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NEWS | Sept. 16, 2020

Corpus Christi Army Depot's (CCAD) Material Engineers utilize Scanning Electron Microscope for Helicopter Forensics

By Story by Kathleen Pettaway-Clarke

CORPUS CHRISTI, TX - In a variety of 'hit' television shows, forensic investigations and crime scenes investigator are often glamorized. Appealing to an audience desire to find the truth and the lure of investigating accidents. In real life, the Analytical Investigation Branch of Corpus Christi Army Depot's team with CCAD’s material engineers can discover how a helicopter accident may have occurred utilizing the Scanning Electron Microscope (SEM).
A story unfolds as each indentation in the metal's microscopic character becomes visible through the SEM. The Analytical Investigation Branch (AIB) often sends a team of experts worldwide to help discover the facts. "There is a group of investigators that will go out to the field and essentially gather all the information; the investigators will filter out what we need," said Johnathan Ramirez, Materials Engineering Branch Chief.
CCAD is renowned for aircraft service overhaul. The depot conducts analytical crash investigations and material failure analysis. While examining an accident scene can often be a scrupulous task to find the reason for the event, CCAD's "Material Engineering Branch (MEB) works hand and hand with the AIB "says Jack Worthington Jr., Material Engineer.
In other words, AIB will send the damaged parts to the MEB for Metallurgical failure analysis, which adopts a variety of observations, inspections, and laboratory techniques to determine root causes for stressors. "The type for problems that end up on our deck are accidents that don't have anything to do with the pilot error, but things such as failure of an engine or transmission." Worthington continued.
To the naked eye, this may seem like an impossible task, but to a forensic engineer, it's a world of infinite theories to be examined and validated thru multiple tests. In these situations, it can be advantageous to survey the ruptured surface using the SEM.
According to Dorian Lucero, Materials Engineer, "The SEM is one of the microscopes we use mainly for failure analysis. For example, chips that come through the oil filter, we can see what components they are coming from."
The ruptured surfaces of components are magnified thousands of times past their standard size and have a considerable depth of field, thus allowing three-dimensional exploration imaging of the surface. The Scanning Electron Microscope (SEM) is the tool that can identify the minuscule topographies of the failure within metals. Lucero continued, "The materials are analyzed because the machine shoots down a beam of electrons to produce an image."
Recently the SEM was updated to include a new low-vacuum system, expanding failure analysis capabilities and chemical image mapping analysis to non-conductive materials (polymers, rubbers, and composites) used on Army aircraft. Lucero explains, "We use the low vacuum system on any materials that are non-conductive, such as epoxy composites and other non-metals."
In the end, the ultimate objective is to help the Soldiers in the field stay the course and remain ready to answer the call to defend the Nation and win against all threats by preventing future incidents of the same caliber.