What happened
On July 16, 2024, at approximately 00:50 UTC, a Cessna 152, registration LV-IQV, was performing a night flight for instructional purposes at the Río Cuarto Aerodrome in Córdoba, Argentina. The flight, operated by Echo Victor, was in the climb phase following a touch-and-go maneuver when the crew detected smoke and a burning odor inside the cockpit.
Simultaneously, the aircraft experienced a failure in its VHF communication system. Due to the smoke, the instructor took control and executed a 180-degree turn, performing an emergency landing with a tailwind. The aircraft stopped on the runway near the threshold of runway 05. At the time of the incident, a commercial aircraft was also authorized to enter the runway, creating a high-risk scenario for a potential runway incursion. Emergency services arrived on the scene and confirmed that no active fire was present.
The investigation
The investigation focused on the electrical failure and the operational risks during the landing. Technical analysis of the RT-385A communication and navigation unit revealed that a connection pin had broken and made contact with the airframe, causing a short circuit. This short circuit generated the heat and smoke observed by the crew and triggered the system fuse, which prevented further damage.
Investigators examined the physical installation of the equipment in its rack. It was noted that while the unit could function with only two millimeters of engagement, a full secure connection required approximately one centimeter. The investigation determined that the equipment was likely not fully seated, allowing for excessive movement within the rack. This displacement, exacerbated by vibrations and the physical forces of repeated landings, likely caused fatigue and the eventual breakage of the connection pin.
Findings
- The primary cause of the smoke and communication loss was a short circuit caused by a broken connection pin in the VHF radio unit.
- The mechanical failure was likely driven by insufficient engagement of the radio unit in its mounting rack, allowing vibrations and landing forces to cause pin fatigue.
- A high risk of a runway incursion was created because the instructional aircraft and a commercial aircraft were authorized to use the same critical runway space within a very short timeframe.
- The instructional aircraft was unable to follow air traffic control instructions to clear the runway due to the loss of communication capabilities.
- The investigation also identified that the aircraft was equipped with a Type A dry chemical extinguisher, which is considered unsuitable for use in the confined space of a cockpit due to visibility and health risks.