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All owners of TC A, B, and F series planes must comply with FAA Directorate Identifier 2007-CE-057-AD and TC Service Bulletin No. 2007-001.
Some of you may have already received postcards from integrated Technologies, inc. offering our services for nondestructive testing of the lower 12" of the lift struts and if so, you got a big surprise when you called the 1-800 number. No we are not an escort service! Fortunately pilots have a great sense of humor and managed to contact us anyway. We have since sent out new postcards with the correct number 1-800-361-2237.
The TC service bulletin provides the option of eddy current (ET) or ultrasonics (UT) and in my opinion both methods would provide the information needed to evaluate the condition of the struts.
The ET method will not be as accurate in determining the wall thickness. The instrument would be calibrated on known thickness and you would evaluate responses on the scope in the form of a meter reading value or a sinusoidal wave, depending on the instrument used. The actual wall thickness value will be approximate only. If cracking was the major failure mode of the struts, eddy current would be the method of choice as it will find cracks.
The UT method is quick, repeatable and accurate. The remaining wall thickness of the strut can be determined with the accuracy of 0.001". This method has been used for years to find internal corrosion pitting in steam pipes, boiler tubes, condensate piping, tanks, vessels and many more components. About 48 data points will be taken on each strut and stored in the instrument for printout. The report will have the plane serial number and strut identification. A UT data report will be generated for each strut. I am recommending the UT over the ET as it will provide quick and accurate assessment of the struts. This data will be used a baseline so comparisons can be made during the 2 year re-inspection intervals.
Either method chosen requires 360 degree access around the strut for the lower 12" as the probe has to be in contact with the strut. Coatings do not have to be removed but any surface corrosion would have to be cleaned to sound metal. Both methods can be used on all of the models affected by the AD.
The struts can be shipped to one of our offices or we can do the inspection at your home airport or other convenient location. If we inspect in our shop the cost will be fixed at approximately $500.00 per plane. If we travel to the plane travel cost would apply. If multiple plane owners in one location can have struts ready for inspection the travel cost would be split between them.
If struts are shipped to us we anticipate a maximum turnaround of 3 days.
I understand there is going to be a Rev. B to the TC service bulletin allowing the use of x-ray to evaluate the struts. This is fine if your are looking for general wastage and pitting as this would be a great screening tool. The x-ray technique however, will not provide you with an accurate remaining thickness of your strut(s). A density comparison of a known thickness step wedge film to the dark areas of the strut film would be made using a film densitometer, and you will only get an approximate value. You may also not be able to get 100% coverage of the lower 12" due to geometry.
Our company is capable of providing visual, eddy current, ultrasonic, x-ray, magnetic particle and liquid penetrant inspection methods so we are not bias to any one method. We believe you will get the best inspection using ultrasonics.
I hope this helps you with your decision. Please call me at 1-800-361-2237 or 860-447-2474 to discuss further.
David M. Orlosky,
iTi V.P. of NDT Services
Some of you may have already received postcards from integrated Technologies, inc. offering our services for nondestructive testing of the lower 12" of the lift struts and if so, you got a big surprise when you called the 1-800 number. No we are not an escort service! Fortunately pilots have a great sense of humor and managed to contact us anyway. We have since sent out new postcards with the correct number 1-800-361-2237.
The TC service bulletin provides the option of eddy current (ET) or ultrasonics (UT) and in my opinion both methods would provide the information needed to evaluate the condition of the struts.
The ET method will not be as accurate in determining the wall thickness. The instrument would be calibrated on known thickness and you would evaluate responses on the scope in the form of a meter reading value or a sinusoidal wave, depending on the instrument used. The actual wall thickness value will be approximate only. If cracking was the major failure mode of the struts, eddy current would be the method of choice as it will find cracks.
The UT method is quick, repeatable and accurate. The remaining wall thickness of the strut can be determined with the accuracy of 0.001". This method has been used for years to find internal corrosion pitting in steam pipes, boiler tubes, condensate piping, tanks, vessels and many more components. About 48 data points will be taken on each strut and stored in the instrument for printout. The report will have the plane serial number and strut identification. A UT data report will be generated for each strut. I am recommending the UT over the ET as it will provide quick and accurate assessment of the struts. This data will be used a baseline so comparisons can be made during the 2 year re-inspection intervals.
Either method chosen requires 360 degree access around the strut for the lower 12" as the probe has to be in contact with the strut. Coatings do not have to be removed but any surface corrosion would have to be cleaned to sound metal. Both methods can be used on all of the models affected by the AD.
The struts can be shipped to one of our offices or we can do the inspection at your home airport or other convenient location. If we inspect in our shop the cost will be fixed at approximately $500.00 per plane. If we travel to the plane travel cost would apply. If multiple plane owners in one location can have struts ready for inspection the travel cost would be split between them.
If struts are shipped to us we anticipate a maximum turnaround of 3 days.
I understand there is going to be a Rev. B to the TC service bulletin allowing the use of x-ray to evaluate the struts. This is fine if your are looking for general wastage and pitting as this would be a great screening tool. The x-ray technique however, will not provide you with an accurate remaining thickness of your strut(s). A density comparison of a known thickness step wedge film to the dark areas of the strut film would be made using a film densitometer, and you will only get an approximate value. You may also not be able to get 100% coverage of the lower 12" due to geometry.
Our company is capable of providing visual, eddy current, ultrasonic, x-ray, magnetic particle and liquid penetrant inspection methods so we are not bias to any one method. We believe you will get the best inspection using ultrasonics.
I hope this helps you with your decision. Please call me at 1-800-361-2237 or 860-447-2474 to discuss further.
David M. Orlosky,
iTi V.P. of NDT Services