What happened
On March 15, 1979, at approximately 09:50 hours, a Cessna 188 "Agwagon" E aircraft, registered as CS-AHS and operated by FOMAL - Sociedade de Fertilizações e Mondas Aéreas, Lda., was conducting agricultural fertilization work over wheat fields in the vicinity of Beja. The aircraft was located at Quinta do Estácio, approximately 3 kilometers from Beja Aerodrome.
While executing a reversal turn to disperse the remaining agricultural product, the pilot initiated a turn that was too tight and centrifugal. This maneuver caused the aircraft to lose airspeed and altitude. As the plane descended, it collided with the canopy of a 15-meter-high plane tree (Platanus). Despite the impact, the aircraft remained controllable. The pilot managed to recover and flew back to Beja Aerodrome, where he landed safely.
The investigation
The GPIAAF investigated the incident, reviewing the flight history, meteorological conditions, and technical status of the aircraft. Weather conditions at the time were calm with no wind. The pilot, Oscar Soares Julião (pilot license number 224), was certified and qualified for the operation.
A technical inspection report detailed the damage sustained by CS-AHS. The right wing suffered significant structural damage, including a bent front spar between stations 71-97, deformed leading edge from the root to station 140:00, and damage to seven false ribs forming the leading edge. The right wing strut was damaged with two dents that could not be repaired. The right wheel rim was bent due to a strong impact, and various fairings were damaged.
Additional damage included a broken right windscreen, a damaged propeller spinner, damaged upper and lower engine cowlings, a broken right landing light, slight dents in the oil radiator tubes (posing a leak risk), and a damaged engine air filter. The aircraft had 1,269 total flight hours at the time of the incident.
Findings
The investigation established that although the aircraft was not heavily loaded with product (approximately 30 kg remaining) at the time of the accident, the turn executed by the pilot was excessively centrifugal. This tight maneuver resulted in a loss of speed and altitude, which directly motivated the collision with the tree.
No anomalies were detected in the various systems or components of the aircraft that could have contributed to the accident without external action. The aircraft was certified, equipped, and maintained in accordance with DGAC regulations. The pilot was certified and qualified for the work being performed.
The probable cause was determined to be the collision with the tree due to the loss of altitude motivated by the tight turn executed by the pilot during a direction reversal. No safety recommendations were issued in this report.
Safety action
None recorded.