms. However, in honor of the Duncan Download’s 200thblog post, I asked our own experts to share 200 aviation-related acronyms that they use most during a normal work day. These overachievers sent me nearly 300.

Do you know them all?

  1. (°C) — Degrees Celsius
  2. (°F) — Degrees Fahrenheit
  3. (A/D) — Analog to Digital Converter
  4. (A/I) — Anti-Icing
  5. (ac) — Alternating Current
  6. (A/C) — Aircraft
  7. (ACO) — Administrative Contracting Officer
  8. (AD) — Airworthiness Directive
  9. (ADC) — Air Data Computer
  10. (ADF) — Automatic Direction Finding
  11. (ADI) — Attitude Indicator
  12. (ADS-B)Automatic Dependent Surveillance - Broadcast
  13. (AES) — Automatic Export System
  14. (AFIS) — Airborne Flight Information System
  15. (AFM) — Aircraft Flight Manual
  16. (AGB) — Accessory Gearbox
  17. (AGC) — Automatic gain control
  18. (AHRS) — Attitude Heading Reference System
  19. (ALI) — Airworthiness Limitation Item
  20. (AMM) — Aircraft Maintenance Manual
  21. (AMS) — Aerospace Material Specification
  22. (ANAC) — Agência Nacional de Aviação Civil
  23. (AOG) — Aircraft on Ground
  24. (APR) — Automatic Power Recovery
  25. (APU) — Auxiliary Power Unit
  26. (ARINC) — Aeronautical Radio Incorporated
  27. (ASAP) — As Soon As Possible
  28. (ASNT) — American Society of Nondestructive testing
  29. (ASSY) — Assembly
  30. (ATA) — Air Transportation Association
  31. (ATC) — Air Traffic Control
  32. (ATIS) — Automatic Terminal Information Service
  33. (ATTCS) — Automatic Take Off Thrust Control System
  34. (BAFO) — Best and Final Offer
  35. (BER) — Beyond economical repair
  36. (BIS) — Bureau of Industry and Security
  37. (BIT) — Binary Digit
  38. (BITE) — Built-in Test Equipment
  39. (BOV) — Bleed-off Valve
  40. (C/P) — Chief Pilot
  41. (C12) — King Air
  42. (C20) — Gulfstream
  43. (C21) — Learjet
  44. (CA) — Certificate of Airworthiness
  45. (CAA) — Civil Aviation Agency
  46. (CAC) — Common Access Card
  47. (CAM) — Certified Aviation Manager
  48. (CAMP) — Computerized Maintenance Program
  49. (CANPASS) — Canadian Passenger Accelerated Service System
  50. (CASP) — Corporate Aircraft Service Program
  51. (CAV) — Commercial Asset Visibility
  52. (CBP) — Customs and Border Patrol
  53. (cc) — Cubic Centimeters
  54. (CCW) — Counterclockwise
  55. (CDP) — Compressor Discharge Pressure
  56. (CDRL) — Contract Data Requirements List
  57. (CDU) — VHF Radio Transceiver
  58. (CFR) — Code of Federal Regulations
  59. (CG) — Center of Gravity
  60. (CIT) — Compressor Inlet Temperature
  61. (CL) — Class
  62. (CLS) — Contractor Logistics Support
  63. (CMR) — Certification Maintenance Requirement
  64. (CMS)Cabin Management System
  65. (COC) — Certificate of Calibration
  66. (Comm) — Communication
  67. (COMSEC) — Communications Security
  68. (CONUS) — Continental United States
  69. (COO) — Country of Origin
  70. (COTR) — Contracting Officer's Technical Representative
  71. (CPAR) — Contractors Performance Assessment Reporting System
  72. (CPCP)Corrosion Prevention Control Program
  73. (CPDLC) — Controller Pilot Data Link Communication
  74. (CPU) — Central Processing Unit
  75. (CRM) — Crew Resource Management
  76. (CRT) — Cathode Ray Tubes
  77. (CSN) — Catalog Sequence Numbers - Cycles Since New
  78. (CVR) — Cockpit Voice Recorder
  79. (CW) — Clockwise
