What happened
On April 4, 2002, a Cessna 172 RG, registration EC-DNG, was conducting a dual-instruction flight departing from Cuatro Vientos airport. The flight, which included an instructor and a student pilot, was intended to be a visual flight rules (VFR) training session. During the flight, the instructor initiated a simulated engine failure procedure by cutting the fuel and applying carburetor heat while the aircraft was at 4,500 feet.
Following the school's emergency procedures, the student pilot reduced speed to the best glide speed of 75 knots and selected an appropriate landing field. The aircraft proceeded through a visual traffic pattern consisting of a downwind, base, and final leg. As the aircraft reached approximately 100 feet on final approach, the instructor identified overhead electrical cables roughly 20 meters ahead. To avoid a direct collision, the instructor took control and attempted to fly beneath the wires, as the aircraft was in a landing configuration with full flaps and lacked engine power.
During the maneuver, the aircraft struck the cables, causing a loud noise and significant vibration. The instructor immediately applied full power and performed a go-around, eventually climbing to 3,000 feet. The instructor then diverted to the nearest airfield, Casarrubios, for an emergency landing. During the descent, the instructor noted that the aircraft's rudder was unresponsive.
The investigation
The investigation examined the structural damage sustained by the Cessna 172 RG and the circumstances surrounding the selection of the emergency landing site. Upon inspection at Casarrubios, investigators found that the upper portion of the vertical stabilizer had been severed and the rudder had sustained two distinct cuts. The rudder remained attached only because the control cables were not severed. The investigation also noted a delay in reporting, as the incident occurred on April 4 but was not reported to the CIAIAC until April 16, after the aircraft had been moved for repairs.
Findings
- The primary cause of the incident was an inadequate assessment of the terrain during the selection of the emergency landing field, which resulted in the failure to identify the presence of electrical cables.
- The instructor and student pilot failed to verify that the selected landing area was clear of obstructions.
- The difficulty in identifying the cables was attributed to the fact that wires can be easily confused with the ground, and widely spaced support towers may be difficult to perceive during flight.