What happened
On June 7, 2014, a Piper PA-28-161, registration YU-DDB, was conducting a specialized vaccine dispersal flight over Bulgaria. The flight originated from Balchik and was following a route that included Dobrich, Razgrad, and Svishtov. While returning from Svishtov toward Razgrad, the aircraft encountered a powerful atmospheric front characterized by heavy cumulonimbus clouds, thunderstorms, and sudden shifts in wind speed and direction.
In an attempt to avoid the worsening weather, the pilot performed holding maneuvers. After an unsuccessful approach to an airfield near Nikola Kozlevo, the pilot sought an alternative landing site. The pilot eventually identified an abandoned airfield near the village of Gradishte in the Shumen region. During the approach to the unpaved strip, the pilot performed a low-level pass to assess the runway condition. During the subsequent landing attempt, a sudden change in wind direction caused the aircraft to drop. The aircraft struck the threshold of the runway, causing the nose and right main landing gear to collapse. The aircraft spun to the right and came to a stop on the strip.
The investigation
The investigation examined the flight's progression, the meteorological conditions, and the technical state of the aircraft. Investigators reviewed the pilot's preparation, the aircraft's maintenance records, and the configuration of the cockpit instruments. The inquiry also looked into the operational compliance of the operator regarding weight and balance, as well as the adequacy of air traffic services provided during the emergency.
Findings
- The immediate cause of the accident was errors in forced landing techniques while operating in complex meteorological conditions.
- The pilot's pre-flight preparation was incomplete, leading to an insufficient assessment of the weather and a lack of familiarity with the Bulgarian Aeronautical Information Publication (AIP) regarding the specific aerodromes used.
- The aircraft was equipped in violation of safety standards; specifically, the placement of flight and navigation instruments was non-compliant, making it difficult for the pilot to maintain situational awareness during the emergency.
- Several other irregularities were identified, including the aircraft exceeding its maximum takeoff mass by 136 kg, the presence of unsecured items in the cabin, and the lack of seat belts in the second row of seats.
- The operator's 100-hour inspection was found to have been performed in an unreasonably short timeframe (less than 3 hours and 40 minutes).
- The landing resulted in serious injuries to the vaccine dispersal operator, while the pilot remained uninjured. The aircraft sustained significant structural damage.
Safety action
- The Civil Aviation Authorities of Bulgaria and Serbia were advised to ensure operators are informed of the report's findings to prevent unauthorized structural modifications.
- The Bulgarian Civil Aviation Administration was recommended to implement stricter controls to prevent unsecured cargo and excess takeoff mass.
- Recommendations were made to review Air Traffic Services (ATS) procedures for handling aircraft in emergency situations involving complex weather.