Aircraft visual inspections are the fastest method of assessing the overall condition of an aircraft and its components. Over 80 percent of inspections on large transport aircraft are visual. As the most recurrent procedure in aviation maintenance, repair, and overhaul (MRO), it can range from a casual walk around to a detailed visual inspection. Here you will learn how a general visual inspection (GVI) ensures the aircraft’s airworthiness.
When aircraft are on the ground, it is time to … hit the books!
As the first line of defense for safety-related issues, a GVI must therefore be accurate and proficient in reporting defects, manufacturing errors, or component fatigue. A GVI is carried out by MRO organizations when an aircraft goes in and out of a hangar to inspect, locate, and evaluate any damage, failure, or anomaly. Cracks, corrosion, and disbanding are common defects that can be detected visually.
It is a challenging and time-consuming process. First, different sources of information must be accessed and reviewed for guiding aircraft engineers in the process of inspecting the aircraft. These include aircraft logbook, checklists, and publications (e.g., manufacturers aircraft maintenance manuals, airworthiness directives, SRM, AMM, etc.)
The Federal Aviation Administration (FAA) defines aircraft visual inspections as “the process of using the eye, alone or in conjunction with various aids, as the sensing mechanism from which judgments may be made about the condition of a unit to be inspected.”
Depending on the difficulty and degree of effectiveness, they can be divided into four different categories, including GVI. Learn the differences here. In any case, the purpose is not only to obtain an overall assessment of the status of a structure, component, or system but also to enable timely damage assessment before it reaches a critical state.
During the GVI, usually performed within a touching distance, additional equipment such as ladders and cherry pickers may be required to enhance visual access to the top of the fuselage.
The subjectivity in general visual inspections of aircraft: what are the risks?
Are general visual inspections of aircraft reliable? Up to a certain point. Here is the reason why. The efficiency and accuracy of aircraft visual inspections can be compromised by factors such as the inspector’s visual acuity, the work-place lighting conditions, or the time available for inspection. Thus, any situation (e.g., tiredness, bad light, time pressure, etc.) that impedes to properly inspect could impact reliable results and, ultimately, a gradual deterioration of an aircraft.
In 2003, the International Air Transport Association (IATA) Safety Report found that approximately 80 percent of aircraft accidents are due to human error (pilots, air traffic controllers, mechanics, etc.) and 20 percent are caused by machine (equipment) failures.
On 16 October 2015, for example, an Airbus A320 operated by Tiger Air experienced the fall of the unlatched fan cowl doors of the left engine during and soon after takeoff. The incident has been attributed to inadequate inspection by both maintenance personnel and flight crew.
At Mainblades, we believe a GVI should be more accurate and less time-consuming. That is why we have developed an automated drone-powered inspection tool to help identify potential issues and address these in a much faster, easier, and safer manner.
When in doubt, choose AI
Can technology help in combating human error in the inspection processes? Here is an industry that can be improved as the one mentioned before: the energy industry. Inspecting electricity generators is a complex process as every four years the rotor must be removed from the stator to undergo a thorough examination. The process takes around 34 days to be completed. To address the problem, Mitsubishi has created a 19,9 mm-tall robot able to fit between the rotor and the stator and perform the inspection with high accuracy in just 6 days.