What happened
On August 21, 2012, an EMB-810D Embraer Neiva, registration PT-WEX, operated by Cleiton Táxi Aéreo, was performing a high-value cargo transport flight from Tabatinga to Tefé, Amazonas. During the cruise phase, approximately 30 nautical miles from Juruá, the pilot noticed a sudden drop in oil pressure in the right engine.
In response to the failure, the pilot immediately reduced power, feathered the propeller, and shut down the affected engine. Due to the proximity of the Juruá airfield, the pilot elected to perform an emergency single-engine landing at the local site. During the approach, the pilot reported that a crosswind caused the aircraft to drift left. Additionally, visibility was compromised when the aircraft entered a smoke-filled area, which hindered the pilot's ability to judge the descent rate.
The aircraft touched down approximately 300 meters from the opposite end of the runway at roughly 100 knots, exceeding the recommended crossing speed of 91 knots. While attempting to maintain control and clear obstacles, the aircraft overran the runway end, traveling 140 meters onto unprepared terrain. The impact resulted in a left wing failure, a sudden engine stoppage, and substantial damage to the central fuselage. The pilot and four passengers sustained light injuries.
The investigation
CENIPA investigators examined the engine components and found that the oil return connection of the right engine's turbocharger had become detached. Upon inspection of the turbocharger, investigators discovered that the internal threads were severely worn, with only two of the original ten threads remaining.
Furthermore, the investigation revealed that thread seal tape had been used on the connection between the special nipple and the turbocharger housing, a practice not authorized by the maintenance manual. Similar use of thread seal tape was found on a T-connection.
Findings
- Maintenance of the aircraft: The use of unauthorized thread seal tape and the presence of severely worn internal threads in the turbocharger.
- Pilot judgment: Errors in flight maneuvering during the emergency approach and exceeding recommended approach speeds.
- Management supervision: Inadequate oversight regarding maintenance practices.