  80. (CZI) — Compressor Zone Inspection
  81. (CZR) — Compressor Zone Repair
  82. (D/A) — Digital to Analogue Converter
  83. (DAR) — Designated Airworthiness Representative
  84. (DCAA) — Defense Contract Audit Agency
  85. (DCMA) — Defense Contracting Management Agency
  86. (DFAR) — Defense Federal Acquisition Regulations
  87. (DFDR) — Digital Flight Data Recorder
  88. (DH) — Decision Height
  89. (DIA) — Diameter
  90. (Dim.) — Dimension
  91. (DME) — Distance Measuring Equipment
  92. (DOD) — Domestic Object Damage
  93. (D.O.D.) — Department of Defense
  94. (DOM) — Director of Maintenance
  95. (DOS) — Department of State
  96. (DPHM) — Diagnostics, Prognostics and Health Management
  97. (DSS) — Defense Security Service
  98. (DUATS) — Direct User Access Terminal Service (weather/flight plan processing)
  99. (e-APIS) — Electronic Advanced Passenger Information System
  100. (EAR) — Export Administration Regulations
  101. (EASA) — European Aviation Safety Agency
  102. (ECCN) — Export Commodity Control Number
  103. (ECS) — Environment Control System
  104. (ECTM) — Engine Condition Trend Monitoring
  105. (EDS) — Engine Diagnostic System
  106. (EDU) — Engine Diagnostic Unit
  107. (EEC) — Electronic Engine Control
  108. (EEI) — Electronic Export Information
  109. (EERM) — Electrically Erasable Read Only Memory
  110. (EFB) — Electronic Flight Bag
  111. (EFD) — Electronic Flight Display
  112. (EFIS) — Electronic Flight Instrument System
  113. (EGWS) — Enhance Ground Proximity Warning System
  114. (EGT) — Exhaust Gas Temperature
  115. (EICAS) — Engine Indication and Crew Alert
  116. (ELT) — Emergency Locator Transmitter
  117. (EPR) — Engine Pressure Ratio
  118. (ESO) — Electronic Sign Off (somewhat unique to Duncan Aviation)
  119. (ESP) — Engine Service Plan
  120. (ET) — Eddy Current Testing
  121. (ETD/(A)/(E) — Estimated Time of Departure/(Arrival)/(Enroute)
  122. (F & C) — Fits and Clearances
  123. (FAA) — Federal Aviation Administration
  124. (FADEC) — Full Authority Digital Electronic Control
  125. (FANS)Future Air Navigation System
  126. (FAR) — Federal Aviation Regulation
  127. (FBO)Fixed Base Operation
  128. (FCPA) — Foreign Corrupt Practices Act
  129. (FCS) — Flight Control System
  130. (FCU) — Fuel Control Unit
  131. (FET) — Federal Excise Tax
  132. (FI) — Flight Idle
  133. (FIR) — Full Indicator Reading
  134. (FIS) — Flight Inspection System
  135. (FMC) — Flight Management Computer
  136. (FMS) — Flight Management System
  137. (FOB) — Fuel On Board
  138. (FOD) — Foreign Object Damage
  139. (FSDO) — Flight Standards District Office
  140. (FSO) — Facility Security Officer
  141. (FSOV) — Fuel Shut-off Valve
  142. (FT) — Function Test
  143. (FTR) — Federal Trade Regulations
  144. (FWD) — Forward
  145. (GBS) — Ground Based Software
  146. (GEAE) — GE Aircraft Engines
  147. (GFP) — Government Furnished Property
  148. (GI) — Ground Idle
  149. (GND) — Ground
  150. (GOM) — General Operations Manual
  151. (GPS) — Global Positioning System
  152. (GPWS) — Ground Proximity Warning System
  153. (H/W) — Hardware
  154. (HIRL) — High Intensity Runway Lighting
  155. (HP) — High Pressure
  156. (HPT) — High Pressure Turbine
  157. (HR.) — Hour
  158. (HSD)High Speed Data
  159. (HSI) — Hot Section Inspection
  160. (HSI)Horizontal Situation Indicator
