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Actual part after removal of corrosion. The shiny areas where it was sanded are clearly visible.

NVision aids aircraft repair station in quickly obtaining FAA approval

A certified FAA repair station recently used a 3-D laser scanning system to document its work on a passenger jet part such that the station was able to obtain the necessary FAA approval for the repair in much less time than usual.

Due to the stress and strain of normal usage, the aircraft component—part of a key system—eventually requires repair after a certain number of hours. By law, the FAA must approve any modification or repair made to an aircraft component to ensure it doesn’t degrade the structural integrity of the part, which could impair its performance and jeopardize the safety of passengers and crew.

The station, which specializes in the repair and overhaul of aerospace components and systems, needed to first remove corrosion from the part to make necessary repairs prior to reassembling the system. However, prior to starting the repairs, they were cognizant of the need to submit a report for FAA approval showing exactly how much metal was removed in the corroded areas. Verifiable accuracy was paramount to the process.

The station brought the part to NVision, with 25-years experience in 3-D laser scanning and reverse engineering, so NVision engineers could 3-D map its exact geometry both before and after the corrosion was removed.

NVision has a wide range of 3-D scanning systems available for aviation work, with ultra-high accuracies starting as precise as 0.0002 in. For this project they utilized the HandHeld 3-D laser scanner, which is very accurate and capable of capturing 60,000 separate measurements per second. The HandHeld Scanner is highly versatile and quickly obtains dimensions from objects of almost any size or shape.

Using the HandHeld Scanner, it took NVision technicians about half a day to scan the part before corrosion was removed and another half day to scan it after the removal of the defects. NVision then created an inspection report, with color deviation chart, precisely documenting the exact amount and location of any corrosion and associated metal that had been removed from the part. The report was reviewed and approved by the FAA.

In another application, the repair station had to urgently repair a faulty bracket on a Boeing 737, which had created an aircraft-on-ground, or AOG, situation. An AOG arises when a problem—for example, a worn, defective, or missing part—is serious enough to prohibit an aircraft from flying. Due to the time, expense, and inconvenience involved in grounding an aircraft, resolving an AOG quickly is a top priority.

The repair station needed make a new bracket as soon as possible. The station technician delivered the bracket to NVision at 1 p.m. and was able to return the next morning at 10 a.m. to receive a completed 3-D CAD model of the part. This 3-D model was imported into a CAM system to generate a milling path. A replacement bracket was quickly made on a CNC machine and installed, allowing the 737 to fly again.

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