What happened
On 13 July 2011, a LET L410UVP-E20, registration PR-NOB, operated by Nordeste Aviação Regional Linhas Aéreas Ltda, was performing a scheduled passenger flight from Recife (SBRF) to Maceió (SBMO). The aircraft was carrying two crewmembers and 14 passengers.
Immediately after takeoff, the aircraft experienced a failure of the left engine. The crew continued the departure on a single engine but elected to return to the airport for an emergency landing on runway 3/36. During the return maneuver, the aircraft deviated from its trajectory, passing over the coastline and performing a series of turns over the sea. While over the water, the crew prepared for an emergency landing on a beach. During this phase, witnesses observed that the left propeller appeared to be feathered and turning loosely. At approximately 0654 local time, the aircraft lost control and crashed into an area between two avenues in Recife, triggering a large post-impact fire. All 16 people on board were killed.
The investigation
CENIPA's investigation focused on the sequence of events following the engine failure and the mechanical state of the propulsion system. Investigators examined the flight data recorder, which showed the aircraft's trajectory and the timing of engine performance changes. The investigation also reviewed the maintenance history of the aircraft, noting that a 300-hour inspection had been completed only 21 hours prior to the accident.
Technical analysis involved coordination with GE Aviation Czech regarding the turbine components. The investigation looked into the possibility of fatigue-related failures in the engine blades. While the manufacturer argued that existing inspection methods were robust, CENIPA noted that no inspection method can entirely guarantee the detection of all subsurface cracks. The investigation also addressed the crew's use of engine power settings and the timing of the propeller feathering process.
Findings
- The primary cause of the accident was an inflight engine failure occurring during the initial climb phase.
- The aircraft experienced a loss of control during the attempt to return to the aerodrome.
- The left engine experienced a loss of thrust, and the manual feathering of the left propeller was performed approximately 120 seconds after the initial failure.
- The investigation identified manufacturing as an undetermined factor regarding the potential for high-cycle fatigue in the engine components.