ATA 56

Windows, Direct Vision:

It has been brought to our attention that some of the DV windows installed in the Westwind fleet are showing signs of cracking / splitting / delaminating on the laminar plane. Part numbers affected are 343017-409, 343017-452 and 343017-97. Please inspect the window for cracking / splitting / delamination along the edge. The seal may have to be removed to see it clearly. Although the DV window is not specifically mentioned in the current revision of the AMM, IAI has determined that if there is this sort of deficiency in the window, it must be replaced. Please see the attached pictures of a window with delamination (dye penetrant was used to clearly show the separation)

ATA 55

Horizontal Stabilizer Aft Fitting inspection: Worthington Aviation has requested and has received an Alternate Method Of Compliance (AMOC) for Airworthiness Directive (AD) 89-12-08. This AD concerns the inspection criteria for the horizontal stabilizer splice (aluminum). The AD states, (paragraph C) “if cracks are found, replace the splice fitting prior to further flight, in accordance with the following IAI Service Bulletin entitled “Horizontal Stabilizer Assembly –Inspection, Repair and Improvement (AFC 2037), as appropriate”. The Service Bulletins listed do no reference the replacement of the fitting with the titanium fitting (453005-509) hence the continued inspection criteria remains in the body of the AD (paragraph B).
Since then IAI has come out with the -509 titanium fitting and had changed the AMM Ch 5 to reflect the changed times for inspection for this part.
This AMOC references the -509 titanium fitting and the changed inspection times for this fitting.

Please refer to the IAI AMM 5-20-06 pg 202
Contact Worthington for a copy of the AMOC for your records (ANM-116-08-212)

ATA 72

Acoustic Fatigue May Cause Engine Inlet Cracking
If you are an operator or technician who is dealing with an engine inlet that continuously cracks, consider accomplishing an acoustic survey. Engines with fans that are balanced but have blades that have been blended or cropped may generate noise that can cause acoustic fatigue. If replaced fasteners loosen or cracks continue to appear in the inlet, the engine may be experiencing this condition. Every 200 hours a visual inspection of the engine inlet is required per Chapter 5-20-07 of the Westwind1124/1124A Maintenance Manual. Pay close attention to the inlet aft frames and barrel for cracks, as well as inspecting the entire structure for loose and missing rivets. An acoustic survey could determine if this noise is the cause of the problem and possibly help you avoid costly inlet repairs.