What happened
On October 2, 2006, an EMB-720C, registration PT-EKA, operated by Litorânea Táxi Aéreo, was performing a cargo transport flight from São Luís to Pinheiro, Maranhão. While on final approach to the Pinheiro Aerodrome, approximately two kilometers from the runway threshold, the aircraft's left wing detached from the fuselage. This structural failure caused an immediate loss of control, leading the aircraft to collide with the ground. The impact was followed by a post-crash fire that consumed the wreckage. The pilot and two passengers sustained fatal injuries at the scene, and the aircraft was completely destroyed.
The investigation
CENIPA investigators focused on the structural failure of the wing and the maintenance history of the aircraft. Technical analysis of the wing spar fragments revealed that the fracture was caused by fatigue originating from corrosion. Microscopic examination identified secondary cracks, intergranular corrosion, and pitting. The investigation also scrutinized the aircraft's flight hour records, discovering significant discrepancies. While the aircraft's logs indicated 4,461.3 total flight hours, a review of historical data revealed the actual total was 5,935.4 hours. This discrepancy meant the aircraft had exceeded the mandatory inspection interval for a specific Airworthiness Directive (DA 87-07-03R2) by 885.4 hours.
Findings
- Inaccurate flight hour tracking prevented the timely execution of a mandatory inspection of the wing spar, which required a visual check for cracks after 5,050 flight hours.
- The failure to comply with the Airworthiness Directive meant that advanced corrosion on the left wing spar went undetected.
- Maintenance supervision failures allowed discrepancies in flight hour records to persist, compromising the aircraft's airworthiness.
- The lack of on-site firefighting services at the Pinheiro Aerodrome contributed to the total destruction of the aircraft following the post-impact fire.