What happened
On June 26, 2023, at approximately 09:30 HLC, a Cessna A188B, registration HK1766, was performing an agricultural spraying mission at the El Convento aerodrome in Pompeya, Meta. The aircraft was configured for fungicide application, carrying 100 gallons of fungicide and 45 gallons of fuel.
During the takeoff roll from runway 04, the pilot observed the airspeed indicator oscillating between 60 and 65 mph after the tail had lifted. Fearing an instrument error or performance issue, the pilot decided to abort the takeoff, reducing power and applying the brakes. However, the aircraft had already traveled approximately 300 meters down the runway. The braking action was insufficient to stop the aircraft within the remaining distance, causing the plane to exit the runway and strike a perimeter fence approximately 60 meters from the runway threshold. The pilot was able to exit the aircraft uninjured.
The investigation
The GRIAA investigation focused on the pilot'-s decision-making process and the mechanical state of the aircraft's instruments. Investigators examined the airspeed indicator and found that the instrument was providing erroneous readings. A technical test at an approved maintenance organization revealed that the hairspring within the unit was experiencing friction with the gear sector, a condition likely caused by vibrations from hard landings or operating on unpaved surfaces.
While the aircraft was found to be in compliance with all maintenance and airworthiness requirements, the investigation also looked into organizational factors. It was noted that the operator's safety management system (SMS) induction training had been conducted by an instructor who did not hold the required specialized certification.
Findings
- Improper decision-making: The pilot aborted the takeoff at a point where there was insufficient runway remaining to safely stop the aircraft.
- Instrument malfunction: The airspeed indicator was providing inaccurate, oscillating readings due to internal mechanical friction.
- Operational environment: The aircraft was operating on a stabilized gravel runway, which may have contributed to the instrument wear.
- Organizational oversight: The company's safety training program utilized an instructor lacking the proper aeronautical authorization for SMS instruction.