  161. (HSR) — Hot Section Refurbishment
  162. (HTS) — Harmonized Tariff System
  163. (Hz) — Hertz
  164. (I) — Incident
  165. (IAW) — In Accordance With
  166. (ICA) — Instructions for Continued Airworthiness
  167. (ICAO) — International Civil Aviation Organization
  168. (ID) — Inside Diameter
  169. (IDG) — Integrated Drive Generator
  170. (IETM) — Interactive Engine Technical Manual
  171. (IFR) — Instrument Flight Rules
  172. (IGV) — Inlet Guide Vane
  173. (ILS) — Instrument Landing System
  174. (in.) — Inch
  175. (INBD) — Inboard
  176. (IPC) — Illustrated Parts Catalog
  177. (ISO) — International Standards Organization
  178. (ITAR)International Traffic and Arms Regulations
  179. (ITT) — Interturbine Temperature
  180. (JAR OPS) — Joint Aviation Requirement for Operation (Europe)
  181. (JPAS) — Joint Personnel Adjudication System
  182. (JTR) — Joint Travel Regulations
  183. (kg.) — Kilogram
  184. (kPa) — Kilopascals
  185. (L/HIRF) — Lightning/High Intensity Radiated Field
  186. (lb.) — Pound
  187. (LOI) — Letter of Intent
  188. (LPT) — Low Pressure Turbine
  189. (LPV)Localizer Performance with Vertical guidance
  190. (LRM) — Line Replaceable Module
  191. (LRU) — Line Replaceable Unit
  192. (M/N) — Model Number
  193. (Max) — Maximum
  194. (MDA) — Minimum Descent Altitude
  195. (MEL) — Minimum Equipment List
  196. (MFC) — Main Fuel Control
  197. (MFD) — Multi-Function Display
  198. (Min) — Minimum
  199. (MLG) — Main Landing Gear
  200. (MM) — Maintenance Manual
  201. (MOA) — Military Operations Area
  202. (MPA) — Maximum Power Assurance
  203. (MPD) — Maintenance Planning Document
  204. (MPI)Major Periodic Inspection
  205. (MPU) — Multifunction Processor Unit
  206. (MRA) — Major Repair/Alteration
  207. (MRB-R) — Maintenance Review Board Report
  208. (MSG-3) — Maintenance Steering Group 3rd Task Force Aircraft Maintenance Program
  209. (MSP) — Maintenance Service Plan
  210. (MT) — Magnetic Particle Testing
  211. (MU) — Measurement Uncertainty
  212. (MUR) — Measurement Uncertainty Ratio
  213. (N2 -) — Nitrogen
  214. (NAA) — National Aviation Agency
  215. (NATO) — North Atlantic Treaty Organization
  216. (NAV) — Navigation
  217. (NBAA) — National Business Aviation Association
  218. (NDB) — Non-Directional Beacon
  219. (NDT) — Non-Destructive Testing
  220. (NextGen)Next Generation Air Transportation System
  221. (NFF) — No Fault Found
  222. (NICAD) — Nickel Cadmium
  223. (NIST) — National Institute of Standards & Technology
  224. (NLG) — Nose landing gear
  225. (NOTAM) — Notice to Airmen
  226. (O2) — Oxygen
  227. (OC) — On condition
  228. (OCONUS) — Outside Continental United States
  229. (ODA)Organization Delegation Authorization
  230. (OH) — Overhaul
  231. (OIML) — International Organization for Legal Metrology
  232. (OOT) — Out of Tolerance
  233. (OUTBD) — Outboard
  234. (P/N) — Part Number
  235. (PAMA) — Professional Aviation Maintenance Association
  236. (PAR) — Previous Authorization Required
  237. (PCO) — Procuring Contracting Officer
  238. (PIC) — Pilot In Command
  239. (PIREP) — Pilot Reports
  240. (PM) — Program Manager
  241. (PMA)Parts Manufacturer Approval
  242. (POA) — Power of Attorney
  243. (PSE) — Primary Structural Element
  244. (PSU) — Passenger service unit
  245. (PT) — Penetrant testing
