Astra / Westwind Fall 2008

• Are You Ready for WAAS?
• Hydraulic Fluid Transfer
• Better Calibration Means Better Performance

Are You Ready for WAAS?

—Steve Elofson

As a critical step in the FAA’s NextGen plans, WAAS GPS approval will open up nearly all U.S. airports for precision approaches. The latest addition to our Straight Talk series explores why WAAS is important to business aviation operations, explains equipment selection and installation and sheds light on the approval processes.

Visit www.DuncanAviation.aero/straighttalk to get the answers to your WAAS questions, subscribe to updates on the issue and join the conversation.

Hydraulic Fluid Transfer

—Tim Garity

Recently, Duncan Aviation has discovered a problem with hydraulic fluid transfers from the main reservoir to the auxiliary reservoir. Two aircraft in the last month have had this issue.

Notice that the main reservoir quantity will decrease, probably below the sight glass and when the air pressure is released from the auxiliary reservoir, fluid will dump overboard.

On the two aircraft Duncan Aviation provided maintenance for, the check valve in the hydraulic line ( P/N V25W712013-501 ) between the reservoirs allowed fluid to transfer back to the auxiliary reservoir. This check valve is not checked adequately during the aircraft’s inspection cycle.

The aircraft has a natural tendency to transfer fluid from the main to the auxiliary reservoirs through brake and park brake operations. Service Bulletin 1125-29-015 was installed on serial numbers 004-029 and 031 to counteract this problem. All other aircraft should have had this modification installed during production. If you have this problem, SB 015 is a good reference for info such as P/Ns and functionality checks.

Duncan Aviation facilities in Lincoln, NE, and Battle Creek, MI, have technicians trained to handle these inspections and repairs for your aircraft. Please contact Tim Garity in Lincoln at 800.228.4277 ext. 1546 or Jim Overheul in Battle Creek at 800.525.2376 ext. 8477 for more information.

Better Calibration Means Better Performance

—James Hood

One of the biggest reasons Duncan Aviation has such a high reputation for quality is tool and instrument calibration. Fortunately, Duncan Aviation has an internal “Cal Lab” team which is the calibration resource for the company and many customers and FBOs. Everything from torque wrenches to air data units are calibrated by this team. To maintain quality, calibration work is extremely important and Duncan Aviation recommends checking the quality of your current calibrations against this seven-point checklist:

• 1. Turntime: Are your standard and quick turns usually met?
• 2. Records: Does your lab record your calibrations?
• 3. Warranty: Does the work have a warranty?
• 4. Documentation: Is the documentation easy to understand?
• 5. Traceability: Are your tools/instruments traceable to NIST?
• 6. Services: Can the shop meet your calibration needs?
• 7. Answers: If you have a question, will they explain until you understand?

For more information about the calibration standards Duncan Aviation recommends, call James Hood at 800.228.1836 ext. 4272. Ask about the magical “calibrated stone!”

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