What happened
On July 9, 2021, a Neiva 56-C-1 aircraft, registration PP-HPA, was conducting a local instructional flight at the Arthur Siqueira State Aerodrome (SBBP) in Bragança Paulista, Brazil. The flight was intended to evaluate a student pilot's performance for solo flight certification. The crew consisted of a flight instructor and a student pilot.
Shortly after takeoff, while the aircraft was between 300 and 400 feet above the ground, the engine RPM suddenly dropped from 2,400 to approximately 1,200 RPM. The instructor took control and attempted to troubleshoot the issue by applying carburetor heat. Realizing the aircraft lacked sufficient altitude to return to the runway, the instructor opted for an emergency landing in an open field ahead. During the landing on the uneven terrain, the aircraft struck the ground and subsequently capsized. The aircraft sustained substantial damage, but both occupants emerged uninjured.
The investigation
CENIPA investigators examined the engine and fuel/oil samples, finding no evidence of contamination. During a functional test of the engine, investigators discovered that the right magneto was inoperable. Upon disassembly of the right magneto, the investigation revealed that ten teeth on the distributor gear had fractured.
Further review of maintenance records showed that while the engine had undergone an overhaul between 2017 and 2019, the magnetos had only received a 500-hour periodic inspection rather than the required overhaul. The investigation established that the failed gear should have been replaced during the engine overhaul, but it had accumulated an additional 1,491 hours of service beyond that point. The investigation also noted discrepancies in the maintenance organization's records regarding the timing of component overhauls.
Findings
- Failure of the distributor gear in the right magneto caused a loss of spark, leading to the engine power loss.
- Inadequate maintenance planning and failure to perform the required magneto overhaul during the engine overhaul period.
- Deficiencies in management supervision regarding the oversight of maintenance processes and record-keeping within the maintenance organization.
Safety action
CENIPA issued recommendations to the National Civil Aviation Agency (ANAC) to ensure the maintenance organization complies with procedures for the overhaul of Continental engines and related components. Additionally, ANAC was advised to ensure the organization provides adequate supervision of all maintenance work to meet airworthiness requirements.