Military Aircraft Composite Tailcone component NDI Requirement

[maverickst]

Hello Everyone;

Nowadays I have been working composite made Tailcone structure of an aircraft. I would like to know how we decide if we should do ultrasonic inspection to our Tailcone detail composite parts or not. For example, Tailcone detail composite parts are categorized as category D which means that their failure has no airworthiness consequences. But Tailcone itself is categorized as category C whose failure doesn't effect airworthiness security either but it might cause a problem on ground if it falls down. So the question is that we have got really stable manufacturing process and we have enough data to prove it. Can we skip ultrasonic inspection step for these composite detail parts of Tailcone ? Because tailcone is a secondary structure. Even they fail , it doesn't affect aircraft security

 

[SWComposites]

What does your customer require?

 

[Sparweb]

There are many methods of inspecting parts, not just ultrasonic. Choose the means of inspection that is appropriate to the aircraft, the part, and the environment of the aircraft and the part, not just the methods you may have used in the past.
The vulnerability of the aircraft is only one factor in choosing the extent of inspection required. What about the replacement cost, compared to the cost of each inspection? Different inspection techniques are less expensive than others, and sometimes you can choose a less invasive, less costly method, even though it may miss some types of damage, if you can increase its frequency, or direct the inspector's attention to the most probable locations and types of damage to watch out for.
What about the vulnerability of the part to damage?
If you can state that all probable sources of damage to the tailcone will be blatantly obvious from the outside, then a general visual inspection is all that may be needed to guarantee the airworthiness of the part. If there is a reason to select ultrasonic inspection after all, you must then determine the frequency of the inspections.
There are so many ways to approach the problem - it is not as simple as asking whether "we should do ultrasonic inspection or not".

STF

 

[berkshire]

In the category of part you are describing , visual inspection together with hardness testing of the cured resin should be sufficient.
B.E.

You are judged not by what you know, but by what you can do.

 

[WKTaylor]

Maverickst...

Usually the fabrication requirements [source control drawing, procurement/etc] specs are very clear/unambiguous regarding required inspections. After-all: all aerospace parts must be inspected to ensure that they attain a minimum level of quality

Suggest You carefully review the base/procurement specifications, and the drawing, that the tailcone is being built to meet. There has to be reference to QA/QC/NDI procedures

Some spec suggestions...

Fabrication
MIL-STD-1944 [CX'd] POLYMER MATRIX COMPOSITES

Inspection proceedures [detailed]
ASTM D4762 Standard Guide for Testing Polymer Matrix Composite Materials
ASTM E2533 Standard Guide for Nondestructive Testing of Polymer Matrix Composites Used in Aerospace Applications

SAE AIR4938 Composite and Bonded Structure Technician/Specialist Training Document
SAE AIR5278 Composite and Bonded Structure Engineers: Training Document
SAE AIR5279 Composite and Bonded Structure Inspector: Training Document
SAE AIR5719 Teaching Points for an Awareness Class on "Critical Issues in Composite Maintenance and Repair
SAE ARP5089 COMPOSITE REPAIR NDT/NDI HANDBOOK
SAE ARP5605 Solid Composite Laminate NDI Reference Standards (Stabilized Type)
SAE ARP5606 Composite Honeycomb NDI Reference Standards (Stabilized Type)
NAS999 [Cx'd] NONDESTRUCTIVE INSPECTION OF ADVANCED COMPOSITE STRUCTURES - Rev 2

MIL-HDBK-731 NONDESTRUCTIVE TESTING METHODS OF COMPOSITE MATERIALS - THERMOGRAPHY
MIL-HDBK-732 NONDESTRUCTIVE TESTING METHODS OF COMPOSITE MATERIALS ACOUSTIC EMISSION
MIL-HDBK-733 NONDESTRUCTIVE TESTING METHODS OF COMPOSITE MATERIALS - RADIOGRAPHY
MIL-HDBK-787 NONDESTRUCTIVE TESTING METHODS OF COMPOSITE MATERIALS-ULTRASONIC
MIL-HDBK-793 NONDESTRUCTIVE TESTING TECHNIQUES FOR STRUCTURAL COMPOSITES

NOTE.
I suspect that a first article inspction, that includes local destructive coupon testing is mandatory; and might be mandatory for a sample part from each production lot.

Regards, Wil Taylor

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