  246. (PWS) — Performance Work Statement
  247. (QA) — Quality Assurance 
  248. (QAR) — Quality Assurance Representative
  249. (QCM) — Quality Control Manual
  250. (QT) — Quick Turn
  251. (RAAS) — Runway Awareness and Advisory System
  252. (RAD) — ALT Radio Altimeter
  253. (RAT) — Ram Air Turbine
  254. (RFI) — Request for Information
  255. (RFM) — Removed From Market
  256. (RFQ)Request for Quote
  257. (RNAV) — Area Navigation
  258. (RNP) — Required Navigation Performance
  259. (ROM) — Rough order of magnitude
  260. (RSGOM) — Repair Station General Operating Manual
  261. (RSM) — Repair Station Manual
  262. (RTS) — Return To Service
  263. (RTU) — Radio Tuning Unit
  264. (RVSM)Reduced Vertical Separation Minimums
  265. (S/N) — Serial Number
  266. (SATCOM)Satellite Communications
  267. (SB) — Service Bulletin
  268. (SBB)Swiftbroadband
  269. (SELCAL) — Selective Calling
  270. (SHOT) — Since Hot Section Overhaul
  271. (SIC) — Second In Command
  272. (SMOH) — Since Major Overhaul (Engines)
  273. (SMS) — Safety Management System
  274. (SOP) — Standard Operating Procedure
  275. (SOW) — Statement of Work
  276. (STC)Supplemental Type Certificate
  277. (TAF) — Terminal Area Forecast
  278. (TAP) — Total Assurance Program
  279. (TAR) — Test Accuracy Ratio
  280. (TAWS) — Terrain Awareness Warning System
  281. (TBO) — Time Between Overhaul
  282. (TCAS) — Traffic Collision Avoidance System
  283. (TCAS MOPS 7.1) — Minimum Operation Performance Specification 7.1
  284. (TCH) — Threshold Crossing Height
  285. (TFR) — Temporary Flight Restriction
  286. (TSA) — Transportation Security Administration
  287. (TSH) — Time Since Hot (Engines)
  288. (TSN) — Time Since New
  289. (TSO) — Time Since Overhaul
  290. (TTSN) — Total Time Since New
  291. (TUR) — Test Uncertainty Ratio
  292. (UC) — Under Contract
  293. (USCG) — United States Coast Guard
  294. (UT) — Ultrasonic Testing
  295. (VFR) — Visual Flight Rules
  296. (VSI) — Vertical Speed Indicator
  297. (WAAS)Wide Area Augmentation System
  298. (Wi-Fi) — Wireless Fidelity

Duncan Aviation is an aircraft service provider supporting the aviation needs of government and business operators and other service providers. Services include major and minor airframe inspections, engine maintenance, major retrofits for cabin and cockpit systems, full paint, interior and modification services and pre-owned aircraft sales and acquisitions. Duncan Aviation also has aircraft components and parts solutions experts available 24/7/365 at 800.228.1836 or 402.475.4125 (international) who can handle any aircraft system problem with immediate exchanges, rotables, loaners or avionics/instrument/accessory/propeller repairs and overhauls.

Complete service facilities are located in Lincoln, Nebraska, and Battle Creek, Michigan. Additional locations include a maintenance facility in Provo, Utah, more than 20 satellite avionics facilities and eight engine Rapid Response Team launch offices strategically located for worldwide support.   

For more information about any of Duncan Aviation’s services, contact us at 402.475.2611 or 800.228.4277. Or visit us on the web at

Tags: Avionics & Instruments, Aircraft Parts, Avionics Installation, Engine Maintenance, Airframe Maintenance, Announcements, AOG


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